Odin class submersibles (1926)

Odin class Submersibles (1928)

Royal Navy Flag Oceanic Submersibles 1924-1945:

HMS Oberon (prototype), HMS Oxley & Otway (Australian order), HMS Odin, Olympus, Orpheus, Osiris, Oswald, Otus

WW2 British Submersibles:
X1 | Odin | Parthian | Rainbow | Thames | Swordfish | Porpoise/Grampus | Shark | Triton | U class | T class | S class | A class

HMS Oberon

HMS Oberon was the Odin-class prototype, more than the Oxley class, a derivative planned for the Royal Austrlian Navy. Originally called “O1” she received a full name, HMS Oberon, after a Shakespearian nickname meaning “noble, bearlike” (the very first to be so named, and 5th RN vessel of that name). Commissioned as part of the 1923 naval programme, she was built after the Anglo-Japanese Alliance expired in 1922, with the admiralty willing to create a fleet of far east oceanic submarines able to of long-range patrols there, and possibly deter Japanese ambitions.

Design of HMS Oberon

HMS Oberon had nothing to do with the previous X1 cruiser submarine. She was not tailored to engage an escort and deal with the convoy’s ships, but of a more conventional design, with engineers starting with L-class submarines instead of a blank page. The design was thoroughly modified on several points: 9.8 m longer, 0.91 m wider, slower by two knots but with almost twice the range, and also twice as many torpedo tubes and torpedoes in reserve.

HMS Oberon had a crew of 54, while being 82m long overall, 8.5m wide, 4.7m in draft when surfaced. Displacement reached 1,332 t surfaced, 1,860 t underwater. This time, the admiralty discarded the idea of “borrowing” German machinery and instead adopted two Admiralty diesel engines, rated at 2,950 hp (2,200 kW), and two electric motors rated at 1,350 hp (1,010 kW). They were mated on a propeller shaft each. Top surfaced speed was not stellar at 13.75 knots (25.47 km/h) -although still enough to catch most merchant ships- and down to 7.5 knots (13.9 km/h) underwater. These figures were obtained on trials, but the blank specs back when ordered specified 15 knots (28 km/h) and 9 knots respectively…

Her pressure hull was made of a 19 mm steel thick plating on which both ballast tanks were mounted. This scheme allowed a max depth of 150 m, but it remained theoretical. While in service she never went below 61 m. She carried no less than 189 t of fuel in riveted outer tanks and later welded tanks due to leakages, when refitted in 1937.

Her original armament comprised a single QF 4 inch/40 Mk IV deck gun (Mk XII in 1937) and no less than eight 533 millimeter torpedo tubes, six in the bow, two in the stern. Provision was for sixteen torpedoes in all, of the Mark IV type and from 1938, Mark VIII.
More importantly, she was the first RN submarine fitted with ASDIC while being constructed. She also had type 709 hydrophones plus a SF type direction finder, really useful in the vast expanses of the Pacific. In WW2 she gained a single 20 mm/70 Mk.IV Oerlikon AA gun on her rear conning tower platform, plus a Type 291W direction finder to provide early air warning by default of a radar.

Royal Navy ww2 HMS Oberon in action

HMS Oberon was completed Chatham Dockyard (Kent) and commissioned on August 24, 1927. Her initial pennant was 21.P, changed to 21.N in 1939, and N.21 in 1940.
Her initial sea trials revealed torsional vibrations in her propulsion machinery. Thus, she was never deployed to the Far East du to the lack of repair facilities there. Instead she was stationed in Portsmouth from 1927 and 1931. She was moved from there to the Mediterranean and back to Portsmouth in 1934. On October 11, 1935, she collided with the destroyer HMS Thanet at Devonport. Placed in reserve in 1937, she returned to fully active service by August 2, 1939. She was not deployed for active missions due to her age and instead, was used for training. She was decommissioned at Blyth on 5 July 1944, sold for scrap on 24 August 1945 and BU by Clayton and Davie (Duntson).

L23 for comparison (1921)

HMS Odin

HMS Oberon

⚙ Oberon specifications

Displacement 1,311 long tons surfaced, 1,892 long tons submerged
Dimensions 270 x 28 ft (82 m x 8.5 m)
Propulsion 2× diesel engines, 4,600 hp (3,400 kW), 2× electric motors, 350 hp (260 kW)
Speed 15.5 knots (17.8 mph; 28.7 km/h) surfaced, 9 knots submerged
Range 8,400 nmi (15,600 km) at 10 kts surfaced, 70 nmi (130 km) at 4 kts submerged
Test Depht (tested, not max) 300 ft (91 m)
Armament 8× 21-in TTs, 16 Torpedoes, QF 4-in (102 mm) Mk XII deck gun, 2× Lewis LMGs AA
Crew 54 officers and ratings

The “Australians”: Oxley and Otway

The Oxleys were Odin-class submarines built to a slightly modified design, for Australian service. Indeed, the oceanian continent had a small but potent surface fleet, but lacked submersibles as a deterrence; which became more a concern after the anglo-japanese alliance treaty was ceased. For the same reasons the construction of HMS Oberon and the Odin class was ordered in the first place, to counter a possible expansion of Japan in the far east, the Royal Navy wanted a group of long-range submeribles able to deter the IJN from encroaching on its colonial waters and interests in the region. Australia not only had the manpower, but also the resource and will to integrate submersibles in its fledging navy, and an agreement was struck. After HMS Oberon, the next two submersibles laid down over a slightly revised design would be completed for Australia.

Design of the class

Fact is they were launched sooner and are often seen almost as a preserie for the Odins, which they were’nt. Measuring 275 feet (84 m) overall, by 29 feet 7 inches (9.02 m) in beam and for a mean draught of 13 feet 3 inches (4.04 m) they were slightly smaller than the Odins. Displacement was limited to 1,350 tons (versus 1780 for group II) surfaced, 1,870 tons submerged (1892 tons for group I, 2030 tons for group II). Compared to the Oberon, they had the same basic Vickers design, but with improvements in hull form (after many basin tests), and were able to reach a marginally better speed. Officially it was still 15.5 knots surfaced.
Like HMS Oberon they had a British powerplant, with diesel engines for surface navigation, also procuring electricity via dynamos and batteries which fed her while underwater through a set of two electric motors, mated each on a single propeller shaft.
Maximum speed was 15.5 knots (28.7 km/h; 17.8 mph) surfaced, 9 knots (17 km/h; 10 mph) submerged, as HMS Oberon and the following Odins.

Oxley and Otway had a crew of 54, their armament were a repeat of Oberon, eight 21-inch (530 mm) torpedo tubes, six forward, two aft and a single 4-inch (100 mm) deck gun, plus two machine guns on their aft platform in the large kiosk.
HMS Oxley (named after explorer John Oxley) was laid down at Vickers-Armstrong in its Barrow-in-Furness facility in March 1925 under the initial designation OA1 (Oberon was “O1”). She was launched on 29 June 1926 and completed on 22 July 1927, commissioned into the RAN (Royal Australian Navy) on 1 April 1927.
Fact is they did not served long for the RAN. In 1931 another deal had them sent back to the Royal Navy between tonnage limits of the London treaty and the unexpected high maintenance cost of the two O class submersibles.

Royal Navy ww2 HMS Oxley in service

After commission, HMS Oxley and Otway were assigned to the 5th Submarine Flotilla but on 8 February 1928, they were sent to Australia, making the longest unescorted voyage for any British submarine. They had to stop in Malta for patching up cracks in both subs engine columns. New improved columns were fabricated and installed and they departed in November, reaching Sydney on 14 February 1929. However with Great Depression, both were placed into reserve in 1930, but made a few exercizes until April 1931 and eventually both were transferred to the RN, economic reaons compounded by London Naval Treaty tonnage limits for Austrlia. Recommissioned on 10 April 1931 they started their second career.

On 29 April, they departed for Malta and once in the Med, multiplied exercizes. In 1939, they were back home in Portsmouth, 5th Submarine Flotilla, then 2nd Submarine Flotilla and August deployed at Dundee and Blyth. Oxley patrolled off the coast of Norway but on 10 September 1939, she was mistook for a U-Boat and sunk by HMS Triton. First submarine loss and first “blue on blue” incident of that nature. It happened when the five submarines of the Second Flotilla (including Triton and Oxley) patrolled on the “Obrestad line” off Norway.

A Board of Enquiry after that event found that Cdr. Steel had done “all he reasonably could” in the circumstances in that HLS Oxley was out of position, although to maintain morale, the loss was attributed to “an accidental explosion”, the info made public only in the 1950s.

Royal Navy ww2 HMS Otway in Service

Otway was laid down in March 1925 as “OA2”, launched on 7 September 1926, commissioned into the RAN on 15 June 1927. She had the same fate as her sister, seeing little service in Austrlia before sent back to the RN between tonnage and budgetary reasons. When back home she was given the pennant number 51. She served in the same unit as her sister, the 5th sub flotilla patrolling in 1939 off Norway. In 1942 she fell under command of Captain Howard Bone, seeing service in the same service and eventually becoming a training sub in 1945. She was discarded and by August 1945, sold to Thos. W. Ward, Inverkeithing in Scotland for dismantling.

⚙ Oxley specifications

Displacement 1,350 long tons surfaced, 1,870 long tons submerged
Dimensions 275 ft x 29 ft 7 in x 13 ft 3 in (83.8 x 9.02 x 4.04 m)
Propulsion Same as Oberon
Speed Same as Oberon
Range Same as Oberon
Test Depth Same as Oberon
Armament Same as Oberon
Crew Same as Oberon

The Odin class


The Odin class was built to replace the WWI vintage L-class submarines which lacked the radius of action to be fit for the Pacific Ocean. The designers cared much for the hull, strongly built in order to resist much greater pressures and be theoretically able to support a dive down to 500 feet (150 m). The “safe” dive was of 300 feet (91 m) in practice. Armament consisted was classic for a large patrol boat with eight tubes in all, 21-inch (533 mm) with six in the bow and two in the stern plus a 4-inch (102 mm) gun, all shared with Oberon and the two Otway.

They used at the time a saddle tank type which carried fuel in riveted external tanks. The problem was rivering as they were external seemed obvious: Leakages after a depth charge damage. Not only the submarine would bled her oil, this also betrayed her position (see later). However the Odin class were first British submarines fitted with Asdic and a VLF radio usable at periscope depth.
The ability to dive quickly as well as deeper were in consideration and the usual objective looked at was at disappearing at two feet per second. The minimum dive time from full buoyancy to periscope depth was to be around a minute.
With the Odin Class a requirement was added for these to be able dive in fresh water (like in the great lakes and some large rivers like the Yangtse). Engineers thus made changes to the compensating water tanks to cope with the water density differences and variations. This the Odins were the only ones able to dive in a specific gravity from 1.00 to 1.30 and stayed a standard for all British Submarines (and not only). It was later moved from 1.015 to 1.03.
Not only the Odin Class, but also the Parthian and Rainbow Classes were designed to at 500 feet but were only tested at 200 feet (Oberon) up to 300 feet for the other ones. It was said at the time, these were safe depht, but like German U-Boats, they were capble of divng way deeper, beyond 500 feet in case of emergency.
The Director of Tactical Division by 1928 estimated this 500 ft capability worked hand in hand woth the capability of withstanding depth charge blasts. There was also the always possible involuntary deep dive mostly due to an issue with the diving planes (jammed), something which was quite frequent.
Conumption was also an issue: When patrolling, the daily fuel consumption was 2.1 tons. It allowed for 12 hours underwater, 12 hours cruising surfaced at low speed, eight hours charging. On this, HMS Orpheus distingushed hersrlf in the Odin class as the only one fitted with a Vulcan clutch and her consumption rose to was 2.6 tons daily.

⚙ Odin Group I specifications

Displacement 1,311 long tons (1,332 t) surfaced 1,892 long tons (1,922 t) submerged
Dimensions 275 x 28 ft (83.8 m x 8.5 m)
Propulsion 2× diesel engines, 4,600 hp (3,400 kW), 2× electric motors, 350 hp (260 kW)
Speed 15.5 knots (17.8 mph; 28.7 km/h) surfaced, 9 knots submerged
Range 8,400 nmi (15,600 km) at 10 kts surfaced, 70 nmi (130 km) at 4 kts submerged
Test Depht (tested, not max) 300 ft (91 m)
Armament 8× 21-in TTs, 16 Torpedoes, QF 4-in (102 mm) Mk XII deck gun, 2× Lewis LMGs AA
Crew 54 officers and ratings

⚙ Odin group II specifications

Displacement 1,781 long tons (1,810 t) surfaced 2,030 long tons (2,060 t) submerged
Dimensions 283 x 30 ft (86.4 m x 9.1 m)
Propulsion Same
Speed 17.5 knots (20.1 mph; 32.4 km/h) surfaced, same submerged
Range same
Test Depht (tested, not max) Same
Armament same
Crew same

The Odin class in action:

Royal Navy ww2 HMS Odin

HMS Odin off Hong Kong in 1931
HMS Odin (N84) was built in Chatham, Kent, on 23 June 1927, launched on 5 May 1928 and commissioned on 21 December 1929. The name was originated on a Danish 74-gun, man-of-war captured by the British in 1807 and used again on an early Cold war british submersible design (Oberon class).
HMS Odin served with the 5th Flotilla in Portsmouth in 1929–1930 for her initial training. Next she was sent to her intended posting, travelling through the Mediterranean and Indian Ocean and up to the join the 4th Flotilla based in Hong Kong, where she served from 1930–1939, but apparently also in Singapore with the 8th flotilla.
With the war coming, she was transferred to the 8th Flotilla moved from Singapore to Colombo, Ceylon by October 1939. In mid November 1939 as the Pocket Battleship Graf Spee rounded the Cape, together with HMS Otus she was dispatched into the Chagos and Maldive Islands when alerted of the German raider’s position. She later patrolling with Olympus in March 1940, searched these Islands until reporting the area was afe enough for a troop convoy carrying ANZAC’s to sail for the Middle East.
By mid-1940, with the entry of Italy into the war she was reassigned to the 1st Flotilla based in Alexandria, with fover other boats including of her class.
When Italy declared war on 10 June 1940, Odin was patrolling off the Italian Naval Base at Taranto.
Her service was short: During one of her first patrols she was spotted surfaced duiring the night, submerged, was depth charged, damaged and forced to surface again, where she was rammed by the Italian destroyers Strale and Baleno. She sank in the Gulf of Taranto, on 13/14 June 1940. One of the first of numerous British submarine loss in this theater. She was lost with all hands, her Captain, 4 officers and 50 men.

Royal Navy ww2 Olympus

Built at William Beardmore and commissioned on 14 June 1930, HMS Olympus made her initial training in home waters like her sister and join her fast east station in Hong Kong. From 1931 to 1939 she served with the 4th Flotilla, the “China Station”. With the war developing she was moved to the Indian Ocean, with the 8th Flotilla in Colombo and in early 1940 redeployed to the Mediterranean. During one of her first wartime sorties on 7 July 1940 she was attacked while docked in Malta by Italian aircraft. She took some damage but aparently no direct hit, so that her repairs and completion of her refit ended by 29 November 1940. She made several sorties throughout the end of the year and most of 1941. On 9 November she spotted and attacked the Italian merchant ship Mauro Croce (1,049 GRT). As torpedoes missed, she surfaced and tried to finish her off gunfire in the Gulf of Genoa but the cargo escaped. Other patrols followed, rather uneventful.
On 8 May 1942, Olympus met her fate, hitting a mine off Malta while just leaving on her way to Gibraltar. The saddest part is that she carried personnel personal from the sunken submersibles Pandora, P36 and P39 destroyed after an air raids (part of the “blitz” in Malta). Still, there were 9 survivors out of 98 aboard which swam 7 miles (11 km) back to Malta.
A team of British and Maltese divers claimed discovery of the wreck in 2008 and later confirmed in 2012, after being explored by a ROV under 115m of water and largely intact apart the mine blast hole.

Royal Navy ww2 Orpheus

Also built at Beardmore, HMS Orpheus was commissioned on 23 September 1930. After her initial training in home waters she departed for the far east and stayed with the China Station from 1931 to 1939. As the war started she was ordered to Ceylon and from there in 1940, to Aleandria. Her service like Odin was short. During one of her first sorties, she was spotted, gunned, and depht-charged by the Italian destroyer Turbine north of Tobruk, on 27 June 1940. Her wreck was never located but the identification by the Italian crew made possible to make the connection with her disappearance.

Royal Navy ww2 Osiris

Commissioned on 25 Jan 1929, and built at Vickers-Armstrongs (Barrow-in-Furness). She was first commissioned for service with the 4th Submarine Flotilla, China Station. By September 1939, she was moved back to the East Indies Station, 8th Flotilla, based in Singapore and later Colombo. By January 1940 she was transferred to the British Mediterranean Fleet at Alexandria, 1st Submarine Flotilla intended to patrol in case Italy joined war.
-16 August 1940: She spotted and sank the Italian merchantman Morea (1,968 tons) 50 nm west of Durazzo in Albania and apparently did it with gunfire after the merchant vessel escaped twice her torpedoes. Despite her small deck gun, she managed to put her on fire, and pierce her unprotected belt, until her demise.
-22 September 1940: Deployed against an Italian convoy in the Otranto Strait, HMS Osiris torpedoed and sank the Italian torpedo boat Palestro (a former WW1 vintage 875 tons destroyer), 40 nm west of Durazzo in Albania. While back returning to Alexandria she was offered a Jolly Roger, duly hoisted, a well known tradition for British submariners after at least one kill in patrol. One was offered for each.

Her proud crew, after receiving two jolley rogers. She was one of the most sucessful O-class submarines and one of the rare to survive WW2.

-14 July 1941: Osiris spots, closed in an damage the Italian merchant ship Capo d’Orso (3,149 tons) with gunfire. This surface engagement happened near Argostolion (Kefalonia) in Greece. The vessel was badly damaged but had enough buoyancy to escape.
-27 June 1943: Osiris sank the Italian sailing vessel Vittorina (11 tons) north of Crete, also with gunfire.
She would later took part in the Allied invasion of Sicily in July-August 1943. Her role was to intercept Italian warships on their way to the landing areas.
From August 1943 she returned to the Eastern Fleet, not for activbe patrols but rather training anti-submarine escorts and from November 1944, joined the new East Indies Fleet based in Ceylon.
She was decommissioned on 7 March 1945, sold by September to a company in Durban, South Africa. She was one of the rare subs of this generation to survive the war and one with a shining record.

Royal Navy ww2 Oswald

HMS Oswald was laid down by Vickers-Armstrongs at Barrow-in-Furness on 30 May 1927, launched on 19 June 1928 and commissioned on 1 May 1929 and presumably went on the same peacetime routine on the far east as her sisters in the China station. However she was back home in 1939. She was sent to the Mediterranean, Malta via Gribraltar in August 1940.
HMS Oswald commanded by Lt.Cdr. David Alexander Fraser, RN, which succeeded to Lt.Cdr. Geoffrey Mainwaring Sladen, RN in February 1940, made a few wartime sorties before meeting her fate in the summer of 1940.

She left Malta for a patrol east of Sicily on 19 July 1940. On 30 July, she spotted a convoy of several merchant ships and attacked by night the convoy but missed. Soon after she escaped and sent a contact report about this convoy transiting the Straits of Messina. She sailed to the Ionian Sea but now the Regia Marina was in high alert looking for her.
On 1 August 1940 she was spotted while surfaced underway 12 nautical miles south of Capo Spartivento (Calabria). Due to the low vibility she was caught just 2,500 meters away by Italian lookouts aboard the Destroyer Division leader. The hunter killer division comprised the Ugolino Vivaldi, Nicoloso da Recco, Antonio da Noli and Antoniotto Usodimare, modern and well equipped destroyers. She stood little chance. It’s Antonia Vivaldi, the closest, which literraly fell on her with gunfire. At 23:05 hours after she was devastated she was apparently finished off by ramming, sinking on 1 August south of Calabria, Cap Spartivento, she went down however slowly enough for 52 crewmen to rescued, 3 lost. Full records

Royal Navy ww2 Otus

HMS Otus was built at Vickers-Armstrongs (Barrow-in-Furness), commissioned on 5 July 1929.
Otus was first commissioned with the 4th Submarine Flotilla, China Station, until 1939. In Sep^tember she was reported between Singapore and Penang. She had a refit.
From there she was deployed with the 1st Submarine Flotilla, Alexandria, probably with a stop at Cingapore and Ceylon. Her service with the Mediterranean Fleet was longer than some of her sisters. After many sorties in 1940 without notable incident or kill, from July to December 1941 she was based at Malta, intercepting axis convoys as part of the 1st Flotilla. Malta however soon fell under the axis air “blitz” damaging one of her sisters and sinking three other submarines of the P class. She had more luck, not being at home when the attacks went on.
She was later moved to Gibraltar. She carried out patrols off the Azores taking part of the souther flank of the Atlantic defence against U-Boats. She escorted or screened HG convoys passing to and from Gibraltar, soldiering with HMS Olympus. The two also patroled off Oran, in the ope of spotting and attacking Vichy Battleship Dunkerque reported trying to force her way to Toulon (Operation Principal). But they never spotted her.
On 14 August 1941, she was caught in a friendly fire incident. She was taken for a prey by HMS Talisman (Lt.Cdr. M. Willmott) but escaped the several torpedoes fired at her. It happened circa 140 nautical miles (260 km; 160 mi) north-west of Alexandria.
On 3 September 1941 under command of Lt. R.M. Favell, she sppotted an enemy armed merchant cruiser of 4,000 tons fired but missed. The ship was never identified. It happed 175 nautical miles east of Valletta harbor (Malta). Nothing to report in 1942 but a refit.
In 1943 she was transferred to Simonstown in South Africa like another of her sister, for anti-submarine training due to her age. Large patrol subs of the 1920s were advantageously replaced by the newly built T-class.
By December 1944 was soon to be withdrawn, was paid-off, placed into Reserve and eventually scuttled off Durban in September 1946. Her wreck was rediscovered in March 2013 approximately 8 kilometres (4.3 nmi) south-east of Harbour entrance under 100 m (330 ft).

General assessment

The Odin class (not Oberon or the Oxleys) spent their peacetime career as intended in Asia, with the China Station, before being moved as the war started in the Indian Ocean, between Singapore, Penang and eventually Ceylon. When transferred in the Mediterranean and starting their war patrols, they were more than once caught by Italian escorts. And revealed soon a deadly issue. Indeed all their fuel was carried in external tanks, which were riveted. They were tested to 20 lb/in2 pressure. But in practice, wether due to the Mediterranean waters conditionds of larger depht charges than anticipated, they leaked so much after a single grenade pass, that the unfortunate submarine, whatever her depht, was betrayed by the panache of heavy fuel oil going straight to the surface. By knowing the underwater speed of a British submarine of that class, Italian captains knew full well where to find their prey.

And this was not all. The “O” class had deplorable construction defects alongside the riverting such as defective plating, weak manhole covers and bad equalising arrangements. They all contributing to these issues. The Odin class were drydocked several times while attempting to cure these defects, but to no avail. It shoud be reminded though, that welding ship construction in the 1920s was in its infancy. There were still considerable problems in this new technique and a lack of trust. The British industry in fact relied to riveting for many more years, also for tanks, practically up to WW2. Welded construction eventually was imposed for the next classes. But in all, on the 19 Overseas Patrol Submarines from the O, P and R classes, 12 were lost on active service, HMS Otus being the last survivor in April 1946.
The Odin class paid dearly for her youth problems, although HMS Osiris was by far the most successful of the pack. The last two survivors were sent in South Africa to spend the rest of the war in training, knowing that the infintely superior “T class” were now entering service frontline in droves and were based on the same specifications. In fact the “A” class were supposed to be their replacement for the far east, but they came very late in the war and most were completed in 1946-47.

Read More


Bastock, Australia’s Ships of War
“HMAS Oxley (I)”. HMA Ship Histories. Sea Power Centre – Royal Australian Navy.
“NMM, vessel ID 327625” (PDF). Warship Histories, vol iii. National Maritime Museum.
Rohwer, p.1 Dundee International Submarine Memorial
Bastock, John (1975). Australia’s Ships of War. Cremorne, NSW: Angus and Robertson.
Rohwer, Jürgen (2005). Chronology of the War at Sea 1939–1945: The Naval History of World War Two (Revised & Expanded ed.). NIP



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Katori class cruisers (1939)

Katori class cruisers (1939)

Japanese Navy Heavy Cruisers Katori, Kashima, Kashii.

The IJN school cruisers

The three Katori class light cruisers, Katori, Kashima and Kashii had been designed as training cruisers in peacetime, that could take on in wartime the role of destroyers and submarine leaders.

Design-wise they were short but beamy, slow, under-armed, and regarded in general of low military value. The antithesis of a Nachi class. Nevertheless in 1941 they were pressed into first line service anyway, engaged in combat with a revised AA, extra 76 mm mounts and no less than twenty five 25 mm AA, while their torpedo tubes were removed to save weight. This AA artillery was further increased and the catapult dismounted in turn. In Combat, IJN Katori was damaged near Truk, finished off by US Navy aircraft in April 1944, Kashii torpedoed and sunk by TBM Avenger in the China Sea (January 1945), but Kashima survived the war in home waters, eventually broken up in 1947.

Design development of the Katori class ()

The Katori-gata renshū-jun’yōkan (香取型練習巡洋艦) or Katori class training cruisers originally came from the Imperial Japanese Navy (IJN) need to have dedicated, modern training ships in the FY1937 and FY1939 Supplementary Naval budgets. The Pacific War saw them used as administrative flagships for several fleets, submarine command and control vessels and and command escort squadrons. Emphasis in the design was put on accomodation and versatility rather than ofenssive capabilities. They were upgraded as the war progressed, but their core design was certainly not favoring first-line duties.

In 1935, the IJN had no shortage of potential training ships. With the Washington treaty, some vessels had been relegated to training roles: IJN Yodo (1907), Yahagi, Hirado, all discarded in 1940 were used for subsidiary duties and mobilizable as training ships, the aicraft carrier Hosho was basically used also as training carrier in 1940. The largest capital ship still on duty was the IJN Settsu, since 1924 used as a disarmed target ship, and used for training aviators in 1940 also. The main TS of the IJN were in fact former armoured cruisers, the four Asama class (1899), IJN Yakumo (1899), Adzuma (1899), and the Kasuga class (1902). But indeed, there was no purpose-built modern training ship in service with the IJN.

In 1936, it was felt the ageing cruisers needed replacement, and that three modern training ships could replace at least the Asama class vessels. A basic design was studied that year, based on sepcifications, then the lead ship was ordered in the 1937 Supplementary Naval budget. These purpose-designed ships were specifically to train officers (cadets) differed from regular cruisers in many aspects. Cost-issues forced a construction to commercial standards (something familiar to us today).

Armament was kept minimal and in fact comprised a destroyer-grade main armament, easier to manage, the minimum of torpedo tubes for training (twin banks) and samples of secondary and tertiary artillery. Emphasis was placed instead on facilities, for command & control. Not only they had pkenty of internal space to accomodate many cadets, their instructors, but also all the necessary amenities to a command staff, in addition to the regular ship’s staff, the captain, officers, and men required to run the ship. This imposed a vessel not tailored for speed but clearly to house a very large crew and act as a mobile base.

Detailed Design, as built

One most striking aspect of these were their high freeboard and compact size. They were beamy, at 1/7 ratio, for greater initial stability. It was ideal not to have trainees unfamiliar with lives at sea not sick for weeks. Katori were the only IJN cruisers with a mixed plant, with steam turbine alongside diesel propulsion, mated on the same two shafts. They were intended to maximize the ships’ instructional value also for the machinery size, while still procuring a better range than usual, rather than speed. they had a combined output of 6,000 kW (8,000 shp) capping them to 18 knots (33 km/h), way too slow for cruiser duties, but more for shore patrols or gunboat duties.
The total inboar personal, in addition to the main crew, was to include 375 cadets, 200 future combat officers and navigators, 100 mechanics, 50 Commissariat officers, 25 doctors. Later, this was reduced to 275. They were supplemented by 315 officers and the crew of the cruiser for a total of 590 people, which required large accomodations.
Living conditions of the crew and cadets indeed far exceeded usual living conditions of the average IJN cruiser. Officers, cadets and lower ranks were housed separately, and special attention was paid to creating classrooms for cadets. In addition, reinforcing their possiblke use as floating HQ in wartime, the rooms could be converted quickly to officers, extra communication systems added, and the ships also had so well-equipped medical rooms that crews from other ships nearby when stationed closed, sent their injured men aboard.

A 2-views of IJN Katori in 1944
A 2-views of IJN Katori in 1944


Detailed plans. Src wargaming forums.
They displaced 5,890 long tons (5,985 t) normal and 6,180 long tons (6,279 t) fully loaded, for a length of 129.77 m (425 ft 9 in), a beam of 15.95 m (52 ft 4 in) and draught of 5.75 m (18 ft 10 in). A fourth ship was planned, Kashihara (橿原) ordered to Mitsubishi at Yokohama. Laid down on 23 August 1941, construction was stopped on 6 November 1941, and she was later scrapped.
The name of the Kashii was taken from “Kashii-Gu”, one of the Shinto shrine for Emperor Chūai and Emperres Jingū (mythological) on Fukuoka city.
On 24 August 1938, IJN Katori was laid down at Yokohama, at Mitsubishi’s shipyard as “Cruiser No. 72”. On 31 March 1939 she is Named KATORI, namesake of the previous KATORI-class light cruisers and provisionally attached to Yokosuka Naval District. On 17 June 1939 she is Launched during well-attended ceremony. On 1 July 1939 Captain (later Vice Admiral) Miyazato Shutoku (40)(former CO of NAKA) is appointed Chief Equipping Officer (CEO) for her completion, but full time CO on 25 September 1939, replaced on November 1939: by Captain Ichioka Hisashi (formerly on IJN YURA) while still commanding her sister KASHIMA until 10 March 1940. Captain Miyazato becomes full time CO on the repair ship AKASHI later.
IJN Kashii is ordered and laid down on 30 May 1940 at Yokohama, Mitsubishi Heavy Industries Shipyard as “Vessel No. 101”, she is launched named on 14 February 1941 and on 1st April 1941 Captain Iwabuchi Sanji became her Chief Equipping Officer (CEO), supervising her completion. She is at last completed on 15 July 1941 while Iwabuchi became her first captain.


Powerplant details and internal subdivisions.
The Katori class shared a two shaft arangement, with geared steam turbines, plus diesel motors for extra range. The Turbines were fed by three Kampon admiralty double-ended VTE HP boilers and the whole powerplant was rated at 8,000 shp (6,000 kW).
To be more precise, these were two Kampon 10 mod.22 four-stroke 10-cylinder diesel engines, and two Kampon steam turbines with Kansei Hoanbu steam boiler in separate rooms. The turbines and diesel engines were linked by a hydraulic transmission, and each pair ran on its own shaft with a propeller. This class carried 600 tons of fuel, divided into 380 tons of oil and 160 tons of diesel. This gave this type a range of 7,000 nautical miles at a speed of 12 knots. The maximum speed of 18 knots was reached at 280 rpm, 8,000 hp from the turbines. This was combining the diesels (3,600 hp) with the turbines (4,400 hp). Economical run was avilable from the turbines also, reaching 13 knots at 200 rpm (2500 HP), or the diesel engines alone (12 knots, 180 rpm, 2000 HP).
The top speed of 18 knots (21 mph; 33 km/h) was acceptable for a school ship, and for escort, less for fleet operations. Range however was expectedly comfortable with 9,000 nautical miles (17,000 km) at 10 knots (19 km/h) thanks to the diesels.


The Katori class being schoolships, not expected to meet frontline action, protection was kept at a bare minimal. Gun turrets were protected by just 10 mm (0.4 in) and the conning tower had walls the same thickness. There was no belt nor armor deck. The rest of the ship, apart 6mm hardeneded steel for the external skin and internal framing, the rest was in mild steel. There was however a strong internal, underwater subdivision and compartimentation to mitigate the effect of a torpedo hit.


The main armament of each ship was the same type used on the light cruiser Yūbari, in “A” and “Y” positions. There was just a pair of 127 mm (5 in) AA guns in “X” position and two pairs of 25 mm AA guns, two pairs of torpedo tubes, 533 mm (21.0 in) Type 96 torpedoes. Four 140 mm (5.5 in)/50 cal. guns in twin turrets, twin 127 mm (5 in)/40 cal. DP guns, four Type 96 25mm AA guns (later increased to 30), eight single 13.2 mm (0.52 in) AA guns, two twin 533 mm (21 in) torpedo tubes. They carried also four single 50 mm saluting guns. They also had a catapult mounted amidships, and single Aichi E13A floatplane, but no hangar. This was basically a “sampling” of all the light to medium ordnance on the IJN.

Note that armament details diverged between ships: IJN Katori and Kashima: had two twin 140/50 3-shiki, a single twin 127mm/40 89-shiki, two twin 25mm/60 96-shiki, and two twin 533mm TT banks while IJN Kashii had the same but four twin 25mm/60 96-shiki, and a different seaplane, a single F1M2 “Pete”.

Twin 140mm/50 Type 3 turrets

Called the “50 caliber 3rd Year Type 14 cm Gun” in Japanese Ordnance, these were also called by the US intel 5.5″/50 (14 cm) 3rd Year Type. Same turrets used on the venerable IJN Yubari in 1924 already. This was an antiquated model, standard secondary gun for 1915 to 1922 capital ships and main gun on light cruisers before 1930 (Tenryû, Kuma, Nagara, Sendai), quite also common in coastal defense works. It was adopted as easier to manage for the average Japanese crewmen commpared to the 6-in caliber, for its lighter shells (83.8 lbs. (38.0 kg)) in 1914. These guns used Welin screw breech-blocks.
Performances: 6-10 rounds per minute, mv 2,805 fps (855 mps), 22,500 yards (20,574 m) range at 35° elevation A2 twin mounts, Barrel Life 500-600 Rounds, circa 200 rounds in supply per barrel. Elevates at 6 degrees per second, 4 degrees per second for traverse. Loading up to 20°, by hand ramming.
Note, for the DP 5-in/40, 25mm and 13mm details are provided in the naval gunnery encyclopedia (check the links above).

Twin 533mm Torpedo Tubes

Twin TTs were a rarity but on early IJN light cruisers such as the Kuma class. The torpedo type concerned were the famous Type 96 “Long Lance”.

IJN Kashii as rearmed in 1944

Onboard aviation

kawanihsi e7k

Katori in 1940. Note the Kawanishi E7K on catapult. Scr: The blueprints.com
It seems they were given successively the Kawanishi E7K “Alf” (1934), Aichi E13A and the Mitsubishi F1M in 1941. They were equipped with a powder-propelled catapult Kure Type 2 Mod. 5 installed amidship. The gooseneck crane of the mainmast was used to retreive them. But there was no hangar.

Kawanishi E7K-2 on IJN Kashii, Burma 1942

Mitsubishi F1M2 “Pete”. One was operated on IJN Kashii in 1940, unlike her sisters, which has the Kawanishi/Nakajima. This is not the current livery presented here. Can’t find any photos.
Note that a source also states the A6M2-N “rufe” was also operated in 1944, but it’s dubious at best.

IJN Kashii in 1944 (the blueprints.com) showing an Aichi E13A on catapult. Both would be removed the same year.


IJN Katori
Author’s HD profile illustration, IJN Katori as built

In mid-1942, Katori and Kashima: received the addition of two twin 25mm/60 Type 96 AA mounts. By April 1944 Kashii had her twin 533mm TT banks removed as well as her catapult and seaplane and in addition gained two extra twin 127mm/40 Type 89 and four triple 25mm/60 Type 96 as well as four DCT, and two DCR for a total pf 300 depht charges and a Type 1 2-go radar. In January 1945 the survivor IJN Kashima had her twin TT banks removed, catapult and seaplane but gained also two twin 127mm/40 Type 89 DP guns and four triple 25mm/60 Type 96 and well as ten single mount 25mm/60 and for ASW escort, four DCT, two DCR and 100 depht charges in reserve and a Type 2, 2-go radar.
To go with their ASW armament, they were given also the following:
-A Type 93 Mod 2 hydrophone
-An active acoustic station Type 93 Mod 3;
-A Radar detection set Type 21 Mod 2 for aerial targets;
-A Type 22 Mod 4 radar for surface target detection;
-Two Type 2 infrared projectors.

Assessment of the class

The design of the Katori class was not even fine for school ships. They were modern, and yet carried old 140 mm models that were no longer relevant. A better choice would have been for example two twin turrets with 8-in guns or 6-in guns, or better, a mix of two with a forward 6-in and aft 8-in, then two 140 mm in single mounts to have a full sampling. By default of armor this armament at least would have made them more valuable in a military role. They were assuredly just too weak and too slow for any frontline role.

Career-wise, Katori served at first with the sixth Fleet, based at Kwajalein. On 1 February 1942, was attacked by torpedo-bombers from USS Enterprise, and sustained damage. Repaired at Yokosuka. During the American attack on Truk on 17–18 February 1944, was attacked by aircraft and hit by a torpedo. Several hours later was attacked again, and sunk by 16-inch (406mm) shells from USS Iowa (BB-61). No survivors were recovered. Struck from the Navy List 31 March 1944.

Kashii was flagship of the Fourth Fleet based at Truk. In 1942 covered the landings at Rabaul and Kavieng, Tulagi and Port Moresby, Rabaul, and New Guinea. In late 1943 reassigned to the Kure Training Division. In dry-dock from November 1943 until January 1944. Served as a transport ship, and modified for the anti-submarine role in late 1944. Struck from the Navy List on 5 October 1945. After the war used as a repatriation transport. Thus, she was the only one to survive the war, scrapped in 1947.

ONI depiction of the class (US Naval Intel).

Kashima was assigned to the Southern Expeditionary Fleet in 1941. In 1942 participated in the invasion of North Sumatra and Burma. In 1943 made transport runs carrying troops and supplies. In 1944 modified for anti-submarine warfare. On 12 January 1945, was attacked by US aircraft, was hit by a torpedo, then two bombs, and sank. Only 19 of 621 aboard were saved.
So, they were indeed pressed into active service by default of something else, and a bit like the old Tenryu and Kuma class, posted at flagship and command ships or escorts of amphibious forces in 1942, and used in mixed roles outside regular operations of the IJN. Katori was never supposed to have been caught by US warhips, less so the strongest capital ship in the USN inventory, it was just a completely one-side fight to start with.

The loss of Kashima was not due to a lack of care in posting but rather the general context in 1944. Despite their AA, domination of the sky practically became uncontested by the USN, and despite her AA, not IJN warhip was immune to now experienced air crews. Unlike Yamato it’s not surprising she succumbed after just an airborne torpedo and two bombs. IJN Kashii only survived thanks to more “cushy” assignations in her career. She escaped in 1944-45 both air and submarine attacks, only thanks to her auxiliary roles, making her escape IJN concentrations.

IJN Katori 1944
Author illustration 2 views, Katori in 1944


Displacement 5,890 t. standard -6 500 t. Full Load
Dimensions 129.77 m long, 15.96 m wide, 5.75 m draft
Propulsion 2 propellers, 2 turbines, diesel engines, 3 boilers, 80,000 hp.
Top speed 18 knots
Armor Belt 50 mm
Armament 4 x 140 (2 × 2), 1 × 2 76 mm, 4 x 25 mm AA, 4 x 533 mm (2 × 2) TTs, 1 floatplane
Crew 160 + 200 students

The Katori class in action

IJN ww2 IJN Katori

Katori in Saiki Bay, September 1941

With the 6th fleet, early service 1940-42

On 20 April 1940, IJN Katori is fully Completed and attached to Yokosuka Naval District as “special service vessel” with Captain Ichioka in Command. On 15 October he is replaced by Mito Hisashi and on 15 November Katori joins SubRon 1, 6th submarine Fleet as flagship. On 6 January 1941 Captain Owada Noboru takes command and on 11 November Vice Admiral Shimizu Mitsumi is appointed to to command the Sixth Fleet (Submarines) and makes a runion with all commanders onboard his flagship KATORI about the planned attack on Pearl Harbor.
On 24 November Katori departs Yokosuka with Vice Admiral Shimizu aboard, and on the 28th, while 160 miles E of Saipan at 17:00 she sees an American convoy of five transports, escorted by a BROOKLYN-class cruiser passing by. On 1st December 1941 she is in Truk and on the 2nd, the signal “Niitakayama nobore 1208” is received on the whole combined fleet and so she departs for Kwajalein.
On 5 December she us in Kwajalein (Marshall) and on the 9th on of her fleet’s subs, I-6, reports sighting a LEXINGTON-class aircraft carrier. Vice Admiral Shimizu in KATORI orders all of SubRon 1 boats to chase her off. Later Katori returned to Truk.
On 3 January 1942, a conference is held aboard aboard to prepare for Operation “R” (invasions of Rabaul and Kavieng) with promised of support from Vice-Admital Shigeyoshi of the 4th Fleet at Truk. RADM Shima Kiyohide Sentai 19’s minelayers and two destroyers would be the close convoy escort.
Air cover was provided by Vice Admiral Nagumo’s First Air Fleet (Kido Butai) escorted by CruDiv 8, BatDiv 3/1, CruDiv 6 under overall command of Admiral Nagumo.
Kaotri departs in January 1942 for Kwajalein and on the 24th Operation “R” commences with a night landing swiftly and occupation of Rabaul and Kavieng.
On 1st February 1942, TF 8 (USS ENTERPRISE) raids Kwajalein and Wotje and SBD Dauntless from VB-6, VS-6, TBD Devastators from VT-6 sink a transport and managed to damage KATORI and submarine I-23 as well as the submarine depot ship YASUKUNI MARU while Vice Admiral Shimizu is wounded.
On 9 February 1942 she departs Kwajalein to be repaired in Yokosuka until 5 March in drydock. On the 18th, she departs with Vice Admiral Marquis Komatsu Teruhisa aboard to command the Sixth Fleet. On the 20th she is back in Kure.

Inactivity in Truk (1942-44)

Three days kater, she moored Fleet Anchorage E, Iseko Jima, Hiroshima Bay (Hashirajima) and VADM Komatsu is called in a general reunion aboard YAMATO. Captain Ishizaki Noboru of ComSubRon 8 and staffs are breiefed by Admiral Yamamoto about a plan to use midget submarines. On 20 April Katori and its fleet is back to Kure, and on 3 May in Kwajalein, Roi and back. On 1st July Nakaoka Nobuki takes command, and in August 1942 she is overhauled in Yokosuka. On the 24th she is back in Truk and has her floatplane transferred ashore on 8 September. On 28 November Miyazaki Takeji replaced Ishizaki. She made another run at Yokosuka in March-May 1943. Nothing much happens, and on 20 July Captain Minakuchi Hyoe takes command (In October Captain Oda Tamekiyo) while VADM Takeo Takagi took command of the 6th fleet in June.

The raid on Truk

On 31 January 1944 as Operation “Flintlock” (Marshall invasion) takes place, VADM Mitscher’s TF 58 lands assaults Kwajalein, Roi-Namur and Majuro and on 15 February, KATORI is reassigned to the General Escort Command, with Operation “Hailstone”, the Attack on Truk proper commencing. TF 58 launches a massive air attack followed by a naval bombardment: At 04:30 the armed merchant cruiser AKAGI MARU departs Truk escorted by KATORI and two destroyers and they are attacked en route by Grumman F6F Hellcat and TBF Avenger from YORKTOWN, INTREPID, BUNKER HILL, COWPENS. They sink AKAGI MARU while KATORI and MAIKAZE are badly damaged.
At 1300 TG 50.9 (USS NEW JERSEY, IOWA escorted by MINNEAPOLIS, NEW ORLEANS and the destroyers BRADFORD and BURNS) starts shelling shippin in Truk atoll. Soon KATORI and MAIKAZE are caught under fire in turn. USS NEW JERSEY concentrates on MAIKAZE at 7,000 yards and the latter launches her torpedoes, they passes between NEW JERSEY and IOWA. MINNEAPOLIS and NEW ORLEANS eventually blew up her magazines and she sinks at 13:43 with all hands. Then Iowa engages KATORI, fires forty-six main HE shells plus 124 secondaries (5-in). Katori is straddled with the eight salvos but launches two torpedoes. At the fourth salvo, KATORI, baldy hit, lists to port and continue to be hammered for 11 minutes before sinking, stern first. There were a lot of survivors but trhey were not rescued and had to swim to shore for thos who can.
The destroyer NOWAKI flees but is chased down at 32.5 knots by Iowa and New Jersey, which straddle her with their first salvos but as it happened in the the sun’s glare from 38,000 yards it’s under radar control. At 22 miles away these were record shots by any American battleships in this war. But NOWAKI eventually escapes to Yokosuka.
On 31 March 1944, IJN Katori is removed from the Navy List.

IJN ww2 IJN Kashii

IJN Kashii in Singapore, 1942 – Colorized by Irootoko Jr.

IJN Kahii is attached to Sasebo Naval District under command of Captain Iwabuchi post-completion for tests. After trials and initial training, she is reassigned on 31 July 1941 to the Southern Expeditionary Fleet, and starts additional, advanced training for the missions at hand. On 15 October 1941 Kojima Hideo takes command and on 18 October she is relocated to Saigon in Indochina as flagship, Vice Admiral Jisaburo Ozawa’s Southern Expeditionary Fleet during the Occupation of this Vichy-French controlled territory. On 18 November, she is relocated to Samah, Hainan Island in Occupied China but Vice Admiral Ozawa moves his flag to IJN CHOKAI.

Invasion of Malaya

On 2 December 1941 the signalled “Niitakayama nobore 1208” being received, she departed on the 5th Cap St. Jacques in Indochina, escorting seven troop transports with the 143rd Infantry Regiment aboard for the Invasion of Malaya on the 8th at 10:00 on Kra Isthmus, Siam. The following day she is reassigned to the No. 1 Escort Unit and departed on the 13th with IJN SENDAI to cover the Second Malaya Convoy (39 transports), landings on the 16th at Singora, Patni, Ban Don and Nakhorn and later another five transports to Kota Bharu. On the 21th she is back in Camranh. Five days later she is reassigned to No. 2 Escort Unit with IJN NATORI, and destroyers, from Camranh Bay. She later departs Mako with the 3rd Malaya Convoy to Malaya and Bangkok. On 3 January 1942 off Hainan Island she rescued survivors of the bruning transport MEIKO MARU. On the 10th she is back in Bangkok, while preparing for operations against the Netherlands East Indies.

Dutch East Indies-Malaya Campaign

On 1 February 1942 she departs Bangkok for Saigon, departs with Army troops West of Borneo to Disembarks them and back to Camranh and on her way again escorting 11 transports (Bangka-Palembang, Sumatra invasion force). Landings starts on the 16th and she is sent to Anambas Islands for escorting another convoy in March, to Singapore, Malaya. She is reassigned to No. 1 Escort Unit and participated in Operation “T”, The Invasion of Northern Sumatra accompanied with the cruiser SENDAI while Ozawa is in distant support with the heavy cruiser CHOKAI and CruDiv 7, DesDiv 11 and 12 as well as the Light aircraft carrier RYUJO and seaplane tender SAGARA MARU. On 12 March the landings takes place. Four days later she is back at Penang and then Singapore escorting other transports.
On 19 March 1942 transport operation “U” to Burma commenced, escorted by No. 2 Escort Unit (KASHII and DesRon 3 destroyers among others).
The convoys arrives on 23 March, 18:00 at Rangoon in Burma and proceededs to landings on the 25th before the escort is back to Penang for another run while underway on 1st April 1942 in the strait of Malacca and Pulau Perak the empty transports YAE MARU and SHUNSEI MARU are torpedoed and sunk by the sub. HMS TRUANT. On 2 April KASHII and 2 destroyers departs Singapore escorting 46 transports (18th Infantry Division), via Penang and KASHII is detached back to Singapore. She becames flagship, Vice Admiral Ozawa’s 1st Southern Expeditionary Fleet (“Malay Force”) bu stays in guardship duties until 3 June, Drydocked for upkeep at Keppel Harbor in Singapore.

Kashii’s fake 2nd funnel () in the summer of 1942. (The blueprints).

Guard Duties in Singapore (1942-43)

On 25 June she passes under command of Shigenaga Kazue Penang and on 4 July departs for Penang and back to Singapore on the 14th while Vice Admiral Okawachi Denshichi replaced Ozawa at the 1st Southern Expeditionary Fleet. On the 31th, Kashii is in Mergui, Burma, and on 10 August in Rangoon and then Port Blair in the Andaman Islands, Sabang and back to Penang and Singapore, a training and inspection cruise, followed by dull Guardship duties until 21 September when she is sent to Saigon to escort an emergency transport mission to reinforce the Solomons, sporting by then a fake second funnel to look like another ship. After Camranh she arrives in Hong Kong to Embark Army troops and sails via San Bernardino Strait to Rabaul, New Britain on 8 October, Disembarking troops and return via Davao to Singapore. She is refitted, refuels in Palembang, Sumatra and back to Singapore.
On 4 December she is relocated to Belawan, Sumatra, the heads for Port Blair, Sabang, Sibolga in West Sumatra and on the 15th takes onboard the 58-man strong Rikusentai Special Naval Landing Force with sailors from KASHII to support this Army unit on Mentawai islands, Sumatra.After landing them at Sabang she is sent to Batavia, Java and departs for Singapore in January 1943. There, Takada Satoshi takes command as CO. After some Drydock upkeep, her masts are truncated, and a “submarine spotting station” added to her foretop.
On 8 February 1943 she sails via Penang to Port Sweetenham in Malaya and on the 18th she is back via Malacca to Singapore, resuming Guardship duties.
On 9 March VADM Endo Yoshikazu takes command of the 1st Southern Expeditionary Fleet. Kashii made a short run at Malacc and later carried Vice Admiral Endo for an inspection tour via Padang, Sibolga, Sabang, Car Nicobar, Port Blair and back to Singapore for upkeep.
On 24-28 july she made a transport run with troops and supplies to Port Blair, another on 17-27 August to Car Nicobar and yet another, when on 29 August en route to Sabang, she is ambushed by the British submarine HMS TRIDENT (Lt. profit), which fires but misses.
She is later drydocked in Singapore and on 21 September 1943 made another transport run to Belawan and Port Blair. She made another one on 6 October via Penang to Car Nicobar, then on the 18th to Port Blair, on the 28th to Car Nicobar, on 24 November to Car Nicobar again, but on 26 December she is sent back home for a well-awarded leave and some upkeep and modernization.

As ASW escort (1944)

On 31 December 1943 IJN Kashii is reassigned to the Kure Training Division and on 1 January 1944 she is Takao, Formosa and refitted at Sasebo until February, heads to Etajima, working for the Naval Academy. On 5 March Matsumura Midori takes command and on the 25th she is reassigned to HQ, General Escort Command, modified as specialized ASW escort in Kure, undocked the 6 April and completed on the 29th, reassigned in May as flagship, Rear Admiral Matsuyama Mitsuharu’s No. 1 Surface Escort Division. She soon departs Moji, escorting convoy HI-65, escorted notably by the carrier SHINYO.
On 2 June 1944 she is off Formosa when ambushed by USS GUITARRO (SS-363) which made at 23:00, a moonlight periscope approach, firing two torpedoes at AWAJI, which is hit and sinks near Yasho Island. GUITARRO flees under attack back to to Australia.
On 4 June Kashii is in Takao, and on the 12 to Singapore. On the 17 she escorts convoy HI-66 (escort carrier KAIYO) to Moji and herself joins Kure for a Refit. On 10 July she departs and on the 13th departs Moji with convoy HI-69 with Rear Admiral Tsutomu Sato, 8th Escort Convoy, 14 merchantmen and the escort carriers TAIYO and KAIYO carrying aircraft to Luzon and SHINYO for air cover. That’s the bulk of the IJN carrier escort fleet and two carriers are inoperable in case of attack.
On 21 July 1944 they arroves at Manila, TAIYO and KAIYO unloading their aircraft on the 24th KASHII with SHINYO escorts the convoy back to Singapore as TAIYO is detached for Formosa and KAIYO remains in Manila.
On 5 August Kashii left Singapore to escort HI-70 to Moji, arriving ten days later, and on the 25thn the “fast convoy” HI-73 departs Moji loosing underway MIZUHO, ARABIA and KOKURYU MARUs (excessive smoke), MANEI MARU having engine problems. They stops in Takao, Formosa and Tsoying, Saei, the convoy splitting between Manila and Singapore.
On 1 September 1944 however while off Luzon Strait a single Nakajima B5N2 “Kate” (931st NAG) spots USS TUNNY (SS-282) and drops two 60-kg depth charges which damaged her hull, eliminating the submersible as a threat. This probably saves Kashii and the convoy a potential loss.
On 7 September they are in Seletar, Singapore, departing on the 13th with Rear Admiral Yoshitomi Setsuzo’s 5th Escort Group. HI-74 heads to Moji with several oilers under escort of the carrier IJN UNYO. On the 16th however, OMUROYAMA MARU is torpedoed by USS QUEENFISH (SS-393). KASHII signals the submarine attack and coordinates the sub-chasers.
But this is a wolfpack. Soon USS BARB (SS-220) launches six torpedoes hitting 10,022-ton oiler AZUSA MARU. The following day (night, 00:40) it’s IJN UNYO’s turn to be hit starboard by the same, ans she sank by the stern in the morning. Kashii tried to save survivors, but she goes down with 48 aircraft plus 36 more in cargo and previous crew and pilots.

On 23 September the convoys enters Moji and heads for Sasebo. Kashii is refitted and Departs for Moji and then with the 5th Escort Group (convoy HI-79) to Singapore.
On 15 November Rear Admiral Shibuya Shiro takes command and her unit is now the 101st Escort Group. On the 17th she flies RADM Yoshitomi’s flag again and departs with convoy HI-80 for Saigon, Van Phong. On 4 December Kashii is back to Sasebo, later reassigned to the 1st Surface Escort Group. She left Moji with HI-85 arriving in Takao by 23 December, and next escorts another convoy to Singapore. On Xmas day, they are attacked off Hainan Island by USAAF B-25 “Mitchell” bombers which sank a transport.
The following day she is in Saigon and Singapore, sailing again with the 101st Escort Group and convoy HI-86 for Saigon, then Van Fong Bay in Indochina, Qui Nhon Bay.

The end: US Attacks on Indochina

On 12 January 1945 TF 38 starts Operation Gratitude, a serie of massive strikes on Indochina just as KASHII departed Qui Nhon. From 11:00 to 17:00 the South China Sea saw many squadrons of Curtiss SB2C “Helldiver” and Avengers from USS LEXINGTON (CV-2) USS ESSEX, TICONDEROGA, LANGLEY and SAN JACINTO attacking HI-86. They sink all ships (a few managed to beach) and just three escorts survived. But not Kashii: At 14:08 she is taken in a pincer by SB2Cs and TBFs, so her manoeuvering was futile. She is soon hit starboard amidships by a torpedo and two bombs which set off her depth charge magazine. Her entire stern blew up. Cut in two, she sank stern first with 621 sailors, 19 rescued. The list of victims includes Captain Matsumura and Rear Admiral Shibuya, both would be awarded higher grades posthumously. IJN Kashii is officially removed from the Navy List on 20 March 1945. This left Kashima as the only survivor of the class.

IJN ww2 IJN Kashima

IJN Kashima freshly commissioned, 1940. Colorized by Irootoko Jr.
On 25 September 1939 Kashima while in early completion receives the visit of her first captain Miyazato Shutoku already on KATORI previously, which is appointed the Chief Equipping Officer (CEO) as additional duty with CO of Katori. On 1st November he is replaced by Ichioka Hisashi (from YURA), also as additional duty and from 10 March 1940, Nabeshima Shunsaku this time as full-time duty captain until the ship is completed on 31 May 1940, attached to Kure Naval District. On 1 June 1940 she joined with her siste Katori the Training Squadron and on 28 July 1940 took part in their only pre-war midshipman (and shakedow for Kashima) cruise, visiting Etajima, Ominato, Dairen, Port Arthur and Shanghai. They were back in Yokosuka by September.
On 1st November Takeda Isamu takes command and on the 15th, she is reassigned to the 4th and became flagship, CruDiv 18. Nothing much happens noticeable before September 1941 and preparations for wartime.

Early Wartime Career

On 1st September 1941 Captain Senda Kinji takes command, and on 1st December she became flagship of Vice Admiral Shigeyoshi Inoue of the 4th based at Truk in the Carolines. Frim 18 January 1942 for Operation “R” (Invasions of Rabaul and Kavieng), she sorties from Truk, to cover the landings and is back on the 31. On 20 February she departs to try to cacth TF 11, a futile effort. On March-April she is on Guard ship duties and in May she taks part in Operation “MO” (Tulagi-Port Moresby invasion) at Rabaul in New Britain as floating HQ. On 4 May 1942 the Battle of the Coral Sea commanced while she is in Tulagi. On the 13th the Japanese thrust is stopped and KASHIMA departs Rabaul for Kavieng in New Ireland and Truk (16 May).
She departs on 20 July and is refitted 6 days later until 3 September, staying in Guard ship duties as flagship, 4th fleet, and with a captain change to Sakae Takada (former XO of MUTSU). On 2 October KASHIMA tasked part in an AA training and on the 8th, held a conference on the construction of defenses in the Pacific, attended by Rear Admiral Matome Ugaki, Combined Fleet CoS plus Army officials of the Defense Construction Department.
On 26 October Baron, Samejima Tomoshige takes the head of the Fourth Fleet on 17 November sails with Kashima for an inspection cruise of the Marshall Islands. Kashima is escorted by the destroyers Asanagi and Yunagi. On the 26 he is in Kwajalein, the Roi, Jaluit, Imieji and back on 2 December. Until 1 April 1943 Kashima serves as guard ship while the same day Vice Admiral Kobayashi Masami replaces VADM Samejima (now CinC, 8th fleet). She is later refitted in April and departs in May for Yokosuka for additional upkeep and is bac at Truk from 29 May until 27 August 1943. In July, Hayashi Shigechika takes command and she departs on the 27 to Kwajalein and on 13 October for Roi, having a new CO change for Captain Kajiwara Sueyoshi. She is back at Truk on 8 November, relieved as flagship by NAGARA.

On 10 November she is redesignated as a training ship, attached to the Kure Training Division together with IJN KASHII. On 18 November while underway with the submarine tender CHOGEI, and the destroyers WAKATSUKI and YAMAGUMO she is intercepted by LtCdr Fred Connaway’s USS SCULPIN’s (SS-191), making night radar contact and tries to catch them by surface running, attacking at 06:40 when spotted by YAMAGUMO at 8,000 meters. Sculpin crash-dives and is depth chargeed but without effect, chased by sonar, and depht charged several times. At past 12:50, with batteries nearly depleted, captain Connaway decides to surface and fight with his deck gun while his crew would Abandon Ship. The duel with Yamagumo is engaged at 13:01. After a harrowing duel, its weapons destroyed, USS SCULPIN is scuttled.

Late career as TS

On 20 November as Operation “Galvanic” took place, Kashima arrives in Japan, and starts a refit and reorganization as a training ship in Kure. Under Nagai Mitsuru and by December Yamazumi Chusaburo she is Drydock until 12 January 1944 and until 15 April 1944 she serves at the Etajima Naval Academy, cruising the western Inland Sea and on 25 March is temporarily attached to the General Escort Command, becoming a month later a “training and patrol vessel” and after 15 May (new CO Captain Koma Masayoshi) she is refitted again, making several transport and escort missions between 26 May and 11 from Shimonoseki to Okinawa.
On 11 July, Operation “RO-GO” commenced with missions to Formosa. On 10 August she is in Naha, Okinawa, Lands personnel and cargo, same on the 16th, and is back to Kure in september.
On the 20th she embarks in Kagoshima elements of the Second Air Fleet and arrived in Keelung, Formosa five days later, then back to Kure, Kagoshima and Keelung again on 19 October, the following dau she is spotted by USS TANG by radar at 30,000 yards. Captain O’Kane closed within 2,000 yards on her port quarter but from 1,650 yards renounced to fire new Mark 18-1 electric torpedoes, which had limited range. He made repeated attempts, but fails to close below 600 yards for a stern shot, before being illuminated by a destroyer’s searchlights, crash diving and escapes. Kashima escaped her second ASW attack.

End of service as ASW escort

On 28 October she is Kure and resumes her training duties until 20 December and new modifications. In addition to her brand new Type 22 surface-search radar she received two Type 2 infra-red communication devices while her aft compartments are transformed as concrete-protected magazines housing 100 depth charges while DC throwers and rails are installed on her quarterdeck, plus Hydrophones and sonar. She starts by January 1945 as flagship, No. 102 Escort Squadron, 1st Escort Fleet, including YASHIRO, MIKURA, and sub-chasers 2, 33, 34 and 35. On 10 Febuary she received extra AA and a Type 13 air-search radar and departed two days later for Shanghai. On the 22th she patrolled in the Chrisan Island area.
On 27 February in the South China Sea off Ningpo, there is another close call with US Submarine USS RASHER (SS-310). She is sighted and attacked by depth charges while a Nakajima E8N2 Dave circles over her. USS Rasher later resurfaced by night but has lost contact.
ASW patrols went on in March-April 1945, off Chrisan Island and by May in Korean waters as convoy-escort. On 19 May in the Tsushima Strait at 01:27 (dead of night) she collides with, and sinks, the cargo ship DAISHIN MARU, having herself a gasoline tank repture and a fire breaking. She makes it in Korea, starts repairs in Chinkai. On 5 June 1945 with Operation “Barney” she is detected b a three-subs “Polecats” but detects them also by sonar,e alarm is raised and as flagship, she coordonates the five IJN subchasers to investigate with aviation called (Mitsubishi G3M Type 96 Nell and On 5 July, No. 102 Escort Squadron is deactivated and Kashima joins VADM Fukuji Kishi and the 1st Escort Fleet. She later operates in the Maizuru area, Sea of Japan until the end of the war.

Postwar service

20 August 1945:
Located at Nanao, she departs on 20 August for Kure, and from 21 September with new markings, she starts a last career as repatriation transport with a new deck house around her main mast and main armament not refited but with the barrels sawn off. She is under command of Iura Shojiro, and later Yokota Minoru and on 5 October is stricken, making a first Repatriation Trip to Jaluit, Marshalls and back at Uraga near Tokyo. In November, she is in Hollandia, New Guinea, Wewak, Mushu, Okinawa and is back home on 8 December. Her 3rd Repatriation Trip is in January 1946 to Mushu, New Guinea and back to Otaka, then Kure, Saeki, for a 4th run to Rabaul, Fauro Island and back to Otaka on 14 February; On 2 March she made a 5th run to Singapore, Saigon, and back to Kure. Her 6th Trip beought her at Hua Lien, Formosa, Saigon and Otaka. Her 7th to Singapore, Rembang (Indonesia) and Otaka, and the 8th to St Jacques, French Indochina, Bangkok, Thailand and Uraga in June. Next she is moved to Korojima, Otaka and on 22 July 1946 starts her 10th Tenth Repatriation Trip, 11th on 15 August, 12th on 26 September (to Singapore, Hong Kong) and back to Sasebo. In total she carried 5,800 troops back home. In the summer of 1947 she is sent to the Home Ministry for scrapping at Kawanami Heavy Industries, Koyagishima Yard, Yokosuka.



on shipmodels.info
on navypedia
Katori on combinedfleet.org
Kahima on combinedfleet.org
The Katori clas (general) on combinedfleet.org
Wikimedia commons open source photos


Editorial department of magazine “Maru” (1990) “THE IMPERIAL JAPANESE NAVY vol9 Light Cruisers II / Gunboats” Kojin-sha publishers pp.161-181
The Society of Naval Architects of Japan (1975) “Plans of ships of the Imperial Japanese Navy, History of shipbuilding in Showa era separated volume”, published by Hara-shobo, p. 65
Fukui Shizuo “ Current status survey of machine gun, radar, IFF etc on each vessels, from “”Blueprints about placement of additions of weapons after operation A-Go”” “, Ushio shobo Kojinsha
Janes’s 1940
Conway’s all the world’s fighting ship 1922-47
Lacroix, Eric & Wells II, Linton (1997). Japanese Cruisers of the Pacific War. Annapolis, Maryland: Naval Institute Press.
Senshi Sōsho Vol.31, Naval armaments and war preparation (1), “Until November 1941”, Asagumo Simbun (Japan), November 1969

Modeller’s corner

On scalemates

German WW2 Torpedo Boats

Kriegsmarine Torpedoboote

Germany (1924-45) – 36 (90 planned)+ 49 TB Ausland (TA), total 84

Why German Torpedo Boats in WW2 ?

The simultaneous christening ceremony of the 4 new German “destroyers” Tiger, Luchs, Jaguar and Leopard at the Wilhelmshaven shipyard, presided by Vice Admiral Bauer. Later they would be reclassidied a torpedo boats, but proved quite capable in their new role

Before WW2, only four nations signatory of the Washington Treaty considered the torpedo boats as a way to go around some limitations in tonnage for destroyers, although this category was largely seen as obsolete after the great war. This “revival” concerned in order of importance given to the category, Italy, Germany, Japan and France*. And these were only the large fleets. Alongside them, a cohort of other nations still had torpedo boats in their inventory. They were cheaper than submersibles, and still usable for narrow waters point defence. The Scandinavian Nations for example still relied on them and built some up to WW2, although motor torpedo boats were also considered and sometimes took their place.

G7/T107, one of the numerous vintage WWI hochseetorpedoboote of the Kaiserlichesmarine modernized in the Reichsmarine. They were still active in WW2.

*Italy had a proficience in this time, with many modern designs and reclassed WWI destroyers to boot, to compensate for destroyer tonnage seen as unsufficient, Japan had only the Tomozuru and Otori class built in 1933-37, but replaced by escorts later, while France only developed the Melpomène (1935) and Le Fier class (1940, never completed). Both countries scrapped their torpedo boats to free tonnage or just through obsolescence. Both Japan and France stopped building torpedo boats were destroyers became the standard anyway, well before WWI. This also made sense in terms of maritime strategy. Both had either an Empire or were building one, and rather wanted a coherent fleet, priority being given to fleet destroyers.

The case of the Reichsmarine

Reichsmarine's torpedo boat prior to 1935
Reichsmarine’s torpedo boat prior to 1935. On top, the torpedo boats and newly built destroyers in service

Now, of the two nations most proficient in torpedo boats, Italy was the only nation of the future axis that was bound by the Washington treaty. The allied powers which submitted Germany to the Versailles Treaty which authorized the Reichsmarine some leeway in this category since it was mostly seen as defensive, not to project power. The Versailles Treaty nevertheless restricted the new Reichsmarine by treaty to twelve torpedo boats and twelve destroyers, nothing more, with a possible replacement of vintage WW1 units plus extra decommissioned ships for cannibalization.

The first replacement programme was in reality a newly designed “destroyer” under severe tonnage limitations, the Type 1923 and Type 1924 better known as the “Raubvögel” and “Raubtiere” based on their names, birds of prey and predators. They were the first “zerstörer” laid down since 1918, and based by default on a mix of features of late WWI designs. They were however classed in the Reicshmarine Book as “torpedo boote” anyway, knowing that they were too small to compete with any contemporary designs. Naturally they were reclassed as Torpedoboote in 1935, when the first of the 1934 type destroyer was launched. The latter had twice their tonnage.

Birth of the Kriegsmarine’s T-Boote (1933-34)

1935-37 naval staff discussions

It’s with the arrival at power of Hitler and more serious funding was given to the Kriegsmarine, then the tonnage increase obtained with the Anglo-German treaty of London redefined priorities. In any case in 1935, albitious programmes were launched in several catgories: Destroyers, Cruisers, the first battleships and aicraft carriers, and a new generations or torpedo boats, of two types, the fleet torpedo boats and coastal ones. The second are essentially motor torpedo boats, the S-Boote. The first type is the object of this article. Where these ships really useful ?

The 1935 debate in the Reichsmarine, soon to be renamed Kriegsmarine and reorganized, procuring or not torpedo boats was put into consideration. The Anglo-German treaty was not signed yet, but de facto would impose on Germany the Washington Treaty conditions. Therefore, tonnage caps were imposed on destroyers, qualitative and quantitative. The 1930 London Naval Treaty had a clause that ships below 600 long tons standard displacement did not count against national tonnage limits.

This was enough for the Kriegsmarine to attempt a design a high-speed, ocean-going torpedo boat based on this 600 long tons. Italy was doing the same since 1933. And both soon realized the same: This proved to be impossible based on high-speed requirement. This forced the use of (troubesome) high-pressure boilers, half the numbers used on a regular Type 1934 destroyer for better standardization. Maintenance problems were exacerbated an even crampier machinery.

the whole concept, with the benefit of hindsight, must be considered a gross waste of men and materials, for these torpedo boats were rarely employed in their designed role.
naval historian M. J. Whitley

So Just like Italy, it was felt torpedo boats were cheap enough to be built in large quantities and perform tasks in restricted seas (in the Baltic in particular) which could free fleet destroyers for their main tasks. Destroyers were to act more agressively as screen vessels and seek combat, while torpedo boats would inherit two other roles: Convoy escort and patrol, still with the possibility of longer range attacks compared to S-Boote. Even within that frame, the Kriegsmarine still ordered a serie of dedicated “escorts”, the “F” class, also launched in 1935. They lacked torpedoes, had the same light main armament but greater emphasis on ASW weapons.

This was a standalone class as soon as it was understood the nimbler and faster R-Bootes could take at the same time the role of coastal minesweepers, minelayers and ASW vessels. The other was self-evident as submarine threat was limited, as the need of escorts. After all, Germany was nearly self-sufficient and apart communicating with Norway for the famous “steel road”, its lines of communications were not as bloated and extensive as Great Britain or France. Thus, torpedo boats being seen as more versatile to attack, and still procure the benefit of an escort, were a good in-between.

Plan Z’ torpedo Boat programme

The new torpedo boats built in the Kriegsmarine were based on Plan Z: The latter planned no less than 90 torpedo boats to be built until 1950. As stated above, they were a kind of escorts, freeing destroyers for more fleet important tasks, but keeping an attack capability. Soon, other tasks were found for them and they were equipped to lay mines, but no consideration was given at any point to ASW defence: From the 1935 to the 1941 types, none had depth charges. More emphasis was put on AA however.

The construction plan was gradual and incremental, following finances and the capabilities of German yards: From the 800-tonnes 1935 type, of which twelve vessels launched 1938-39 were just ready on time for the Norwegian campaign. The expansion was fast, as the 1939 Type reached 1,700 and 1941 type 2,000 tonnes. The latter was still conventional but now to the size of a “small” destroyer (only in comparison to German destroyer standards). The 1940 type however were complete oddballs that can’t be regarded in the this context: They were ordered in the Netherlands and reaching 2,500 tonnes fully loaded, reusing the machinery of gutted destroyers of the Tjerk Hiddes class, with a total of twelve ordered, to be fitted out in Germany. Their design was closer to standard destroyers with a forecastle and generous artillery in superfiring positions.

The first true T-Boote: 1935/37 Types

The 1935 and 1937 Types were very close in design, and formed a coherent force of 21 ships in completion when WW2 started. The initial 1935 design was as narrow and light as possible to “fit the bill” of a 600-tonner, but it was soon judged impossible to meet requirements and revised in 1936, the bar raised to 800 tonnes. By default at the time, little consideration was given to allied inspection on these programmes.

In Italy, the Spica class however realized the impossible by achieving a 600+ tonnes design, but at great sacrifice. It soon showed its limits, notably in terms of sturdiness, seaworthiness and stability. The Mediterranean has relatively comparable conditions to the Baltic, but since the German designs were supposed to go out in the north sea to attack British lines of communications from the Jade, a sturdied hull was needed, yet while trying to find any ways to reduce tonnage.

Thus, the most distinctive design point of German WW2 torpedo boats, unique compared to all other designs of the time, was the choice of a flush-deck hull.
Italian, French, Japanese torpedo boats all had a forecastle and mimicked a destroyer in many ways.
The hull had a particular shape with a renforced prow, relatively large, and slanted hull, clipper bow, to battle large waves in winter. The hull shape was a way to rationalize construction and gain weight. Still, they had a low silhouette and were pretty “wet” in most conditions.

The particular semi-transom stern of T35, a Type 39.

Another particular was their armament: Main armament was standard, revolving around the 100 mm caliber, but just a single one aft, which was highly unusual, and unlike Italian designs they carried standard 21-inches (533 mm) torpedoes, for the maximal hitting power whereas armament was purely defensive. The accent was on first strike capabilities above all else, which contradicted their escort capabilities (the task they performed eventually).
Why lacking a forward gun ? It seems that due to their low freeboard, and despite their flare, a forward gun would be just sprayed to such point of being unusable. The lessons on the USN with their “flush-deckers” built in 1918-1921 was well understood.

The new wartime standard: 1939/41 Types

The design of the Type 1935/37 was definitely more suited to escort than attack, and thus, a mich larger type, reflecting the upscaling of German destroyers at the time, with some armed with 6-in guns, an enlarged and faster Type 1937 was sought after, soon called the Type 1939. They really fit the bill of Plan Z and were intended for long range operations. They were the brainchild of Grand Admiral Erich Raeder, CiC of the Kriegsmarine at the time, and not pleased with the too modest 1938B-class destroyer ordered in 1939. To compensate he wanted a 1,265 metric ton and 95-meter-long (311 ft 8 in) all-purpose torpedo boat, which specifications were written on 8 July. The idea that it could be built in larger quantities than proper destroyers. By September 1939 the shipbuilding program was reevaluated, the Type 1938B cacelled and the Type 1936A-class destroyer ordered instead. The Type 39 torpedo boat was far larger that previous types and the same high-pressure boilers but arranged into separate units (for safety, also giving them two funnels). They were alsmot equivalments to the 1938B design between their 102.5 meters (336 ft 3 in) overall, for 1,318t standard/ 1,780 metric tons deeply load and their hull was divided into 13 watertight compartments and double bottom. They ended as excellent, agile seaboats.

Hull shape and structure model, Type 1939

-The Type 1941 Type were a completely different matter: As the war started, Yards were soon starved of resources and personal, diverted to active army units and the Luftwaffe. One immediate effect was the outright cancellation of the Type 39 TBs with only 15 ships ordered, many never completed. It was decided later to create an enlarged version with a better propulsion machinery to reach 34 knots and adding another twin FLAK 37mm. They were, like the Type 1939, intended to take the pklace of sunken destroyers and assumed relatively similar roles.
In the end, on the 15 planned only a few were launched: T37–T42 in Schichau and later T43–T48, then T49–T51. The yeard being located in East Prussia the planned completion in 1945, soon fell through between labor shortages and the Soviet advance. All work ceased on 22 January and only three were towed further west for completion in Deschimag and Kiel but they were all captured.

Near-destroyers: 1940 Types

The transition towards a more ocean-going type saw some maturation in the concept. However they were very different:
-The Type 1940 was in all effect, practical destroyers ordered… in the Netherlands for the Dutch Navy in 1938. When the country fell in May 1940, the Germans soon captured all yards and vessels under construction were examined, documentation seized by the Kriegsmarine. These four Gerard Callenburgh class destroyers were now deprived of HNLMS Isaac Sweers, towed to be completed in UK, but Gerard Callenburgh was completed as ZH1. Philips van Almonde and Tjerk Hiddes were BU, but mist of their propulsion machinery was intact as well as some equipments, so the Kriegsmarine decided to design a ship tailored to be built in the Netherlands while recycling this now surplus material. If they were classed as torpedo boats, the Type 40 design were effectively destroyers in shape and tonnage.

In fact, using both Dutch yards and forced skilled workforce, which lacked in Germany, ambitious plans were to built no less 24 of these Type 1940, reclassed officially as Flottentorpedoboot and tasked to take the place of regular destroyers now in short supply.
However as the war went on, the enterprise looked grimer by the day and 12 were cancelled, and between sabotages and generally uncooperative workforce, and then shortages of all kind, none of these were completed before D-Day. The first three, most complete, were towed to Germany to be completed, one sank en route by Allied fighter-bombers and the last pair never completed. The remaining ones were BU in 1946.

Specifics of German WW2 Torpedo Boats

Main Guns:

12.8 cm SK/L45 C34:

These German guns were a fairly common models, internationally classed as 5-in (127 mm) but of slighlty larger caliber. They equipped the Type 34, Type 36 and Type 36B destroyers and other vessels, but also the Leopard and Luchs after conversion. For what we are concerned they were to equip the Dutch-built Type 1940. 15–18 rpm; mv 830 mps (2,700 ft/s); range 17,400 m (19,000 yd).

105 mm (or 10.5 cm) SK/L45 C16:

These equipped the vintage but modernized T107 group and T139 group. But also the Type 1923/24 “destroyers”. These WWI vintage guns were first developed for the first generation of German dreadnoughts like the Nassau class in 1907. The late C16 type was a single pedestal mounts in open half-shield version. The wartime modification was the one use, since there were still many in storage. They elevated −10° to +30 and hard a ax range of 17.6 km (10.9 mi). They were replaced by C28 or C32 during their 1936 refit and thus the model was no longer in use but on the T107 group and older TBs.

10.5 cm SK/L55 C28:

Use on the 1923/1924 types. Some were bored out to become the 12.7 cm/45 (5″) SK C/34 used on the Leopard and Luchs only. Firing the HE – 32.4 lbs. (14.7 kg), elevating -10 +30°, range 18,860 yards (17,250 m), mv 3,035 fps (925 mps), ROF 15 rpm.

10.5 cm SK/L45 C34:

Adopted for the 1935/37 Type and Type 1939. In their improved (nR, “nachgebohrte Rorhe” or “improved drilled barrel”) version they had better performances. ROF 15 rpm, firing the HE L/4,4: 53.4 lbs. (24.2 kg) Illumination round L/4,1: 50.0 lbs. (22.7 kg). Range 16,600 yards (15,175 m), hand-operated.

10.5 cm SK/L45 L44B:

Dual purpose models adopted for the never completed Type 1941 and Type 1944. On the latter, in two twin mounts located fore and aft. These elevated up to +75° and fired 15.5-or-17-kilogram (34 or 37 lb) shell at 835 or 785 m/s (2,740 or 2,580 ft/s) depending of the type. The 17-kgs shell could land at 19,000 meters (21,000 yd) from +48°. Rate of fire was 12–14 rounds per minute and 400 rounds were carried per gun. Added to the generous lighter AA, radar warning and radar-guided FCS, both the Type 1941 and especially the Type 1944 had a considerably better AA capability for escort.

Anti-aircraft artillery:

In standard, the 1923/24 types had two single 20 mm Rheinmetall guns. Not changed in the 1936 refit, but augmented to seven in all, in a Flakvierling (quad) mount and three single in 1944.
The Type 1935/37 had a more substantial AA when completed, with a single 37mm L83 C33 and fice to eight single 20mm C38 in various locations. A bow sponson extra 37 mm C33 was added on their bow in wartime, and some even had two 40mm L70 Bofors guns in place of their aft TT bank.
As completed the larger Type 1939 had four 37mm M42 AA (two twin mounts) and seven to twelve 20 mm AA guns, most likely with one or two Flakvierling and the rest in single mounts.
The planned, Dutch-built 1940 type had two twin 37mm as standard and two Flakvierling. The planned type 1941 had the same for 37 mm but only one Flakvierling and two twin 20 mm C38.

Torpedo Tubes

This was a mix in the interwar due to the origin of the vintage TBs from 1906 to 1913. They had still in the interwar the two twin ortiginal 450 mm TTs based of remaining WWI stocks. The 1923-24 type destroyers (later TBs) had 500 mm torpedo tubes. Possibly derived from the 50 cm (19.7″) G7 in service from 1913 on capital ships and some U-Boat types. Completely obsolete they were replaced by the standard 533 mm (21 in) during their 1936 refit. Conways says 1931, but the model was not in service yet (1935).
53.3 cm (21″) G7a T1: Standard for all types in WW2, two triple banks for the 1923/24, 1935/37, 1939/41 types but quadruple on the Type 1940.
Weight: 1,528 kg (3,369 lbs)
Overall Length: 7.186 m (23 ft. 7 in)
Warhead: 280 kg (617 lbs.) Hexanite
Settings: 6,000 m/44 kts, 8,000 m/40 kts, 14,000 m/30 kts
Powerplant: Decahydronaphthalene (Decalin) Wet-Heater
The German TBs also carried mines, but the type is unspecified. It can be the same model used by R-Bootes. They are not showing depht charge racks but the Type 39 were the only ones carrying four depht charge throwers and carrying a S-Gerät sonar. Both the 1941 and 1944 types were more AA escorts.

Organisation & Tactics

Z24 and T24 under aerial attack on 25 August 1944
Z24 and T24 under aerial attack on 25 August 1944. A good way to show that German TBs ended often in the same escort missions as destroyers despite their obvious limitations.

German torpedo boats were administratively grouped into several torpedo-boat flotillas (TBFs).

Flotilla Formed Assigned vessels Primary Class
1. Torpedobootsflottille 1935 T1, T2, T3, T4, T9, T10 Type 35 torpedo boat
2. Torpedobootsflottille T5, T6, T7, T8, T11, T12
3. Torpedobootsflottille 1937 T13, T14, T15, T16, T17, T18, T19, T20, T21 Type 37 torpedo boat
4. Torpedobootsflottille T22, T23, T24, T25, T26, T27 Elbing-class torpedo boat
5. Torpedobootsflottille 1938 TB Albatross, TB Greif, TB Falke, TB Kondor, TB Möwe Type 23 torpedo boat
TB Tiger (ex-Thor) Sleipner-class destroyer
T34, T35, T36 Elbing-class torpedo boat
6. Torpedobootsflottille 1937 T28, T29, T30, T31, T32, T33
7. Torpedobootsflottille 1940 TB Panther (Ex-Odin), TB Löwe (ex-Gyller) Sleipner-class destroyer
TB Leopard Type 24 torpedo boat
9. Torpedobootsflottille 1943 TA14, TA15, TA16, TA17, TA18, TA19, TA37, TA38, TA39 Torpedoboot Ausland
10. Torpedobootsflottille 1944 TA23, TA24, TA27, TA28, TA29, TA30, TA31, TA32, TA33

As for tactics, operational examples shows some clues on how they were used. In the interwar, they were supposed to enemy communication lines and avoid combat in which classic destroyers were at ease. The latter indeed were assigned to the fleet as escorts with the task of deterring other destroyers or cruisers. Thus, TBs were dispensed on paper of these fleet escorting and screening tasks, having neither the range or armament to face enemy destroyers. Oustide preying on enemy trade in relative proxmity, they were to be used for escorting convoys as they did during the early phase of the war, off Poland and Norway. Each flotilla could be used as an entire entity, but in reality they were spread in wartime and depending of assignations.
The 1935/1937 Type had only a single aft gun, giving clues that they were supposed to arrive fast, and in a stealthy way, launch a full torpedo broadside and retreat under enemy fire, again possibly under smoke. The 1939/41 types were more rounded with artillery and AA and thus were closer to “substitute destroyers” in their roles, with tactics closer to standard destroyers flotillas.

In wartime indeed they were tasked of the following:
-Escort: Troopship or transport convoys but also fleet escort (ie with destroyers, of cruisers and even capital ships) in many occasions and for relatively short trips.
-Minelaying: Not only they replaced destroyers when escorting minelayers and participating themselves in minelaying operations.
-Attack: They rarely had the occasion of preting on allied lines of communications but in the gulf of gascony and channel, and were only occasionally used in this role, such as the Normandy landing night raids. They were easy prey for patrolling allied destroyers.
-Evacuation: A last resort used forced by the events, notably Operation Hannibal in 1945.

Operations: Three examples

To illustrated the operating side, since space is lackng on this post to dwelve into the career of each and every of the 36 torpedo boats concerned (they were be seen in due time on individual class posts), here is three career examples, three picked-up among all those in service from three classes among the most remarkable ships to illustrate what their wartime career felt like. All in all, 12 (the totality) of the 1923/24 early types were lost in action during WW2. They were soon made “maids of all work” in the Kriesgmarine, and saw heavy action from the campaign of Norway (Albatros by fortified batteries of Olsofjord in 1940), Seeadler by MTBs, and the remainder by air raids. The 1924 type had more diverse fate: Collision, mine, torpedo (2), and air raids. The torpeding by British Submersibles of such shallow draft, fast vessels was no small feat.
As for the Type 1935 and 1937, the majority were sunk also by air raids, with a few suviving to end was Soviet and French reparations. The 1939 Type had a longer range and thus, could be operated on ports less under direct reach by the RAF. Three were claimed by German mines during a navigation error, two after a fatal encounter with British cruisers (Glasgow and Enteprise), one by cruisers and destroyers, one by Soviet MTBs, one mined and bombed. Those which survived were attributed to the US and Britain and soon handed over back to France and USSR, seeing some service in the 1950s after alterations.

Seeadler of the 1923 Type

Leopard of the 1924 type. Can’t find any photo of Seeadler but this one on alamy.
KMS Leopard was commissioned on 15 May 1928. She spent her time with the baltic fleet, and by the end of 1936 served with the 2nd Torpedo Boat Flotilla, deployed off Spain during the Civil War. She ran aground while leaving Cadiz in November 1936 and was towed back for repairs by Albatros. KMS Deutschland was hit by two Republican aircraft bombs on 29 May 1937, abd Adolf Hitler ordered Admiral Scheer to shell Almería in retaliation and on 31 May, joined by the 2nd Flotilla, notably silencing coastal artillery by Seeadler and Albatros. In June 1938, she was transferred to the 4th TB Flotilla (TBF).
Her unit was disbanded in 1939, and she joined the 6th TBD escorting the North Sea mining operations from 3 September. On 13 and 18-19 November, escort by two light cruisers they escorted back destroyers off the English coast. They patrolled the Skagerrak, inspecting neutral shipping. In December, Seeadler and Jaguar controlled six ships. In retaliation for the loss of Altmark in neutral Norwegian waters on 16 February, Operation Nordmark was mounted and Seeadler searched for Allied merchant shipping in the North Sea, up to the Shetland Islands. The 2nd Destroyer Flotilla, Seeadler and Luchs escorted Scharnhorst and Gneisenau and the heavy cruiser Admiral Hipper on 18 February and returned to the Skaggerak.

She took part in the Invasion of Norway in April 1940, in Group 4 (Kapitän Friedrich Rieve), escorted KMS Karlsruhe, to Kristiansand., departing on 8 April, arriving in heavy fog. Coast-defense guns at Odderøya Fortress fired on Karlsruhe at 05:32 and Seeadler and Luchs returned fire. Rieve turned away under a smoke screen at 05:45 though. But soon He 111 bombers exploded an ammunition dump next to the fortress and Rieve came back at 05:55 to provide them better Accuracy, but he withdrew again at 06:23, then trying to bombard the fortress at long range from 06:50, ordering Seeadler and Luchs to take the narrows until stopped by the fog. Rieve withdrew for good at 07:30, and came back at 09:00 as the fog lifted but withdrew again. Troops were moved to four E-boats to storm the harbor and the Norwegians spotted the Seeadler and Luchs approaching with the four E-boats, reporting them, but mistaking them for Allied, failing to open fire, making the landing and occupation successful at 10:45.

Underway back to Kiel at 18:00 Karlruhe proceeded with Seeadler, Greif and Luchs when torpedoed by the ambushung British submarine HMS Truant. Luchs evaded the other nine torpedoes and tracked the launcher, depht-charging Truant for the next several hours with the other TBs. Truant was damaged but survived. Rieve ordered the TBs to evacuate his crew and Greif to finish off ship. Lützow being also hit by a British submarine on 11 April, the three TBs were soon there to assist her too. On 18 April, Seeadler, Möwe, Greif, Wolf escorted minelayers in the Kattegat. She was later refitted at Wesermünde in May-August and moved to a Frenche port, freshly acquired, assigned to the 5th Flotilla with Greif, Falke, Kondor. They started minelaying the English Channel on 30 September to 1 October. With Wolf and Jaguar, they sortied without results off the Isle of Wight on 8–9 October. In their 11–12 October sortie they sank two Free French submarine chasers, two British armed trawlers. The 5th Flotilla was moved to St. Nazaire and they laid a minefield off Dover (3–4 December) and the Channel (21–22 December).

With Iltis and the Z4 Richard Beitzen they escorted another minelaying mission at the northern entrance to the Channel (23–24 January 1941). After another refit in Rotterdam in March-May 1941 she returned to the Skagerrak, on convoy escort. She was again refitted in Rotterdam (Dec. 1941 – Feb. 1942) and assigned back to the 5th TBF., escorting Scharnhorst, Gneisenau, Prinz Eugen on 12 February 1942 off Cap Gris-Nez (Channel Dash). On 12 March – 2 April they escorted the first sortie of the commerce raider Michel through the Channel, fighting off HMS Walpole and Fernie on their way. They did the same for Stier (12-19 May) but this time met heavy opposition, and on 13th, British MTBs locked on Seeadler, which took at least twop torpedo hits and capsized, broke in tow, and went down with 85 of her crew.

T17 of the 1937 Type

T21, 2 July 1946
No cc photo for T17, here is T21 of the same class, being tested by by the British in July 1946.
T17 was built in Schichau, and commissioned on 28 August 1941, plagued by shortages of skilled labor and raw materials. After initial training and fixes in October she served in the Baltic, in convoy escort. In early 1942 she was moved to France, and on 12 February as part of the 2nd TBF (T2, T4, T5, T11, T12) and 3rd TBF (T13, T15, T16, T17) she met KMS Gneisenau and Scharnhorst, Prinz Eugen for the famous “Channel Dash” back to Germany. On 19-21 March, T17, T15, T16 were transferred to Norway, escorting Admiral Hipper to Trondheim. Later T17 was refitted refitted in Kiel. On 1–3 October she was in the Baltic escorting Scharnhorst, Leipzig and Nürnberg and Z25, Z31 and Z37 ad some of her sisters.

T17 T28 of the 1939 Type

T 35 as DD-935 US seas August 1945
No cc photo for T28, here is T35 of the same class, being tested by the USN.
T28 was was built in Schichau, Elbing, commissioned on 19 June 1943. T28 and T29 were assitgned to Western France by late January 1944 and en route shelled by British coastal artillery and then two British Fairey Albacore. Near misses caused minor leaks in T28’s boiler room. She was refitted upon arrival until June. After the landings in Normandy on the 6th, theur unit, the 5th Torpedo Boat Flotilla (T28, Falke, Jaguar, Möwe) based in Le Havre made several sorties against the armada, mostly by night to the allied air superiority. They rather targeted isolated Allied shipping. Over time they encountered many, launched 50 torpedoes and spent mich ammunition but only managed to sink the Norwegian destroyer HNoMS Svenner. T28 was submitted to a RAF night raid on 14/15 June (clamining Falke and Jaguar) but emerged victorious. On the night of 21/22 July with three E-boats she sailed from Le Havre to Boulogne and encountered on her way HMS Melbreak, but ultimately she went back to Germany on the 27th despite multiple allied attacks.

On 20–21 August with T23 she escorted Prinz Eugen off Tukums, Latvia. She assisted the evacuation of Tallinn (Estonia) by mid-September 1944, and minelaying ops. in the Gulf of Finland. On 22 October with T23 she shelled Soviet positions near Sworbe, Saaremaa. On 19 November they did the same but had to fold up. In December she escorted the 6th Destroyer Flotilla (Z35, Z36 and Z43) to lay a new minefield off the Estonian coast. She herself laid 46 mines. The flotilla on the 11th encountered fould weather and Z35, Z36 due to poor visibility ended on “Nashorn” minefield, and sank. T28 came back and was refitted in Gotenhafen until December 1944.

Next, she escorted Prinz Eugen with two destroyers and her sister T23 for a counterattack against Soviet forces near Cranz (29–30 January 1945). She also escorted Admiral Scheer with T23 and T35 off the East Prussian coast (2–5 February) to shell Soviet positions near Frauenburg and again on 9–10 February. She also escorted Lützow foing the same south of Danzig (27 March) and then escorted evacuation convoys from Hela. On 5 May she recued part of 45,000 refugees from East Prussia, evacuated to Denmark, the others in Glücksburg on the 9th.
As a surviving ship she was allocated a war reparation vessel to the British by late 1945 and then retransferred to France on 4 February 1946, recommissioned as Le Lorrain. Overhauled in Cherbourg with a US radar and FCS, and 40mm Bofors guns installed, she was fully recommissioned in December 1949, escorting the Mediterranean Squadron from Toulon and later the ASW, ended her career as trials ship, stricken on 31 October 1955 and sold for BU.

Read More


Conway’s all the worlds fighting ships 1922-46 (Sieche, Erwin (1980). “Germany”.)
Campbell, John (1985). Naval Weapons of World War II. Annapolis, Maryland: Naval Institute Press.
Friedman, Norman (1981). Naval Radar. London: Conway Maritime Press.
Gröner, Erich (1990). German Warships 1815–1945. Vol. 1: Major Surface Warships. NIP
Whitley, M. J. (2000). Destroyers of World War Two: An International Encyclopedia. London: Cassell & Co.
Whitley, M. J. (1991). German Destroyers of World War Two. NIP
Campbell, John (1985). Naval Weapons of World War II. Annapolis, Maryland: Naval Institute Press.
Colledge, J. J.; Warlow, Ben & Bush, Steve (2020). Ships of the Royal Navy: The Complete Record Seaforth Publishing
Saibène, Marc (2004). Les torpilleurs légers français 1937-1945. Marines.
Salou, Charles (2004). Les torpilleurs de 600 tW du type “la Melpomène” Collection Navires et Histoire des marines du monde, Lela Presse.
Whitley, M. J. (2000). Destroyers of World War Two: An International Encyclopedia. London: Cassell & Co.


T23 on kbismarck.com/
type 23 on german-navy.de/
type 24 on german-navy.de/
on battleships-cruisers.co.uk
Torpedoboot Ausland
ZT107 on avalanchepress.com
TBs on navypedia.org
navweaps.com 10.5 cm L45 sk C32 gun
navweaps.com german Torpedoes
Type 23Type 24Type 35Type 37Type 39Type 40Type 41Type 44
On web.archive.org Melpomene TA9
surface flotillas of the Kriegsmarine
Torpedoboote Ausland german-navy.de

Model Kits

Heller 1031 T 23 Torpedo boat Type 1939-class
NIKO MODEL 7110 German torpedo-boat type 24 JAGUAR 1940
1/700 Niko Models German torpedo-boat type 37 T18 1941
NIKO MODEL German torpedo-boat Type 35 – T1
Niko Model German torpedo-boat Type 39 – T35 1945 1:700
WSW Modellbau German Torpedoboot T-23 N° 700-22-04 | 1:700

T-Boote nomenclature

Kriegsmarine T107 class (WWI)

The former G7 (T107) after her second reconstruction and modernization (pinterest).
In 1919, the Reichsmarine counted two series of old “destroyers” authorized in the entente classification. These twelve ships were the six former V1 class, 670 tonnes (1911) and the six of the G7 class, 660 tonnes (1912-13). Needless to say all post-1914 built HochseeTBs had been interned in Scapa Flow and/or distributed as war reparation to the entente nations and others. With the arrival of the Type 1923, the six boats of the V1 class were stricken in 1929 and kept as a reserve of parts to be cannibalized and keep the G7 group operational. With the 1924 Type in service, they were in turn reclassed as Torpedo boats, although all were assimilated as TBs anyway. The classification difference was only communicated to the armistice commission and retained by most authors de describe them.
As for proper “torpedo boats”, the Reichsmarine counted quite a disparate fleet of former destroyers (Hochsee TBs):
-T139-149 which were 1906-1907 533 tonnes models and T151 to T158 which were 558 tonnes. Due to their age, half were discarded before 1939.
T141 was retained for parts, BU 1933. T143,44,46,48,49 were discarded in 1927-28. T152 and 154 were discarded in 1928-31.
Next, there was a mix of assorted models of various types and tonnage: T168 (1911, 665t) stricken 1927, T175 (1910, 700t) stricken 1926. The T158, 190 and 196 were retained for service, as the smaller, older T139, T151, 153, 155-158.

For reasons of simplification, we will see in one swoop both T107 and T150 series will be seen here. The were World War I “torpedo boats” (Hochseetorpedoboote), technically in WWI assimilated to destroyers but classed in Germany still as large ocean-going TBs. They were still active in the interwar, and were modernized in the 1920s and 1930s. They were sent in auxiliary duties in 1939 but T107, T108, T110, T111 and T196 were still listed as active TBs. T151, T153, T155, T156, T157, T158 and T190 were rearmed by late 1939 and tooo, part in escort missions during the invasion of Poland and Norway and stayed active until Operation Hannibal, the east prussian evacuations.

T107 group: Former G7 type, they were reboilered in 1921-23, and underwent another major reconstruction in 1935-37 or later. They gained two modern 105mm/45, were lenghtened and displacement rose to 15%. They retained their prewar prefic letter related to their builders, V for AG Vulkan, S for Schichau, and G for Germaniawerft. In 1937 they were reclassified as “TB” properly with T-numbers. Precise information are had to get, as photos. If enough is found, they will be the object of a dedicated article.

T139 group: This is a highly artificial classfification as the ten boats kept active until 1939 and in WW2 were of various tonnage and capabilities (see above). They were modernized in Wilhelmshaven in the early 1920s, boilers changed, and had remodelled bridges and funnels layout. Again, if enough information is available, they will be the object of a dedicated post in the future. During their interwar carrer they were alternatively disarmed and rearmed, but used for auxiliary tasks. In 1927, T139 and 141 became the radio control ships “Pfeil” and “Blitz”. T153 became the rangefinder training ship Edward Jungmann in 1938.Apparently T151 and T156-57-58 and T196 were active, but T155, T175, T185 were in reserve in 1939. They all survived the war but T157 which hit a mine in 22 October 1943. T155 and 156 were scuttled in April and May 1945 due to the Soviet advance. T151, T153, T190 were attributed to the USA in 1945-46 and promtly scrapped. T158, 185 and 196 were attributed to the USSR. Same fate but T158 which became Prosorlivi in 1945 and was active for some time, and lated scrapped at an unknown date.

Kriegsmarine Type 1923 (1924)

Albatross, Falke, Greif, Kondor, Möwe, Seeadler

The six Type 23 torpedo boats (Raubvogel) were developed from 1918 unbuilt Hochsee TBs plans, unrealized and laid down as zerstörer (Destroyers) for the first time in the Riehchsmarine. The term reflected the Versailles treaty and Washington treaty classification to avoid confusion as Germany was specified to have twelve ships of each type, TB and Destroyers. Thus, the Reichsmarine built them to replace former Hochsee TBs that were themselves reclassed as “Torpedoboote”, helping to retire the WWI vintage TBs still in service. Thus two classes were ordered the Type 1923 and 1924, two batches of six to contitute a coherent twelve-ship destroyer force.

They entered service in 1926-1927. All built at Naval Dockyard at Wilhelmshaven, named and half launched the same day, leading to a grand ceremony. They were the also first to German ships built with the help of electrical welding, to reduce displacement. They were also the first with geared steam turbines. Indeed, even the models of destroyers planned in 1918 still had VTEs. Overall they were successful sea-boats, with good speed and agility, but based on such low tonnage, they were seen more as coastal ships, not on par with standard destroyers of the time and light away from large ones.

They mostly served with the 4th Torpedo Boat Half Flotilla and by 1936 and Albatros and Seeadler were in the 2nd TBF, Falke, Greif, Kondor, Möwe were in the 4th TBF, patrolling during the Spanish Civil War, especially after Deutschland was bombed by Republican aircraft in 1938, shelling Almería. In 1938 Seeadler joined the 4th Flotilla, Greif, Kondor and Möwe, the 5th TBF. The other were in refit at that time. WW2 was fierce for them: All supported the North Sea mining operations, they patrolled the Skagerrak, took part in 1940 to the Norwegian Operations, and they went on for various operations until 1944; notably mining the channel. All in all, Möwe was sunk by aviation on 16 June 1944, Falke too on 14/15 June, Greif on 24 May 1944, Kondor hit a mine on 23 May 1944, Albatros ran aground on 9 April 1940 and Seeadler was torpedoed by British MTBs on 13 May 1942.

Characteristics: (As built 1926)

Displacement: 798/923 long tons standard, 1,213/1,290 long tons FL
Dimensions: 87/87.7 x 8.25 x 3.65 m (287 ft 9 in x 27 ft 1 in x 12 ft) (o/a)
Propulsion: 2 shafts turbines, 3 × WT boilers, 23,000 shp (17,000 kW)
Speed: 32–34 knots (59–63 km/h; 37–39 mph)
Range: 1,800 nmi (3,300 km; 2,100 mi) at 17 kts
Crew: 127
Armament: 3× 10.5 cm (4.1 in), 2×3 500 mm (19.7 in) TTs, 30 mines

Kriegsmarine Type 1924 (1926)

Iltis, Jaguar, Leopard, Luchs, Tiger, Wolf

Torpedoboot “Luchs”

Six ships of 1924 Type “Raubtier” or “predator” class had been planned to carry the 12.7 cm (5-in) gun but instead went for the older 10.5 cm weapons. All were from the same Wilhelmshaven yard, but with speed and range improved but overall pretty close to the “Raubvogels” and upgraded in the late 1930s after entering service in 1927-1928. Like the former they had a lot of weather helm and thus “almost impossible to hold on course in wind at low speed”, and equipped with too many torpedoes for their role with the same six 50 cm (19.7 in) torpedo tubes in two triple mounts. Their AA was expanded, notably 20 mm guns in WW2, and by 1944 Jaguar received a FuMB 4 Sumatra radar detector and a proper Fumo surface radar.
Pushed hard they were all lost but one by mid-1942:
Wolf hit a mine on 8 January 1941, Iltis (Polecat) was sunk by British MTBs on 13 May 1942, Jaguar by aircraft on 14 June 1944, Leopard by collision with KMS Preussen on 30 April 1940, Luchs (Lynx) torpedoed by HMS Thames on 26 July 1940 and Tiger by collision with Z3 Max Schultz on 27 August 1939.

Displacement: 933 long tons standard, 1,320 long tons (1,340 t) FL
Dimensions: 92.6 x 8.65 x 3.52 m (303 ft 10 in x 28 ft 5 in x 11 ft 7 in)
Range: 1,997 nmi (3,698 km; 2,298 mi) at 17 knots

Kriegsmarine Type 1935 (1938)

T-1, ONI
T-1, ONI
The Type 35 torpedo boat were the first modern type specifically as torpedo bootes, and despite being called Type 1935, they were completed a few months after the start of World War II and still training when the Norwegian Campaign commenced in April–June 1940. Design-wise, German authorities lied when reporting theior official tonnage, 600 standard. In reality they displaced 859 long tons (873 t) standard and 1,108 long tons (1,126 t) at deep load, but even more in 1944 with AA additions. Very different design compared to the Type 23/24 they had no forward artillery, just a single aft gun and two torpedo tubes banks of the larger 21-in cal. They were also flush deck with a large raked bow to deal with heavy weather, alrhough it proved not enough and many had their bows raised and sharpened, clipper-style. Engineers soon realized that it was impossible to stick on the 600 tonnes limit after the 1930 London Naval Treaty and it was decided to scrap the clause entirely.

More so, the design was plagued by boilers issues to such a point that naval historian M. J. Whitley later stated “the whole concept, with the benefit of hindsight, must be considered a gross waste of men and materials, for these torpedo boats were rarely employed in their designed role.”. In all, twelve were built to replace older WWI units (T1-T12). The very last was commissioned on 4 july 1940. Nevertheless compared to previous ships they hhad one more boiler for more ouptut, better top speed, reduced crew and range.
They spent most their time escorting convoys and minelayers in North Sea, English Channel and later transferred to Norway trying to prey against shipping along the Scottish coast. Refitted in early 1941 they ended in the Baltic Sea to support operations from June. Four ended in reserve (manpower shortages) as well as in 1942, four were sent to France, escorting commerce raiders and later the “channel dash”. Two ended in the Torpedo School and the rest in 1943. Later in 1944 most were back in the Baltic. All in all, there were all sunk but three: T1 by aviation, 10 April 1945 as T2 (29 July 1944), T3 (19 September 1940), repaired, then mines, 14 March 1945, T4 (survived, Transferred US), T5 (mines 14 March 1945) T6 (same 7 November 1940), T7 (aircraft, 29 July 1944), T8 (same 3 May 1945), T9 (sunk 4 July 1940), T10 (aviation 19 December 1944), and T11 went UK and France, T12 to USSR, 1946.

T1 as the Type 1935 lead ship as completed
T1 as the Type 1935 lead ship as completed.

Characteristics: (As built 1938)

Displacement: 859 long tons standard, 1,108 long tons FL
Dimensions: 84.3 x 8.62 x 2.83 m (276 ft 7 in x 28 ft 3 in x 9 ft 3 in)
Propulsion: 2 shafts turbines, 4× WT boilers, 31,000 shp (23,000 kW)
Speed: 35 knots (65 km/h; 40 mph)
Range: 1,200 nmi (2,200 km; 1,400 mi) at 19 kts
Crew: 119
Armament: 1× 10.5 cm (4.1 in), 1x 37mm, 2x 20mm, 2×3 500 mm (19.7 in) TTs, 60 mines

Kriegsmarine Type 1937 (1940)

T21 of the Type 1937 after the war
T21 of the Type 1937 after the war
The Type 37 torpedo boat were only nine built, completed in 1941–1942 but the remaining were cancelled as the Type 39 was preferred at this point. Design wise they were virtually a repeat of the Type 35, better range, but the same troublesome boilers, assorted with maintenance issues exacerbated by poor access. They were commissioned qute late to participate to major operations and went on performing teh same tasks as the Type 35 boats like escorting commerce raiders, the “Channel Dash”, Operations from France, from Norway, from the Baltic, assignment to the Torpedo School. Those in Norway by early escorted vessels and off Francen they laid minefields. By 1944 some served as training ships and were pressed to support German forces in the Baltic. Five out of nine survived the war, ending as war reparations. The Soviet Union used its one was a test ship scrapped in 1960.

T13 in 1944
T13 in 1944

Characteristics: (As built 1940)

Displacement: 888 t standard, 1,139 t deep load
Dimensions: 85.2 x 8.87 x 2.83 m (279 ft 6 in x 29 ft 1 in x 9 ft 2 in)
Range: 1,600 nmi (3,000 km; 1,800 mi) at 19 kts

Kriegsmarine Type 1939 (1941-42)

T22 to T-36: 15 TBs

T35 as DD 395 in US tests, August 1945
T35 as DD 395 in US tests, August 1945
Großadmiral Erich Raeder, Kriegsmarine’s CiC saw the proposed Type 1938B-class destroyer in 1939 as too small for effective use and instead proposed a 1,265 tons 311 feet all-purpose torpedo boat instead. The new design was evaluated on 8 July and by September the Kriegsmarine, caught off-guard at the start of Plan Z, was forced to re-evaluate the whole shipbuilding program. The Type 1938B was definitely cancelled, more Type 1936A-class destroyers ordered as the Type 39 TBs. The latter represented a drastic leap forward in design, much larger and better armed than the puny Type 35/37 that still tried to “stick” to treaty limits.
The Type 39 was a properly designed torpedo boat with full features, adding to thier initial torpedo attack role, better escort and attack capabilities due to their large artillery, and better range due to a tonnage almost twice as large as treaty limits (from 600 to 1,300 tonnes). They however still share the same troubesome high-pressure boilers but their new propulsion machinery was separated in two widely spaced compartment to avoid a single hit any crippling effect, compounded by the addition of 13 watertight compartments and a double bottom covering 67–69% of their length. Their survivability increased thus several folds.
With a 336 ft 3 in long by 32 ft 10 in wide hull, 1,780 metric tons (1,750 long tons) fully loaded, increased height clipper bow, this time the new TBs were soon reputed excellent seaboats, very maneuverable in stark contrast of their precedessors. However they needed a larger crew, with 206 officers and sailors and in wartime, previous Type 35/37 were often placed in reserve due to manpower issue, the Kriegsmarine preferring reaffecting them to the new Type 39.

T35 in USN trials of Boston, September 1945
T35 in USN trials of Boston, September 1945

The Type 39 ships’s Wagner geared steam turbines, connected to three-bladed 2.5-meter (8 ft 2 in) propellers were fed by four Wagner water-tube boilers working at 70 kg/cm2 (6,865 kPa; 996 psi), 460 °C (860 °F) for 32,000 shaft horsepower (24,000 kW), reaching 33.5 knots (62.0 km/h; 38.6 mph). In service however steam consumption of the auxiliary machinery proved excessive, boilers failing to aise enough steam and lowering their top speed in practice (in moderate load and perfect weather, to 31 knots) their range also went from 2,300 to just 2,085 nmi (3,861 km; 2,399 mi) at the same 19 knots.

Armament-wise, they were a leap forward compared to the weak Type 35/37: Four 10.5 cm (4.1 in) guns instead of just one, and better AA (two twin 3.7 cm (1.5 in) and Fmakvierling and two single 2 cm (0.8 in)), but keeping the same two triple 533 mm (21 in) torpedo tubes. They could aso carry twice as many mines upt to 60 and for the first time, introduced four depth charge launchers to better perform their ASW escort role. This was completed by a S-Gerät sonar and FuMO 21 search radar from completion. They were started in Schichau, Elbing in 1940-4
and for that reason were almso called te “Elbing class”.

In wartime, they arrived late, at a time losses for the Kriegsmarine had been high: T22, the lead vessel, was commissioned in February 1942 but production issues delayed the others: T36 was only completed on 9 December 1944 and could do little at that stage. Apart T27 which ran aground in 1944 and T23, 28, 33 and 35 attributed respectively to France(2), USSR and USA, they were all sunk by aviation, mines, gunfire and torpedo. This class as the others will be covered on detail in a dedicated post in the future, including notably full careers.

Rendition of the Type 44, T25
Rendition of the Type 39, T25
Conways profile of T37, Type 1939

Characteristics: (As built 1938)

Displacement: 859 long tons standard, 1,108 long tons FL
Dimensions: 84.3 x 8.62 x 2.83 m (276 ft 7 in x 28 ft 3 in x 9 ft 3 in)
Propulsion: 2 shafts turbines, 4× WT boilers, 31,000 shp (23,000 kW)
Speed: 35 knots (65 km/h; 40 mph)
Range: 1,200 nmi (2,200 km; 1,400 mi) at 19 kts
Crew: 119
Armament: 1× 10.5 cm (4.1 in), 1x 37mm, 2x 20mm, 2×3 500 mm (19.7 in) TTs, 60 mines

Kriegsmarine Type 1940 (1944)

Rendition of the Type 1940 (conways)

“The Type 1940 torpedo boats were a group of 24 torpedo boats that were intended to be built for Germany’s Kriegsmarine during World War II. Although classed as fleet torpedo boats (Flottentorpedoboot) by the Germans, they were comparable to contemporary large destroyers. They were designed around surplus Dutch propulsion machinery available after the Germans conquered the Netherlands in May 1940 and were to be built in Dutch shipyards. Hampered by uncooperative Dutch workers and material shortages, none of the ships were completed before the Allies invaded Normandy (Operation Neptune) on June 1944. The Germans towed the three ships that were most complete to Germany to be finished, but one was sunk en route by Allied fighter-bombers and no further work was done of the pair that did arrive successfully. The remaining ships in the Netherlands were later broken up for scrap and the two that reached Germany were scuttled in 1946.”

Characteristics: (As built 1938)

Displacement: 859 long tons standard, 1,108 long tons FL
Dimensions: 84.3 x 8.62 x 2.83 m (276 ft 7 in x 28 ft 3 in x 9 ft 3 in)
Propulsion: 2 shafts turbines, 4× WT boilers, 31,000 shp (23,000 kW)
Speed: 35 knots (65 km/h; 40 mph)
Range: 1,200 nmi (2,200 km; 1,400 mi) at 19 kts
Crew: 119
Armament: 1× 10.5 cm (4.1 in), 1x 37mm, 2x 20mm, 2×3 500 mm (19.7 in) TTs, 60 mines

Kriegsmarine Type 1941 (1944)

T37 to T50: 14 boats planned, 5 to 96% complete.

T37 of the Type 1941 (conways)
In September 1939 the war caused the cancellation the bulk of Type 39 torpedo boats orders, with only 15 retained. Labor and material shortages also hampered their construction which dragged on until really starting by 1941. To compensate for the destroyers losses and spare strategic materials and labour time, the Kriesgmarine championed the idea in 1941 on a slightly enlarged Type 39 with an improvedmore propulsion machinery to reclaim 34 knots and more space to accomodate extra 3.7-centimeter (1.5 in) AA twin mounts.
In the end, the new Type 1941 reached 106 meters (347 ft 9 in) long for a 10.7 meters (35 ft 1 in) beam and 1,493/2,155 long tons displacement. They also had widely separated machinery spaces and 13 watertight compartments, 69% long double bottom. Using the same Wagner geared steam turbines and water-tube boilers they reached 40,000 shp (instead of 32,000) and carried 559 metric tons of fuel oil for 2,800 nautical miles. This was considered not good enough to replace destroyers and Schichau started work on an electric auxliary machinery, that was planned for the Type 1944, reaching 4,200 nm this time.

The main armament was essentially the same as the former Type 39, with four single 10.5 cm (4.1 in) guns (Although the KM44 dual purpose was planned to replace these), twin 3.7 cm a quadruple and two single 2 cm AA, same two triple torpedo tubes banks and four depth charge launchers. They also were to be fitted with the same S-Gërat sonar, but also the FuMO 21 radar, FuMB7 “Naxos” plus FuMB8 “Wanz G” radar detectors. Construction was postponed at Schichau until the first were laid down in October 1943, Fabruary and June 1944 and in 1945. None was completed. When captured by the allies, hulls were between 5% (T50) and 96.5% for T37, the lead boat. T38 and 39 were 84 and 76% respectively, both captured and scuttled by the British in 1946 while T37 went to the US for evaluation, in 1946. All the remainder were demolished on slipway but T40 that was launched and towed while in completion, accidentally ran aground on 12 March 1945, and was later scuttled by the British Forces.

Characteristics: (As planned 1945)

Displacement: 1,493t standard, 2,155t deep load
Dimensions: 106 x 10.7 x 3.72 m (348 x 35 x 12 ft)
Propulsion: 2 shafts turbines, 4× WT boilers, 40,000 shp (30,000 kW)
Speed: 34 knots (63 km/h; 39 mph)
Range: 2,800 nmi (5,200 km; 3,200 mi) at 19 knots
Crew: 210
Armament: 1× 10.5 cm (4.1 in), 3×2 37mm, 8x 20mm, 2×3 500 mm (19.7 in) TTs, 4 DCT

Kriegsmarine Type 1944 (1944)

T52 of the Type 44 as planned. It looked more compact and bulky than previous designs, more destroyer-like.
As the previous Type 39 torpedo boats, the Type 44s were general-purpose TBs, but improved over steam consumption of the Type 39′ auxiliary machinery. At the time, revolutionary three-phase electric motor which was found far more effective for a relatively small ship’s auxiliary machinery, partially automated to boot and fast-starting. Dipl.-Ing. Illies at Schichau-Werke’s shipyard, Elbing (East Prussia) which worked on this programme, had it ready for tests in 1942 and trialled connect with a single boiler, plus full-size mockups of turbine-boiler rooms were made for demonstrations. The Kriegsmarine’s staff however doubted the “Illies-Schichau” machinery would be ready before 1944 and so the Type 44 was designed with alternative powerplants in mind.

The hull was about the same as the Type 39, 103 meters (337 ft 11 in) long for 10.1 meters (33 ft 2 in) so a bit larger, and displacing 100 tonnes more at 1,418 long tons (1,441 t) standard, a protection including 12 watertight compartments, double bottom on 70%. Eventually two sets of Wagner geared steam turbines and four Wagner water-tube boilers were chosen, improved and producing 52,000 shaft horsepower (39,000 kW) versus 32,000 on the Type 39. This enabled the far more respectable top speed of 37 knots. This 300 metric tons of fuel oil aboard they also reached 4,500 nautical miles (8,300 km; 5,200 mi) at 19 knots, better than any destroyers of the time. The auxiliary intended electric machinery however only reached 25 knots but greatly increasing the range.

The planned main armament was essentually the same as the Type 39 but with KM44 dual-purpose guns in two twin-gun mounts instead of three singles. It was completed by an AA director on the bridge’s roof and a comfortable AA overall with no less than ten 3.7-centimeter in five twin mounts (with reserve to add Flakvierling or 20 mm quad mounts) and the same 533-mm banks amidships plus rails for 30 mines. This was quite an improvement over the Type 39, however at that stage, the nine Type 44s (T52–T60) ordered from Schichau on 28 March 1944 (yard n° 1720–1745 and 1447–1449) were scheduled for completion on 15 September 1946, but the fall of east Prussia to Soviet forces in January 1945 cancelled the facto these plans with little work done.

Characteristics: (As planned 1945)

Displacement: 1,418 long tons standard, 1,794 long tons FL
Dimensions: 103 x 10.1 x 3.7m (337 x 33 12 ft 2 in)
Propulsion: 2 shafts turbines, 4× WT boilers, 2 elec. mot. 52,000 shp (39,000 kW)
Speed: 37 knots (69 km/h; 43 mph)
Range: 4,500 nmi (8,300 km; 5,200 mi) at 19 kts
Crew: 222
Armament: 2×2 10.5 cm, 5×2 37mm, 2×3 533 mm TTs, 30 mines

Torpedoboot Ausland

Le Fier class plans
Le Fier class plans (later TA 1 class). Original, not German modified.
36 completed torpedo boats was not a lot to be sure, less than Italy, a droplet compared to the mass of escort destroyers built by US yards. But fortunately for the Kriegsmarine, the real estate area captured in 1940 provided a wealth of yards, and ships at anchor, under construction or completion which could be pressed into the Kriegsmarine. And in WW2 this force was nothing less than considerable, albeit very disparate to say the least: 49, so far more than “regular” torpedo boats, from which part were not even built in German Yards but in the Netherlands (12 in all):
They were not given the usual prefix “T-” but “TA-” for “Torpedoboot Ausland”, literrally “foreign torpedo boats”. The Kriegsmarine’s list went for TA-1 to TA-49, in order of capture. The paradox was that the first series were ex-French and Norwegian vessels never completed while the bulk of later series were ex-Italian vessels captured in late 1943.
Here is a review of these cases, class by class:

Kriegsmarine TA-1 class (French Le Fier, 1940)

The Le Fier class were sea-going torpedo boats laid down in 1940, they were incomplete at the fall of France. The shipyards were sized in June 1940, and Le Fier, L’Agile, L’Entreprenant, Le Farouche, L’Alsacien, and Le Corse were examined for completion to German standards. Le Breton was scrapped, seven others cancelled. The remaining ones were completed and modified with revised specifications by the Kriegsmarine as TA1-TA6. See the tables for the final specs.

Displacement was increased but dimensions were shrunk a bit (see the tables below), engines and propulsion remained the same, with full power reduced but they were rearmed with three 10.5 cm SK C/32 naval guns, two 3.7 cm SK C/30, nine 2 cm SK c/38 guns (Flakvierling + 5 single) and two triple 533 mm (21.0 in) G7 torpedo tubes. Work under German supervision was limited by material shortages and French sabotage and they never reached completion in 1945. By April 1943 already, efforts were concentrated to complete TA1 and TA4, using cannibalized parts. TA2 and TA4 were sunk by USAF aviation, refloated but work stopped after the Normandy landings. They were scuttled on 11 August 1944. For the anecdote the Spanish Audaz-class reused German plans and documents for these.

Characteristics: (As planned for 1944-45)

Displacement: 1,087 tons standard, 1,443 tons FL*
Dimensions: 93.2 x 9.28 x 3.08 m (305.8 x 30.4 ft x 10.1 ft)**
Propulsion: 2 shafts turbines, 4× WT boilers, 28,000 bhp (20,900 kW)***
Speed: 34 knots (estimated)
Crew: 119
Armament: 3x 10.5 cm, 2x 37mm, 9x 20mm, 2×3 533mm TTs****
*Original 859 long tons standard, 1,108 long tons FL
**Original 84.3 x 8.62 x 2.83 m (276 ft 7 in x 28 ft 3 in x 9 ft 3 in)
***Original 31,000 shp (23,000 kW)
****1× 10.5 cm (4.1 in), 1x 37mm, 2x 20mm, 2×3 500 mm (19.7 in) TTs, 60 mines

Kriegsmarine TA-7 class (Norwegian Sleipner, 1939)

HNoMS Sleipner
The Sleipner class were six Norwegian destroyers built from 1936, but not completed during the German invasion in 1940. Theu used aluminium bridges and superstructure, mast and funnel. Hull in extra strength special steel. Good main guns, AA artillery ASW weapons. Æger was bombed by German planes on 9 April 1940. Sleipner took refuge in UK, served with the Free Norwegian Navy. Gyller and Odin were captured by the Germans in 1940 at Kristiansand. Balder and Tor were captured uncomplete in the shipyard, complete by the Germans. They were used until 1945 as Torpedoboot Ausland as Löwe, Panther, Leopard, and Tiger. In 1945 Löwe escorted Wilhelm Gustloff whe she was was torpedoed, rescuing 472 passengers (worst sinking of all time).

Characteristics: (As built 1938)

Displacement: 735 tons long tons standard
Dimensions: 74.30 x 7.80 x 4.15 m (243.77 x 25.59 x 13.62 ft)
Propulsion: 2 shafts De Laval turbines, 4 WT boilers, 12,500 shp (9,300 kW)
Speed: 32 knots (59.26 km/h)
Crew: 75
Armament: 3× 10 cm, 1x 40mm Bofors, 2x 12.7mm AA, 1×2 533 mm TTs, 4 DCT

Kriegsmarine TA-9 class (Ex-French, La Melpomène)

La Melpomène class were 12 French torpedo boats (1933-1935) in service with the Marine Nationale, which after the armistice passed onto the Vichy French Navy (some Free French Navy, Royal Navy and Royal Netherlands Navy). After the scuttling of Toulon, the Regia Marina ceized most of them, to refloat.
a Melpomène was in a British port in June 1940. After brief service with the Royal Navy, she was transferred into FNFL (Free French) service. In 1950 was sold for scrap.
-La Pomone was seized by the Italians at Bizerte in November 1942: FR42, then German TA10 in May 1943. Duelled with HMS Eclipse near Rhodes, badly damaged, scuttled on 27 September 1943.
-L’Iphigénie Seized by the Italians at Bizerte, FR43, German TA11 (May 43), sunk by Italian MAS at Piombino, 10 September 1943.
-La Bayonnaise scuttled in Toulon, raised by the Italians as FR44. Seized by the Germans, TA13. Scuttled on 23 August 1944.
-Bombarde seized by the Italians at Bizerte, FR41 from September 1943 renamed TA9. Snk by aircraft off Toulon, 23 August 1944.
-Baliste scuttled in Toulon, raised by the Italians as FR45. German TA12, sunk by Allied aircraft on 22 August 1943.

Characteristics: (As built 1938)

Displacement: 610 tons standard, 834 tons full load
Dimensions: 81 x 10.5 x 2.65m (265 ft 9 in x 34 ft 5 in x 8 ft 8 in)
Propulsion: 2 shafts Geared turbines 4 boilers 33,000 shp (25,000 kW)
Speed: 34.5 knots (63.9 km/h; 39.7 mph)
Range: 1,200 nmi (2,200 km; 1,400 mi) at 19 kts
Crew: 8+94
Armament: 2× 10 cm, 2x 37mm, 2x 13.2mm, 3x 550 mm TTs

Kriegsmarine TA-14-49 class (Ex-Italian, various)

Solferino, of the Curtatone class in 1943, later TA 18 src

Curtatone class: TA16 class (ex-Castelfidardo), Achilles (ex-Calatafimi), TA15, TA19
TA16 had two twin 102/45 S-A M1919, four single Breda 20mm/65 M1939, 2×3 – 450mm TT, 16 mines. TA19: Twin 102mm/45 S-A M1919, One 102mm/45 S-A M1919, 5x 20mm/65 M1939, Twin 533mm TT, 16 mines captured in Aegean Sea in September, 1943. TA16 entered the Kriegsmarine on 14.11.1943, TA19 on 13.10.1943. By that time they reached 24kts and 600 at 12 nm.
By late 1943, triple 450mm TT; single 40mm/56 FlaK 28, Flakvierling C/38, single 20mm/65 M1939 or single 37/80 SK C/30. Both served in Aegean Sea. TA16 was damaged by British aircraft 31.5.1944, fore end was broken off, 2.6.1944 she was lost at Heraklion (Crete) as a result of explosion on s/s Gertrud, attacked by British bombers. TA19 was damaged by missiles from British aircraft 19.6.1944 and was under repair 1 month, 9.8.1944 she was sunk by a torpedo from Greek submarine Pipinos at Samos.
The full list (a dedicated article will be done on these ex-Italian Torpedoboote Ausland(i) for “Italien”).

TA14 (1927) 28.10.1943 in German service, sunk 15.09.1944
TA15 (1925), 30.10.1943, sunk 08.03.1944
TA16 (1922), 14.10.1943, sunk 02.06.1944
TA17 (1920), 28.10.1943, sunk 12.10.1944
TA18 (1920), 25.07.1944, sunk 19.10.1944
TA19 (1923), 19.09.1943, sunk 09.08.1944
TA20 (1915), 21.10.1943, sunk 01.11.1944
TA21 (1913), 08.11.1943, sunk 05.11.1944
TA22 (1915), 11.08.1944, blown up 03.05.1945
TA23 (1942) com. 17.10.1943, sunk 25.04.1944
TA24 (1943) com. 04.10.1943, sunk 18.03.1945
TA25 (1942) 16.01.1944, sunk 06.07.1944
TA26 (1943) com. 18.12.1943, sunk 15.07.1944
TA27 (1943) com. 28.12.1943, sunk 09.06.1944
TA28 (1943) com. 23.01.1944 sunk 04.09.1944
TA29 (1943) com. 06.03.1944, sunk 18.03.1945
TA30 (1943) com. 15.04.1944, sunk 15.06.1944
TA31 (1930) 17.06.1944 sunk 24.04.1945
TA32 (1931) 18.08.1944, destroyed 24.04.1945
TA33 (1942) destroyed 04.09.1944
TA34 (1916) 17.06.1944, sunk 24.06.1944
TA35 (1915) 09.06.1944, sunk 17.08.1944
TA36 (1943) sunk 18.03.1944
TA37 (1943) sunk 07.10.1944
TA38 (1943) scuttled 13.10.1944
TA39 (1943) sunk 16.10.1944
TA40 (1943) destroyed 04.05.1945
TA41 (1944) com. 07.09.1944, sunk 17.02.1945
TA42 (1944) com. 27.09.1944, sunk 21.03.1945
TA43 (1937) 22.02.1945, scuttled 01.05.1945
TA44 (1929) 14.10.1944, sunk 17.02.1945
TA45 (1944) comm. 08.09.1944, sunk 13.04.1945
TA46 (1944) comm. 20.02.1945
TA47 (1942) scrapped 1971
TA48 (1914) 16.10.1943 sunk 20.02.1945
TA49 (1937) comm. 01.01.1938, sunk 04.11.1944

Sendai class Cruisers (1923)

Sendai class Cruisers (1923)

Japanese Navy Imperial Japanese Navy, 1923-44.
IJN Sendai, Jintsū, Naka (+Kako, Ayase, Minase, Otonase, unnamed- cancelled)

The “four pipers” light cruisers

The cruisers of the Sendai class were very close in their general design compared to the previous Nagara, but with larger dimensions, new machinery for greater speed traduced in a new funnel. The fourth of the class, 1st batch, IJN Kako, was broken up soon after launch, as the following 2nd batch because of the Washington Treaty limitations, just signed.
The three cruisers received a catapult for reconnaissance in 1929, and by 1943, a powerful AA. All were sunk in action, Naka in February 1944 during the air raid on Truk, Sendai by aviation after the Battle of the Bay of Empress Augusta, and Jintsu by gunfire at the battle of Kolombangara.

Design Development

Their origin was the same as previous Kuma and Nagara class: The very ambitious 1920 naval 8-8 fleet programme. They were to lead destroyer flotillas and perform reconnaissance missions for the fleet. Incremental steps from the Kuma class, started in 1918, led to this design, somewhat outdated in 1926 when the last was completed. Essentially a development of the preceding Nagara they had their boilers relocated, and four funnels instead of three due to this. Mirroring what was tested in the Royal Navy at the time, they also inaugurated a flying-off platform and hangar in front of their bridges, before a more conventional floatplane and catapul were fitted from 1929.

ONI depiction of the class

In fact, eight additional 5,500-ton cruisers of the same, or derived class were planned under the “Eight-eight” fleet Program (eight battleships & eight battlecruisers). Four Sendai were authorised in 1921 and laid down, but the last one, IJN Kako was scrapped on slipway as the regulations of the 1922 Washington Naval Treaty obliged. She just had been laid down at Sasebo Naval Arsenal on 15 February 1922 and thus, when the provisions were signed on 17 March 1922, little work has been done, easing its scrapping. Budget and part of the steel were reused for the new Furutaka class.
Another batch of four units were authorised to be built to the same design in 1922, also cancelled after the signing of the Treaty, whereas the naval staff decided to focus on the more promising concept of heavy cruisers defined at the same time. The Furutaka and Kako took the place of this second batch essentially.

“Flared bow, small mount on the bridge marked as “orange c” on Sendai but we notice that it doesnt have windows, we notice that her first funnel is taller than the rest, we see that her forward torpedo tubes between funnel 1 and 2 have been removed and plated over, we notice that her bridge face isnt completely square and flat and we notice that the pole sticking out of her rear mast is not completely solid. We now know that we are looking at Naka.”

Design of the Sendai class

Hull and general design

The Sendai class were generally similar to previous cruisers, although slightly longer: Overall, they reached 152.4 meters (500 feets) between perpendiculars (pp), 158.5 meters (520 ft) at the waterline (wl) and 163 meters (537 ft) overall (oa) compared to 162.1 m (531 ft 10 in) o/a for the Kuma and Nagara. The biggest change was in the bow: IJN Sendai had the traditional “iceabreaker” bow, rounded, while her sisters Jintsu and Naka had the new flared bow, although the former only received it in 1932 after repairs.
They were 14.2m in beam (46 ft 7 in), same as previous cruisers, and had a similar draught of 4.8-4.9 meters (15 ft 9 in – 16 ft).

The general silhouette was very similar, with the two back-to-back forward main guns and bridge and tripod mast, albeit they diverged in the bridge’s shape among builders. Some details are identical between Sendai and Naka, like the position of the secondary fire control telemeters, mounted lower on Jintsu, but with a slightly larger platform on Naka. Sendai had a slightly bigger gap between the bridge tower and mast, thah her sisters, which bridge towers extend out towards the mast. Jintsu windows were a bit less extensive and the forward section of the bridge was divided a bit differently than her sisters, much more flatter. whereas her sisters had a slight indent about halfway up the face. The upper deck is slightly longer and position of the the searchlight on Sendai, and another boxy structure larger on Jintsu which also had a straight mast top. All three had their main telemeter and fire control tower mounted on top of the tower.
The tripod mast supported four platforms at different levels, including two supporting projectors, and two for spotting, one semi-open and another generously glassed, both with many pintl-mounted optics.

All three had the same three funnels in the amidship section, the one better protected, but a fourth one aft of the tripod, taller than the others due to the boilers repartition. This was the easiest recoignition point by far. Funnel-wise by the way, this fourth funnel was at the same height as the others on Sendai at first. Close to this area, Sendai was the only one keeping her forward twin torpedo tubes (so she had two quadruple aft, two twin forward for 12 total) and didnt have them plated over unlike her sisters.

For the aft torpedo tubes banks there were also a few differences: On Sendai again, she had a “slot” for the torpedo tube slimmer, with more rounded edges unlike her sisters. All three had the same tripod masts, however Sendai again was the only one with a “solid” boom, the other two having lighter lattice booms. The tripod supported an utility platform, upper mast for wireless rigging (which also plan differed between ships) and a forward-mounted projector platform.

It’s in wartime that this section differed most: On Sendai, the N°5 gun (first aft, forward of the tripod) was removed entirely and likely not replaced. It was swapped for a tewin dual purpose AA mount on Naka. On Jintsu, this position was replaced by the radio room and its antenna, which was different on both her sisters and closer to the aft funnel.
By the way all three had the torpedo tubes telemeter mounted between funnel 3 and 4.
The aft section was very much a repeat of previous designs. All main guns were mounted on the upper deck.

Armour protection layout

Like all previous cruisers, it was weak. They were intended to lead destroyers and deal with other destroyer’s or light cruiser’s rounds, betting on speed. Thus, only two parts were armored:
-Their main armoured deck above the waterline, which was 2.9 cm (1.1 in) in thickness all along the hull. This flat deck was connected to the upper edge of the belt.
-Their main belt protected by 6.4 cm (2.5 in) thick plating. The main belt was short, only protecting the machinery, 7.32m high () total with its upper part (76.9m long x 3m high) being only 51mm thick (2 in) and its lower part (72m long x 4.32m high) 63 cm thick.
Against their own caliber this was woefully unsufficient. The 2/3 of the hull forward and aft were completely unarmoured.
-The Conning Tower bleing into the bridge had 51 mm sides and a 25 mm roof.
Some structural parts were built with thicker steel, like the bridge’s integrated conning tower, but the rest was standard sheet thin.
The gun shields were probably only 0.8 in thick to protect against shrapnels.
For ASW protection, the machinery below the waterline was highly subdivided, with longitudinal and transverse bulkheads. The four turbine rooms and all four boilers rooms (three in each) were also separated.


These cruisers were fitted by four sets of geared steam turbines (Brown-Curtiss in Jintsū, Mitsubishi-Parsons-Gihon in Sendai and Naka. These were a new generation of turbines, promising better performances. They were coupled with twelve Kampon boilers, eight oil-fed and four coal-fed. In contrast to the older Kuma and their four Curtis-Parsons axial deceleration turbines mated with 12 mixed boilers and 90,000 hp (67,000 kW), the Nagara had the same, but ten boilers burning heavy oil, with two remaining burning coal.

They still reached 36 knots, while the Sendai were intended to do the same. After 1934, with expected weight additions, they were refitted with ten brand new oil-fired Kampon boilers after 1934. They still obtained the same output of 90,000 shp (67,000 kW). This was coupled with electrical generators fed by diesels, for a total of 154 kW rated at 110V for all onboard systems.
In the end, their average speed was a bit lower at 35.25 kn (65.28 km/h; 40.56 mph) sustained in normal load, for a no stellar range of 5,000 nmi (9,300 km; 5,800 mi) at 14 knots (26 km/h; 16 mph), about the same as the Nagara class.



Each of the three cruisers counted seven 140 mm (5.5 in)/50 guns:
The 14 cm/50 3rd Year Type naval gun was an old, dependable secondary battery on Japanese battleships, a low-angle weapon introduced during World War I. It had a welin breech bloc, used separate-loading, with bagged charge, firing 38 kgs. (84 lb), 14 centimeters (5.5 in) shells up to +35° on the cruiser’s mounts. They left the barrel at Muzzle velocity 850–855 meters per second (2,790–2,810 ft/s). These guns would fire at 6 rounds per minute and max 19,750 meters (21,600 yd) at +35°. The seven guns were located at the same place as for the Nagara class: Two back to back in front on the bridge, forecastle, two wing cannons abaft the bridge, and three axial aft. One was sacrified later to be replaced by a dual purpose 5-in gun.


Two 8 cm/40 3rd Year Type naval anti-aircraft guns. The 8 cm/40 3rd Year Type naval gun entered service in 1897 and was a typical prewar heavy AA gun first designed in 1893. Although 8 cm/40 it was assimilated in the literrature as a 3 inches, it’s real caliber. Sub-variants included the 40 caliber Type 88 and 25 caliber Type 41. It weighted 2,401 kg (5,293 lb) for a barrel length of 3.2 m (10 ft 6 in) and fired a fixed 76.2 x 405R shell (5.7–6 kg) with extact caliber 76.2 mm (3 in). It used a sliding block breech and Hydro-pneumatic recoil and coukd elevate to +75°, firing at 13–20 rounds per minute and 670–685 m/s (2,200–2,250 ft/s) muzzle velocity. Its effective range was 5.4 km (18,000 ft) in ceiling but against sea targets, up to 10,800 m (11,800 yd) at +45°.
Needless to say it was completely obsolete in the 1930s and replaced.


Torpedo Tubes

The real strenght of these cruisers, like those that preceded them, as their superb torpedo battery. It consisted of eight 610 mm (24 in) torpedo tubes managed in four twin banks, installed, along the central section of the hull, on both sides, close to the waterline. The first pair was no longer on open air, in a recess aft of the bridge, but like the second pair they were located in enclosed recesses under the deck, and closer together compared to the Nagara class.
They packed quite a punch, carrying the legendary Type 96 Torpedo, better known as “long lance”. The repartition changed over time: At first, they had four twin banks, but from 1941, the forward banks were removed and the aft ones were swapped for quad banks instead. As a remainder, these “secret weapons” of the IJN carried a 500 Kgs. (1080 Ibs) warhread at 22,000 m (24,000 yd) and 50 kn or double, 40,400 m at 35 kn, well beyond the range of existing torpedoes at the time. Early engagements proved their value, especially by night in the confines of the Solomons.


They had 56 naval mines, spread on two rails mounted along the deck and dropped by stern chutes. Likely Type 93 with Hertz horns. src

Anti-Aircraft artillery

Originally the two 8 cm/40 3rd Year type guns seen above, which were replaced by twin Type 96 25 mm (0.98 in) AA guns instead as the war was close in 1941. Also two single 13.2 mm Type 93 Heavy Machine Guns Other additions of twin and triple mounts, were made during the war. If they had survived past 1944, single ones would have been added in droves.

The most single important change was the removal and replacement of their number five gun (first axial aft) by a 5-in (127mm)/40 Type 89 twin mount. It was done on Naka, but uncertain for Sendai, although her Number 5 main gun was also removed. Like replaced by two triple 25 mm Type 96 AA mounts.

Construction and Modifications

IJN Sendai was ordered at Mitsubishi Nagasaki Shipyard, started on 16 February 1922, launched on 30 October 1923 and completed on 29 April 1924 on 2 November 1943 (19 years career)
IJN Jintsū was ordered from Kōbe-Kawasaki Shipbuilding Yard in 1922, laid down on 4 August 1922 (the last ordered) and by 8 December 1923 launched, then completed on 31 July 1925, Sunk at Kolombangara in July 1943, the first of the class to go.

IJN Naka was ordered to Yokohama Dock Company, laid down on 10 June 1922, but delayed: Her Hull was completely destroyed after the great Kanto earthquake. What was left was scrapped and she was Laid down again on 24 May 1924 and then only launched on 24 March 1925, completed on 30 November 1925. She was the last Sunken during Operation Hailstone in February 1944. None survived to mid-1944.
IJN Kako was the last of the first batch. She was laid down at Sasebo Naval Arsenal on 15 February 1922, so actually the earliest of the group (the class could have been named Kako), but construction was discontinued by Washington Naval Treaty negociations, as calculations showed she was already over tonnage. Construction was suspended a mere weeks after work started. On 17 March 1922 it was agreed she would be scrapped but budget reallocation for the next Furutaka-class, and its sister ship also named Kako.

The next batch of four was to comprised Ayase (綾瀬), which after Cancellation was and re-planned as IJN Furutaka in March 1922, but also Minase (水無瀬), Otonase (音無瀬) and a fourth unnamed cruiser at the time, all cancelled in 1922, with initial plans to lay them down in 1923. There were the last light cruisers before the Agano class.


Apart differences in the location of their flying-off platform, their bridge was also modified, and other aspects making them all different in the end.
Originally, only Naka and Jintsu were completed with a small flight deck built above their forward guns. It extended from their bridge towers doubling as hangars, just like on some British cruisers C-D designs tested in 1918-1921. In both cases there were simple platforms supported by a pillar between the two gun, for a braked launched, which was done for a wheeled model, in a one-ticket mode. However they proved unpracticable over time and were removed by 1935, Naka having a simpler structure supporting a triple 25 mm AA in wartime.

The 1930s refits:
In 1933 – 1935, Naka, Sendai had their two old 8cm DP guns and two single 6.5mm/115 machine guns removed. They were replaced by a quad 13.2mm/76 HMG mount and tw single ones, and two single 7.7mm/80 light AA mahine guns, and a catapult between No 6 & 7 guns. Also importantly, their boilers were all converted to oil burning with a fuel stowage ported to 1600t of oil. In 1934 Jintsu went through the same process, but her catapult was moved between No 6 & 7 guns. Her AA was the same, as her boilers were also modified.
Until 1939 all saw solid and liquid ballasts added for better underwater protection. Full displacement rose to 8,000t, speed fell to 32 knots but they also gains two single extra 13.2mm/76 HMG and two twin 25mm/60 Type AA guns mounts. Before the war in 1942 their torpedo tubes were augmented, at last on Naka and Jintsu which had their forward twin tubes banks eliminated and the hull plated over for better seakeeping, but keeping their aft banks, now upgraded to quadruple ones for the same “long lance”. Eight tubes, but the same number or reloads (so 16 torpedoes in all).

Wartime Modifications:
-IJN Naka by the Spring of 1941 had two twin Type 96 25 mm (0.98 in) anti-aircraft autocannons instead of her old 8cm dual purpose guns, but also two single 13.2 mm (0.52 in) Type ??? anti-aircraft heavy machine guns (2×1). She retained her 610 mm (24 in) torpedo tubes but depth charges racks were added at her stern for ASW patrols.
-All received also two single extra 7.7mm/80 LMGs.
-By January 1943, Jintsu kept her quadruple 13.2mm/76 and had in addition two triple 25mm/60 Type 96 and a single twon 13.2mm/76 Type 93.
-By March 1943 IJN Naka had one 140 mm (5.5 in) gun removed to make room for a twin 127 mm (5 in)/40 dual purpose gun as seen above, and ten 25 mm (0.98 in) with two triple and two twin mounts, keeping her single 13.2 mm HMGs and aft torpedo Tubes.
-By June 1943, IJN Sendai had her number 5 140mm/50 removed and not replaced but two triple 25mm/60 Type 96 AA mounts added plus two Depht Charge Racks at the bow (minelaying capability lost) with 36 depht-charges in reserve.

In April 1943, Naka received a 1-shiki 2-go radar, and Sendai could had her fitted by June 1943. It was also called the Type 2 Mark 2, Model 1 Air Search Radar, 1st generation, which detection range and precision left much to be desired.

Onboard Aviation

E7K2 model 2 on IJN Sendai, 19 December 1941, invasion of Malaya. That day she detected and reported the Dutch submarine O-20, later sunk by destroyers.
Aircraft carried: They tested a wheeled fighter (Mitsubishi 1MF) on a flying-off platform for a time. Tests performed in the early 1920s were not that conclusive due to the poor range of the model. It was recoignised in 1928 that only floatplanes, reusable, were a satisfactory solution, combined with a catapult. So from 1933 an axial catapult was fitted on all three ships. They carried apparently the same floatplane for their whole carrer, the Kawanishi E7K floatplane was used. However during the China compaign, IJN Sendai carried a Nakajima E8N, which was more agile and managed to shoot down Chinese boombers.

Author’s illustrations

Sendai class HD

⚙ IJN Sendai specifications 1925

Displacement 5,200 t. standard 7,100 t. Fully Loaded
Dimensions 163 x 14,17 x 5m (532 x 46 ft 6 in x 15 ft 9 in or 29 ft FL)
Propulsion 2 shafts, 4 Gihon turbines, 12 Kampon boilers, 90,000 hp, 154kW 110V electrical
Speed 35,2 knots (65.28 km/h; 40.56 mph)
Range 5,000 nmi (9,300 km; 5,800 mi)/14 knots (oil 1010 tons, coal 570 tons)
Armament 7x 140mm/50, 2x 76mm, 2x 13.2mm AA, 4×2 610 mm TTs, 1 seaplane, 80 mines
Protection Armor scheme – 28 to 65 mm, see notes
Crew 450 (1925)

Read More


Conway’s all the world’s fighting ships 1906-1921
Lacroix, Eric & Wells II, Linton (1997). Japanese Cruisers of the Pacific War. Annapolis, Maryland: Naval Institute Press.
Model Art Ship Modelling Special No.29, 5,500 tons class cruisers, Model Art Co. Ltd. (Japan), September 2008
“Rekishi Gunzō”., History of Pacific War Vol.32 Light cruiser Kuma/Nagara/Sendai classes, Gakken (Japan), August 2001
Daiji Katagiri, Ship Name Chronicles of the Imperial Japanese Navy Combined Fleet, Kōjinsha (Japan), June 1988
The Maru Special, Japanese Naval Vessels No.27 Sendai class cruisers, Ushio Shobō (Japan), May 1979
Brown, David (1990). Warship Losses of World War Two. Naval Institute Press.
D’Albas, Andrieu (1965). Death of a Navy: Japanese Naval Action in World War II. Devin-Adair Pub.
Dull, Paul S. (1978). A Battle History of the Imperial Japanese Navy, 1941-1945. NIS
Evans, David (1979). Kaigun : Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941. Naval Institute Press.
Howarth, Stephen (1983). The Fighting Ships of the Rising Sun: The drama of the Imperial Japanese Navy, 1895-1945. Atheneum.
Jentsura, Hansgeorg (1976). Warships of the Imperial Japanese Navy, 1869-1945. NIS
Whitley, M.J. (1995). Cruisers of World War Two: An International Encyclopedia. NIS


On navypedia.org/
The Sendai class on combinedfleet.com
Sendai TROM on combinedfleet.com
Jintsu TROM – combinedfleet.com/
Naka TROM – combinedfleet.com
ww2db.com naka
ww2db.com jintsu

Model Kits

3D reconstruction by the Warthunder Team
On artstation

IJN ww2 IJN Sendai (川内)

Prewar service

IJN Sendai was completed at the Mitsubishi Nagasaki shipyards, on 29 April 1924. Her first Captain (later Vice Admiral) was Kiyohiro Ijichi, formerly on IJN SUNOSAKI, replaced on 2 July 1925 by an unknown officer and by 1 November 1926 Captain Sagara Tatsuo, on 21 December 1927 Captain Ban Jiro and by 10 December 1928 Captain Wada Senzo, 1st May 1929 Nohara Nobuharu, 1st December 1930 Kishimoto Kaneji and by 1 December 1932 Takasaki Takeo. All this time she trained hard in home waters, and took part quite rapidly made her initial shakedown cruise in the China sea and assigned to Yangtze River patrol in China. In 1933 the “Tomozuru incident” led to some drastic strenghtening of many IJN ships, but the Sendai class is spared this for the moment.

On 4 July 1934 Captain Yoshida Tsunemitsu was appointed and she took part in large scale fleet manoeuvers on 26 September 1935 with the 4th Fleet. This led to a famous incident as she is baldy damaged by a typhoon as the rest of the fleet. Later, she not underwent repairs, but stiffering measures, adjunction of ballasts and change of boilers, as well as modernization of the AA. On 15 November 1935 she is at sea again, fully recommissioned under command of Captain Nakajima Torahiko (formerely on IJN IWATE), replaced in December 1936 Yamamoto Masao.

War with China

She played an important role outright in the Battle of Shanghai and took part in the Second Sino-Japanese War from 1937, covering landings of Japanese troops in southern China:
On 14 August 1937 “Bloody Saturday” commenced in Shanghai when Flagship USS AUGUSTA (CA-31) with CINC Asiatic Fleet Admiral Harry E. Yarnell arrives from Tsingtao after battling a typhoon, dropping anchor in Whangpoa River when the the Chinese Air Force under Claire L. Chennault looking to attack IJN flagship’s IZUMO bombed instead HMS CUMBERLAND, fortunately without damage, whereas two bombs near-misses USS AUGUSTA. Meanwhile a Type 95 floatplane (E8N) attacks CAF formations, shooting down a bomber while a Type 90 (E4N) from IZUMO shoots down a fighter. On 1st December 1937 Captain Kimura Susumu is appointed and replaced on 15 December 1938 by Izaki Shunji while the ship stayed in action all this time, with a resupply run to Japan in between.
On 15 July 1940 with her new Captain Shimazaki Toshio she is back in action in China. Back home from 20 November 1941 she is prepared for the newt operation plannes in the Pacific and becomes Flagship of Rear Admiral Shintaro Hashimoto at the head of the third destroyer squadron (DesRon 3). He leaves Hashirajima with DesDivs 11, 12, 19 and 20 as part of the unit.
On 26 November 1941 he Arrives at Samah, off Hainan Island in Occupied China, taking position for future operations.

Japanese Invasion of Malaya

On 4 December 1941 the formation led by Sendai left Samah with DesDivs 12, 19 and 20 to escort 18 troopships and Lt.Gen. Tomoyuki Yamashita (future “Tiger of Malaya”) at the head of the 25th Army, to the Gulf of Thailand. As Pearl Harbor took place, IJN Sendai arrived on destination at Kota Bharu by 23:45 on 7 December, and with the destroyer squadron (Ayanami, Isonami, Shikinami, and Uranami) started to bombard the city’s defences. Seven RAAF Hudson bombers raided the formation but only managed to sink a transports, damaging two.

On 9 December 1941, I-65 reported sighting Force Z with Prince of Wales and Repulse underway from Singapore. It is received by Sendai then relayed to Vice Admiral Jisaburō Ozawa aboard IJN Chōkai. Reception is poor however, the message took 90 minutes to decode and so when received, the heading of Force Z is now obsolete. Nevertheless, Force Z is spotted again the next day and soon overwhelmed by a torpedo bomber attack of the 22nd Air Flotilla.

On 19 December 1941, still off Kota Bahru the Ducth submarine HNLMS O 20 sights Sendai, DesRon3 escorting a second Convoy of 39 transports and at 11:15, the cruiser launched her Kawanishi E7K2, which spots and bombs O 20, which dives. Duly reported, she is soon caught by her escorts, the destroyers IJN Ayanami and Yūgiri, making several passes of depth charges. While she is just surfaced to recharge her batteries a single exhaust flame from her exhaust is spotted by IJN Uranami still on patrol, that immediately rushed forward for the kill. There was also an attack by nine Lockheed Hudsons of No. 1 and No. 8 Squadrons, and 12 Vickers Vildebeests, which was repelled with heavy losses.

Battle of Endau

IJN Sendai made three more reinforcement troop convoy runs to Malaya, the fourth on 10 January 1942. During this one, she is spotted by the Sargo-class USS Seadragon spotted the convoy and fired two torpedoes at the last transport but missed.

The fifth run on 26 January saw Sendai attacked by ABDA destroyers HMS Thanet and HMAS Vampire, some 80 nmi (148 km) north of Singapore: This was the Battle off Endau. Lt.Cdr B. S. Davies’ on the WW1-vintage HMS THANET (one of the few surviving S-class destroyers from 1917-18) and Lt.Cdr W. T. A. Moran onboard HMAS VAMPIRE (equally old V-class from 1917) are dispatched to make a night attack on the Japanese troop tansports, expecting to meet them off Endau, 80 miles North of Singapore. At 02:37, while approaching Endau, they soon spot and engage a warship they take to be a destroyer, but proved to be the minesweeper W-1. Two torpedoes are launched by Vampire but missed. Curcially, the minesweeper raises the alarm and the entire squadron is on edge. The decided to continue towards Endau at 03:18, HMS VAMPIRE sights IJN SHIRAYUKI to port. She launches two torpedoes but missed, followed by THANET (all four, they had twin banks only) and also misses. This was brave to the extreme, but payback was quick: While the Allied destroyers open fire with their 4-inch guns, IJN SENDAI and SHIRAYUKI returned a blistering fire, and the two destroyer, completely outmatched, soon broke off and retired to the South-East at maximum speed.

HMAS Vampire in the interwar.

However they had now the Japanese on their tail and at about 04:00, HMS THANET is hit by 140 mm rounds in the engine rooms, whuich shuts down. Loosing speed, she is caught and soon more shells caused and explosion, possible a hit inside one ammunition locker, which wrecks the old destroyer, dead in the water she started to list heavily to starboard and sink. VAMPIRE meanwhile tried to lay a protective smoke screen, but its too late for THANET which burns furiously and is soon caught by FUBUKI, HATSUYUKI, ASAGIRI, AMAGIRI, YUGIRI plus W-1, all guns blazing. She is rduced to a wreck in less than 10 min. and sunk for good as 04:15, leaving survivors. The Japanese having no time to pick them up but SHIRAYUKI which picks up 31, later duly interrogated and executed as reprisals. The rest returned to the convoy at full speed, while VAMPIRE, unscathed and without casualties makes it for Singapore. Their only success was some damage on KANSAI MARU and KANBERA MARU.

In February-March, IJN Sendai cover the Japanese landings in Sumatra. She also patrolled the waters and sea lanes in the Strait of Malacca in search of escaping vessels from Singapore. By the end of the month, she covered the landing of single battalion of the IJA’s 18th Infantry Division, at Port Blair in the Andaman Islands. By late April she was back to Sasebo for well needed upkeep, maintenance and repairs.

Battle of Midway: On 29 May 1942, IJN Sendai departed to join the Combined Fleet, gathered for Operation Mi (for Midway). As part as of this force she stayed 600 nmi behind Vice Admiral Chuichi Nagumo’s First Carrier Striking Force. She did not engaged and was back to Kure on 14 June 1942 for a short resplenishment stop at Sasebo on 27 June. On the 30th she was tasked to escort a troop convoy from Kure and by July 1942 she was operating in the Ryukyus, notably for antisubmarine patrols. On the 15th, she joined “BT” Sakusen, the Raids in the Indian Ocean as part of the Southwest Force, departing Amami-O-Shima. After a stop at Mako in the Pescadores, Takao, Singapore (23-28th) she arrives at Sabang on the 29th.

Solomons campaigns

On 15 July 1942, DesRon 3 was ordered to join the “Southwest Force” operating in Burma and the fleet gathered for the Indian Ocean raid. She was at Port Blair with seven DesRon 3 destroyers when ordered westof the Andamans. Arriving at Mergui, Burma on 31 July fter the US landings at Guadalcanal, she is ordered back to Makassar and joined Truk instead via Davao, escorting reinforcement troop convoys to Rabaul but also to the island of Shortland in Bougainville.
On 8 September, she bombarded US occupied Tulagi. On 12 September with Shikinami, Fubuki and Suzukaze bombarded she shelled Henderson Field, “Bloody Ridge” together with SHIKINAMI, FUBUKI and SUZUKAZE and returned to Shortland. On the 18th, she departed with four destroyers to spot and intercept a USN reinforcement convoy to Guadalcanal, but failed and instead shelled Marine positions at Lunga Point before heading back to Shortland. No other sortie is planned before October.

On 14 October at 22:00, she escorts the seaplane tender NISSHIN, escorted also by the light cruiser YURA and the destroyers ASAGUMO, AKATSUKI, IKAZUCHI and SHIRAYUKI. Together, they formed one of the earliest “tokyo express”, landing 1,100 troops on Cape Esperance, Guadalcanal. On 3 November, she is again out of Shortland, only with DesDiv 11’s (HATSUYUKI and SHIRAYUKI). On the 6th they arrived in Truk.

1st and second Battles of Guadalcanal

Three days after, she departed with DesDiv, DesDiv 19 (AYANAMI, SHIKINAMI and URANAMI) to escort IJN JUNYO and BatDiv 3 (IJN KONGO and HARUNA), CruDiv 8 (IJN TONE). She is tasked to provide distant support from Ontong Java to VADM Abe Hiroaki’s Bombardment Force deployed against Henderson Field.

In the first Naval Battle of Guadalcanal she remained as distant cover and does not see action.
On 14 November 1942 however with DesRon 3, DesDiv 19 as a sweeping Unit she is still holding station as distant cover but the folloing day at the “Iron Bottom Sound” off Savo RADM Willis A. Lee and his TF 64 Tare spotted near Guadalcanal on a northerly course in column, USS WALKE in the lead, then BENHAM, PRESTON and GWIN. The flagship is USS WASHINGTON (Capt. Glenn B. Davis) followed by USS South Dakota (Captain Thomas L. Gatch), some 5,000 yards behind.

At 00:01 USS WASHINGTON’s radar spot the Japanese some 18,000 yards away east of Savo Island and 16 min. latter she opens fire on IJN SENDAI with her main battery, but the latter is straddled, layes smoke and is able to retire undamaged. Meanwhile IJN NAGARA and destroyers launches their “Long Lance” torpedoes, missing the battleships but hitting PRESTON, WALKE while BENHAM would be later scuttled. WASHINGTON and KIRISHIMA later duelled, the latter would be soon crippled. SOUTH DAKOTA and WASHINGTON also hit AYANAMI. On 18 November 1942 SENDAI was back to Truk.

On 25 February 1943, is reassigned to the Eighth Fleet, Rabaul (VADM Mikawa) patrolling around until April. On the 21 of April she arrives at Kavieng and takes in two the damaged heavy cruiser IJN AOBA, departing with the destroyers HATSUZUKI and NAGATSUKI for Truk and arrived in Sasebo by 4 May.
This May, she is refitted in Sasebo and modified. On 20 May she had a new captain, Shoji Kiichiro. On 28 June 1943 she stopps in Yokosuka to load troops, departing on the 30th, and on 5 July arrives at Truk on her way back to Rabaul. RADM Baron Matsuji Ijuin takes command of DesRon 3 (flagship sendai) on the 7th, and for three months Sendai conitued escorting convoys and patrolling, while troopships are sent to Buin and Shortland.

On 18 July 1943 DesRon 3 is attacked off Kolombangara by USMC Grumman TBF Avenger based at Henderson field. KUMANO and CHOKAI had their aft hull plates damaged by near-misses. Soon after on 20 July while underway back in Rabaul, she is attacked by a raid of North American B-25 Mitchell medium bombers. The transport group is lost two transports and DesDiv 27’s YUGURE and DesDiv 31’s KIYONAMI, sunk with all hands. But sendai remained unscaved.

On 1st November 1943 is launched Operation “SHOESTRING II”, the Invasion of Bougainville and RADM Theodore S. Wilkinson Third Amphibious Force (TF 31) lands Gen. Vandegrift’s 1st Marine Amphibious Corps at Cape Torokina in Empress Augusta Bay (Bougainville), closing the Solomons. DesRon 3 is thus assigned to RADM Omori Sentaro combined fleet with CruDiv 5 (HAGURO, MYOKO) and RADM Matsubara Hiroshi DesRon 2 (AGANO, leading the destroyers NAGANAMI, WAKATSUKI and HATSUKAZE). She also escaped damage after a raid of Consolidated B-24 Liberators this day.


Battle of Empress Augusta Bay

The next day, on 3 November the Battle of Empress Augusta Bay, a Japanese reinforcement force is planned for Bougainville. This force is commanded by Vice Admiral Omori, departing Rabaul with 1,000 IJA troops.

The force comprises CruDiv 5 (same) RADM Ijuin’s DesRon 3 (SENDAI, destroyers SHIGURE, SAMIDARE and SHIRATSUYU), RADM Osugi DesRon 10 (same as before) and the destroyer-transports IJN AMAGIRI, YUNAGI, UZUKI and FUZUKI. At 00:26, HAGURO launches a Mitsubishi F1M “Pete” and at 00:31 they are spotted by radar by Aaron S. Merrill’s TF 39. hey spotted first CruDiv 12 from USS CLEVELAND, which is followed by USS COLUMBIA, MONTPELIER, DENVER and the destroyers USS STANLY, CHARLES F. AUSBURNE, CLAXTON, DYSON, CONVERSE, FOOTE, SPENCE, THATCHER.

At 00:40 HAGURO’s floatplane spots them 20 mile South of their position, and the vanguard of Captain Arleight Burke with four destroyers is the first on site, launching some twenty five Mark-15 steam torpedoes. 00:45 IJN SHIGURE spot them in turn at 7,500 yards, turns hard starboard, launches eight torpedoes. SENDAI did the same but went too close to SHIGURE which barely avoids collision while SAMIDARE collided (scrapping her hull port) with SHIRATSUYU.

At 00:50 Merrill’s cruisers spots SENDAI by radar and srarts firing with an overwhelming number of 6-in guns. They hit her with a first salvo. Meanwhile, IJN MYOKO collides with HATSUKAZE, the latter loosing her bow while USS FOOTE is badly hit by a torpedo. MYOKO and HAGURO comes in turn under heavy fire, launched 24 torpedoes but missed. Damage would be minor however as they retired.
At 01:34 Omori orders full withdrawl indeed and requested a submarine for survivors while frantic efforts to save SENDAI, dead in the water, are abandoned half an hour later. 236 would be rescued rescued by destroyers. HATSUKAZE, also dead in the water, would be finished off by Burke.
SENDAI only sank at 04:30, with Captain Shoji and 184 crewmen, the latter being posthumously promoted read admiral. She was removed from the lists on 5 January 1944.

IJN ww2 IJN Jintsū (神通)

IJN Jintsu

IJN cruiser Jintsu on trial run in 1939

Prewar Service

Jintsū was laid down on 4 August 1922, launched on 8 December 1923, completed at Kawasaki Shipyards (Kobe) on 21 July 1925. From 2 February 1925 her first Captain was Fukushima Kanzo and from 31 July she was attached to Kure Naval District. From December 1925 Captain Yamauchi Toyonaka takes command and on 1st November 1926 Mizushiro Keiji.
During night training exercise off Jizosaki Lighthouse (Shimane Prefecture) on 24 August 1927, she collided, with rammed and sank the destroyer IJN Warabi (taking with her 92 sailors). As for the cruiser, her bow has been completely crushed down to the first bulkhead and she had to be towed by IJN Kongo. Repaired in Maizuru Naval Arsenal she received a new flared bow. Captain Keiji Mizushiro was blamed and later committed suicide during court proceedings. Afterwards, Jintsū ended her repairs in Kure by 5 September.

IJN cruiser Jintsu damaged in 1927
IJN cruiser Jintsu damaged in 1927

Out of repairs she is placed under command of Captain Mitsuya Shiro by November and from 10 December 1928 he is replaced by Machida Shinichiro. Following the Jihan incident, she covered landings in Shandong of Japanese troops and was based in Tsingtao. From 1929 she was assigned to patrols off the coast of China, also providing convoy escort, cover and landing support, now from 30 November under command of Captain Toyama Hikoji and from 1st December 1930 by Izawa Haruma. From October 1931 back home in Kure a Type No. 2 Model 2 catapult is installed aft (formerly on KINU), together with an Aichi E3A1 floatplane.

Nothing much happens afterwards. She continues her missions off China, under a new captain from December 1931, Iwashita Yasutaro, on 15 November 1932 Okuma Masakichi, and on 25 August 1933 after her annual Special Great Maneuvers she takes part in 16th Naval Review at Yokohama. On 11 September she leaved Tateyama, towing Destroyer Hulk No. 3 (IJN MATSU) to be used as gunnery target ship. On the 15th she had an outbreak of dysentery and is quarantined in Yokosuka, until 4 October. On 10 October she rejoins Kure for to be placed in reserve from November, under Captain Suzuki Kozo, which supervising her major overhaul, from 27 November to 15 July the next year.

Chinese Operations 1937-1940

Under command of Hara Kenzaburo then Abe Koso she is prepared for further operations to China: On 20 August 1937 she departs Atsuta with ASHIGARA, HAGURO, MAYA, MYOKO and NACHI, the destroyers AKEBONO, AMAGIRI, ASAGIRI, AYANAMI, ISONAMI, OBORO, SHIKINAMI and YUGIRI with rhz 1st Battalion, 6th Infantry Regiment onboard for a major landing in Shanghai. The following day she stops at Ma’an Islands, North East of the Zhoushan archipelago while troops are transferred. On 1 December 1936 she has a new commander, Abe Hiroaki, and from 1st December 1937 Tanaka Raizo. She returns twice to assist operations of the Second Sino-Japanese War.

From 15 December 1938 Nanba Sukenobu taked command, followed by Izaki Shunji, also in charge of MIKUMA during her refit back home. On 5 December 1939 he is replaced by Kimura Masatomi and from 15 October 1940 Kasai Torazo. From March to May 1941 she takes part in intensive training for the Expedition Preparations, having in Kure two quadruple Type 92 Torpedo Tubes mounted aft and her forward banks slots plated over, welded shut. She now carried sixteen Type 93 “Long Lance” torpedoes. On 8-15 April she is no longer flagship of DesRon 2, temporarily transferred to IJN NATSUSHIO, her esciort destroyer during these modifications.
On 26 November, she is flagship again bearing the mark of Admiral Tanaka Raizo and departind the Terashima Strait for the Palau Islands. On 2 December 1941 DesRon 2 integrates VADM Takahashi’s Third Fleet (Southern Force) created to attack the Philippine on the 7th, western time. The signal “Niitakayama nobore 1208” specified 8 December, Japan time.

Early Pacific War: Philippines Invasion

On the 7th, Operation “M” commenced and DesRon 2, flagship Jintsū (leading the destroyers of DesDiv 24 YAMAKAZE, SUZUKAZE and UMIKAZE, DesDiv 16 TOKITSUKAZE), is based out of Palau to jump-start the invasion of Mindanao, tsaked to export seven troopships from Kubo Kyuji’s “Fourth Surprise Attack Force” carrying the IJA 16th Infantry Division and the Kure No. 1 Special Naval Landing Force (SNLF) to Davao, Legaspi and Jolo landing areas. She is joined by IJN Nagara. At first they covered the landings at Davao and Legaspi. while DesRon 2’s DesDiv 15 (HAYASHIO, NATSUSHIO, OYASHIO and KUROSHIO) and DesDiv 16 (now YUKIKAZE, HATSUKAZE and AMATSUKAZE), plus DesDiv 20 (ASAGIRI) are providing gunnery cover. The fleet is backup by CruDiv 5 (NACHI, MYOKO and HAGURO under RADM Takeo).
Air cover is soon provided by IJN RYUJO escorted by SHIOKAZE, and CarDiv 11 (seaplane carriers CHITOSE and MIZUHO).

On 10 December 1941 JINTSU and DesDiv 15 (HAYASHIO and NATSUSHIO) are detached to escort MineDiv 17 (minelayer YAEYAMA) which during the night to 11 December lays 133 mines in the Surigao Strait to prevent any flanking attack escape of reinforcement from the US fleet.
On 12 December 1941 she is back to take part in the Invasion of Legaspi, in the main island of Luzon. About noon, she covers the landing of 2,500 Kimura’s 16th Infantry Division’s, 33rd Infantry Regiment and a battery of the 22d Field Artillery plus engineer detachments, plus the 1st Kure SNLF. They lands without opposition and by 09:00 the airfield is secured. JINTSU with DesDiv 15 and 16, CruDiv 5 stays all this time in distant cover with RYUJO for air cover. Two days later she moves back to Kossol Roads in Palau to resupply and crew’s rest.

On the 17th is launched Operation “M”, The Attack on the Southern Philippines, and she covers 14 transports from Palau with Shizuo’s 56th Regimental Group onboard, plus the 2nd Kure SNLF and a naval airfield maintenance unit. As usual she leds DesDivs 15 and 16 with CruDiv 5 in distant cover, RYUJO and CHITOSE for air cover. Two days later while 200 miles Eeast of Davao RYUJO destroyed the radio station at Cape San Augustin and CHITOSE launched all her seaplanes in a wide reconnaissance mission to identify US and Philippines units on the area. The landings proper takes place on 19/20 December, the first troops ashore at 04:00. A 15:00 Davao and its airfield are secured and work commence on a seaplane base.

On the 23th Jintsu takes part in the Invasion of Jolo, escorting nine transports from Davao (4,000 men, half an infantry battalion with full organic support and the 2nd Kure SNLF). As usual DesRon 2 is covered by RYUJO and CHITOSE and langings takes place on 24 December, secured the following day. On the 29th, Jintsu dropped anchor at Malalag Bay near Davao and is reassigned to RADM Kubo’s “Eastern Netherlands East Indies Seizure Force”.

The Dutch East Indies Campaign

On 9 January 1942, Jintsū departs Davao to take part in the invasion of the Celebes. She was to escort eight troopships carrying Sasebo’s No. 1 Combined SNLF. Operation “H” local convoy is under command of Mori Kunizo’s and RASL Kubo’s “1st Base Force” cruiser NAGARA, with patrol boats, minesweepers and Subchasers. The main escorts counts RADM Tanaka DesRon 2 (JINTSU), leading DesDiv 8/1 (OSHIO, ASASHIO), 15-16 as usual and patrol boat PB-39. Air cover is provided by RADM Fujita’s CarDiv 11 (MIZUHO, CHITOSE) and supported by CruDiv 5 (NACHI and HAGURO) and DesDiv 6 under Takagi.
On the 11th the SNLF lands on Kema in the Celebes, Menado, while the 1st Yokosuka SNLF (Marine Paratroopers) jumped from G3M1-L “Nell” to secured bridges and reaguard in the Menado-Kema area and secure Langoan airfield. The following day, 185 more paratroopers are sent in reinforcement, and on the 17th JINTSU launches her Kawanish E7K2 in reconnaissance. En rout she woulld spot and shot down a Dutch Lockheed A-29 “Hudson” near Menado, before being shot down in turn.
The following day she arrives at Malalag Bay and departs on the 26 for Bangka Roads.
On the 31 the second phase commences, the invasion of Ambon Island, Jintsu escorting ten transports (820 men, 1st Kure SNLF, some from Sasebo SNLF and the 228th IJA IR) under RADM Hatakeyama. DesRon 2 still provides escort under RADM Tanaka from JINTSU, DesDiv 8 (ASASHIO, OSHIO, ARASHIO, MICHISHIO) and DesDiv 15 (HAYASHIO, KUROSHIO, NATSUSHIO OYASHIO) DesDiv 16 (AMATSUKAZE, HATSUKAZE, TOKITSUKAZE), Minesweeper, Subchasers and patrol boats plus CarDiv 11 air cover, CruDiv 5+ DesDiv 6 distant cover.
On 2 February 1942 Laha airfield is captured, and the area is secured enough for the escort to enter Ambon Bay two days later. On the 8th she departs for Kendari in the Celebes and returned on 9 February. The next targets are Dutch and Portuguese Timor and eastern Java. On 20 February jintsu is spotted and ambushed, but missed off Alor Island by USS Pickerel.

On 17 February she escorts nine transports (228th IJA IR, 3rd Yokosuka SNLF) to Kupang in Dutch Timor. She conducts DesDiv 7, 15, 16 and 24 destroyers. The following day she escorts five more troopships for Dili this time, in Portugese Timor. They are partly the converted destroyer PB-1, PB-2 and PB-34 and are escorted by DesDiv 24, Minesweepers and a submarine chaser. As usual CruDiv 5, DesDiv 6-7 are in distant cover but air cover is limited to the Mitsubishi F1M2 “Pete” floatplanes from IJN MIZUHO. These fast, agile and powerful models took an active part in the strafing and close support missions in addition to reconnaissance.

On the 19th the two convoys arrive off Timor while ABDA is gathering to oppose them. USS PIKE (SS-173, Lt.Cdr W. New) and USS Tarpon (SS-175, Wallace) PICKEREL (SS-177, Bacon) spots ahd shadows the invasion invasion force. On the 20th at 02:43, PIKE attacks the minesweepers W-7 and W-8 with torpedoes from 4,000 yards, missing. Dawn saw JINTSU launching a Kawanishi E7K2 and while throttling to idle speed to recover it, PICKEREL is on a perfect spot, but too slow to approach and JINTSU moves out of range. PICKEREL is detected and hunted down, while TARPON never got close enough.
Meanwhile on Timor Island 308 paratroops of the 3rd Yokosuka SNLF are paradropped at Dili-Kupang, seizing Penfoei airfield. On the 21 323 more SNLF are paradropped in support and on the 24th, the fleet departs the area for Makassar, Celebes. JINTSU joins NAKA to provide escort for another a troop convoy, bound for eastern Java.

Battle of the Java Sea, 27 February 1942

The awaited clash between ABDA and this invasion force is met on 27 February 1942. Jintsū leads DesDiv 7 (Ushio, Sazanami, Yamakaze and Kawakaze), DesDiv 16 (Yukikaze, Tokitsukaze, Amatsukaze, Hatsukaze) and there is the always present distant cover of IJN Nachi, Haguro, and Naka. At 15:47 they spots and engage RADM Karel W. F. M. Doorman Strike Force’s: Led by HNMS DE RUYTER, HMS EXETER, USS HOUSTON, HMAS PERTH, HNMS JAVA and the destroyers HMS ELECTRA, ENCOUNTER, JUPITER, HNMS KORTENAER, WITTE de WITH, USS ALDEN, JOHN D. EDWARDS, JOHN D. FORD and PAUL JONES, the latter being old flush-deckers.

Floatplanes are launched from Jintsū, Naka and Nachi to precise positions and started gunnery spotting. At 17:27 Jintsū delivered the “full broadside” of her eight Type 93 “Long Lance” torpedoes, reloading in between the two launches added to those of DesRon 2 for a total of 72 torpedoes, all missing. Jintsū opens fire and co-destroys HMS Electra. Later, Takagi would recalls all five recon planes while dark fell and searchlights are lit-up, flares fired. At 23:36 JAVA is hit by a torpedo, stern breaking off, dead in the water and finished off later at 23:45. HNMS DE RUYTER is also hit by a torpedo from HAGURO, is dead in th water but stays afloat for hours, sinking the 28 with most of the crew. HOUSTON and PERTH retired and manages to join Batavia (Jakarta).

On 2 March while underway on the Java Sea, near Balwean Island in early hourse, USS S-38 spots JINTSU and a destroyer, submerges and fires a full broadside, reloads and launches two more at the destroyer, hearing explosions and later claiming the cruiser, later escaping a counter-attack. The claim was not valid as Jintsu escapes any damage. She arrives at Tarakan in Borneo on the 4th, resupplies and refuels and then leaves for Makassar on 12 March and reaches Kure on the 23th for a refit. She is undocked on 6 April 1942, transferred to Hashirajima anchorage to await orders.

On 18 April 1942 It’s the Doolittle raid, and Jintsu is pressed in a high speed run to try and locate the US Task Force on 19 April. However Halsey’s carriers are no longer there. She reaches east of Miyake Jima and Hachijo Jima and on the 23 returned to Kure, spending the next days training in the Inland Sea. On the 21 she departs with DesDiv 15, 16 and 18 (IJN Kagero) and the converted fast transport destroyers SHIRANUHI, KASUMI and ARARE. She arrived at Saipan on 25 May.

Operation MI (Battle of Midway)

She joins the Midway Invasion Force to escort transports and oilers bound for Midway. On 28 May under Kondo’s command of the Midway Invasion Force, DesRon 2 escorts the oiler AKEBONO MARU, and the transports KIYOZUMI, ZENYO, ARGENTINA, BRAZIL, AZUMA, KEIYO, GOSHU, KANO, HOKURIKU, KIRISHIMA and NANKAI MARUs, TOA MARU 2, ecorted by the seaplane carriers CHITOSE and KAMIKAWA MARU. The convoy is intended to land an airfield construction unit, an IJA detachment plus two battalions of SNLF. The battle took place in between, which is a disaster for the 1st Air fleet. On 3 June 1942 the convoy is bombed in altitude by nine Boeing B-17 followed by a torpedo attack of Consolidated PBY Catalinas, claiming the Oiler AKEBONO MARU. The invasion is cancelled and the convoys sails back.
On 13 June the transports disembark the airfield construction uni and on the 15, they are back to Truk, then Guam and DesRon 2 is back in Yokopsuka by 21 June, sails to Hashirajima and back and spengin the rest of July in ASW training.

Somomons Campaign

From 14 July 1942 the 8th Fleet also called “Outer South Seas Force” is reorganized under VADM Mikawa and Jintsū is reassigned to answer the recent invasion of Guadalcanal on 1st August, and the cruiser via Truk heads for the Solomon Islands. On 16 August 1942, Jintsū departs Truk, escorting a major reinforcement force. On 20 August, troops are landed but they failed to retake Henderson Field. RADM Tanaka is signalled an approaching US Task Force and rushed his convoy northwards. However VADM Mikawa (8th Fleet) counter-ordered him, compromised, changing course, bringing him 190 nm south of Guadalcanal.

20 former carrier planes lands at Henderson (Cactus Air Force) from USS Long Island and learning this Admiral Isoroku Yamamoto orders Nagumo’s 3rd Fleet (Shōkaku, Zuikaku, Ryūjō) escorted by IJN Hiei, Kirishima and the cruisers Kumano, Suzuya, Chikuma, Tone and Nagara to reinforce Tanaka, left only with Jintsū.

On 23 August, 200 nautical miles north of Guadalcanal, Tanaka’s convoy is detcted by a lone PBY Catalina and at 08:30, he receives an order from Mikawa to head north but at 14:30, again, he received a conflicting order from VADM Tsukahara to land his troops on Guadalcanal on the 24th. He answered not able to comply but soon the Battle of the Eastern Solomons woud happen anyway on 24 August. Jintsū met Ryūjō which launched two air strikes against Henderson Field but both are soon attacked by USS Saratoga planes, she would be lost despire the firce AA fire from Jintsū.

On the 25 August, still north of Guadalcanal, DesRon 2 is attacked by six USMC Douglas SBD Dauntless, sinking one transport, damaging another but also managing to hit the cruiser with a 500 Ib bomb. Fires brokes out and the flooding pump is activated in her forward magazines to prevent explosion. She also lost 24 crewmen while Admiral Tanaka is injured. Her moves on Kagerō while Jintsū manages to escape to Shortland. From there she sails to Truk for emergency repairs with IJN Akashi. In October she is able to sail back to Japan, receiving repairs and AA addition until 8 January 1943.

Battle of Kolombangara

On 16 January, IJN Jintsū is again reassigned as flagship, DesRon 2. She leaves Kure for Truk, now tasked to escort convoy of retiring IJA troops from Guadalcanal (Operation “KE”). She made several runs with success, reaching notably Truk, Roi and Kwajalein. On 12 February 1943 Captain Sato Torajiro is appointed as her new CO but she is laregly inactive in April-May in Japan. On 14 June she departs Truk for another transport run notably with maintenance personnel from IJN JUNYO, disembarked in Roi (Kwajalein). She is back in Truk on 19 June and departs on 8 July with DesDiv 31 (IJN KIYONAMI) for Rabaul. On the 12 at 05:30 she departs with RADM Izaki and leading DesDiv 16 (YUKIKAZE), DesDiv 17 (HAMAKAZE) DesDiv 27 (YUGURE), DesDiv 30 (MIKAZUKI), DesDiv 31 (KIYONAMI) to escot the fast transport destroyers SATSUKI, MINAZUKI, YUNAGI and MATSUKAZE coming from Buin with 1,100 troops onboard and 100 tons of equipment, bound for Kolombangara Island in New Georgia.
Soon after arrival, her freshly installed radar detect ships, which happened to be the cruisers USS Honolulu, St. Louis (both of the fifteen 6-in armed Brooklyn class), HMNZS Leander, escorted by the destroyers USS Ralph Talbot, Maury, Gwin, Woodworth, Buchanan, Radford, Jenkins, Nicholas, O’Bannon and Taylor.

Admiral Isaki tries a night torpedo attack. His ships launched 31 Type 93 “Long Lance” torpedoes while Jintsū illuminates their targets with searchlights, but this proves fatal. Immediately her position is revealed in turn and she is hit by all three cruisers unleashing a rain of 6-in gunsn radar-directed with deadly precision. She is hit by dozens of rounds at once, killing many, putting the ship alight and killing outright botth Rear Admiral Isaki and Captain Sato when the bridge is destroyed. She also received a destroyer torpedo starboard, flooding her aft engine room.
Captain Zenjirō from IJN Yukikaze then assumed command of the convoy fleet, ordering a desperate counterattack and in the firce melee that follows, managed to sink USS Gwin, and damage both the cruisers Leander and St. Louis. But Jintsū eventually breaks in two, sinking rapidly at 23:48 hours, with a few survivors picked later by USS Nicholas, then I-180 (21 more) and other in the morning hours b various ships. But most of her crew is lost, 482 men in all. IJN Jintsū is written off on 10 September.
Her wreck was rediscivered on 26 April 2019 by RV Petrel close to Kula Gulf (Solomons) under 900 meters (2,952 feet), her bow section lying to port, the stern staying upright. She is classed as a war grave, but as it happens too often these ships are regularly pillaged by souvenir hunters and for scrap metal.

IJN ww2 IJN Naka (那珂)

IJN Naka
IJN Naka was completed at Mitsubishi Yard in Yokohama) on 30 November 1925. She was the very last of a design created in 1918, as a madd-produced extended design of the Tenryu class light scout cruiser.

Naka’s interwar career.

Her early career is as following: From 15 April 1925 she was under command of Cdr Inoue Choji as Chief Equipping Officer and after completion, Inoue becomes her first CNO until replaced in December 1926 by Nakamura Kamezaburo, then from 5 April 1927 Captain Mito Motosuke, whereas she performs her primary training, gunnery drills, and annual fleet manoeuvers. On 10 December 1928 Ban Jiro is her new CO followed on 30 November 1929 by Chuchui Nagumo (yes, that one, former instructor at the Naval Academy and future admiral). On 1st December 1930 he is replaced by Yamada Sadao and the next in 1931 by Yamamoto Koki, same date bu December 1932 by Sonoda Shigeru and from 15 November 1933 by Goto Eiji. In between she had a short refit and overhaul while early operations took place in China, but she is not sent there.

The “Tomozuru incident” led to a large scale examination of all vessels for their structural conditions and some modifications, which will be done. On 15 November 1934 Abe Kasuke takes command and newt yeat on 25 May 1935 Marquis, Daigo Tadashige and from 15 November Captain Goto Aritomo, from 1st December 1936 Abe Koso and from 2 August 1937 Nakamura Motoji (second refit), soon after from 1st December 1937 Kono Chimaki. Nex year, still without notably incident and no depployment in China unlike her sisters, on 15 November 1938 Miyazato Shutoku, formerly commanding YUBARI takes command, then by December 1938 Takama Tamotsu and by 15 November 1939 Akiyama Teruo. From 15 October 1940 Baron, Ijuin Matsuji takes command and from 11 August 1941 Tawara Yoshioki, which stays as her first wartime commander while from 26 November 1941 she becomes flagship, Rear Admiral Shoji Nishimura as DesRon 4. She is prepared for the incoming campaign and departs the Terashima Strait to join her area of operations.

Early Pacific Operations: Philippines

DesRon 4 or the 4th Destroyer Flotilla was assigned to the invasion of the southern Philippines, integrated into the 3rd fleet VADM Takahashi Ibo). She was tasked on 7 December 1941 to escort six transports carrying IJA’s 48th Infantry Division (2000 men of the Kanno Detachment), called Operation “M”. The group was called “Philippines Seizure Force”, and simply “Southern Force”. She departs Mako and on 10 December while at Luzon she covers multiple landings at Pandan, while the formation is attacked, bombed and strafed by five Boeing B-17 “Flying Fortresses” escorted by Seversky P-35A and Curtiss P-40B Kittyhawk of the US Far East Air Force. A Japanese minesweeper is sunk, transports OIGAWA MARU and TAKAO MARU badly damaged, beached and lost. IJN NAKA and her escort destroyer IJN MURASAME are also damaged, but merely by strafing. Her last task was to escort a convoy of 28 transports 7th Tank Regiment and an infantry regiment of the 48th Infantry Division. Departing Mako, on 22 December 1941 they are landed at Caba, Lingayen Gulf. By the 29th she departs Takao for Formosa and on 2 January 1942 she returns to Davao in the Philippines.

Netherlands East Indies

In January 1942, DesRon 4 was assigned to the invasion of the Netherlands East Indies. On 7 January is launched Operation “H”, the Invasion of the Celebes and she departs Davao with the No. 1 Escort Unit: 16 transports with Sakaguchi Brigade, 56th Regimental Group, Kure No. 2 SNLF. Her close escort comparised 4 patrol boats, 3 minesweepers and 3 subchasers (CH-10-12). By 10 January she was in Tarakan, Borneo and lands the following day troops on Tarakan. IJN Naka as DesRon 2 command Desdiv 2 (YUDACHI, SAMIDARE, HARUSAME), 9 (ASAGUMO, MURASAME, MINEGUMO, NATSUGUMO) and 24 (KAWAKAZE, YAMAKAZE and UMIKAZE).

After the landings on 24 January 1942 at Balikpapan, she is spotted by the submersible HNLMS K XVIII while on the surface due to the appealing weather. She fired four torpedoes but missed.
At the same time, ABDA’s own air reconnaissance was hampered by the same weather, before locating eventually the invasion force and deploying the submarines USS S-40, PORPOISE, PICKEREL, STURGEON, SAURY, SPEARFISH and in addition to the aforementioned K XVIII, the K-XIV. As said, only the Dutch submersibles picked them, but without success. But ABDA destroyers did. These old flush-deck destroyers made DesDiv 59 under command of Cdr Paul H. Talbot. Behind them were Admiral W. Glassford’s TF 5 cruisers, USS MARBLEHEAD and BOISE. Later, Glassford while heading north to intercept the invasion force, had BOISE running aground on an uncharted reef, in Sape Strait. MARBLEHEAD (an old Omaha class) had issues with her machinery and at 15 knots was not able to catch up. Thus, DesDiv 59 was detached to 27 knots to fell on the Japanese on January 23rd.
IJN Destroyers and Naka are menawhile in hot produit of the Dutch submersible but around midnight they are recalled back frantically as the convoy left without protection is now suddenly attacked by USN Task Force 5: Destroyers USS Parrott, Pope, John D. Ford and Paul Jones.
At 03:16, the destroyers rampaged through the convoy unoppose with their 4-inch guns, launching ten torpedoes on the now anchored transports. They “missed” despite of this (Type 14 torpedoes again) and since there was still no relief in sight after the first pass, Cdr Talbot orders another one at 03:30. This time, at close range, USS Pope launched a devastating volley and sunks the 3,519-ton transport SUMANOURA MARU. At 03:35 USS PARROTT and PAUL JONES claims together the TATSUGAMI MARU, also with torpedoes. At 03:45 USS FORD sinks the KURETAKE MARU and two other transports stays afloat despite heavy damage, in shallow waters. Only protection there were smal ships, and the patrol boat P37 is sunk while trying to intervene.
At 03:50, all torpedoes spent, DesDiv 59 flees southward while Rear Admiral Nishimura intercepts ABDA communication about the attack, abandoning the sub chase and launches behind the destroyers, never to find them.
Next starts another escort mission, carrying the 48th Infantry Division to Makassar (41 transports) in the Celebes from Jolo, and eastern Java. Naka, DesRon 4 leads 6 destroyers. She teams with Desron 2 (flagship Jintsū) with IJN Nachi and Haguro in distant cover. IJN Naka departs Makassar on 25 February 1942, but the eastern Java Invasion Force is not unopposed:

Battle of Java Sea, 27 February 1942.

At 15:47, IJN Haguro, Nachi, DesDiv 6 destroyer (IJN Inazuma) and Jintsū (DesDiv 7 and 16 – destroyers Inazuma, Yukikaze, Tokitsukaze, Amatsukaze and Hatsukaze, Ushio, Sazanami, Yamakaze and Kawakaze) spots ABDA’s force led by RADM Karel W. F. M. Doorman. At 16:03, IJN Naka, leading Asagumo, Minegumo, Murasame, Harukaze, Samidare and Yūdachi launched some forty-three Type 93 “Long Lance” torpedoes from 16,250 yards (14,860 m), but only sank Kortenaer. Asagumo duelled with Electra and sink her, Jupiter hit a mine, later De Ruyter and Java are hit by torpedoes.
Battle of Sunda Strait: The next day on 28 February 1942, Naka is not present when the survivors of the previous battle, HMAS Perth and USS Houston, are caught by the Japanese.
At 19:00, after refueling at Batavia, USS HOUSTON and HMAS PERTH sailed for Tjilatjap via the Sunda Strait when at 22:15 they spots the Japanese troop convoy escorted by HARUKAZE, HATAKAZE and FUBUKI, laying smoke and charging on both cruisers for a torpedo run. Later at 23:00, MIKUMA and MOGAMI followed by NATORI and five destroyers arrives in turn and soon both cruisers are overwhelmes by gunfire and torpedoes. About pas midnight, both sank. On the morning CruDiv 5 found HMS EXETER, later joined by ASHIGARA and MYOKO and they fired at the small HMS EXETER group. At 12:50 she is left for dead and sinks at 13:30. Later USS POPE would be caught by Aichi D3A “Val” from CHITOSE, MIZUHO and RYUJO plus six Nakajima B5N2 “Kate” and she is finished off.

Later Operations

on 2-8 March 1942 Naka was patrolling off Kragan, Java and on the 12th she was in Makassar, Celebes. Two days after, with the occupation of Java complete she is recalled by the Imperial General Headquarters and prepared to occupy Christmas Island. This is Operation “X” on 18 March 1942. That force consisted of Naka (DesRon 4), CruDiv 16 (Nagara, Natori), DesDiv 9 (Minegumo and Natsugumo), 22 (Satsuki, Minazuki, Fumizuki and Nagatsuki), 16 (Amatsukaze and Hatsukaze) and in support the oiler Akebono Maru, transports Kimishima Maru and Kumagawa Maru.
Landing operations went on unopposed but on the 31th USS Seawolf arrives, and fired four torpedoes at Naka, missing. Undetected she tried again on 1st April and succeed: One hit starboard, close to Naka’s No. 1 boiler. However bulkhead hold firm and the damage control team managed to halt the flooding. She is towed to safety by IJN Natori to Bantam Bay in Java, for emrergency repairs, before she is able to proceed to Singapore and from there, to Japan for complete repairs from June in drydock. Delays means she is placed in reserve until April 1943. Nakazato Takaharu is appointed 10 July 1942 as new CO, then Captain Nakazato Takaharu and from 1st October 1942 Captain Takagi Banjiro and from 25 March 1943, Captain Imaizumi Yoshijiro.

Later Operations: Marshalls and Rabaul

On 1st April 1943, Naka, now under command of Yoshijiro Imaizumi, she is reassigned to CruDiv 14 (Rear Admiral Kenzo Ito) with her escort, IJN Isuzu. She arrived at Truk Lagoon on 30 April 1943 and spent the rest of the following time in transport runs around the Marshall Islands and Nauru: In April, she made a run from Yokosuka to Truk, then Jaluit in May, and another in June when back to Truk. However on 21 June at 02:41, lookouts on USS SPEARFISH (Cdr George A. Sharp) spots the convoy, identifying three carriers, a battlesgip, a cruiser and destroyers. Not in good position for the cruiser, he swapped for the “carrier” and fires at 03:37 but misses. Later on the 25th she would land the 2nd Yokosuka SNLF at Nauru.

In july Naka went at Kwajalein from Truk, Mili, Wotje and back to Truk on the 24th. In September, she departs Truk, always with her unique escort, the destroyer IJN ISUZU, for another troop transport/supply mission to Kwajalein, Taroa and back to Truk on 10 September. Two days after she assists the oiler SHIRETOKO and aircraft ferry FUJIKAWA MARU just torpedoed by USS PERMIT.
On the 15th, USN codebreakers caught the message from ComCruDiv14 about NAKA and KATORI MARU towing SHIRETOKO. No interception could be mounted through. Naka reaches Kwajalein, arrives at Mili on the 20th, Wotje the following day and back to Kwajalein, then Jaluit (28-29) and she is back to Truk on 3 October 1943, departing on the 11th for Shanghai, reached the 18.

On 21 October 1943, Naka and Isuzu embarked Army troops there, and departs. But they are intercepted by USS Shad (picking them by her SJ radar at 15,000 yards) in the East China Sea, two days later. Shad fired 10 torpedoes but misses. She is the only one in position to do anything as new decrypts from “Ultra” sent Charles B. “Swede” Momsen Task Group 17.14: USS CERO, GRAYBACK and SHAD. Shad will be hunted down but escaped the depth-charge counter-attack.

Next, they arrived in Truk on the 28, and by 1st November she is taking the helm of the second echelon, convoy “Tei No. 4” plan to depart Truk, and training extensively. Two days later while 60 miles N of Kavieng at 11:29, the convoy is spotted and attacked by some 19 USAAF (13th Air Force) B-24 “Liberator” bombers. As often for this high altitude affairs, this is pretty innacurate. IJN NAKA and GOKOKU MARU only had near misses, but still, shrapnel killed 7 and injured 20 while KIYOSUMI MARU is damaged to such a point she taken in two by ISUZU.

On 4 November YUBARI, MINAZUKI and ISOKAZE and sent to meet KIYOSUMI MARU and try to take her under tow after ISUZU with NAKA and ISOKAZE in cover. The crews of Naka managed to free the cargo of 166 men, four antitank guns, YUBARI taked 196 troops, three field, ISUZU 196 men, four regimental guns out in case she sank, MINAZUKI takes onboard 267 troops, ISOKAZE 236 troops and two mountain guns while Ammunition and supplies are transferred on GOKOKU MARU. So at 17:00, they arrives at Kavieng where troops are landed.
Naka is bombed again during the attack on Rabaul on 5 November 1943, slightly damaged, also by near-misses. 20 November is launched Operation “Galvanic”, the Invasion of the Gilbert, concerning Tarawa and Makin Islands. it’s a a too big priz for the Japanese, with 200 ships (notably 13 battleships and 11 carriers). On 23 November she departs for Ponape with troops onboard bound for Tarawa, which fell before it could be done.

The end: Operation Hailstone

On 17–18 February 1944, Naka was sent to help the cruiser Agano torpedoed by USS Skate. And just after her departure, Truk is attacked by Tf 58, Operation Hailstone. 31 transports, 2 cruisers, 4 destroyers, 4 auxiliaries are sunk, 200 aircraft destroyed in the air, 100 on the ground, installations and fuel depots are flattened and burned. It’s a catastrophy as Truk is pretty much eliminated as a curcial advanced base for the IJN.
With som much planes in the air, it’s no long before IJN Naka is spotted in turn. She is attacked some 35 nautical miles west of Truk. In all, three waves of Curtiss SB2C Helldivers, Grumman TBF Avengers from USS Bunker Hill and Cowpens fell on her. Although she escaped the first two strikes in the third she faced more experimented pilots which tried a pincer method to prevent her dodging torpedoes and bombs. She soon took a hit of both. This is fatal, she broke in two and sink quickly, carrying 240 crewmen were her. Later patrol boats would rescued 210, including Captain Sutezawa.
She is stricken on 31 March.

Tordenskjold-class coastal defence ship (1897)

Tordenskjold-class coastal defence ship (1897)

Coast Defence Ships (panserskipet) – Norwegian Navy 1896-1948
HNoMS Tordenskjold, Harald Haarfagre

The Norwegian Capital Ships of two wars

Brassey’s engraving, Brassey’s naval annual 1900
HNoMS Tordenskjold and Harald Haarfagre constituted for 50 years the bulk of Norwegian naval defence. They were ordered as part as the general rearmament until the 1905 union separation from Sweden and with the lighter, more modern Eidsvold class formed the backbone of the Royal Norwegian Navy until retired on the mid-1930s. This did not ended their career there, as both were captured by the Germans which used them as floating batteries (Flakschiff), and they were only BU in 1948.

The small Royal Norwegian Navy capitalized like the others Scandinavian Navies on a particular coastal defence asset, aside mines, torpedo boats and coastal batteries: Coastal Battleships. In Norwegian this was even more generic as “panserskipet” (armoured ship). Both were misleading and that’s why modern consensus is simply to call them “coast defence ships”, which also concerned similar vessels in the Swedish, Finnish, Dutch and Danish Navies. They lacked indeed a lot to be compared to true sea going battleships: Better speed, range armor, and armament. Their purpose was mostly to deter cruisers and destroyers in a combined arms defence. If their concept was relevant in WWI, it was no longer so in the interwar, notably due to new long-range artillery, the danger of submarines and aviation.
Their role changed, but even though they stayed active from the mid-1930s as training vessels, potentially doubling as harbor defence ships in case of war. With Operation Weserübung (German invasion of Norway) in 1940 both were seized and requitioned by the Kriegsmarine to be converted as Flak batteries. They ended as barrack ships postwar, then were sold for scrapping.

Design of the Tordenskjold class

Conway's profile
Conway’s profile
The Harald Haarfagre and Tordenskjold, followed by the Eidsvold and Norge were part of a general rearmament intended to protect Norway against a possible military action by Sweden until the 1905 dissolution of the Swedish-Norwegian personal union. The Norwegian Parliament authorized the construction of four new Panserskipp in 1895 to replace the existing, obsolete monitors. Political tensions led them to be ordered in Britain, all four. In 1896, Armstrong Whitworth shipyard was conformed an order for two 3,500 tons vessels armed with two Vickers 21 cm guns and 12 cm artillery as secondary battery. They were mentioned as very comparable to the German Siegfried class.

Thes vessels were designed and built like pre-dreadnought battleships in reduction. They were well suiteed between their draft and diemnsions to the fjords and narrow waters of the rugged coast of the country and carried a full barrery betwen German-built 21cm, 12cm, 7.6 cm and 1-pdr guns, while the protection was designed to withstand similar similar caliber artillery (notably heavy cruisers) but it was not enough to resist shells above 10 inches, nor underwater attacks due to unsufficient compartimentation. They used Harvey Armour, between 7 to 8 inches for the best protected parts.

top view Tordenskjold_class
Top view, Conway’s

They had a symmetrical appearance, relatively low feeboard and flush deck preventing their use on rough weather and open sea in the north Atlantic, two tall masts and a single, tall funnel. The appearance indeed mimicked those of pre-dreadnoughts, which could play in part as deterrence. Both were built in Great Britain, at Vickers-Arsmtrong yard. They were built quickly, at Low Walker shipyard short of civilian orders at the time, rather than in Elswick. Harald Haarfagre was laid down on 18 March 1896, launched on 4 January 1897 and completed on 10 June 1897 and Tordenskjold laid down on 18 March 1896, launched on 10 Mar 1897 and completed on 2 April 1898.

About their names, “Tordenskjold” was the nickname of sea hero Peter Wessel and “Harald Haarfagre” (Harold “fair hair”), the first king of Norway (c. 850 – c. 932) which became a national icon of Norway and symbol of independence, conciding with the expected political split with Sweden.

Hull and general design

Prow view, detail, of the Tordenskjold in Nylas drydock, showing the prow’s decorative plaque, dedicated to the Royal Norwegian Family. CC photos from the Norwegian National Library’s image collection.

These armored ships intended for coastal waters became in any case, the largest Norwegian warships ever in service, later completed by the similar, but smaller Eidsvold class.
These ships displaced 3,852 tonnes standard, probably around 3,920 fully loaded. The hull was 92,66 meter long (304 ft) overall, 85.34 m (280 ft) between perpendiculars and 14,78 meter in beam (48 ft 6in) for a draft of 5,38 meters (17ft 8in). The ratio was favourable to speed, but still they were manoeuvrable. When first built, their forward bridge was open, built above the conning tower. Later in the 1910s, a fully enclosed bridge was built above, with an open bridge on top. The tall, 4-segmented masts fore and aft supported telegraphy cables, and also two fighting tops each, platforms carrying a projector for the lower one. The lower fighting top aft had light 1-pdr guns installed.
The central “island” suprestructure was built around the large funnel, with all the secondary artillery on sponsons, and the service boats located between the funnel and aft mast.

Armour protection layout

Armour details in a German publication of the time
Armour details in a German publication of the time.
As said above, they had Harvey armor for theior main Belt 7 in (178 mm) amidships, covering the machinery space, barbettes and ammunition magazines, then it was tapered down to 4 in (102 mm) to both ends. The main turrets were protected by 8 inches walls (203 mm) with 5 inches (127 mm) on their roof and back. The conning tower had walls 6-in thick (152 mm). The armoured deck’s thickness is unknow, likely 5-in. The secondary 4.5-in guns had protective shields only stopping shrapnels.


These vessels had to shafts connected to two Vickers Coal-fired vertical triple-expansion steam engines, fed by two Yarrow 3-drum horizontal boilers, which were rated for a total of 4,500 ihp (3,356 kW). This was enough to ensure a top speed of 16.9 knots (31.3 km/h; 19.4 mph), which was good for a coastal ship and close to pre-dreadnought standards. Autonomy was limited (3,000 nm?) since they only carried 550 tons of coal in normal conditions.


At the roadstead of Trondhjem, 1906
At the roadstead of Trondhjem, 1906


These ships mirrored pre-dreadnoughts with a main turret fore and aft of the central superstructure. The first difference was the single turret, instead of twin, and 21 cm L/44 (8.26 in) caliber instead of 12-in (300 mm). A substantial difference, more to scare off cruisers than battleships they were not designed to engage.
These 21 cm Skl/45 were not Krupp guns, but rather were classed Arsmstrong nomenclature. These were officially 209mm/44 Armstrong B types (no specs).
They had similarities though with the Krupp 21 cm Schnelladekanone Länge 40 used on the Victoria Luise class protected cruisers. The TL C/97 could elevate to 30°, and had a 4-5 rounds per minute fire rate. Range should be around and beyond 18 km (12 mi) at +30°.


The Tordenskjold class was given a secondary battery of Armstrong 120mm/44 Armstrong Y type guns, six of them along the central superstructures in sponons and under shields. Produced by Elswick, they were specific to these export designs (no more info available). They could reach a target 10,000 yards (9,000 m) away at 20° and fired at a rate of 6 round per minuute in ideal conditions.

Anti-Torpedo Boat Armament

To defend themselves against torpedo boats, these coast defence ships had a battery of six 12 pdr-QF (standard 75 mm Vickers guns) located on the turrets (2), forward bridge (2) and aft superstructure (2). Same specs as standard Armstrong 12-Pdr QF of the time.
This was completed by six 1.5 pdr (37 mm) Hotchkiss guns, four in the broadsides under masks, two aft, and possibly later according to photos two in a forward fighting top.
They also carried for close quarters a pair of 450 mm torpedo tubes, placed in the beam, fixed above the belt. Standard Whitehead 18-in type of the era.

Models of the HNoMS Eidsvold and HNoMS Tordenskiold

⚙ Tordenskjold-class specifications

Displacement 3,380t standard, 3858t FL
Dimensions 92.7 oa x 14.8 x 5.38 max ( x x feets)
Propulsion 2 shafts VTE, 3 cylindrical boilers, 4,000 shp
Speed 16.9 kts ()
Range coal 500 tons, 5,000 nm at 10 kts
Armament 2x 209mm/44, 6x 120mm/44, 6x 76mm/40, 6x 37mm/45 Hotchkiss, 2x 450mm TTs
Protection Belt: 178-100mm, turrets 203-127mm, decks 51-37mm, CT 152mm
Crew 245

Career of the Tordenskjold class

Norwegian Navy Tordenskjold class

The admiralty dispute (1901-1910)

There was great disagreement within the Norwegian fleet command about their use when Norway declared independence. On one hand, they did not want to provoke Sweden by mobilizing too many and too large forces and on the other still wanted to leave no doubt about their will to defend the country. Commanding admiral Vice-Admiral Christian Sparre and his chief of staff, Rear-Admiral Jacob Børresen disagreed strongly on these points, leading to emerging factions and endless debates in which the new armored ships were central.

Disagreements also emerged about their supposed battle tactics. Jacob Børresen wanted to meet the Swedish squadron at sea head-on and force it to retreat, whereas Christian Sparre wanted to keep them safer at Tønsberg, to prevent a landing of Swedish troops there. He wanted them not concentrated ina single squadron but at the contrary to have them distributed in several local forces completed by cruisers and torpedo boats. The final word was that no suitable tactics had been designed for a possible fight against the Swedes, while the Norwegian navy was just too new and freshly equipped with these modern vessels to develop any experience of this kind.

The bitter “admiral dispute” was not settled until 1910. There was an arbitration court, set up in the Legislative Hall in the Storting. The later reviewed all arguments and data for many hourse and concluded by ruling against VADM C. Sparre, forced to seek resignation from his position as commanding admiral. Børresen however was not spared criticism for his performance in 1905 and also had to resign.

Norway indeed declared independence by 7 June 1905, and both Børresen and Sparre trained intensively with their new armored ships and torpedo boats in the Oslo Fjord. Three months of continuous exercises in all kinds of weather brought some drilling experience until the squadron was disbanded on 29 July. In the meantime, the Swedes also built up their largest battle fleet in Gothenburg harbor, and on 13 September they were mobilized, fully coaled, manned, supplies in ammunition and ready to go. Tension only lessened on 14 October, then the crisis was diffused by negociations and the crews received a leave.

Tordenskjold in Nylas Floating Dock in 1909 – National Library’s image collection.


Pre- and WWI service

The Harald Haarfagre class stayed grouped together. They provided routine exercizes and training trips, in 1901 they both made a long training cruise along the Norwegian coast with the sister ship Tordenskjold plus the newly completed HNoMs Norge and the destroyer Valkyrjen. Harald Haarfagre made foreign visits alone as well, including a visit to the United States in 1907, marking the 300th anniversary of the first settlement of the United States. She arrived in New York on June 18 with 25 additional sea cadets on board, first Norwegian warship there after independence. She proceeded to Hampton Roads, visited the Jamestown Exhibition accompanied with the brand new armored cruiser Fylgia. She then proceeded for home via Madeira in portugal. In 1911, she visited Copenhagen, escorting the Norwegian state yacht of King Haakon VII. During the “great war”, from 1914, Harald Haarfagre remained widely in home waters, to ensure Norwegian neutrality.

Until 1918, Tordenskjold made also training trips and foreign visits. In 1900, she took part in a visit to Kiel by a Norwegian formation included the gunboat Frithjof, destroyer Valkyrjen and the four new Storm class torpedo boats. In, 1901 she made a long voyage along the Norwegian coast with her sister ship Haarfagre, and Norge plus the destroyer Valkyrjen.

As World War I broke out she also remained in Norwegian waters but from 1918 she became a training ship, and later made a total of 18 training trips. In 1923, she had twi new anti-aircraft guns installed. By August 29, 1933, a shell exploded in one of her 21 cm gun turret, causing four dead and several injured sailors. By the very end of the 1930s she was retired due to obsolescence, becoming an utility Hulk with her two 21 cm guns removed as most of her secondary and light artillery, a new one fitted (see above).

In WW2

Post-WWI, there were some modernization attempts carried out in the 1920s. In 1923 both received two extra 47mm/46 QF Mk I guns capable of AA fire. No info is available about the modernization of their fire control systems however. In in the second half of the 1930s, Harfaarge was decommissioned due to obsolescence. She became a storage hulk, disarmed, as her two 21 cm guns were removed and recycled in coastal artillery (they will see action in 1940). However, her machinery remained fully operational if needed. However with the war starting in 1939 they were rearmed with two single 76mm/28 Bofors M36 guns and two single 20mm/70 Oerlikon M36 AA guns plus two 12.7mm/90 (0.5 in) AA heavy machine guns.

Then came WW2 and the Norwegian Campaign (Operation Weserübung): During the German occupation they both fell into German hands, were thoroughky inspected and their engines tests, still showed a top speed of around 14 knots. So they sailed to Kiel in Germany in order to be modernized and reused, converted as floating anti-aircraft battery (FLAKschiff) returning into service for the Kriegsmarine on February 1, 1941 for Harfaarge, renamed KMS Thetis.

Their displacement rose to 3,858 tonnes, armament consisting of six twin 10.5 cm Flak 38, two Bofors 4 cm Flak and fourteen 2 cm Flak 30. Her bridge was modernized, she had two tall projectors tops, a new pole mast with wireless radio. It seems KMS Nymphe was not armed exactly the same way, with only five twin 10.5 cm FLAK 38.
Unlike most FLAKschiffs of the Kriegsmarine, Nymphe and Thetis were among the only ines capable to move under their own power, making them precious for point-defence. KMS Thetis stayed in northern Norway, stationed in the Ofotfjord, off Narvik and later in the Altafjord, providing AA protection for the battleship Tirpitz. It was not that successful as operations showed.

In the last days of the war, KMS Thetis was located in Kilbotn Bay, south of Harstad, where a U-Boat base was stationed from the autumn of 1944. She survived a massive air raid by the Royal Navy on May 4, 1945, called Operation Judgment, destroying residential area and the depot ship Black Watch, plus sinking the U-Boat U-711. However Thetis remained largely unscathed due to her locations on the west bank of the bay, and due to the relief around and camouflage, did not offer an easy target.

On her side, Tordenskjold also fell into German hands and sailed to Kiel to be converted, recommissioned on February 1, 1941 as KMS Nymphe, 3,858 t in displacement with the same armament, but in 1944, she received two additional 20mm Flakvierling (quad mounts). She was initially stationed in Kiel, but transferred to Tromsø in August 1941. Like her sister ship she was used to protect Tirpitz in her anchorage in northern Norway. After her sinking on November 12, 1944, KMS nymph was moved back to Kiel, staying there until the end of the war.

Postwar Fate

After the German surrender in May 1945, Nymphe was taken back to Narvik by its German crew, to be returned to Norway. She however ran aground underway on May 17, 1945, partially sinking. She was eventually raised and given back her old name, her AA guns removed and still used as part of the coastal artillery. The hull used as a residential ship for some time but by 1947 it was sold for BU, scrapped in 1948.
On her side Haarfarge was just at the right place after the war, she was just reverted to her original name. The anti-aircraft guns were removedand recycled into the coastal artillery while her hull was reused as as accomodation barrack, notably transporting German POW back home from Norway. In 1947, she was sold for scrap, which was done in 1948.

Read More


Frank Abelsen: Norwegian naval ships 1939–1945. Sem & Stenersen, Oslo, 1986 (S. 290)
Peter Brooke: Warships for Export: Armstrong Warships 1867–1927, World Ship Society, Gravesend (1999)
Robert Gardiner (Hg.): Conway’s All the World’s Fighting Ships 1922–1946. Conway Maritime Press, London, 1987.
Hans H. Hildebrand, Albert Röhr, Hans-Otto Steinmetz: Die deutschen Kriegsschiffe, Mundus Verlag, Ratingen, 1979
Bruno Weyer: Taschenbuch der Kriegsflotten 1905, 2. Auflage, J.F. Lehmann Verlag, München auf archive.org



Model Kits

Colossus class light fleet Aircraft Carriers (1944)

Colossus class (1944)

United Kingdom – 1942 Design Light Fleet Carrier (1944)
Colossus, Glory, Ocean, Venerable, Vengeance, Pioneer, Warrior, Theseus, Triumph, Perseus

WW1/WW2 RN Aircraft Carriers:
ww1 seaplane carriers | Ark royal (1914) | Campania | Furious | Argus | Hermes | Eagle | Courageous class | Ark Royal (1936) | Illustrious class | Implacable class | Colossus class | Majestic class | Centaur class | Unicorn | Audacity | Archer | Avenger class | Attacker class | HMS Activity | HMS Pretoria Castle | Ameer class | Merchant Aircraft Carriers | Vindex class

The 1942 light fleet carrier program

The Colossus class also called 1942 Design Light Fleet Carriers, was the last British fleet carriers to be completed in WW2. They were also arguably the most ambitious capital ship programme in the history of the Royal Navy since the dreadnoughts. These vessels were indeed designed for “mass production” and took priority in British Naval Yards over all else, with civilian yards taking on the construction of lighter ASW vessels as well. They were not however a repeat of the prewar Illustrious or the derived Indefatigable class. There were much smaller and cheaper, but the admiralty resolved that their small but versatile air group was tailored for both escort missions and traditional fleet operations.

The 1942 Design Light Fleet Carrier were essentially light aircraft carrier to be constructed by civilian shipyards as an intermediary type between military yards full-size fleet aircraft carriers and smaller escort carriers. They were not armored, and thus could store more aircraft complaining for this lack of protection by a larger air group for their size. Still, this air group was small compared to US standard (see later).

They could be seen in fact as an in-between an Independence (34 aircraft) and an Essex class (100), with their 52 planes between the hangar and deck. The average escort carrier had 21. No fewer than ten were started under this emergency program in 1942, the last was laid down in June 1943 but completion of the lead ship, HMS Colossus only coming by 16 December 1944. HMS Glory, Ocean, Venerable and Vengeance followed in 1945, seeing very little wartime service, and Theseus, Triumph and Warrior in 1946, saw cold war service only. The last two, HMS Perseus and Pioneer, caught in the context of postwar massive budget cuts were converted instead as auxiliary fleet maintenance workshops, and ferry carriers.

In a sense, they were lightened, smaller versions of the Illustrious, with a better AA and a better balanced protection resulting from early wartime experience, notably in the Mediterranean. Their watertight subdivision for example was much improved, to stay afloat even with many submerged compartments. Their initial permanent air group, given their hangar, was only 37 aircraft initially, but more were added as a permanent deck park following later war practices. There was a sub-class modified and slightly enlarged called the Majestic class with six started in 1943, one cancelled, all other completed postwar.

Apart HMS Ocean operational in August 1945 six actually saw some WW2 service, with the war almost over in Europe and in the atlantic and so they were sent straight for the Pacific, seeing final operations on the Japanese home Islands. The four Colossus-class British Pacific Fleet carriers were mostly used to repatriate British soldiers and POWs. Postwar they were used as testbeds for new aircraft and technology, with the last piston-powered aircraft and first jets (Like HMS Ocean inaugurating the De Havilland Sea Vampire) while an angled flight deck was tested by HMS Triumph and Warrior had a rubberised flexible deck and new landing deck, HMS Perseus testing a new steam catapult. They also changed hands and saw considerable foreign service: HMS Colossus became the French FS Arromanches (until 1974), Venerable became HNLMS Karel Doorman (until 1968) and later ARA Veinticinco de Mayo (decomm. 1999), Vengeance became HMAS Vengeance and later Minas Gerais (decomm. 2001) while Warrior, later HMCS Warrior became ARA Independencia (decomm. 1971).

hms triumph 1940
HMS Triumph in 1950

design development

The 1942 Design Light Fleet Carrier had for first challenge to be built by civilian shipyards, as regular military ones were already busy with completing ships on order and repair others. In fact the combat intensisity was such as west coast US shipyards also took part in this enterprise. The admiralty knew the fleet could not afford in wartime to built more armoured fleet carriers, and needed rather numbers, looking for a cheaper, smaller, intermediate step between fleet aircraft carriers escort carriers. They were to be faster than the latter, carrying almost double air group, and could be used for a larger variety of missions.

On the deck of those in charge of the design were dozens of combat reports of experiences in the early part of the war, inclusing limited expoerience with escort carriers, which were few in numbers at the time, starting with HMS Audacity. At least these shown the need for defensive air cover for convoys wether in the Atlantic or Mediterranean. Their conclusion, the same as the USN for the Pacific theater later, was just more aircraft carriers.
By mid-1941 already the Director of Naval Construction (DNC) was ordered to look out how to shorten the normal process of a lengthy construction for a carrier, with options such as:
-Converting the two Hawkins-class heavy cruisers (Hawkins and Forbisher), old but fast and large, with flight decks and aviation facilities.
-Convert large merchant vessels and better, passenger liners available into better versions of the merchant aircraft carriers (MAC)
-Create a brand new, simple and cheap design of lightly armed and unarmoured carriers, (such as Woolworth carriers)*.
In December 1941 after much arguing, the latter option was chosen, but a step further than escort carriers.
*Name given on the RN for commercial hull-based escorts, called in the US “jeep carrier” or “baby flattop”.

It was argued that The design had to be as simple as possible so construction time was reduced and include more shipyards into the construction scheme, and this including vivilian ones, those without naval construction experience. And still, the admirakty wanted these ships sophisticated enough to take part in fleet actions, not just escort. That implied a greater speed and greater air grooup, better faclities than fleet escorts. Quite a daunting prospect for engineers. The project was first dubbed ‘Intermediate Aircraft Carrier’, and as it evolved, ‘Light Fleet Carriers’ but since the naval design staff was completely underwater, the best available desig bureau next in Great Britain for this task was at the shipbuilding office of Vickers-Armstrong.
So these carriers could also be called the “Vickers Carriers” as they were indeed their design in very large part.

Another aspect was that Vickers and the admiralty intended these as “disposable warships”, to be scrapped after the war. But as a testimony to the soundness of their design and construction, they largely exceeded all expectation, having enough modularity for many upgrades and reconstructions, and seeing most of the cold war under other flags, the last being retired in 2001.


Construction was eventually approved by the Naval Board in February 1942, as soon as the Vickers design was overviewed. The first batch of orders comprised HMS Colossus and Glory laid down in March.
In total, no less than sixteen were planned, and so fourteen more of now “Colossus class” were laid down and assigned to eight shipyards: The lead ship, naturally was laid down at Vickers-Armstrong on 1st June (and later HMS Pioneer and Perseus), followed by renowned large civilian yards also with in some case, warship construction experience: Harland & Wolff (Glory and Warrior) or Titanic fame, Stephen & Sons (HMS Ocean), and by those also more accustomed to military ships: Cammell Laird (Venerable) and Swan Hunter (Vengeance), Fairfield (Theseus) and Hawthorne Leslie (Triumph), until then more accustomed to destroyers.
For the next sub-class Majestic, the same but HM Dockyard Devonport were added to this list. All in all, the two more “prolific builders” were Irish Harland & Wolff and London’s Vickers-Armstrong which also built the most carriers (5)n with the exception of HMS Hercules started there but fitted out at Harland & Wolff.

Originally the admiralty planned a “keel laying to commission” time of 21 months, but many modifications in design had these plans shattered and the standard duration went to 27 months, two years and more which meant they were certainly too late for the show for most. Builders even omitted many of the intended equipments, notably those for backup, but just two ships were built on 27 months.
Those launched from late 1943 were all commissioned in 1945 (with a single exception in December 1944) and thus in the end only four were ready on time to be massed into a single coherent fleet unit called the 11th Aircraft Carrier Squadron: Colossus, Glory, Venerable, and Vengeance. Only eight out of sixteen were completed on the original design. All the other were modified by taking in account war lessopns, starting with the Majetic class, of which none saw wartime service. The design was heavily criticized though, beyond poor living conditions until hammocks were banned for fixed bunks like the USN and centralised eating arrangements.


Hull construction & protection

Arromanches/Colossus hull design, docking drawings

The Light Fleet design was completed quickly, in February 1942, and Vickers engineers just took the Illustrious and scaled it down as a base for work. The rest was mostly simplifications left and right. The final displacement was setup at 13,190 tons standard for 18,040 tons fully loaded and the total lenght stretched to 680 feet (210 m) at flight deck level but 695 feet (212 m) overall at the poop, and 80 feet (24 m) in beam, just enough for plances to be stored, wings extended in the hangar, or some having room to take off with some stored on the side of the deck. The ship also had a projected draught of 18 feet 6 inches (5.64 m) standard displacement and up to 23 feet 6 inches (7.16 m) fully loaded. The interesing part was that the hull was built to Lloyd’s specifications for merchant vessels with however better compartment subdivision under the waterline. As planned, there was no armour nor specific areas of protection.

In overall appearance, these carriers indeed looked like reduced Illustrious carriers. The most disctintive traits common to these classes were the forward flared flight deck/bow connection or “hurricane bow” (something ported later on their Essex class under construction after painful experience with typhoons), and a smaller island, but still structured the same way with a three-stage bridge, tripod mast supporting the main fire director and radars, and a single, main straight funnel.

Arromanches/Colossus hull design, exterior fittings


The propulsion machinery was however to cruiser standards, those of the Fiji-class cruisers, with four 10,000 shp Parsons steam turbines coming from additional cancelled cruisers. These turbines would be placed into two single compartments, each fed by two Admiralty 3-drum boilers. The two turbines however were staggered en echelon, the starboard compartment being forward of the port ones, combined onto a single shaft. In total, they were rated for 40,000 shaft horsepower, enough for 25 knots (46 km/h; 29 mph) and 15 knots while cruising. This was indeed less than large fleet carriers, but far better than escort ones so that they could take part in fleet actions if needed. This also proved a rugged and dependable machinery, as testified by their long service life.


HMS Colossus, Glory, Venerable, Vengeance had the original armament of six quad 2pdr (40mm/39) QF Mk VIII, but also eleven twin and ten simple 20mm/70 Oerlikon Mk II/IV and a permanent hangar park of 37 aircraft. HMS Theseus and Warrior were however completed with less “pompoms” and more Bofors: Nineteen single 40mm/60 Mk III Bofors and six quad 40mm/39 Mk VII, no Oerlikon. Their hangar park was also of 37 aircraft, with the latter types (see below).
HMS Triumph was uniquely armed with twelve single Bofors 40mm/60 Mk III, and six quad 40mm/39 QF Mk VII pompom but received soon three single additional Mk VIII. (same air park)
HMS Ocean had six quad pompom Mk VIII plus seven single, and ten twin 20mm/70 Oerlikon Mk II/IV and a permanent park of 32 aircraft.

2-pdr QF pompom Mk.VII/VIII

pompom on hms nizam
The original six quad pompom were located on deck sponsons, four abaft the two axial lifts, one in front of the island, one aft of the funnel, on the island’s roof. The Mk.VIII was an old piece of kit already but more effective when combined with the MK IV Director and Gyro Rate Unit plus the Type 282 radar. War lessons, notably with HMS Illustrious′s Mk VIII (HV) mountings was very effective but still some recoignised that the performances of the few Bofors on HMS Prince of Wales when air attacked near near Singapore with their tracers were more effective than a multiple pom-pom in director control: The pom-poms lacked tracer ammunition, and the latter deteriorated in ready use lockers whereas the Type 282 radar failed in the equatorial heat.

In the end, the Royal Navy judged the pom-pom’s effectiveness as half the Bofors per gun in range, and same level against both torpedo planes and Kamikaze. Thanks to its octuple mounts it still outnumbered the Bofors in Commonwealth ships and served upt to 1945.
By 1944, both Remote Power Control (RPC) and radar tachymetric direction increased accuracy while issues with fuses and reliability were solved. In fact the single mount Mk.VII started to replace the 20 mm Oerlikon on a one-to-one basis since the latter had insufficient stopping power, and also to alleviate the lack of Bofors guns supplied.

20mm/70 Oerlikon Mk.II/IV

The Oerlikon guns were located in four groups of three, two sponsons forward and two aft, plus individual sponsons along the decks. It was clear by the summer of 1945 that this caliber was too weak to be of service against the latest generation of IJN aircraft and especially Kamikaze. They were replaced gradually at a one-per-one basis by single Bofors Mk.III on the four WW2 service carriers, and omitted completely on the Theseus, Warrior, and Triumph. The fact they were also on HMS Ocean has more to do with surplus.

40mm/60 Mk.III M Bofors

They were fitted on the late completed vessels, between single and quad mounts, knowing the latter replaced QF 2-pdr Pompom on a one-per-one basis, so on the same locations, and the single ones in place of the 20mm Oerlikon. This became the standard during transfers post-war in 1946-47. The USN in the summer of 1945 also reached the same conclusion and starte to remove the 20 mm Oerlikons and replaced them by single Bofors mounts when possible.

ONI depiction of the class
ONI depiction of the class

Aircraft Facilities

Hangar design

These ships were given the same flight deck design as for the Illustrious and Indefatigable classes, but smaller, measuring 210.3 m x 24.4m (390 x 80 feets) representing a surface area of 5,131m² (55,229.62 square feet). It was caraterized by two axial lifts, both rectlangular and the same size at 13.7 x 10.4m (45 x 34 feets) and weighting 6.8t (13.600 Ibs). They were located at equal distances from the prow and stern, the first used to launch aircraft as it was immediately close to the catapult.
There was a single catapult BH-III forward to the left side, capable of launching a 6.4t (12,800 Ibs) aircraft at 122km/h (75 mph).
There were ten arrestor cables, starting from the stern landing deck’s edge to about 2/5 of the deck, one crossing the aft lift. There was no crash barrier.
HMS Triumph would be the first in 1952 to test an angled flight deck, an idea from Navy Captain David Campbell.

The hangar measured 135.6 m (445 ft) overall in lenght, 15.8 m (52 ft) in width, and 5.3 m (13.4 ft) in height. This represented a total area of 2,142m² (23,000 sq.ft) and a total volume of 11,355m³ (400,000 Cubic Ft). As a reminder, 15.8 was larger the span of the Barracuda, wings unfolded. Since they all had wings folded, this was enough to store two aircraft side by side.

Aircraft fuel stowage carried onboard was 448,200 liters. They were located deep inside the hull, with backup safety for the pumping system up to the hangar there they were refuelled. The storage was judged adequate, but during their service in the pacific, autonomy left to be desired, and they needed more resplenishments, reducing their avialability. Resplenishment at sea was made mandatory for the next Majestic class, includung if possible aviation gasoline capacity was reduced further.

Air Group

Originally, all four carriers in service with the BPF (HMS Colossus, Glory, Venerable, Vengeance) had a permanent hangar park of 37 models, with fighters such as the Supermarine Seafire and FB like the Fairey Firefly, but certainly not the Wildcat IV (planned, still, in 1942), rarely the Hellcat (see below), but certainly the Corsair, standard with the BPF. It seems they were planned to carry the Swordfish also in early 1942, but it was replaced when commissioned by the Fairey Barracuda, and not the Avenger despite some sources saying so. Blackburn Firebrand: It seems only HMS Implacable and later HMS Indomitable used this model postwar, and they saw little service, as well as the HMS Eagle until it disbanded on 19 November 1952. No reference or photo about any use exists or is mentioned to my knowledge on the Colossus/Majestic class. The seafire and firebrand were apparently only used until their transfer to the Pacific, and back from it.

Supermarine Seafire

Supermarine Seafire Mk.47, VP480, N°800 NAS, 13th Carrier air group, HMS Triumph, North Korea July 1950. This was the only wartime action of this type for this class. These models carried “invasion bands” below and above the wings and aft of the fuselage.
The Mark 47 was probably the ultimate variant of a history-making classic, derived for naval use from the Spitfire. Among others it has a five-bladed propeller and a top speed in excess of 441 mph (710 km/h, 383 kn) and with the FS supercharger gear could climb at 29,500 ft. But the seafire Mk.I to Mk.III really had serious issues for carrier service: Converting a short-range land-based interceptor was not easy and compromises led to many structural damage due to heavy landings, while indeed at sea its short range condemned it to CAP (Carrier Air Patrol) work only. These problems were mostly cured by the time the Mk.14 arrived, more so on the “ultimate” Mk.47, which prodcution was slow and limited, and it only arrived in service from January 1948, seeing action on only a few light fleet carriers in Korea.

Fairey Firefly

Firefly FR MkI
Author’s illustration of the Firefly FR. Mk.I of the 837 Sqadron, HMS Glory, BPF 1945
A well-documented use. The Firefly also served in the RNAAF, notably as late as in Korea. The replacement for the triple cap Fairey Fulmar. It was a long range fighter/reconnaissance/ASW patrol aircraft which could double as attack aircraft with 4 × 20 mm (0.787 in) Hispano Mk.V wings cannons, 16x RP-3 60 lb (27.2 kg) rockets and up to two 1,000 lb (454 kg) bombs. Introduced from March 1943, about at the same time as the Barracuda, it was fast and powerful, way superior to the Fulmar. Proving very sturdy, long-ranged and docile it was declined into nine main variants and over 1700 were built, seeing also action in the cold war and with seven other countries aside the Commonwealth.
See also 1

Fairey Barracuda

Author’s illustration of a Barracuda Mk.II from 812 NAS, HMS Vengeance, BPF, 1945
The replacement for the Fairey Albacore, itself replacing the venerable Swordfish. This unusual high-wing monoplane was fitted with a set of large Fairey-Youngman flaps doubling as dive brakes to perform both the roles of torpedo carrier and dive bomber to replace the obsolete Skua. Underpowered at first, the main production versions swapped on the RR 1,640 hp (1,220 kW) Merlin 32, which was good all around but had no supercharger for high altitude missions.

Fairey Barracuda Mk.II, 814 Naval Air Squadron
Deployed from early 1943 on FAA Carriers, it took part notably in Operation Mascot and Operation Goodwood agains Tirpitz, but was also deployed with the British Pacific Fleet at the end of the war, not replaced by the Firefly which was a long range fighter/attack aircraft. It should have been replaced by the Blackburn Firebrand. They formed the backbone of the 11th ACS from June 1945, each with onboard the same single Barracuda and single Corsair squadrons. They were proferred over the Avenger which mostly served with armoured carriers.

Hellcat Mk.II (1944)

Seems there are contradictory information here. The only fleet carriers using these were HMS Indomitable and the only Colossus class was HMS Venerable (photos). No side photo to make a profile though. If you know one, thanks to point it out ! Other sources states HMS Ocean carried them but i can’t confirm this in my sources nor i could not found photos. Ex.

Corsair Mk.II (1944)

Corsair Mark II hms colossus
Author’s profile of a Corsair Mark II (F4U-1D) onboard HMS Colossus in February 1945
Deployed on all four British Pacific Fleet Carriers from February 1945. Here is one from HMS Colossus at that date. It was the standard fighter-bomber for light fleet carriers of the BPF mostly for standardization, as it was fully integrated with the US TF 38/58 and referred accordingly as Task Force 37/57. The BPF was formed in November 1944 but the light fleet carriers really started frontline operation by June 1945. The British FAA was an early adopter of the Corsair for carrier operations, starting in November 1943 with 95 Vought F4U-1. They soon found a way to its landing visbility issue, with a visual display system later adopted by the USN as until then it was relegated to land-based USMC operations in the Pacific.
By the time the 11th Aircraft Carrier Squadron was constituted in the Pacific they had received two squadrons only, one of Corsair Mk.IV (Goodyear FG-1A and FG-1D) introduced in early 1943 and replaced later from mid-1944 by the Corsair Mk.II (F4U-1D), of which 150 were delivered. With 21-24 (2 each) on each carrier, the 11th ACS had 51 of this total affected. They acted as fighter bombers from June 1944 and there was a lot of emulation and co-training with USN Corsair pilots during the last summer mission over Japan related to combined tactics.

Corsair II on HMS Glory off Rabaul, 1945

Corsair II being pushed on elevator, HMS Glory, 1945
On HMS Glory in August 1945, at the war’s end, had 21 Corsair and 18 Barracuda on board. This was quite representative of the end of the war for BPF carriers. After the war, cost-cutting obliged, air groups dwindled down.

Hawker Sea Fury

Author’s illustration of the Sea Fury
Post-war use only. A development of the land-based Hawker Tempest, adapted for naval use, the Sea Fury really was the last piston-engine model to enter service with the RN, boasting even with the full additional ordinance, a top speed of 460 mph and 20,000 feet climbed in just under five minutes, while staying very agile. It was almost overpowered with a 3,000 hp (2,200 kW) Bristol Centaurus engine coupled to a five-bladed propeller. If the Tempest was rugged, the Sea Fury was even sturdier, but also more compact and lighter. It was comparable in a sense to the Grumman Bearcat. From 1948, the Sea Fury entered service on nearly all light fleet carriers completed and those not yet leased or transferred, and saw plenty of action in Korea. A superb machine, production only stopped in 1955 and it served until 1968 in the Malay air Force among others.

Sea Fury taking off from HMS Ocean (R68) at Sasebo, 1952

Hawker Sea Fury F.B.11 during the Suez crisis, 1954

De Havilland Sea Hornet

Post-war use only. The Sea Mosquito was a first step into the reconnaissance/attack role in the fleet air arm already, and it was toughout a dedicated long range fighter based on the same basic features, including a new wood glue, Redux, and alcad, insertion of aluminium as reinforcements. Apart from the structure modernized, the wings represented a sythesis of the aerodynamic knowledge accumulated since the Mosquito with a laminar flow. The Sea Hornet entered in service too late for WW2, in 1946 and was indeed deployed on post war light carriers, used notably during the malay insurrection (1948-60) with success. With only 383 built, it was retired in 1956 from the frontline.

In 1950, HMS Vengeance carried 12 Firefly Mk.5, 8 Sea Hornet NF.21 and Triumph the same but 12 Supermarine Seafire F.47 instead of the Sea Hornets, while in action in Korea. Two years later, HMS Ocean carried 22 Sea Fury FB.11 and 12 Firefly AS.5 and three years later, she was reconverted as an helicopter carrier, carrying 6 Whirlwind HAR.1 and 6 Sycamore HAR.1, while HMS Theseus had ten Whirlwind HAR.1 on board.

De Havilland Vampire tested aboard HMS Ocean, Dec. 1945. The carriers completed with postwar modifications were used for many tests, includind those of early jets, such as the De Havilland Vampire here, as a 1st gen naval jet fighter.

Fairey Firefly over HMS Glory, Korea 1953
Westland Whirlwinds taking off from HMS Theseus (R64) at Suez, 1956
Bristol Sycamore and officers on HMS Vengeance


Type-293 AUR antenna upper center aboard HMS Swiftsure, Scapa Flow

At the end of their career, they allegedly carried a Type 79B, a type 281B radars and six type 282 fire control radars and the type 144 sonar
HMS Ocean: One SM-1 radar, six type 282, type 293 radars, type 144 sonar
Type 293 Air/Surface Search Radar: Designed as a short-range aerial-search radar in 1945, used the same transmitted as the Type 277 but new antenna design to also provide air warning. It had a stabilised “cheese” antenna 6 feet (1.8 m) in diameter, later 8 feet (2.4 m) and 12 feet postwar as the Type 293Q.
Type 291 Air Warning Radar: Designed as a destroyer type ship search radar in 1942 it became widespread on any slight ship. It worked at 214 MHz with a PRF of 500 per second, Beamwidth of 40°, Pulsewidth of 1.1 μs, Range of 9 nmi (17 km; 10 mi) and working on a 100 kW power.
Type 277 Height Finder Radar: The Type 277 was a surface search/secondary aircraft early warning radar developed from the Type 271 radar with more power and better signal processing as well as new displays and new antennas. It started to replace the type 271 in 1943 the largest ships, down to the destroyer.


INS Vikrant (ex-Hercules) in the 1980s. She has going through many modifications from 1946 and was decomm. in 2014, the oldest of all of these carriers.
The ships were barely in service in WW2 and already changes were made in AA artillery and radars as well as air group. But it’s for the completed ships postwar that the greatest changes occured.
In the 1950s it was clear that classic straight flight decks were not an optimal solution to manage air operations aboard, with always dangerous landings where there was a possibility of a crewh into the ones disposed for take off. This led to the idea of side lifts (which was dropped due to too much complications), but also of angled decks.

Angled Decks

Animation of a simple 6° angle deck on HMS centaur. Not much modifications needed in that case. On US carriers when air group operations were larger (meaning two taking off from the bow, not one like here), the angled deck had to be much more offset to port. An obligation since the island, obviously was always located to starboard. Modified SBC-27 Essex had two forward catapults and a much more angled deck, to 8-9°.

British angled decks development goes to RN Captain (later Rear Admiral) Dennis Cambell, working on a design study started in the winter of 1944–1945 after seeing so many frustrating deck operations and accidents. His report carried enough weight to be reviewed by a committee of senior Royal Navy officers, which decided that the future, with jets which obviously needed more deck space due to their higher landing speeds urged this modification to be ported on all existing carriers and those in construction.

Also called the “skewed deck”, “canted deck”, “waist angle deck”, or simply the “angle”, this was not just limited to a mere repainting of the deck. The aft part of the deck was widened, a separate runway was positioned at an angle from the centreline, ending with a specially built hull sponson-type extension (replacing existing sponsons by the way), reorientation of the arrestor wires, and new crash barrier, further forward. At least if the jet missed, it had some extra margin to take off again or ditch at sea but at least not collide with planes waiting for takeoff forward. This was a crucial evolution since the invention of the catapult to segment flight operations and a necessary adaptation since the biplane era of the interwar or landing speeds were much lower.

Calculations of landing speeds for the new jets in development, such as the De Havilland Vampire (which first flew in 20 September 1943, and it’s naval variant, the Sea Vampire, in 1944) and designs by 1945 of an angled flight deck commence in the idea of almost taking the entire lenght of the flight deck. The main advantage, since the forward lift was directly behind the starboard catapult, to streamline air operations, having simultaneous launch and recoveries, and abort landings, saving lives and materials.

This angled deck also displaced further portside the landing area and thus freed some margin for engineers to mount of a larger island, for improving ship-handlingn flight control, mount larger antenna and radar arrays, etc. This also still left a large open area amidships for arming and fueling parked planes and do some damage control. All in all, despite the limitation of small carriers like the Colossus and 1942 programme light fleet carriers in general, it became the staple of STOBAR and CATOBAR cold war developments. It was all experimented on the Colossus class vessels:

To be more prescise, it had to wait until 1952, when HMS Triumph was mofified at first with simply painting angled deck markings onto the centerline for touch-and-go landings, and on the other side of the pond on USS Midway. But by September to December 1952, USS Antietam obtaine a new sponson installed for a true angled-deck, making full arrested landings trias proving that solution was superior. In 1953, USS Antietam had British naval units training on it, and HMS Centaur became the first modified with a proper overhanging angled flight deck in 1954. In February 1955, HMS Ark Royal became the first fleet carrier to be constructed with an integrated angled deck. It was retrofitted for many other ships of the Majestic class such as HMAS Melbourne.

Reinforce Decks, larger catapults, lifts, etc.

Operating jets forced upon engineers a rethinking of the whole structure as well. The first goal in 1946 when were started to be completed the modified Majestic class was to accomodate 15 to 18,000 Ibs aicraft, but by 1955 the new standard was 20,000 Ibs+. Unlike wood and canvas structures of the 1920s with a small radial engine, jets were “full like an egg” between the turbojet and electronics, in addition of being all-metal. These models imposed by definition a much heavier deck.
It should be noted that rubberized decks were tested at some point

HMS Colossus in 1945, old author’s illustration. It was the typical camouflage of the day, with some alterations from one ship to another: Central dark navy blue band typical of allied camouflage in 1945 for large vessels, and wavy medium blue-grey bands on either sides.

HMS Ocean in 1945
A model of HMS Ocean in 1945, showing it’s own camouflage

HMS Perseus in 1950
HMS Perseus in 1950

HMS Triumph as a test ship in 1979
HMS Triumph as a test ship in 1979

HMS Colossus (1944)

Dimensions 695 ft oa x 80 ft x 18 ft 6 in st./ 23 ft 3 in FL (211,3 x 24,8 x 7,1 m)
Displacement 13 500 t. standard, 18-19,000 t. Fully loaded
Propulsion 2 shaft Parsons geared turbines, 4 Admiralty boilers 40 000 hp (30.000 KW).
Speed top speed 25 knots (46 km/h; 29 mph)
Range 12,000 nm (22,000 km)/14 knots (26 kph or 16 mph)
Armor Belt, decks max 190 mm
Armament 6×4 2pdr pompom AA, 16x 20 mm Oerlikon AA*
Air Group 37-52 aircraft (1945)
Crew 1,050 to 1,300 wartime with air group personal

Wartime service: 11th Aircraft Carrier Squadron

Following the retirement of the RN from the Indian Ocean in 1942, no operation could be mounted in the South West Pacific theatre until at least 17 May 1944. This time, with transfers and completion with US ships Operation Transom was launched on Surabaya. However since the US were in effect liberating British territories it was seen as an extension of their influence, urgeing as a political and military imperative to restore a British presence and take part in the pacific campaign, but also to retake Hong Kong and Singapore using British forces alone. However Churchill argued against it, as he did want to be only a junior partner, or that effort should be concentrated on Burma and Malaya. Naval planners, supported still supported the naval staff in what it was essential to restore British influence.

After transom, the British proposed a limited British role in the Pacific, but Admiral Ernest King was reluctant to this prospect, until the future Fleet send there should be self-sufficient, not depending on US resplenishment and supply netwwork. However during a meeting President Franklin D. Roosevelt overruled Admiral King’s opinion on that matter. The Australian Government was a good example of integrated combined operation with the US counterparts, having a common strategy and also wanted the British to counterbalance US omnipresence there.
The British Pacific Fleet or BPF was constituted around Admiral Sir Bruce Fraser at Trincomalee. It was called at first the “British Eastern Fleet” but his flagship was… the gunboat Tarantula. Later he would move his flag to the more suitable battleship HMS Howe.
The new Eastern Fleet was based in Ceylon and merged into the British East Indies Fleet to create the British Pacific Fleet, starting operations with limited means on Sumatra and later moved to Sydney.

HMS Venerable in 1946

The Royal Navy mobilized capital ships, aicraft carriers, cruisers and destroyers plus the Royal Fleet Auxiliary (RFA), and tried to aggregate the Royal Australian Navy (RAN), Royal Canadian Navy (RCN) and Royal New Zealand Navy (RNZN) elements, now that the Atlantic campaign was ending. It happened that on aircraft carriers in particular, many naval aviators were New Zealanders and Canadians. Personal from the South African Navy (SAN) was also aggregated, and a complement of ships by the USN, operating from facilities in Australia and New Zealand and soon a new CiC, Admiral Sir Bruce Fraser, with tactical command delegated to Vice-Admiral Sir Bernard Rawlings, whereas Vice-Admiral Sir Philip Vian was in charge of FAA operations. For a better integration with the USN, it was referred to as Task Force 37 or 57 (depending on the command), mirroring the US TF 38/58. The indispensible Fleet Train was called Task Force 113, with all FAA groups aggregated into the 1st Aircraft Carrier Squadron, based on four armoured aicraft carriers.

However the self-sufficient requirement was difficult to comply with, since the constitution of a fleet supporting a naval force at sea for weeks or months lacked proper infrastructures in the Pacific. However many officers did not agreed with King’s decisions and USN logistics authorities interpreted self-sufficiency in a “very liberal sense.” foortunately for the PBF. The fleet train at first indeed was only constituted with 20 vessels, whereas 134 merchant ships (1½ million gross tons) were expected, so the remainder was to make due between British merchant ships out of a pool of 560, already strained, and US vessels. Everything was being setup in February 1944, but it’s only by December that the BPF was ready to take part in major Pacific Operations.
A forward base was established at Seeadler Harbor in Manus atoll (Admiralty Islands) since Sydney was too far away and the FAA established Mobile Naval Air Bases (MONABs) in Australia mostly for supply and technical support, starting operations in January 1945.

The first major operation was Operation Meridian, air strikes in January 1945 against oil production at Palembang, Sumatra. The BPF now renamed Task Force 57 was named so when joining Spruance’s 5th Fleet on 15 March 1945, and TF-37 for Admiral William Halsey’s 3rd fleet. Its first combined operation was for Okinawa: The BPF supported the invasion by operating against the Sakishima Islands in full autonomy. However, when it arrived in Sydney by June-July, ofter after a stop at Manus (admiralties), the 11th ACS had little operations to do. The war ended in August and in the end they really never took part in frontline operations against the Japanese Home Island. This was just too late. Instead, they were often spread up for the British to retake Shanghai, Hong Kong and Singapore among others, as planned. They provided cover during troop landings and re-occupation, rounding up Japanese prisoners, locating and dealing with those still waging guerillas, accepting official surrenders of local officers, and when back home, providing much needed repatriation notably for POWs. For some, like the modified HMS Pioneer, they also provided reconstruction services, restablishing infrastructure.

Therefore, they never really “fought” in WW2, being either working up, fixing issues, qualifying pilots and training underway, despire being commissioned in late 1944 or early to mid-1945. Four month was the bare minimum to be operational.
When they were deployed, they carrier the following, standardized air groups:
Colossus: 24 Corsairs, 18 Barracudas
Glory: 21 Corsairs, 18 Barracudas
Venerable: 21 Corsairs, 18 Barracudas
Vengeance: 24 Corsairs, 18 Barracudas
Essentially, having no armour, meant these carriers needed to be kept away from known attack area of Kamikazes, in a second line. They could not really take on the same tasks as the armoured fleet carriers of the BPF, but provide them only distant support, scrambling air patrols on demand and operate in relatively uncontested areas against ground targets. In this, the Corsairs provided the means of attacks and fighter protection, while the Barracdua (which was disliked by pilots as underpowered and plagued by poor flight controls, they were confined to the 11th ACS, whereas replaced by Avengers on the active armoured fleet carriers of the BPF, with relief.

Having practically no use so close to the end of the war, these “disposable emergency carriers” could have been simultaneously one of the greatest waste of money of British taxpayer’s money ever, but in reality if some were indeed placed in reserve, they almost all served in Korea. Those not sold were scrapped in the late 1950s (Pioneer was a bit of an exception, BU in 1954) and early 1960s, some were transformed as floating workshops, many postwar new techniques and transformations were tested on these ships, having an influence on post-war completion of new aicraft carriers: Reconstruction of Victorious, modified sub-class Centaur comp. 1953-54, HMS Eagle (ex-Audacious), HMS Ark Royal -started 1942-, and HMS Hermes -started 1944- the last “classic British fleet carriers” before the STOBAR 1980s Invincible and 2010s Queen Elisabeth class.

But half were also sold: Colossus, Venerable, Vengeance, Warrior, Magnificient, Terrible, Powerful, Majestic, Hercules, being modernized sometimes twice or thrice, before and after transfer, seeing service for some with three navies (RN, Netherlands, Brazil for example), and being that cheap to acquire (based notably on their civilian construction), giving these countries an unexpected entry into the “great navies privilege”, the new capital ship that really counts. Some navies got rid of them over time, not based on limitations but simply on budget reaffectations, especially Australia, Canada and the Netherlands. It should not be forgotten that these vessels are costly to operate and maintain due due to their large size, consumption and crew. And they lacked proper armament anyway (they just had some room for 40mm Bofors, which were pretty useless against modern jets of the 1970-80s), could not operate good, large modern fighters (the A4 Skyhawk of the Argentines and Australians for exemple were no match for soviet-block interceptors such as the Mig-21 and beyond), or, like the Indians, only VTOL aircraft such as the Harrier. The lack of adequate ASW escort also condemned ARA Ventincinco de Mayo to be stuck in port for safety during the Falkland war due to the danger of British SSNs.

A remarkable post war career

NRB Minas GeraisNRB Minas Gerais
The whole class, especially the Majestics, saw action much more in the Korean war, than in WW2, making mpultiple tours of duty and taking part in the first air attack against Korea. HMS Ocean was deployed twice and Glory thrice, Theseus even ten times. They especially deployed the Sea Fury, pinnacle of the British piston-engine fighter, and an equally good fighter and bomber, which was the first to manage to shot down a Mig-15 in 1952. A rare case of piston-powered fighter preying on its jet analogue, symbolic of this transitional era. HMAS Sydney, former HMS Terrible, also operated in Korea and carrying out 2,366 sorties, with ten aircraft lost, usually to AA. Sydney would also have also later a tour of duty in Vietnam, as a troop carrier.

The French Navy loaned the lead ship, HMS Colossus, which was later purchased and renamed Arromanches, to serve in the Indochina war, seafires making 152 sorties, but with many accidents, and later she made three other deployments this time with Grumman Bearcat and Hellcat fighters.
In 1956 during the Suez Crisis, three carriers of the Colossus class took part in operationals against the Egyptian Navy. HMS Ocean and Theseus conducted the world’s first large scale heliborne assault, from a fleet of Westland Whirlwind and Bristol Sycamore. During the same event, FS Arromanches joined the fray by launching F4U attacks against Cairo’s defences.

The RCN also operated three of these carriers, not at the same time and exclusively for ASW patrols until new models of helicopter-carrying frigates made the cost of maintenance of such carrier redundant. A role similar to the HNLMS Karel Doorman, as part of the Royal Netherlands Navy, escorted by two new cruisers and destroyers, until she was deployed during the West Guinea dispute. There was a ceasefire between the latter and Indonesia before it could deployed it’s freshly arrived Soviet bombers against her.

The 1982 Falklands war which pitted the Argentine fleet to the Royal Navy, the former Doorman now renamed Veinticinco de Mayo provided cover for the landings on the falkland islands. However knowing the SSN HMS Splendid was deployed to hunt her down, and nearly succeeded to torpedo her out in the exclusion zone (order denied by political reason) she was sent back in pert. This proved wide as proven by the loss of ARA Belgrano by HMS Conqueror.

India acquired the incompleted HMS Hercules in 1957 (Majestic class), and Vikrant participated in the annexation of Goa. She was kept in the drydock during the 1965 Indo-Pakistani war, but took part in the 1971 war. She was deployed in the east (future Bangladesh) while a Pakistani GUPPY deployed there to hunt her down. However the latter sunk for unknown causes. Vikrant’s air group notably attacked Chittagong, Kulna, Mongla among others, speeding up the Pakistani defeat.
The only one which saw little action was the Brazilian Minas Gerais, decommissioned eventually in 2001. But the very last was the rebuilt INS Vikrant, former HMS Hercules, rebuilt and acquired in 1957, and seeing action until decommissioned 31 January 1997 but scrapped in 2014. There had been some prospects of preserving her as a museum ship, but this was never funded.


The Colossus class was just the first of a massive serie generally divided by authors into three classes: Colossus, Majestic and Triumph/Centaur. They all resurrected names of former pre-dreanoughts of the Royal Navy, in contrast to the adjectives used on interwar and wartime fleet carriers (from Furious to Indefatigable). The only exception would have been the Malta class, named also HMS Africa, Gibraltar and New Zealand.

Improved Colossus: The Majestic class

HMAS Sydney 1949
Both the Majestic and Colossus are assimilated in the same 1942 design by most authors. They were launched between September 1944 and September 1945, but construction was suspended at V-Day pending decision. Eventually, all would be completed post-war except HMS Leviathan, BU incomplete in 1968, on a modified design taking in account all lessons of the late phase of the war. The six ships of this class had an upgraded catapult, more powerful in order to launch the next generation of aicraft (jets included), arrestors cables were reinforced as well as the lifts, and the flight deck. They had a reduced fuel and petrol stowage (75,000 gallons) to compensate for strengthened decks and fittings to operate larger crafts. They also had more advanced weaponry and the latest radars, and were capable of resplenishment at sea (RAS). HMS Hercules, Leviathan, Magnificent, Majestic, Powerful, Terrible were completed respectively on 1961 (for India), never (BU 1968), 1948, 1955, 1957 and 1949.

All but one were sold at a very fair price on the international market in the post-1945 recession and budget cuts. This became equally a popular class during the cold war, with plenty of service and modernizations. Not the best fit for heavy and large jets many happened to operate the nimble A4 Skyhawk and STOVL like the Harrier. HMS Hercules became the Indian Vikrant in 1957, HMS Magnificent remained in RN service until 1965, Majestic became HMAS Melbourne in 1955, HMS Powerful became the RCAN HMCS Bonaventure in 1952, Terrible HMAS Sydney in 1948.

1944 Light Fleet Carrier Design: The Centaur class

HMS Hermes was later resold to India, becoming INS Viraat and seeing service until… 2017.
The last four derived from the 1942 design were the Centaur class light fleet carriers. They were further improved on many points and much larger, closing on the size of the previous Illustrious class. Otherwise generally similar to the Centaurs, eight hulls were laid down in 1944, the last one being HMS Bulwark (by Harland & Wolff), with HMS Albion, Arrogant, Bulwark, Centaur, Hermes, Monmouth, Polyphemus. However four (Arrogant, Hermes, Monmouth, polyphemus) were cancelled in October 1945, never laid down. The four remaining were seriously modified and launched 1947-53 to carry modern jets. They served for most of the cold war, Hermes seeing action in the Falklands.

Design-wise, they were larger and displaced more, had a better powerplant with larger 3-drum Admiralty boilers for 76,000 shp (instead of 40,000 shp) for 29.5 knots (vs. 25) and carried more oil, 4,000 tons (3,000) and a permanent park of 42 aicraft initially instead of 37, nbut slighlty less with jets in the 1950s. Their armament introduced four twin 4.5 in/45 (114 mm dual purpose guns) MkIII HA and sextuple Bofors plus no less than eleven twin mounts 20 mm Oerlikon, the best of all Britsh carriers so far. Their thick deck proved able to operate 30,000 ibs aircraft while their new catapults could launched this weight at 75 knots. The lifts were larger also and the hangar taller. Overall, all these reasons made them a better fit for extensive cold war modernizaiton and service unlike the previous vessels. Note, that like the Majestic class, these will be treated as a standalone post in 2023.

Conclusion: Disposable ? – Not bad for 50+ years of career

HMS Triumph in 1950
HMS Triumph in 1950
For starters, they were not “Light” carriers, like the American Independence class, as being larger, and officially designed as “light fleet carriers”. An ideal in-between escort carriers and fleet carriers. They were simpler, cheaper and developed with lessons learned culminating with the Majestic sub-class and Centaur class, which is so different it is separated by most authors. Redesigns plagued and extended their construction time so much that in the en only four would be in service in the Royal Navy by eatly 1945, Colossus being the first , had to wait for the others to contitute a coherent unit. So between training and qualification at home, and next acclimatization in the Pacific, they saw little service overall, especially compared to the Illustrious and Implacable classes, which does not really tell anything for their fighting qualities.

The four same Colossus however saw service in the Korean war, and when at home, extensively used as test beds for the latest carrier technology: They notably introduced the Angled deck and Mirror landing system, but their small size precluded the use of larger jets whereas many systems were obsolete. Stripped of funding and materials, the RN was reluctant to invest in their modernization and they were retired by the mid 1960s with the exception of HMS Triumph, converted into a service ship.

HMS Triumph in pre-wetting trials 1964
HMS Triumph in pre-wetting trials, 1964, the last active of this class, albeit no longer used as an aircraft carrier.

The four remaining (reserve) Colossus hulls and all five Majestic were only completed to be sold off on the international market. They were delivered brand new with many design updates, and for nations willing to still use piston-powered aicraft, early light jets and helicopters, they had an extensive lifespan due to their pristine state, despite their limitations. Given their price, they equipped many new navies, giving them at least experience in something until then reserved to “great fleets” (such as the US, UK, and Japan). France, the Netherlands, Australia, Canada, Brazil, Argentina, India, all their fleets massively benefited from these carriers. In contrast, the USN sold few of their immense armada of carriers. The mighty Essex class were modrnized and kept into the fleet as long as possible, and in the end only two former Independence class were sold. UK just did not have the budget of the US, but despite this in the 1950s, the country boasted still a large carrier fleet, especially compared to the rest of Europe, some brand new fleet carriers completed by some of the Centaur class.

Scr/Read More

RCNAF Sea Fury
Deck Landing Control Officer (DLCO) signaling Hawker Sea Fury to take off, on an RCN aircraft carrier, circa 1947-57. Original color. LAC 4950873/WO-A057319


http://3dPlans arromanches/ Colossus on history.de


HMS Venerable in 1945
HMS Venerable in 1945
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HMS Warrior recommissioned for the Korean War – British Pathé

Model Kits

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1:700 IHP hms colossus 1945 Kit review
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The Colossus class in service

This chapter will focus on their British service, in WW2 or afterwards and not on their national career under other flags, with just succint mentions of their fate. Arromanches, Karel Doorman, Veinticinco de Mayo, HMAS Vengeance, Minas Gerais, HMCS Warrior, Independencia would have their own dedicated post in the future. The years given are for the launch date.

HMS Colossus (1943)

HMS Colossus(R15) at Greenock c1945

WW2 service

After completion on 16 December 1944,HMS Colossus made her shakedown run and fixes close to the yard in January-March, under command of Captain G.H. Stokes. She left Glasgow on 12 March 1945 for the Far East, with 24 Vought Corsair IV fighters freshly arrived, from 1846 NAS plus 18 Fairey Barracuda Mk.II torpedo bombers from 827 NAS. She sailed south to the Channel, Gulf of Gascony, Spanish coast down to Gibraltar, then crossed the Mediterranean, the Suez canal, and arrived at Colombo in Ceylon on 13 June 1945.

On 7 Jul 1945, she was escorted underway by the battleship HMS Anson from Trincomalee for Fremantle after conducting refuelling exercises off Trincomalee. With HMS Vengeance and Colussus she arrived in Fremantle, joined underway by HMS Venerable (flagship, Rear-Admiral R.J.H. Harcourt) from Colombo and later joined by HMS Anson, which refuelled destroyers en route.
after arrival on 16 July 1945, HMS Anson escorted HMS Venerable, Vengeance, Colussus and the destroyers HMS Tyrian and Tuscan for Sydney. They all arrived at Sydney in the morning of 22 July except Tuscan (afternoon) and HMS Colossus which which entered Jervis Bay a bit earlier than the others.

Sydney, Australia, was the rear operating base of the BPF, and the unit was worked up throughout the remainder of July. Upon arrival, she saw her 20 mm Oerlikon guns replaced by single 40 mm Bofors guns and by August she became flagship, Rear Admiral Cecil Harcourt at the head of the 11th Aircraft Carrier Squadron with her sisters HMS Venerable, Vengeance, and Glory. The war ended as they were underway.

The first operation was a sortie to re-occupy Hong Kong (19 August), and together with Colossus were the carrier HMS VENERABLE, the cruiser SWIFTSURE, EURYALUS, the monitor PRINCE ROBERT and the destroyers KEMPENFELT, URSA, WHIRLWIND and QUADRANT under the operational name of Task Group 111.2 under orders of Rear Admiral Cecil Harcourt.
She was the floating HQ for the occupation task force on Shanghai with the cruisers Bermuda and Argonaut, plus five destroyers. She was alone as the head of Task Group 111.3 with HMS BERMUDA (Flying the Flag of Rear Admiral Servaes, Flag Officer Commanding 2nd Cruiser Squadron). Argonaut as said, plus the destroyers TYRIAN, TUMULT, TUSCAN and QUIBERON.

HMS Colossus (R15) off Shanghai 1945
HMS Colossus (R15) off Shanghai 1945

Cold War service

In December 1945, HMS Colossus carried Dutch POW back to Colombo. On 17 January 1946, Colossus arrived off Cape Town to fly off her Barracuda and Corsair to Naval Air Station Wingfield, prior to drydock refit in the Selborne dry dock of Simonstown. Refit was carried out notably to repair her damaged bow. On March 26th she was floated out, and went on with the refit at berth until April, sailed around Cape Point, Table Bay, recuperating her Corsair from RNAS Wingfield base. One however during landing operations veered to port and ditched to the sea. The pilot was rescued by the frigate HMSAS Transvaal close to her as safety ship.

In July 1946, she had completed her first tour of duty in the Far East. On 6 August, HMS Colossus was transferred to France, for a five year loan. She was recommissioned in Toulon under the new name “Arromanches” (A beachead in Normandy, part of the British landing zone “Gold”). In 1951, Arromanches was officially purchased as the loan expired, after two deployments to Indo China. She would make two more deployments until 1954. Later that same year she was back in the Mediterranean and took part in Suez operations flying Corsairs and Avengers. In 1957-1958 she was completely refitted, following British advances, with a 4° angled flight, mirror landing device. She would ne refitted again in 1968 as a multirole helicopter carrier and serve until 1974, BU in Toulon 1978. A full article will be written on Arromanches in the future.

HMS Glory (1943)

HMS Glory was commissioned on 2 April 1945, and spent the rest of her time working out and receiving with her Barracudas from 837 NAS and Corsairs from 1831 NAS. While at Sydney, she joined the 11th Aircraft Carrier Squadron, BPF, under command of Anthony Wass Buzzard.

HMS Glory (R62) with HMS Wizard (R72) in the Pacific, August 1945

The unit never really had the time to operate and arrived in Rabaul shortly after the end of the war, on 6 September 1945, accepting the surrender of the Japanese garrison there while other carriers of the same units were dispatched to to do the same at Hong Kong and Shanghai. She had on board Charles Causley, Cornish poet and broadcaster acting as Chief Petty Officer Coder, which wrote ‘The Song of the Dying Gunner AA1’ and two other pieces, ‘HMS Glory’ and ‘HMS Glory at Sydney’ describing notably the Japanese surrender.
After Rabaul, Glory arrived for the same in Hong Kong, and returned Australia. There, she took on board Commonwealth troops to their respective countries, starting with Canada. After this british “magic carpet” operation she was back home in 1947, to be placed in reserve. In November 1949, she went out of reserve, reconditioned to fill service by December 1950 as the war in Korea broke out.

HMS Glory in The Grand Harbour, Malta 1954
HMS Glory in The Grand Harbour, Malta 1954

She made a first tour of duty in by April 1951, the first of three. This first deployment saw heavy action and ended in September. She was back again in Korea from January to May 1952. Her third tour was between November 1952 and May 1953. After this, she served from 1954 as a ferry and troop carrier, but also helicopter base, back home. She started to experiment helicopter warfare. However due to the budget cuts of the time, by default of a resell, in 1956 the admiralty signed her planned retirement. She was sent in reserve, until 1960 when written off, sold for BU in 1961, Glory to Thos. W. Ward and scrapped in Inverkeithing.

HMS Ocean (1943)

hms ocean
After commission on 8 August 1945 (she was built at Stephen & Sons, Scotland) she departed to Cammell Laird, Birkenhead for modifications. The admiralty planned to use her to operate night fighters which included a new US-built SM-1 radar in place of her Type 277 height-finding one, as well as improved direction-finding system.

She departed in November 1945, completely missing operation on the Pacific and the end of the war, or any meaningful wartime operation. HMS Ocean was sent to Rosyth for flying trials and test her new equipments, and notably qualifications of her new De Havilland Sea Hornet air group, but also -amazingly- of her radar, night-capable Fairey Swordfish.

On 3 December 1945 she was the first to see a De Havilland Sea Vampire (flown by superstar test pilot Eric “Winkle” Brown) for a first ever jet carrier landing, on HMS Ocean. This was a world’s first as back in the US the composite Ryan FR-1 Fireball made the same.

HMS Belfast and HMS Ocean
HMS Belfast and HMS Ocean

In December 1945, Ocean departed for the Mediterranean Fleet. It had a mixed air group of very late pist-on powered models, the Supermarine Seafire Mk.37 (805, 816 Naval Air Squadrons) and modified Fairey Firefly as night fighters. She disembarked this air group at Malta, in June 1946, and was converted as troopship, bound to Singapore. From October 1946 she provided support to the destroyers HMS Saumarez and Volage damaged by mines in the Corfu Channel incident. In May 1948 she took the head of a task force supporting British troops withdrawal from Palestine and provided air cover for the also evacuated RAF bases there.

Next came the war in Korea: HMS Ocean made two deployements in May-October 1952 and May-November 1953. In August 1952, her onboard Hawker Sea Fury engaged incoming North Korean MiG-15 jets and one was shot down. It was one of the only rare dogfights between jets and piston-powered models and HMS Glory, again, inaugurated a “first” of the kind. In August 1954, she joined the Home Fleet’s training squadron. Soon however she was prepared for a new action, the Suez crisis.

She was converted and prepared to act as impromtu assault ship, helicopter carrier. She inaugurated the first ever large-scale heliborne assault with Westland Whirlwind and Bristol Sycamore onboard, together woth HMS Theseus: Both landed 425 men, 45 Commando and 23 tons of equipments dirtectly into Port Said, in a mere 90 minutes. Back home, her active service saw nothing notable in 1956 and by September 1957, she visited Helsinki, prompting complains of the USSR. This was her last overseas deployment. Back home, she entered extended reserve in 1958. In 1961 she as written off, and sold for BU, scrapped in 1962 at Faslane.

HMS Venerable (1944)

HMS Venerable in 1945
HMS Venerable in 1945
HMS Venerable (R63) was completed at Cammell Laird on 17 January 1945, second of the class after Colossus. She was worked out for her sea trials, post-trials fixes, and made a short shakedown cruise with intensive training, prepared to join the BPF in the Pacific. She sailed for the Far East as soon as possible, joining the 11th Aircraft Carrier Squadron with her sisters Colossus, Glory and Vengeance, loaded with forty F4U Corsair fighters and Fairey Barracuda on board. compléter !!!!!!!!!!!!!
Cold War Career:
In 1948, she was sold to the Netherlands as HNLMS Karel Doorman, taking part in the 1962 in Western New Guinea. The format of the Dutch Netherlands Navy was reviewed down afterwards, and after her 1968 boiler fire she was repaired, overhauled but resold to Argentina, renamed ARA Veinticinco de Mayo. She famously took part in the Falklands War. By 1990, declared inoperable she was resold to be cannibalized to the Brazilian Navy, operating Minas Gerais of the same class. Her gutted hull was eventually sold for BU, scrapped in Alang, India in 2000. Both Karel Doorman and Veinticinco de Mayo would be seen in their own dedicated posts.

HMS Venerable in 1945, other view
HMS Venerable in 1945, other view

HMS Venerable 1947
HMS Venerable in 1947

HMS Vengeance (1944)

HMS Vengeance 1945
WW2 service
HMS Vengeance (R71, Commisionned 15 January 1945) was only ready by 11 March 1945 when she left the River Clyde (Built at Swan Hunter) for her working-up trials in the Mediterranea, Malta, before proceeding to the far east. These trials were completed on 21 May so she assigned to the 11th Aircraft Carrier Squadron, BPF.

From Alexandria and Port Said she arrived to Trincomalee in the Indian Ocean before proceeding to Fremantle and Sydney, on 26 July. There, she had eight Oerlikons replaced with Bofors 40 mm guns and she was assigned to Task Group 111.2 to attack Truk. However as she was prepared, war ended on 15 August, while still in Sydney. Instead she was dispatched in Hong Kong for the Jpanese surrender and covering the occupation force, and was present on 3 September as the place was this surrender took place.

She was still there until December 1945, before proceeding to Austrlia for her refit, and came bacj afterwards to Hong Kong, only departing later for another mission: She landed in April 1946 No. 11 and No. 17 Squadrons RAF to Miho, Ibaraki in Japan, assigned to the British Commonwealth Occupation Force of the achipelago. She was assigned there until 20 July 1946 and departed for home, Devonport, reached on 13 August after stopping in Trincomalee. By December 1946 she was sent in Scotland to serve as a training carrier.

HMS Vengeance (R71) underway in 1945
HMS Vengeance (R71) underway in 1945

The cold war
During this career she brought cadets to Oslo and Trondheim in June 1947, hosting First Sea Lord Sir John Cunningham and by early 1948, joined the 3rd Aircraft Carrier Squadron of the Home Fleet. She visited St Helena island in October and then led the Squadron to South African by November. After reutrning home she was converted for Arctic conditions. From 5 February to 8 March 1949 she took part in Operation Rusty, a little known experimental cruise in Arctic waters, testing the fleet in extreme cold. It reflect a similar USN operation HighJump in 1947. Seems common objectives were also how to wage war on USSR under these latitudes.

By June 1951, Australian Defence Committee recommended the acquisition of another carrier on loan while waiting for HMAS Melbourne (freshly renamed and in completion at the time, 21 months beyond schedule) was ready. The RAN looked for a four-year loan, from late 1952 to late 1956, until HMAS Melbourne would be fully operational, while upgrading HMAS Sydney, and modified to operate the Sea Venom and Gannet dyring the Sydney upgrade. However the British Admiralty announced that for these, the installation of a new arrestor cable system would further delay introduction, and based on Australia’s taxpayer money.

HMS Vengeance was selected for this loan and minor modifications were complete by January 1952, with the crews locally drawn from the just reserved light cruiser HMAS Hobart. Australia paid the modifications and operational costs, not the loan, which started by mid-1952 when the liner Asturias carrying the intended crew arrived in UK. The rest of her carrer, as HAMS Vengeance started from 13 November. She became a TS by 1954 and was decommissioned on 25 October 1955 to prepare crews for HMS Melbourne. Her motto was: “I Strike I Cover”.
Afterwards, she was underway for UK by June, stopping in Singapore to collect RN helicopters and arriving on 13 August before decommission, her crew being repatriated onboard HMS Melbourne commissioned on 28 October.

HMS Vengance with her new flight deck before transfer to Brazil, 1960

HMS Vengeance was not reactivated. Instead on 14 December 1956, a contract was signed wit Brazil for a hard sell to US$9 million. From mid-1957 until December 1960 however, she was compehensively refitted and reconstructed at Verolme Dock, Rotterdam at US$27 million (to compare to the purchase cost). She notabkly earned a 8.5° angled flight deck, better steam catapult, arresting gear, and reinforced hangar lifts, better mirror landing system and other modifications to operated jet aircraft. The superstructure was changed also with a new lattice, new radar suite, fire control system.She also had new Boilers, all the electric al system was overhauled, expanded and converted to AC power. She was commissioned as NAeL Minas Gerais on 6 December 1960, arrived in Rio by January 1961 and after a well fill new career, ended service with a decommission on 16 October 2001, the last ever WW2 aircaft carrier in service.

HMS Pioneer (1944)

HMS Pioneer
HMS Pioneer (R76) was completed at Vickers on 8 February 1945. She was fitted out and commissioned as an aicraft repair ship, part of the “supply and maintenance train” of the British Pacific Fleet. She was worked up to shape and without time to make a proper shakedown cruiser, was rushed for Australia on 30 March 1945 via the Mediterranean and Indian Ocean, arriving in Sydney on 13 May, to be prepared and transferred to Manus Island (Admiralty Is.) on 21 June, preparing for the last operations on the coast of Japan.

However she was still in Manus when the Japanese surrendered on 15 August. Meanwhile she received 24 aircraft and repaired them. She was later sent to Hong Kong by late September, helping with rebuilding infrastructures. Her well tooled crew restored power, telephone, transports, cleared streets. Afterwards she returned to Manus to resupply and was back for the same mission in Hong Kong by late November. She then departed for Sydney in December and stayed there during Xmas and the new year for the crew’s first leave, until departing for UK on 17 February 1946. She was placed in reserve on arrival, and amidst 1950s budget cuts and without much interest for export, she sold for BU to Thos. W. Ward in September 1954, broken up in Inverkeithing, having the shortest career of any Colossus class carrier.

HMS Warrior (1944)


Planned for the far east campaign

HMS Warrior was at first laid down and intended for the RN, but as construction went on at Harland & Wolff, by May 1944 it was already clear that the European theater was now settled and the Royal Navy was to focus on the Pacific. Therefore, focus shifted to this theater and at the same time, the general staff of the Royal Canadian Navy, now freed from most of the fighting in the Atlantic, which was mostly over, thought how to contribute to operations in the Asian theater as well, calculating it would required a larger fleet, both in numbers and size.

The RCN planned to return its escort carriers on loan, HMS Puncher and Nabob to the RN in exchange for loaning two of the new Colossus light fleet carriers in completion. Negociation started by July 1944 but they were only finalised in April 1945: The RN staff decided to allocate HMS Warrior and Magnificent on loan, with a purchase option at a later date. Negotiations followed for the air group deliovery and ended in May for what naval air squadrons would be needed, but in between, both vessels were completed, HMS Warrior by 2 April 1945.

HCMS Warrior (1946)

The air groups of the new Canadian naval aviation were materialized through the creation of four squadrons, transferred from the Fleet Air Arm, all for HMS Warrior: The 803, 883 Squadrons (Supermarine Seafires) 825, 826 Squadron (Fairey Firefly). HCMS Warrior was eventually transferred, but the war ended in between. She was indeed only commissioned by 24 January 1946, and so never ventured in the far east as intended. She was under command of Captain Frank Houghton during her Sea trial, completed in March 1946, then qualifications performed at Spithead in April. When steaming to Canada she carried only 803 and 825 Squadrons (One of each type). 883 and 826 Squadrons were paid off instead, amidst budget cuts.

HMCS Warrior passing under the Lion's Gate Bridge
HMCS Warrior passing under the Lion’s Gate Bridge

HCMS Warrior arrived in Halifax on 31 March 1946, escorted by HMCS Micmac and the minesweeper HMCS Middlesex, assigned to the Canadian Atlantic Fleet on 23 March. April-May were spent in yard fixes, and she started major fleet operations, with a first accident in August, a Firefly from 825 Sqn ditching when landing, pilot and observer rescued. On 23 August while transiting St. Lawrence River, she ran aground at Pointe Sainte Antoine near Montreal, after her rudder jammed. Tugboats eventually had her unstuck and she resumed her trip to Montreal, being the largest ship ever visiting the old French Canadian City.

HMCS Warrior in Vancouver, British Columbia

The RCN however soon realized she carrier was not optimal for great cold operations, lacking heating equipment for effective service in the North Atlantic waters. She she was transferred to Esquimalt in British Columbia by November 1946, for a round of Pacific service. She made a long trip south, via Bermuda, Acapulco, Mexico and San Diego in California, where she arrived by December.

On 18 January 1947, Commodore Harry DeWolf became her new captain while undergoing repairs (for her St Lawrence grounding). On 31 January, she lost another Firefly off Portland Island. However soon further budget cuts had the Canadian admiralrt review its loan and concluded they could no longer operate two aircraft carriers which would become obsolescent. Negotiations to return them were assorted by the fact the RCN considered Warrior unfit due to the lack of heating. By February 1947 she returned to Halifax and was prepared to depart for UK escorted by the cruiser HCMS Uganda and destroyer HMS Crescent.

Back to the RN and rubber deck trials

The “task force” transited the Panama Canal and were escorted out by the Canadian destroyers Nootka and Micmac, visiting Havana in Cuba and bacl to Halifax on 27 March, sailing afterwards to Bermuda with HMS Nootka for her last naval exercise with the Royal Navy, and next an overhaul in Halifax, plus exercises alons the east coast. By August she was back in UK to received new squadrons with Firefly IV and Hawker Sea Fury, and returned tp Halifax on 28 August 1947. HCMS Warrior escorted by Haida sailed to Bermuda to be paid off and departed for UK on 12 February, arriving at Belfast on the 20th and on 1st March to Spithead to have her aviation fuel removed. She was retintegrated officially in the Royal Navy on 23 March 1948, at Portsmouth.

As HMS Warrior she was modernized in drydock at Devonport: She received a new “flexible” flight deck, testing undercarriage-less aircraft with modified De Havilland Sea Vampires, successful but not implemented for service, with its ingenious rubber sheet supported by air bags, extending from the bow to the barrier forward of the island over the existing flight deck. Aft of it was located akso a a light steel ramp 2 feet 6 inches (0.8 m) high and single arrestor wire. Trials were over by March 1949 and the carrier was paid off, reserve, in Portsmouth.

HMS Warrior in Korea-Indochina

HMS Warrior, USS Des Moines and HMS Gambia at Malta, 1951
HMS Warrior, USS Des Moines and HMS Gambia at Malta, 1951 (IWM)
Reactivated in June 1950 this time she was modified to carry troops and aircraft to the Far East: This was the start of the Korean War. She departing in August for her first tout of duty and sailed back home. By June 1951 she was sent to the Mediterranean, again carrying aboard troops (in that case the 16 Parachute Brigade). They headed to Cyprus, as the middle east crisis developed. Back home, HMS Warrior was refitted in 1952-1953 in Devonport drydock, modernized: New, strong lattice mast for new radars, Type 281Q and Type 277Q radars, IFF (Identification friend or foe) aerials, enlarged bridge, enclosed. When done, she prepared qualifications of the FAA 811 Squ. (Sea Fury) and 825 Sqn (Firefly) after her sea trials.

She made another tout of duty off Korea in 1954, patrolling the coast after the ceasefire. At the same time, the Indochina war was all but lost by the French and negociation soon ended with a separation between north and south, which also provoqued reprisals and refugees in the north. By September, she took part ot Operation Passage to Freedom, evacuating anti-Communist refugees from Haiphong in North Vietnam, to Vung Tau in South Vietnam (3,221 in two trips). Later her captain was awarded the South Vietnamese Presidential Citation.

Her last service leg

HMS Warrior (R31) in the 1950s
Back home, she was teken over for her last refit in 1955 at Devonport, this time to operate jets, with the same modifications as comparable carriers of her class:
-Angled flight deck, 5° portside amidships
-Portside sponsons removed
-Reinforced deck to support 20,000 pounds (9,072 kg) jets.
-Catapult upgraded to launch 20,000-pound aircraft
-Arrester wire system improved to stop the same at 60 knots (111 km/h).
-Reinforced lifts for the same standard
-New modern mirror landing aid system
-New Type 961 CCA radar.
It was intended to turn her as training and trials vessels for further upgrades to other ships of the class (and Majestic class).
She acted first as training ship until dispatched to the Pacific for Operation Grapple as the ship HQ for the first British hydrogen bomb tests. She operate a flight of Westland Whirlwind helicopters and Grumman Avenger AS4 aircraft, collecting air samples for lab tests. Before departing, the Avengers were thrown into the sea, contaminated as well as surplus to requirements. Back home, HMS Warrior was decommissioned in February 1958. She was offered for sale, notably when transiting via Argentina, and making more port visits and demonstrations in the country as a bid to concluded a sell.

As ARA Independencia

ARA Independencia, showing her brightly colored Texan trainers. Src. Taringa via pinterest

This proved fruitful as the government accepted the request and she was sold, renamed ARA Independencia, officially transferred on 6 August 1958. But back in the UK, and the ensign was only raised on 4 November at Portsmouth, time for her to receive her assigned crew and returned to Argentina on 10 December. The Argentine Naval Aviation started qualifications on 8 June 1959, and official commission was done on 8 July 1959. At the time she only carried eight Bofors but by May 1962 she earned a quadruple and nine twin Bofors in addition.

She also had a new air group befitting on her 1955 modernization: She carried 24 aircraft, a squadron of Vought F4U Corsairs, completed by North American SNJ-5Cs Texans and Grumman S2F-1 (S-2A) Trackers. Soon she also adopted a flight of Grumman F9F Panther from August 1963 and TF-9J Cougar, but only for tests as they proved unsuitable. She also later received NA T-28 Trojan trainers in replacement of her Texans. However as the more modern ARA Veinticinco de Mayo entered service in 1969 she was placed in reserve the next year and scrapped in 1971.

HMS Theseus (1944)

HMS Theseus was not completed before peace came up by August 1945. After working up and post shakedown fixes, she went through basic training to be used as a training vessel basically until the Korean War.
In 1946, she conducted aircraft qualification and a large battery of trials without the emergency of being sent to the Pacific. Operational service really commenced by late 1946, after being prepared for a first our of duty in the Far East and join the British Pacific Fleet based at Singapore. She was to act as Flagship, Flag Officer Air, Far East. In 1947, she hold the same role but as the 1st Aircraft Carrier Squadron, BPF. On her return home she was refitted for Home Fleet service and after completion joined the 3rd Aircraft Carrier Squadron at Scapa Flow.

HMS Theseus in the Korean War
In 1950, she was deployed to Korea for standard carrier operations, suppressing enemy defences and communications at Chinnampo and other sites, and for her second mission, provided Combat Air Patrols. It happened her dysfunctional catapult was unable to launch heavily armed aicraft as intended. Her third mission was as part of the Commonwealth Task Force, reaching Sasebo in Japan. Back in Korea she launched powerful air strikes on bridges, troops concentration or multiplied patrols in search of opportunity targets mostlu around the Chinnampo area.

HMS Theseus off Japan 1951
HMS Theseus off Japan, 1951

During her fourth operational patrol from December 1950, a single Fury with rockets rampaged land gathered Chinese vehicles in heavy snow. Later Chinese troops were “visited” daily by her air group. After her fourth tour had had 1,630 hours under her belt, with 1,400 rockets spent.

From 5 January 1951 after some rest at Sasebo and resplenishment, HMS Theseus resumed operation for her her fifth patrol, this time in close support of the American 25th Division south of Osan (South Korea). On 15 January, was celebrated her 1,000 accident-free landing. Her Carrier Air Group were awarded the Boyd Trophy afterwards for its achievements. She made a sixth operational patrol by late January, with some accidents. On 26 January one landing aicraft spinned out of control into the sea, no suvivor coulkd be located by her escort HMS Cossack. A second was one short down by AA fire, the pilot bailing out off Tongduchon-ni and rescued by a USN helicopter 90 minutes later. On 2 February, a Sea Fury burst a tyre while landing.

HMS Theseus’ seventh operational patrol saw a casualty by Firefly gun misfire, and intensive close air support for the U.S. IX Corps, Wonju area. The eight patrol started on 4 March 1951, in the area of Chinnampo to Kuhsa-Sung, as a diversion for a fake amphibious assault. She had two more crashes and her ninth patrol on 24 March saw one Fury shooting down a Mig. One day, a squadron attacked and rampged six North Korean vessels.

HMS Theseus

The tenth patrol was her last of this war. It started on 8 April 1951, from the Sea of Japan and with the carrier USS Bataan, and a combined allied destroyer screen (HMS Consort, HMAS Bataan, HMCS Huron, USS English and USS Sperry). On 10 April, two Sea Furies shortly duelled with USN Corsairs in a friendly-fire incident. One was seriously damaged while in reconnaissance duties. Another was shot down and the pilot taken prisoner, down by flak, but later escaped capture. Two more were shot down trying to locate him. If the first was soon rescued the other, injured, had to flee his North Korean purusers under fire of a Sea Fury remaining as close support before a helicopter arrived some 38 minutes later.

More strikes would follow and Theseus deplored another aicraft shot down. The American helicopter pilot that picked the pilot up under heavy fire was later awarded the DSC for outstanding bravery at the British Consulate in Seattle on 15 January 1952. Task force operations ended, Bataan departed for Sasebo but Theseus remained behind, now patrolling the east coast. She lost another aircraft, which ditched due to engine failure. Operations ended to days later as she was relieved by HMS Glory and returned to Sasebo.

By late 1951 she was back in the Home Fleet as Flagship, 2nd Aircraft Carrier Squadron and year later, as Home Fleet Flagship, detached to the Mediterranean to relieve HMS Glory and taking part in joint exercises in Mediterranean. By February–March 1952, she was assigned the 14th Carrier Air Group for NATO Exercise Grand Slam. The next year back home, she took part in the Cornonation Fleet Review of Queen Elizabeth II.

HMS Theseus at Suez 1956

Suez Crisis:
In 1956, Theseus carried a heliborne commando carrier with HMS Ocean, during the Suez Crisis, by November-December. Her helicopters carried troops ashore and started a noria to evacuate wounded soldiers. This was her last wartime action. Back home due to budget cuts she was placed in reserve in 1957 and decision was made in 1961 to write her off. She was sold and BU at Inverkeithing in 1962.

HMS Triumph (1944)

HMS Triumph
HMS Triumph
HMS Triumph was launched on 2 October 1944 and commissioned on 6 May 1946. After working up and training, doing pilot qualiifications, by February 1947 she was assigned to the 2nd Aircraft Carrier Squadron based in Mediterranean Fleet, until August 1948. Back home she was refitted and placed in reserve, then recommissioned in 1950 for the Korean war.
Korean War service
She was prepared and departed for Japan, assigned to the Far East Fleet based in Sasebo, as tensions grew in the the region. Before going there she learned off Hong Kong as war breoke out in the peninsula so she was placed in state of high alert as her escort, the destroyer Cossack, also in charge of HMS Theseus. All refuelled at the Royal Australian Naval base at Kure in Japan and the destroyer Consort and the cruiser Jamaica joined the fleet as the Australian River-class frigate Shoalhaven and Fleet Auxiliary tanker Wave Conqueror.

The task force sailed for Okinawa to refuel and proceeded to the western Korean coast to join other assests of the Royal Navy. Beng the first, and sole British carrier in the Far East at the time, she was to be given a considerable role. This force joined the US Fleet with the 827 Naval Air Squadron (Triumph’s air group) with Fairey Firefly on board loaded with rockets to commence operations. They were escorted by 800 NAS Seafires.
Thus air group operated with the Corsairs and Bearcats of the USS Valley Forge. They concentrated on airfields at Pyongyang and Haeju (3 July). It happened soon however the resemblance of the Seafire to the North Korean Yak-9 play in a tragic “blue on blue” on 19 July 1950. The pilot was rescued by a Supermarine Sea Otter (replacement for the Walrus).

HMS Triumph (R16) off Iwakuni
HMS Triumph (R16) off Iwakuni

On 28 July, a flight of Seafires investigated a flight of American B-29 bombers, which mistook them for Yaks and fired, downing one of the Seafires. The pilot was later rescued by USS Eversole due to the weather conditions. Seafires provided mostly CAP and Fireflies ASW patrols when not used for air attacks. Eventually HMS Triumph left for Kure to resplenish and rest for eight days. On 9 July she was back escorted by the cruiser HMS Kenya, destroyer Comus and the Canadian Athabaskan and Sioux. Seafires also started photo-reconnaissance missions over Mokpo, Kunsan, Chinnam and Incheon for the UN forces and later destroyed two North Korean gunboats. They also dealt with railway tracks, coasters and oil tanks.

On 23 August HMS Triumph sufferring the attrition rate of its seafires and firefly only had nine operational aircraft left. She departed for Saseb with USS Valley Forge and Philippine Sea. Meanwhule the North Korean managed to badly damage HMS Comus, sent to Kure for repair escorted by Consort. After this, CAP were doubled down. On 29 August, a Firefly missed, ended in the safety barrier and a piece of propeller blade penetrated the operations room, killing Lt. Cdr. I. M. McLachlan (800 NAS). On 30 August she returned to Sasebo, received 14 new aircraft from HMS Unicorn. On 3 September, HMS Triumph departed Sasebo for the West Coast, and started to perform CAP and reconnaissance, bombardment spotting notably for Jamaica and Charity.

From the 6 September escorted by Athabaskan, Warramunga and Bataan she replaced the US 7th Fleet on the east coast, launching operations from the 8th, but bad weather almost stopped them on the 9th. An airfield at Koryo was devastated still. 800 NAS later was down to six aircraft and the ship proceeded back to Sasebo. She would be soon recalled to take part in the Battle of Inchon.
On 12 September, escorted by Warramunga, Charity, Cockade and Concord, HMS Triumph departed to cover the landings at Incheon as part of CTF 91 (Commonwealth Task Force 91). HMS Ceylon and HMAS Bataan of the Northern Group completed the escort. The Southern Group comprised Athabaskan, Cayuga and Sioux. Triumph provided ASW patrols, interdiction and spotting. Fireflies also made bombardment spotting for Jamaica and Kenya, obliterating North Korean positions and a weapons cache, decapitating a hill and creating a 8,000 feet smoke plume.
Admiral Andrewes and UN commander General Douglas MacArthur congratulated the carrier with “My heartiest felicitations on the splendid conduct of the Fleet units under your command. They have added another glamorous page to the long and brilliant histories of the Navies of the British Commonwealth.”

On 17 September, North Korean aviation maaged to arrive at low altiude not to be radar-picked and damaged the cruisers Rochester and Jamaica, so CAPs doubled down. On 21 September HMS Triumph was bacl to Sasebo for the last time, in dry dock for fixes and sailed to Hong Kong on 25 September, relieved by HMS Theseus.

Later carrer:
Back from Korea, HMS Triumph replaced the old Country-class HMS Devonshire as cadet training ship. She carried 100 RN and Commonwealth cadets on three yearly cruises (West Indies, Scandinavia and British Islands, and Mediterranean). At the time she also had three training Boulton Sea Balliol aboard.
In 1952, she was used for angled flight deck markings trials, which success led to the development of this new design, before further modifications were made. In 1954, she ferried survivors of the troopship Empire Windrush from North Africa to Gibraltar.

In 1955 she made a ‘goodwill’ visit to Leningrad with her new captaibn, Varyl Begg. Cadet training duties ended the same year after the autumn cruise, now redundant. The admirakty decided toconvert her as a repair ship, a new career between 1956 and 1965, an new pennant “A108”. She based in Singapore, taking part in major international exercises in 1968. She was also used to transport troops during the Vietnam war. In 1975, back home, she was placed in reserve at Chatham Dockyard but only struck in 1981, scrapped in Spain, the very last Colossus class in British service.

HMS Perseus (1944)

HMS Perseus
HMS Perseus
HMS Perseus (R51) was launched as HMS Edgar on 26 March 1944, but renamed Perseus in July 1944 when it was decided to convert her as an aircraft maintenance ship. She was completed on 19 October 1945 after this redesign.

Conversion as repair and maintenance carrier
To maximize space for workshops and stores, her arresting gear and catapult were not fitted. All facilities for flying operations were removed as well and instead, two large deckhouses were constructed, port of the island and at the rear of the flight deck. Her single hangar was modified to maximize storage and she kept her two aircraft lifts and had two large cranes mounted on the flight deck and two small self-propelled lighters for carrying unflyable aircraft and transfer them between ships or shore. She also carried more bulk petrol storage, 98,600 imperial gallons (448,000 l; 118,400 US gal) total and had a crew of 854 and an additional 222 repair personal.
All repair tests were carried out aboard in the hangar or on deck, and she had workshops for engine repair and component manufacturing tooling of needed, plus large reserves of spares for all types in service.

Early service in the far east
HMS Perseus arrived in Portsmouth on 24 October 1945, started working up until departing for Australia on 17 November, arriving in Sydney on 21 December, taking charge of the “Air Train” supporting the British Pacific Fleet. She later returned to Melbourne and departed on 26 March 1946 with a load of aircraft to return home, arriving at Rosyth on 17 May. She was placed in reserve amidst postwar austerity.

Catapult Test ship (1950-52)
In 1950 she was used to test an experimental steam catapult, placed on top of her existing flight deck, the port deckhouse being removed. This large catapult intended for jest made some 1,560 launches with at first 1,000 wheeled dead-loads of varying weights, up to unmanned aircraft and manned aircraft of all Fleet Air Arm types. She was sent to Philadelphia, USA, on 14 January 1952 to demonstrate it to the Navy staff, launching 127 manned aircraft, including of USN models of various types. After this, HMS Perseus was back in Portsmouth on 21 March, her catapult removed as her maintenance equipment. She was converted now as a ferry carrier.

Ferry carrier (1953-57)
On 10 December 1952 she carried her first load of Westland Whirlwinds helicipters (848 Sqn) to Singapore, arriving on 8 January 1953 and back to Portsmouth on 11 February. Then she carried a part of embarked part of the 100 Grumman Avengers transferred until the Mutual Defense Assistance Act back in the US, Norfolk, on 16 March. She loaded the remaining one on 29 April. HMS Perseus back home was refitted to carry VIPs, with a temporary grandstand seatin by June. She hosted the press during Elizabeth II’s Coronation Fleet Review in Spithead. She also carried later in 1953 troops and equipment to the Far East.

On 20 January 1954, ASW trials by the Whirlwind helicopter were made, and successful. Redesignated the 845 Squadron it was ferried to Malta in April 1954. Back home, Perseur made another supply run to Singapore this time, for the remaining combat in Korea. Back home she went into reserve from 12 July. It was planned to convert her as a submarine depot ship and she was sent to Belfast for the conversion by 1955, but it was delayed and in 1957 the Defence White Paper had it abruplty cancelled. Instead she was towed to Gare Loch and stayed there until sold for BY by May 1958, towed to Port Glasgow for scrapping.

HSwMS Clas Fleming (1912)

HSwMS Clas Fleming (1912)

Swedish Navy – Minelayer cruiser 1911-1960

Commissioned in 1914, Clas Fleming was among the first Swedish warships using Parsons steam turbines. Faitly small for cruiser standards in WWI with just 1550 tons of displacement, she was still armed with four 120 mm (4.7 in) guns, had some armor in vital spaces and could carry and lay 190 naval mines. It had one upgrade in 1926 and in 1939 when fitted with an extended section to house brand new diesel engines used as gas generators for the turbines, one idea that will ultimately led to the Gas Turbines and CODOG/COGOG systems of today. Clas Fleming was ultimately decommissioned in 1959. #swedishnavy #ww1 #ww2 #svenskamarinen #clasfleming

Design Development

Before WWI, Sweden had only a few cruisers, mostly resting on armoured monitors and coast defence ships, torpedo boats and minelayers. But at the turn of the century the Navy was rapidly modernizing, with the development of destroyers started in 1902, with the Mode class, and of submarines, with Hajen launched in 1904. In terms of cruisers, this was disparate: Five ships of the örnen type, 1896 small Torpedo Cruisers, and from 1905 the armoured cruiser Fylgia we already saw. But aside Gunboats, there was no dedicated minelayer in service. Other nations, notably Germany (with the Nautilus class) were looking at this new type, and Sweden soon wanted to enquire about the validity of acquiring one.

Clas Fleming post-WWI reconstruction with her raised aft deck, rebuilt mines chutes and doors

HMS Clas Fleming, known as a Minkryssare (“Minecruiser”) was designed after a naval staff specifically for this role in 1908. She was to be large enough to carry a sufficient number of naval mines, and well armed to defend against other destroyers and torpedo boats. But moreover to have a good seaworthiness in all weathers and be quickly out of the area after laying mines.
In addition, the new ship should be used for reconnaissance. In 1909, funds were granted, after the final specifications were drawn up, as the new cruiser was approved by the Riksdag. She was ordered on 17 May 1910 for FY1911, attributed to Bergsund’s Mekaniska Verkstad (Bergsund Finnboda, Stockholm) which already had previously built the cruiser HMS Fylgia. She was laid down presumably in early 1911 (date unknown) and launched on 14 December 1912.

Clas Fleming was ultimately commissioned on 23 February 1914. Based on precise and innovative specifications, she was Sweden’s first ship intended specifically for quick mine laying. Since it was necessary to escape if caught by an enemy squadron, for the first time it was decided to equip the ship with steam turbines. Having no previous experience in the matter, Sweden turned to the world’s leader at that time, Parsons of Great Britain. However the limited size of the cruiser, which seemed acceptable on paper, changed in reality many factors.

Appearance in 1914 as completed

Hull and general design

Clas Fleming was pretty small for a cruiser, more related to 1880s unprotected ones and gunboats. She was 80 meters long, for 10.4 meters wide (1/8 ratio) for a 4.3 meters draft (263 ft 1 in long, 34 ft 1 in wide, 14 ft 1 in draft). Standard displacement was 1,640 tonnes, maximum displacement, fully loaded was 1,850 tonnes.
The silhouette looked conventional, but more for a gunboat than a cruiser. She was relatively tall, between the forecastle with good seaworthiness, and superstructures taking much of the space. Her artillery was placed in superfiring positions fore and aft, and a lower deck, partially protected, an amidship section for two tall funnels and air scoops around, plus six light service boats in davits on the sides.
Clas Fleming had two tall pole military masts fore and aft. The forward one had a walled spotting top. She carried on the second a projector, and another was located aft of the upper bridge’s open deck. The bridge was located above the behind the Conning Tower and was used as the main navigation bridge at all times.
The crew amounted to approximately 160 men, with 8 officers, 23 non-commissioned officers housed in their own cabins, the 129 ratings laying in bunks below. Since at the time landing parties were still a thing, it was planned for the ship to house and operate a force of 47 marines.

However the small design was criticized over several points:
-Excessively cramped boiler rooms
-Low armour deck which participated in this narrow space
-Wet in rough seas

Armour protection layout

As per the specifications, the level of protection was that of a protected cruiser: She had an armored deck 16–25 mm thick. This was quite weak for any engagement with something larger than a destroyer. The other feature was the usual conning tower, complete with backup fire control and navigation and was protected by 75 mm (3 inches) walls all around. By default, it is estimated to be Krupp armor. For ASW protection, the hull was divided into 14 watertight compartments. The main guns had no shields, which were added in the interwar.

Operator of the machinery


The machinery consisted of steam boilers and steam turbines. Eight coal-fired steam boilers, divided into two groups and set up in two furnaces, supplied steam at 17 bar pressure to two steam turbines which together developed 6,500 horsepower, giving the ship a speed of 20.3 knots. The ship was the first in the Swedish fleet, along with the destroyers HMS Hugin (24) and HMS Munin (8) to be equipped with steam turbines. The turbines were directly connected to each propeller shaft, giving the ship two propellers.



It consisted in four 12 cm m/11 guns or 120mm/48 K/50 Model 11 (4.7 in), of Swedish Bofors Manufacture. There were two in the bow, two in the stern in superfiring positions.
The closest model was the previous 12 cm cannon m/94 45 caliber was common on Swedish torpedo cruisers from 1898 and the remainder went to the Coast Artillery (battery Mojner, Gotland notably). They were used on the monitors Tirfing and Thordön and the Svea, Oden, Thor and Niord. Weight 3507 kg, 21 kg shell, elevation +15°, rate of fire 7-10 rounds/min, effective range 12 km for the L/48.


There was no secondary armament, which was rare for a cruiser, but dictated in large part by the small dimensions of the intermediate deck and for stability concerns. To defend against destroyers, the main armament was the only answer, but still, Clas Fleming had four single 6.5 mm/80 caliber m/10 machine guns installed on pivots on the upper decks, for close range, and possibly used during landings as well.


As a mine cruiser, around 190 could be taken on board, 130 stored directly on deck and moved by railings, the standard fitting of the time. The remainder 60 were kept below decks, moved up to these railings using a ramp. It’s hard to find relevant infos on this pre-WWI Swedish Mines. The first large-scale use of of sea mines was the Russo-Japanese War of 1904–1905, which draw a lot of interest of the Swedish Admiralty and a coast defence deterrent. Early types were probably ordered abroad, in Britain or Germany. Swedish complied to the eighth Hague Convention in 1907, introducing rules for mine warfare, including a ban on drift mines and notifications of seafarers where laid. Sweden remaining neutral in WWI, the minefields were all signalled.

Author's rendition of Clas Fleming
Author’s rendition of Clas Fleming

⚙ specifications

Displacement 1,550 long tons (1,575 t)
Dimensions 80.2 x 10.4 x 4.3 m (263 ft 1 in x 34 ft 1 in x 14 ft 1 in)
Propulsion 2 shaft Parsons steam turbines, 8 Yarrow boilers, 6,500 ihp (4,847 kW)
Speed 20 knots (23 mph; 37 km/h)
Range Unknown
Armament 4 × 1 – 4.7 in (120 mm) guns, 4 MGs, 190 mines
Protection Deck: 16–25 mm (0.63–0.98 in), Conning tower: 75 mm (3 in)
Crew 161

Career of Clas Fleming 1914-1959

WW1 and interwar service

Clas Fleming entered service in May 1914 as the sole and only Swedish fleet minesweeper, named after Admiral Clas Larsson Fleming of the Russo-Swedish war. The same summer she started training and fleet exercizes, onl interruopted in August by the start of the First World War. Exercises were still carried out, this time to test different methods of “minute minelaying”. It went on until 1917 when regulations were issued for how these should be carried out. Clas Fleming was only to lay offensive minefields, older vessls freshly converted would lay defensive minefields. In addition the admiralty decreted that all Swedish destroyers would be in the future fitted with mine rails and join Clas Fleming in the laying of offensive minefields.
The different between the two was simply that in case onf a sea invasion of territorial waters, Clas Fleming would go out in the estimated path of the incoming fleet and quickly lay a minefield before escaping at full speed.

Before the war ended on 24 October 1917 already, Clas Fleming was ordered to Stockholm for partial disarmament. During the First World War, Sweden being neutral was deployed in order to guarantee safe passage of merchant traffic to and from Sweden and up to the Skagerrak, by enforing the respect of Swedish territorial waters. Clas Fleming ship provided valuable knowledge in mine warfare by placing several of these to defend some areas.

In service she had shown some issues. Her stern was found to be very wet on rough seas. It had been discovered also that the mine ports were too close to the water’s surface, causing a blowback and possible detonation when waves came in from the stern. So while in Stockholm, she was placed in drydock in 1918-19 to rebuilt her poop deck, extended to the stern. The gates were raised, and the minerails after were covered by a full deck, also, the aft guns had to be relocated and the two superfiring guns were moved to a old-fashioned amidships sponsons position.

In 1926, she underwent other modifications as three 25 mm (0.98 in) anti-aircraft guns were added in place of the light machine guns, atop the conning tower two more at the stern, abaft the amidships 120 mm guns. Also a modern range finder was installed on top of the bridge.
Her interwar service was quiet, and in 1938, there was a reorganization in the Swedish Navy, Clas Fleming being part of the coastal fleet’s 2nd cruiser division. According to the regulations of the time she was considered too old to be part of it at that stage. She should have been transferred to local forces as early as 1938, but this was delayed. By September 1939 a commission examined her fate. She had not received any upgrades since 1929, with a brief exception to lower her high operating costs.

New AA Bofors guns after reconstuction

Refit and WW2 service

In order to reduce these costs, it was planned to replace her machinery for which would much more efficient. Funds were granted by the Riskdag in the first half of the 1930s already but never carried out before the Second World War broke out. Instead of a full reconstruction, the emergency dictated a simple replacement of the engines, although it was concluded that she still was in great need of a more intensive modernisation.

Appearance as completed and recommissioned in 1940, with her two “true” funnels, far apart.

At last she was taken in hands for a full reconstruction in 1939-1940, and by November, she was sent in drydock at Götaverken, Gothenburg: Her hull was lengthened by 6 meters (20 feets), with a whole new section added amidship, the Parsons steam turbines were removed and replaced by a brand new experimental machnery designed also in Götaverken.
It was in essence the world’s first-ever gas turbine:
This consisted in choosing two modified Laval geared turbine sets, keeping of eight original coal-fired, only two modified to fire oil, to feed the turbines, and adding four six-cylinder two-stroke diesel engines used as gas generators, to also feed the turbines. Indeed instead of connecting the the diesels to the propeller shafts, the engines exhaust gases were used to drive the turbines, connected to the shafts. This was a clever, low engineering solution, but proved quite an innovation. The ship only had two new funnels, set further apart, but a second dummy one was installed between them in 1941, to mimick the silhouette of Swedish destroyers of the time as deterrence.

Clas Fleming in WW2
Clas Fleming in WW2

The artillery was also modernized, the mounted were modified so that the firing range jumped to 16,000 meters and the guns were protected by lightly armoed shields. Air defense was strengthened by thz adoption of three 40 mm m/36 Bofors autocannons, and tow depht charge racks at the stern for ASW defence. The aft mast was removed, the foremast was shortened and modified, the new funnels were raked and shaped differently so completely changing her silhouette.

⚙ specifications 1940

Displacement 1640t standard, 1850t FL
Dimensions 86 x 10.4 x 4.30m (282 x 34 x 14 feets)
Propulsion De Laval steam+gas turbines, same boilers+4 diesel generators
Speed 20.3 kts
Range 7,200 nm
Armament Same but 3x 40mm/56 K/60 M32, 3x 25mm/55 K/58 M32, 200 mines, 2 DCR
Crew 160

Cold War service 1945-1959

Clas Fleming postwar, with her three funnels.
On 8 August 1940, Clas Fleming was recommissioned, deployed to the Coastal Fleet, where she remained for the remainder of the war. After 1945, Clas Fleming was disarmed at Stockholm’s shipyard, now way to old for effective fleet service. But she was kept in reserve, and not stricken from the list and decommissioned before 1959. All valuable material was removed so that she could be converted as a target ship for firing exercises. In the fall of 1960, at last, after being at sea for more than half a century, Clas Fleming was sold, and scrapped in Ystad.

Read More


Gardiner, Robert; Gray, Randal, eds. (1985). Conway’s All the World’s Fighting Ships: 1906–1921.
Harris, Daniel G. (2004). Preston, Antony (ed.). Minelayer Clas Fleming: An Early Gas Turbine Ship. Warship. Vol. 2004. Conway
Borgenstam, Curt; Insulander, Per; Åhlund, Bertil (1993), Kryssare : med svenska flottans kryssare under 75 år (1:a)
Lagvall, Bertil (1991), Flottans Neutralitetsvakt 1939–1945, Karlskrona: Marinlitteraturföreningen nr 71
von Hofsten, Gustav; Waernberg, Jan (2003), Örlogsfartyg: Svenska maskindrivna fartyg under tretungad flagg (1:a), Karlskrona: Svenskt Militärhistoriskt Bibliotek
Borgenstam, Insulander & Åhlund 1993
Von Hofsten & Waernberg 2003, s. 136.
Holmquist 1972, s. 198-199.



Model Kits

Oyodo (1943)

Ōyodo (1943) – The last IJN cruiser

Japanese Navy IJN Heavy Cruiser 1942-45: Oyodo, Niyodo (cancelled), 11 more.

The last IJN cruiser

She was the last cruiser class of the Imperial Japanese Empire (the fourth Agano class was really the last one), and by extension, the last Japanese cruiser since none was built since in the JMSDF. Initially designed she was designed as a hybrid scouting cruiser like the Tone class, but setup for wartime production. She was able to carry and operate six long-range seaplanes thanks to a 45-meter (147 feet) long aft catapult, screen forward of oceanic submarine fleets. However when completed in late 1943, the situation had changed completely and her 12 sister ships of the 1939 and 1942 naval plans were cancelled. Her military value was put into question as a “submarine leader”. She only performed a few missions but was stuck in Kure short of fuel when destroyed by USN aviation on July 28, 1945.


A leader for IJN Submarine Sentai

The genesis of the Oyodo class cruisers was a prewar concept, which mirrorred the development of the Agano class. The latter were designed to lead destroyers and replace the old Kuma, Nagara and Sendai classes scheduled for replacement. This was an ambitious program with a dozen planned in the fourth Fleet Supplemental Budget. Similarly, Japanese strategists planned the use of their submarines in a way quite different than their axis partners, Germany. Instead of hunting down US commercial lines, which were mostly concentrated in the Atlantic, their goal was to hunt down the US fleet itself, preying on aircraft carriers, capital ships and cruisers, by using large and long range submersible types (see WW2 IJN submarines for more).

Oyodo colorized by Irootoko Jr. Few photos of this ship exists.

Previous experiences of submarine leaders

Back in WWI, the IJN trialled a first major Japanese submarine formation, the 4th destroyer squadron (sentai), formed on December 13, 1915, as part of the First Fleet. The name was counter-intuitive as it included two divisions of three submarines each and two mother ships called “Karasaki” and “Komahashi”. Submarine divisions were managed together with destroyer divisions in the fleet. On April 1, 1919, the 4th DesRon was reorganized into the 1st submarine squadron (sensuisentai). At first it consisted only of submarines attached to mother ships but as the models became larger and grew as their cruising range the admiralty felt it was time to replace the tender by a proper flagship. From December 1, 1921, Yahagi (Chikuma class) became such flagship, while Karasaki remained attached to the unit. A year later on December 1, 1922, the 2nd SubRon was formed, including a flagship, IJN Chikuma and a Tener (Mansyu).

The Japanese Naval General Staff faced a choice about blending the roles of flagship and tender or stick with by different ships, knowing the tender was more vulnerable and slower. Requirements for them were indeed too different. The flagship was required to have extensive communication facilities and accommodating headquarters, high cruising range and speed and powerful armament in order to oppose enemy scout ships. The tender however were expected to have much roomier accomodations to house all the submarine crews and very large replenishing stocks of torpedoes, shells, food, fresh water, and a complete workshiop to perform repairs at sea.
The Chikuma-class cruisers used for this could only perform as flagships after some modifications, but they were obviously ill-suited as tenders. Karasaki and Manshu were also unsuitable as flagships. however the situation was resolved by the lainching of a new generation of submarine tenders in 1923-24, IJN Jingei and Chogei: They combined a top speed of 18-knot speed, a powerful armament and extensive facilities to act as headquarters. Also in the early 1930s, speed and range of new Japanse cruiser submarines grew and the concept of submarine tender started to be obsolete, only kept as a pretext to be converted later as aicraft carriers, cheating treaties. The question return as how to lead these two formation with a more advanced flagship.

A new submersible flagship (1938)

On December 8, 1938, the minister approved a draft as part of the 4th fleet replenishment program calling for two 8,200 ton, 35 knot flagship for submarine squadrons. They were provisionally called cruisers “C” with numbers 136 and 137. On December 26, the program was presented at the 74th session of the Japanese Parliament. After discussion, it was adopted on March 6, 1939. According to this program the construction cost was estimated to 31.16 million yen (10,470,160 for the hull, 7,583,610 for the power plant, 12,609,871 for the equipment, 469,359 for the design and administrative expenses of the program).

The final requirements were approved in October 1938 and the fourth section of the Marine Technical Department was assigned the development of project “Cruiser C” under the leadership of Captain 3rd Rank Daisuke Ozono, supervised by the section’s chief, Rear Admiral Keiji Fukuda. C-42 project was completed by October 6, 1939 in parallel with C-41 (future Agano type) and so both shared a lot of elements. The project requirements drafted were as follows:
-Standard displacement of 9,800 tons;
-Main armament of two 155 mm triple turrets and four twin 100 mm DP turrets plus six twin 25 mm AA guns
-The number and location of torpedo tubes was not decided
-One dedicated 45m catapult (main feature here)
-Extensive facilities for six seaplanes (Model of 280 knots top speed, 2,000 nautical miles range at 200 knots)
-Four steam turbines rated for 110,000 sho working at 300 rpm and six boilers
-Top speed 35 knots
-Range 8,700 nautical miles at 18 knots

I-400, representative of these behemoth of cruiser submarines. Oyodo was to lead smaller wartime versions without a seaplane to spare space and complications.

The IJN’s submarine squadrons (sentai) were tailored to wage warfare at extended ranges, using onboard seaplanes themselves for some (this went up to one which carried three for an operation on the Panama Canal). These were to be coordinated by a cruiser acting as floating HQ and providing intel by screening for them, using an extra force of reconnaissance aircraft. At first it was believed the Agano-class cruisers could perform this role, but they proved too cramped for this. The hull could not accomodate more than two turrets forward making them too weak as flagships.


So in 1939, the Imperial Japanese Navy Staff discussed a new set of specifications tailored for seven hybrid cruisers, each leading a submarine squadron. Funding for the first two of this new class was approved as we saw as part of the 4th Replenishment Program. The lead ship was IJN Ōyodo, acted as a prototype.
Order for the lead ship, Cruiser C No.136, was issued to the Fleet Arsenal, Kure on December 6, 1939. It was planned to lay down her keel in June 1940 with a construction time estimated to 30 months. However, due to an extensive workload she had to wait to be laid down until February 14, 1941. On March 10, 1942, she was officially named “Oyodo” after a river in the prefectures of Kagoshima and Miyazaki. She was launched on April 4, 1942 and completed by January-February 1943 with a construction tim og 26 months, shorter that what was planned. The construciton of the latter was eventually cancelled.
Worst still, after completion, Oyodo was was now irrelevant as the initial concept she was tailored for has been terminated. There was no role for her.


Hull construction & general characteristics

Nice HD view of the ship in 1943

Instead of starting from a blank page, designers of the Ōyodo’ started from the well rounded Agano desig, modified and enlarged for her tasks. She retained the same general hull design, with a flush deck, bulbous bow, superstructure and armament improved. She was better suited to take a command role, and her armament was heavier, concentrated forward. Her final design showed a 189.73 meters (622 ft 6 in) long hull overall, 16.6 meters (54 ft 6 in) wide and with a 6.1 meters (20 ft 0 in) draft, a displacement 35% heavier, at 10,987 metric tons (10,813 long tons). She was given a metacentric height of 1.38 meters (4 ft 6 in) while deeply load.

Apart perhaps the prominent hangar aft and large catapult, the design of the Oyodo still kept with the same elegant silhouette as the Agano, with a flush deck hull and slightly raised prow, superfiring turrets, a tall bridge with a standard command deck and admiral bridge, extra facilities, but also a derrick foremast aft of it, which was new compared to the Agano’s tripod, and another derrick maintast on top of the hangar. The whole designed looked like a “stretched agano”, the larger deck surface alowed more AA to be added in the course of the war.
As completed she had a crew composed of 33 officers and 532 ratings.

About 32% of her normal displacement was allocated to the hull, 10% went to armor protection, 42% for the structure, 12% for the armament, 19% for the powerplant, wich gave her a power-to-weight ratio of 55.4 hp/ton. less than the Mogami, but more than ‘A’ cruisers (Agano). Normal displacement was initially 9,980 tons but after construction alterations it went to 10,330 tons and by February 1943 10,416.5 tons. Still engineers were satisfied this overload amounted to “only” 106.5 tons, a bit over 1%.

Flagship Facilities

Radio equipments according to the original project was quiote extensive for the time: It included nice transmitters and 21 receivers in order communicated with all the squadron submarines, as well as with the HQ for perfect coordination. Their actual composition differed during construction and in the end, there were 8 transmitters, including two LW bands (type 92 No.4 mod 2), and one LW-HF band (type 91 No. 4, mod 1), the five HF transmitter of the type 95 No.3 mode 1 and No.4, 5, thena Type 97 No. 6, and an experimental Type 97 No.2. This was completed by no less than 24 receivers: Three type 91, 18 DV-KV type 92, mod 4 and three kV type 97.
Receivers were located in two radio rooms, located on the roof of the seaplane hangar, and the other in the middle deck below the hangar, cabled being held by the mainmast aft on top of the hangar. Transmitters were in two separate rooms, one the front of the AA deck and the second on the hold deck, starboard side of the main battery. Six radio stations were equipped for radiotelephone communication initially, ten installed in the end: Fove transmitters (of 1.5-watt VHF type 90, 50-watt VHF type 93, and 30-watt MW No. 2) and then five receivers (VHF type 90, VHF type 93, SV-KV type 92) located at three radiotelephone posts in front of the AA deck, lower tier of the port superstructure and middle tier of the superstructure.


Kampon Turbines

The cruiser being larger than the Agano class (Type A), she had a more generous powerplant to compensate, helped by a larger hull. She was given a four-shaft steam turbine system like the Agano with a total output of 110,000 shp (80.905 MW). Initially, this powerplant was developed by the 4th section of the Naval Technical Department: Kansei Hombu, abbreviated as “Kampon”. These were to be same same as the Agano-class cruisers. But the output was 110,000 hp versus 100,000 due to a different layout of the engine and boiler rooms, 4 turbines, 6 boilers versus three turbines, five boilers, for a maximum design speed of 35 knots.

The four Kampon No.3-C model 1936 had a capacity of 27,500 hp each or 20.226 MW, at 340 rpm. They were located in four engine rooms separated by longitudinal and transverse bulkheads, over a total length of 32.2 m, 16 m for the front pair room, 16.2 m for the rear pair. Each unit included a combined high pressure (9250 hp at 3632 rpm) section, a medium pressure one (9150 hp at 3385 rpm) and a low pressure one (9100 hp at 2327 rpm) single-stream and double-stream. The gearbox had an helicoid gear with a single central gear and three drive gears from the turbines, having gear ratios of 10.68, 9.95, and 6.84. The front pair drive the outer shafts, the rear ones the inboard shafts. Total of the turbines was 162 tons, while the gearboxes totalled 112 tons.

Within the low-pressure turbines housing were located reverse turbines, with a total capacity of 27,500 liters, 6875 hp at 1471 rpm each, rotating the shafts in opposite direction to propellers rotation in forward speed. For cruising, two Kampon No. 3-A model 136 cruising turbines (6320 rpm) using a gear ratio of 4.03 were connected to the unit’s gearbox. Exhaust steam from the cruising turbine entered the other units and together produced 4250 hp (8500) at 150 rpm for a cruise speed of 18 knots. At full speed the cruise turbines were disconnected from the gearboxes, steam flowing directly to the first stage.

Other equipments

The exhaust steam went into four single-flow Uniflux condensers one for each turbine unit, which had a total cooled area of 3864.8 m². Each condenser was equipped with two steam jet pumps and steam jet coolers plus a feed water heater and one turbine-driven main circulation pump. There were two drain condensating coolers with pumps, and two desalination plants handling 96 tons of water per day each, also usable by the crew. They were installed in the forward engine rooms. Each of the engine rooms comprised also eight pressure, eight exhaust fans of 745 and 795 mm with a capacity of 9 and 11 m³/sec. respectively. They also had two fuel transfer pumps with a capacity of 30 m³ per hour, four fire and bilge pumps of 30 and 60 m³/h respectively, usable in different modes, as well as four oil coolers and eight oil pumps (forced lubrication system).

Steam Boilers

The turbo-geared units were fed with steam coming from six three-drum water-tube boilers. They were of the Campon Ro Go type. They comprised an oil heating system with superheaters and air preheating to accelerate their start. Operating pressure for the superheated steam was 30.0 kgf/cm², at 350 °C. Total area of the heating surface was 981 m² while the steam generating tubes represented 810 m² and the superheater 171 m². Total volume was 39.8 m³.
Each boiler was in its own boiler room, 9.8 m long. In turn these rooms were arranged in pairs. As fir the Agano class, steam was supplied in the same way although steam lines scheme diverged. The first Boilers rooms were arranged through their lines to feed the front pair of turbines, and the two others through lines closer to the keel fed the rear turbines.

Two vertical fans of 94 cm, with a capacity 22 m³/sec. completed the circulation of steam, and each boiler was assisted by main and auxiliary feed water pumps and water heater, fuel pump and fuel heater, oil pump and cooling water pump, and oil cooler and three fire and bilge pumps installed per boiler room. The latter were electric and one driven by the turbine and had a capacity of 30 to 60 m³ per hour. Combustion products exhausted through several exhaust lines converging into a single truncated funnel for all boilers, raked, and located behind the tower bridge.

Shafts and Propellers

Oyodo had four three-blade propellers. they had the same diameter of 3.6 m (), a pitch of 3.96 m (), and revolution speed of 340 rpm maximum. its full development area reached 7.56 m² and according to the original design, this was only 300 rpm, but with smaller (3.5 m) propellers initially. The shafts were lubricated constantly using a stock of fuel oil of 2,453 tons placed in 82 fuel tanks, representing a total volume of 2732.6 m³, located in the bow, stern, and sides, participating in the ASW protection.

Electrical Power

Electric power output usable when she had her engines cold and to run all vital system on board comprised three 400 kW turbogenerators and two 270 kW diesel generators (total 1740 kW combined). They produced direct current rated at 440 V same as for the Agano class. They were located in two compartments outside the engine rooms or the armored citadel, which made them vunlerable to flooding. The front group was located under the weather deck, in front of boiler rooms No. 1 and 2. The second was located in the lower deck, behind the engine rooms with a diesel generator (port) and two turbo generators (starboard).


Designed range was 8,700 nautical miles at 18-knot cruiser speed. But better results were obtained in the sea trials of January 1943: 10,315 miles at 18 knots in fact. Oyodo was still capable of running 7,714 miles at 21 knots and down to 3,861 miles at 28 knots, then 2,051 miles at full speed. These sea trials started on January 23, 1943 at Misaki Garden, Ise Bay. Oyodo managed to reach a top speed 35.199 knots based on 10,381 tons, her plant managing an output of 110,430 hp. at 340.3 rpm. The machinery was overheated and boosted later to 115,950 hp, 346.3 rpm, and she reached 35.31 knots which was her absolute limit. Handling tests were performed on February 18 which it was reported that at 34 knots, rudder hard over to port at 34.7°, her tactical diameter was 4.42 ship lengths along the waterline. On February 19, she managed a long run at 35.3 knots based on 10,467 tons and output of 111,220 hp, 339.4 rpm.

Armor Protection

The armor protection of Oyodo was based on the need to withstand direct hits from 6-in semi-armor-piercing (SAP) shells, and 250-kg bombs from 3,000 m. The Type of steel used ws composed of Chrome-nickel-copper containing 0.08-0.46% carbon, 2.5-3.0% nickel, 0.9-1.3% copper and 0.8-1.3% chromium. An analogue of NVNC chromium-nickel armor steel with the replacement of some of the scarce nickel with copper, has been produced since 1931 for plates up to 75 mm thick. High strength structural steel containing 0.25-0.30% carbon and 1.2-1.6% manganese. Developed by British David Colville & Sons (Ducol steel or “D”) in 1925 and stronger than HT, it was also used throughout the ship for structural armor.

Main Belt
The CNC steel main armor belt was 60 mm thick, and covered compartments over the machinery spaces, the rear electric generators and ammunition stores located between frames 92 and 155. It was 2.35 m wide above the waterline. The ship having a design draft of 5.95 m, it was supposed to rise by 1.56 m above the waterline.

An armored middle deck also made of CNC plates was 30 mm thick for the amidship section, 28 mm (1.1 in) on both edges, and 2 meters in width. Forward the armored deck started where the citadel ended, enclosed with a 35 mm transverse bulkhead connected from below to the lower deck. The aft 35 mm bulkhead (1.4 in) descended to the hold deck level. The 5-meter section between the lower and hold deck was given an increased thickness, up to 50 mm, as it was the aft wall next to the ammunition store.

The citadel ran from frames 55 to 92, divided into two unequal parts. The forwards section was between frames 55 to 83 and covered the ammunition storage, so quite serious protection including an internal armor belt which was 2.6 m wide (10.2 feet), assembled from CNC wedge-shaped plates. It was 75 mm thick (3 inches) at the top, 40 mm (1.57 in) at the bottom. From above, it was combined with a 50 mm (2 in) armored lower deck also in CNC, connected from below and resting on the double hull bottom.
The aft citadel section, frames 83 to 92, protected the 6 in and secondary guns along with the second radio room. It was joint to a 28 mm (1.1 in) armored lower deck. The forward part of the citadel was also bonded to the main armored deck by a 60 mm, tapered down to 25 mm bulkhead, the forward and aft section separated by a 10 to 16 mm (0.6 in) bulkhead, made of ordinary D steel plating.

Turrets, Barbettes, Ammo wells
The 6-in turret barbettes had walls of CNC steel 20 mm thick (0.8 in), with 25 mm (1 in) support rings. Below the middle deck, the barbettes were downgraded to a 35 mm thick ring, which was conical with 120° angled plates. Beyond the armored lower deck thickness was reduced from to 25 mm, but continued by a tube with 25 mm walls, inclined to 60°. Outside the barbette, elevators for the 25 mm and 100 mm ammunition went in tubes respectively in front and behind the barbette of B turret. About one meter above the lower deck, they were covered by CNC plates 55 mm thick (2.16 in) 35 mm front and rear plates.

Tower bridge
The bridge was protected by 40mm CNC steel plates forward, 20mm D steel plates on its sides and rear. It was enclosed at the top by 20mm CNC plating. Between the bridge and control posts, under the armored deck they were communication tibes with 8 mm D steel plates.

Funnels, exhausts, ventilation
The funnel bases were protected by D type steel metal sheet, 10 mm thick (0.4 in) front and rear. The sides received 16 mm plating, but also 30 cm below (11 in) and 70 cm (27 in) above the middle deck. Ventilation ducts of the engine rooms had the same protection all along their truncation. The steering control room was protected on all sides by CNC plates 40 mm thick (1.57 in) down to 20 mm at the front and 25 mm at the rear.

Middle Deck
The middle deck above them used a sandwich protection, with two layers, one upper 20 mm CNC plate and a lower 16 mm D steel plate.

The shell elevator was protected up to the middle deck level with 35 mm CNC plating (1.37 in) on all sides. The communication shafts between the engine rooms and steering gear were covered by 10-16 mm D steel plating. The aviation fuel tanks had 16 mm D steel plating as well.

Underwater Protection
IJN oyodo’s underwater protection was poor however. First off due to the reduced beam of just 16.6 m, there was of course no armored anti-torpedo bulkheads. Designers instead relied on high subdivision of the hull into many watertight compartments, an old and proven solution, many of these side compartments filled with oil or seawater. The double hull bottom had 94 compartments and space between this double hull and main hold deck comprised 159 subdivisions, while the rest of the hull above the hold deck had 28 watertight compartments that could be filled artificially by automated valves, used for counter-flooding. A total of up to 613.3 tons of water was supported to correct a listing port or starboard.

The machinery compartments were separated by a longitudinal bulkhead making it possible to continually operate avec after a single torpedo hit. However, with her tight waist, IJN Oyodo had little margin for stability. Calculations showed it could withstand the flooding of only one engine room and one boiler, listing to 15°. This is what happened on July 28, 1945, but the crew at the time was unable to counterbalance the multiple torpedo hits in time by proper counter-flooding, so the cruiser capsized as a result.


Oyodo’s armament comprised two triple 6-in guns (155 mm) at first, same as the Mogami-class, but as the war progressed, she obtained surplus twin 8-in turrets.

Main Battery

The main armament was composed on paper of the same six 155-mm type 3 guns as for the Agano class, but to free space aft, they were in two three-gun turrets. This ordnance was originally created under the guidance of engineer Chiyokiti Hata in 1930-32 for the Mogami-class cruisers, adopted on May 7, 1934. The gun was 60 calibers, enabling a muzzile velocity of 920 m/s for a maximum rate of fire of 7 rounds per minute. The barrel was of monoblock design and weighted 12.7 tons. The entire gun turrets with their turret mounts were those removed from the Mogami-class cruisers when they swapped to 8-in guns with the start of the war.

The rurrets were superfiring forward, “B” being on a barbette 15.8 m tall barbette, the other 13m (). They had a 300° traverse, the reliquate being blocked by a stopper to avoid hitting the bridge tower. This was quite generous arc of fire, the rest being brought by the ship’s orientation. Total weight of both turrets reached 360 tons. The turret mount was developed in 1932 with a ring diameter of 5.71 m. The barbette was protected by a circular armor in NVNC plates, 25 mm (1 inch) thick.

The fighting compartment housed the guns and carriages with hydraulic recoil cylinders and pneumatic knurlers. Distance between barrels was 1.55 m, too short for a side rloading apparatus so the bolt mechanism was rotated 45° to allow it. There were two hydraulic pumps working on mineral oil as a pressure of 70.0 kgf/cm² powered by two electric motors (100 hp each) to actuate hydraulic drives ans rotate the turret through a worm gear at 6° per second. It was also responsible of the elevation and depression through a vertical aiming mechanism with pneumatic drive at 10° per second. The same system powered the rammer, lifts and breech closure.

Ammunitions were 55.87-kg shells coming from racks below, fed to the reloading compartment using a roller conveyor, and pusher lifts rising in just 3 seconds, and so enabling a record 6 shells per minute. 19.5-kg charges were also delivered from a separate reloading compartment below, lifted by using bucket-type hoists and separated from the reloading compartment by double fireproof hatches. Thsy could be raised in 4 seconds (5 full charges delivered per minute). Each gun had its own pusher and bucket lift. Loading was performed at a fixed angle of 7°, mechanized, the bagged charges being loaded manually.

Four types shells types were used:
-Armor-piercing shell with ballistic cap type 91 (1.152 kg type 91 composition). It could penetrate a 100mm hardened plate from 15 km at 60°
-General purpose (HE) type 0, 6.8 kg trinitrophenol also usable against air targets on a 23 m () radius
-Illumination shell with parachute Type B
-Practice shell
The Oyodo carried 900 rounds, 150 per barrel, like on Mogami prewar. Maximum elevation was 55° and at 45 ° range was 27.4 km, shells climbing to 12 km. Each turret was operated by 24 men, plus 7 in the reloading compartment below, 10 in the bagged charges compartment so 41 per turret, 82 for both.

Secondary Battery

The medium anti-aircraft/ anti-ship duel purpose artillery comprised eight 100-mm type 98 guns.
They were located in four twin mounts abaft the funnel. These guns were designed in 1938 under the direction of Chiyokiti Hata, same as for Agano, an destined to replace the slower 5-in DP in widespread use in the USN as well as being a new destroyer gun standard. The barrel length was 65 calibers for a 1,030 m/s velocity and maximum rate of fire of 15 rounds per minute.
Its range was 19.5 km against surface targets, 14.7 km in AA mode (ceiling), with the most effective, accurate range between 11 and 14 km. Theu used twin mounts type A, 1st mod weighting 20 tons and a ring diameter of 2.28 m.

This was a semi-open mount, with 3 mm steel shielding designed against water spray but not shrapnel. The turret mount was hydraulically powered via an electric motor of 15hp with a 11.4°/s rate revolition and 16°/s elevation. IJN Taiho had similar guns, as well as Akizuki class destroyers, but with fully enclosed dome-shaped turrets. Regular ammunition load was 1600 shells of a single HE type, or 200 per barrel.
These 27.15 kg shells with 13 kg tip HE could be exhanged for a practice dud head. They came for ammunition rooms located under the armored lower deck, behind “B” turret barbette, to the upper deck via four bucket elevators, one for each. They were manually transported below and stored in fenders. Loading used semi-automatic rammers at all elevation angles. They also used fuse settings, separated.

AA Battery

The AA artillery in the original project comprised only six twin 25-mm type 96. Two were located in front of the bridge, four on the roof of the seaplane hangar.
But as construction (and the war) progressed, the need of a beefier AA was soon given priority and more AA guns were installed, starting by installing two more mounts on the hangar roof, when completed. Ammunition was stored in a room located between the barbettes of main guns, with 2000 shells per barrel, 24,000 then 36,000 total when completed. From there, the rounds travelled through a large bucket elevator to the middle deck and transferred via three smaller elevators then dispatched into the three main storage areas.

Fire Direction control

The ship was equipped with a main fire control director on top of the bridge. It comprised a Type 94 gunnery director for the main armament. The director housed a 6m (19 ft 8 in) span rangefinder but as a backup, the superfiring “B” turret was equipped with a 8-meter (26 ft 3 in) rangefinder.

The Type 98 secondary guns were assisted by two Type 94 directors, located at the base of the bridge. These included 4.5-meter span rangefinders, completed by an anti-aircraft fire control post with a ballistic analogic computer located under the lower deck.

The light anti-aicraft battery was assisted by three Type 95 directors installed on the forward bridge superstructure on various decks. Two direction finders type 93 No.1 were also installed at the rear of the compass bridge in separate rooms between the funnel and seaplane hangar. The three type 95 directors were located each next to their own AA group. They were relocated during completion to avoid fire damage. They all had type 97 stereoscopic rangefinders. The issues of the 25 mm AA guns, long derived from a 1914 Hotchkiss design, were known: Excessive vibrations, blinding illumination when firing, poor targeting optics and slow traverse/elevation. Fortunately the 100 mm were far more effective.
Until 1945, this was augmented: (to come)

Air group and Aircraft Facilities

Aichi E13A
Aichi E13A1 “Jake” of the Oyodo in 1944

IJN Oyodo was designed to carry six high-speed reconnaissance floatplanes, but the type was not disclosed. Four could be housed, with folded wings, in the massive aft hangar measuring 25.25 x 13.6 x 7.25m () and the remainder two on the rail system on deck. Handling seaplanes was done by using two 15.5-meter cargo booms, eaching with a lifting capacity of 6 tons. They were located aft of the hangar on pivot mounts, usable both to recover seaplanes and lift them to position on the catapult.

Aerial bombs which can be mounted on these seaplanes were stored in a room located inside the armored citadel, below the main deck and behind the engine rooms. Supply up to the upper deck used an armored elevator. Eighten 60-kg bombs No.6 were stored as well as two “special” 60 kg bombs and three 30 kg bombs No.3, plus 7.7 mm machine guns 57,600 rounds. Three gasoline fuel tanks were located aft, under the hold deck with a capacity of 98,780 liters (68.55 tons).

The main feature here was the special catapult type 2 No.1, model 10 installed at the stern designed in 1942. It was 44 m long for 65 tons making it the largest ever put on a IJN ship. It used compressed air to accelerate a 4.5-ton loded aircraft at 80 knots or 148 km/h or 5-ton at 70 knots/130 km/h (2.5 g acceleration). It was capable of rapid reload, for a launche every four minutes. Place in the axis it hade a 30° traverse port and the same starboard, 60° total, launching aft.

Oyodo’s planned air group

Kawanishi-E15K Shiun
Author’s rendition of the planned Kawanishi E15K1 “Shiun”
For the mission at hand, the IJN drew specs for a high-speed seaplane (14-C) and proposed to the seaplane specialist Kawanishi right for the start, in July 1939. The company needed to provide twelve less spares to the No.136 and N°137 C-Class as well as four less spares for B cruisers No.132 to 135 (Agano class). As specified they needed a top speed of 518.5 kph (280 knots) and 3,700 km (2,000 nautical miles) range a 370 kph (200 knots).
The first prototype called K-10 flew on December 5, 1941, using a single center float and underwing floats swiveling shut under the wings. This was supposed to lower the drag inflight, but was also the main source of issues with this model. On October 7, 1942 many modifications has been done and the first two prototypes were put into service as type 2 high-speed reconnaissance seaplane. When Oyodo entered service the first six pre-production were in service, and before they joined the cruiser, still being tested, two Aichi E13A1 “Jake” were assigned instead. By August 1943, the new model’s shortcomings and accidents being delaying production were officially introduced as the Kawanishi E15K1 “Siun” (model 11). But more problems reports had the production discontinued in February 1944 with only nine more delivered. It was lambasted for its low speed, excessive float drag, weak armament, and poor protection. Neither the Agano-class or Oyodo ever operated them, sticking to their “Jake” until 1945.

IJN Oyodo
Author’s profile illustration Oyodo 1944

⚙ Oyodo specifications

Displacement 8,164 t. standard -10 252 t. Full Load
Dimensions 192.10 x16.60 x 5.9 m draft ( x x feets)
Propulsion 4 shaft turbines, 6 boilers, 110,000 hp
Speed 35 knots
Range 10,600 nmi (19,600 km; 12,200 mi) at 18 knots (33 km/h; 21 mph)
Armament 2×3 155mm, 4×2 100 mm DP, 12×25 mm AA, 2-4 floatplanes
Protection 50 to 25 mm, see notes
Crew 600-780

IJN Oyodo in combat

Artwork (boxart) showing Oyodo

After commission on February 28, 1943, she stayed in Yokosuka naval base for training under command of Captain Sadatoshi Tomioka (previously on IJN Aoba). On March 7, she moved to Tokuyama and arrived in Yokosuka training until April 15 in Tokyo Bay. She had been completed without any radar only receivd a Type 21 early-warning radar in April 1943 while still working up.
Since her designed role was no longer appropriate the Navy wanted to act as an ordinary light cruiser and transport. There were however some heated discussions, the some firmly insisting on her specific design as befitted a special task, notably as combined fleet flagship. But on April 1, it was decided to transfer her to the Third carrier mainly due to her range and good anti-aircraft defence. So she was assigned to the Third Fleet, joining the Mobile Force in May.

Her first planned operation was the invasion of Attu Island (11 May 1943) where she met a rapid reaction force of three battleships, two aircraft carriers and five heavy cruisers gathered in Tokyo Bay on 22 May. Attu however fell to US forces before even the force departed.
Oyodo would receive a short refit in Kure.
Then she was assigned a new mission of transport, loading troops and supplies on 9 July at Shinagawa and arrived at Truk in the Caroline Islands on 15 July. From there she sailed to Rabaul, arriving on the 21st and returning to Truk five days later, reassigned to the Third Fleet. On 29 August captain 1st rank (taisa) Sadatoshi Tomioka became her new CO. After the US carrier raid on Tarawa (18 September) she followed the fleet in response to Eniwetok looking for the US forces without success, and back to Truk on 23 September.

Oyodo in Yokosuka April 1944, colorized by Irootoko Jr.

Interception of American radio traffic suggested an attack on Wake Island so 17 October IJN Ōyodo departed with the fleet to Eniwetok, right planed for an interception, wihich never materialized. The fleet was back to Truk. Then, as her command facilities were at last recoignised, Vice Admiral Jisaburō Ozawa, Third Fleet commander, hoisted his flag aboard on 6 December. On 30 December, Ōyodo took part in a reinforcement of the garrisons at Rabaul and Kavieng, loading troops and supplies.

Back to Truk on 1 January 1944, Ōyodo was attacked and damaged by aicraft of Task Group 50.2. She had two crewmen killed, six wounded by strafing and near-misses. The 2 January saw her rescuing 71 survivors from Kiyosumi Maru torpedoed by an US submarine. She was back to Yokosuka on 16 February after the US invasion of Kwajalein. There, she loaded torpedoes and supplies for Saipan, and made a high speed run to deliver them on 22 February.

Conversion as command ship

Oyodo catapult modifications
She returned in Yokosuka for a full conversion as a command ship, which was completed by the start of 1944.
Additional weapons and equipment were installed: Her 45-meter catapult was removed and replaced by a conventional 25-meter Type 5 catapult. She received two Aichi E13A seaplanes and other deck modifications. The vacated hangar was completely refitted as headquarters with three storeys, tons of equipments for long range communications, map tables and housing for extra flagship personal. Two more tripe 25-mm anti-aircraft guns were installed at the stern and the same one deck, behind the hangar and on the bridge superstructure. All previously installed twin 25-mm machine guns were replaced new ones of a more moder, triple type. Also on deck, twelve additional single-barrel 25-mm were installed. Her mast was also fitted with a new Type 21 radar and Type 22 radars for fire control in the forward superstructure. A Type 13 aerial warning and surveillance radar was installed on the foremast as well.

Evolution of the design 1943-45

The Battle of Cape Engaño

The day after the refit was completed on 31 March 1944, Ōyodo became flagship of the entire Combined Fleet, but Kurita was replaced by Admiral Soemu Toyoda, which hoisted in turn his flag on 4 May. Ōyodo remained in Japanese waters until 11 October but on 29 September, Admiral Toyoda and his staff were transferred to new underground headquarters of the IJN in Yokohama as the aerial superiority of the USN as well as depredations of USN subs made fear that she could be sunk. By that time, she had received six additional Type 96 AA guns in single mounts by early October while her Type 22 radars were modified to be used for more accurate fire control.

IJN Ōyodo was back in the 1st Mobile Fleet (Jizaburo Ozawa) on 5 October. She departed Yokosuka on the 11th but was ambusged en route by USS Trepang. The latter fired six torpedoes but missed. She stopped an route to the resupply point of Yashima anchorage, on 20 October and headed for the Philippines to take part of Operation Sho-Ichi-Go. The goal was to defeat the American invasion using am ambitious and risky three-prone attack and a bait. This was a well-conceived plan that might have succeeded.

Oyodo seen from Zuikaku at the Battle of Cape Engano

Ōyodo was part of Ozawa’s Northern Mobile, precisely the “Decoy” Force, drawing north TF 58 away from the main strike. The bait force mostly comprised the remaining carriers, with a token air group, which were to be sacrificed in this mission. Ōyodo being the only one ship in Ozawa’s force with reconnaissance floatplanes, she launched both her E13A1’s in scouting and anti-submarine patrols.

On the morning of 24 October, the carriers launched all their forces to attack the US Task Force as distraction. They were all shoot down while inflicting no damage but succeeded on that Halsey’s Force departed to find them. US planes eventually catched and spotted Ozawa’s bait fleet at 16:40, 200 miles (320 km) east of Cape Engaño (northeastern tip of Luzon). Since it was too late to launch an air strike, Halsey took new positions to launch an airstrike on the morning. Ozawa reversed course during the night, assuming he would do exatcly that and started to head north drawing him out of the US landing area.

VADM Kisarazu on IJN Oyodo in 1944
VADM Kisarazu on IJN Oyodo in 1944

On the morning around 07:35 contact was made again by US aviation of Ozawa’s force, and this allowed to redirect the airstrike (180 aircraft) already in flight 50 miles (80 km) ahead. In all, Halsey would lauch five airstrikes that day. The first strike saw IJN Ōyodo having two near-misses already. At 08:48 she received a bomb hit, badly damaging a boiler room. She still had the remainder ones and could follow the fleet and evade other attacks. Repairs were on the way.

At 10:54, Ozawa was forced to left the sinking IJN Zuikaku, his HQ, and naturally transferred his flag to Ōyodo which was wel fitted to the job and less conspicuous as target. However spared by the third attack, she was hit during the fourth, by two rockets from F6F Hellcat and shook by another near-miss. At 19:00 Ozawa learned about a vuagiard cruiser and destroyer US Force catching and destroying IJN Chiyoda, damaging and driving off Japanese destroyers rescuing survivors so Ozawa decided to turn back and engage them, sending the two Ise-class. He deployed his reconnaissance plans but was unable to find the US force and reversed course northwards again at 23:30, tryng to join Amami Ōshima, arriving on the 27th. Admiral Ozawa then transferred his flag to Hyūga while Ōyodo was sent in repairs.

Later Operations (1944-45)

On 29-31 October 1944 after some summary repairs, she was unassigned from CarDiv 4 group and detached, leaving Amami-Oshima for a transport run to Manila, arriving on 1st November 1944, and leaving three days later for Brunei Bay. On the 8th, after arriving she Joins IJN HARUNA, and the cruisers HAGURO and ASHIGARA ecorted by DesDiv 43’s (IJN KIRI and UME), departing Brunei on the 17th for the Spratly Islands.
CarDiv 4 (ISE and HYUGA), accompanied by the destroyer IJN SHIMOTSUKI were there, unloading troops and supplies after fleeing Manila due to US air attacks. 5th fleet’s Vice Admiral Shima Kiyohide also arrived from Manila on IJN HATSUSHIMO with ASASHIMO, KASUMI and USHIO from various divisions, transferring his flag to IJN ASHIGARA.

On 20 November, OYODO departed the Spratlys with the fleet for Lingga (22) and then departed with just the flagship Ashigara on 12 December for Cap St. Jacques, near Saigon. ASHIGARA went on to Camranh Bay but Aoyodo remained there. On the 24th, she left in turn for Camranh. At 09:00 she departed with ASHIGARA carrying RADM Kimura Masatomi and the destroyers KIYOSHIMO, KASUMI, ASASHIMO, SUGI, KASHI, KAYA for a raid on US American beachhead at San Jose, Mindoro in the Philippines.

The Raid on Mindoro

IJN Oyodo in the spring of 1944

On the 26 December durung their approach on Mindoro they are spotted and attacked by USN bombers. At 20:45, ASASHIMO had a near-miss, and at 2101, OYODO is bombed by B-24s at high altitude, but thanks to Norden sights, she is hit by two 500-lb bombs,one being dud, the otther not going through and only causing slight damage. At 21:15 KIYOSHIMO is sunk and at 21:24 ASHIGARA follows, badly damaged by a 500-lb bomb. At 21:30 KAYA is hit.
Air attacks stopped due to night conditions but alrady PT boats are on their way to intercept them. At 22:10, the KASUMI, ASHIGARA and OYODO spotted and fired at approaching PT-boats. One is hit, disabled, and the other fled. At 23:03, ASHIGARA and OYODO fires illuminating shells into Mangarin Bay and eventually sighted an American convoy. They closed in and 23:10, the destroyer IJN KASUMI fires four torpedoes at these troop transports but missed. At 23:15, IJN KIYOSHIMO is caught by USS PT-223 and sunk, one of the rare successes of the latter. She explodes and sinks, and by 23:26, KASHI and KAYA also fireed torpedoes claim sinking four transports (none reported sunk in reality). From 23:45 to 00:04, KASUMI, ASASHIMO, ASHIGARA and OYODO on the short sighted a supply dump on the mouht of Kasuang River and put it on fire. They also managed to damage the freighter JAMES H. BREASTED in Ilin Strait, still able to land its 600 Army troops. She would be bombed by possibly an US aicraft by error, havinf her cargo of gasoline on fire, and she would be later abandoned.

Operation “REI” in San Jose

The following 27 December, ASHIGARA and OYODO spotted and shelled USN ships identified as “gunboats”. At 03:45, ASASHIMO is attacked but undamaged and at 23:25 hit again. She was spotted by the submarine USS BAYA (SS-318, Cdr Arnold H. Holtz) and soon ASHIGARA and OYODO as well, as well as their escorting destroyers while returning to Camranh Bay. Holtz submerged to radar depth ahead of the approaching Japanese force and carried out his attack by sound, firing a full salvo of six at 22:07 from 3,200 yards, but missing the vanguard destroyer ASASHIMO.
At 1830 on the 28th, the fleet is back unharmed in Camranh Bay. The following day, Oyodo left via Cap St. Jacques to Singapore, reached on 1 January 1945. On the 8th her trip is revealed by codebreakers at the USN Melbourn Radio Unit which signalled OYODO, Ashigara and the 4th Carrier Division in Singapore. They next signalled a move to Camranh Bay to rendezvous with 43rd Destroyer Division but Oyodo remained between the 9 and 29 January in Singapore, repaired and refitted at the 101st Facility.
She departs for Lingga, staying until 6 February for the force to gather, and saild out with ISE, HYUGA, the destroyers KASUMI, ASASHIMO and HATSUSHIMO for Singapore.

Operation “KITA” (February 1945)

On 7-9 February 1945 Operation “KITA” is launched, basically a transport run for the Japanese industry. OYODO carried 300 tons of rubber, zinc, mercury and tin and 70 tons of aviation gasoline plus 159 oil field service personnel and other personal back to Japan.
On 10 February she is attached to CarDiv 4 and at night’s fall joins the “Completion Force” (Kan Butai) made of IJN ISE, HYUGA, OYODO, destroyers KASUMI, ASASHIMO and HATSUSHIMO back to Singapore.
On 11 February they are spotted by HMS TANTALUS which tried to attack but is bombed by the IJN air escort and flee. On the 13th in the South China Sea USS BERGALL (SS-320) spotted them through poor weather conditions off Hainan. He was forced to submerged and could not close beyond 4,800 yards, fires six torpedoes but miss. He is chased down by destroyers using their new larger depth-charges. Later that day they are also attacked by USS BLOWER (SS-325), firing five but missing again.

At 15:30 that day, while under a rainsquall OYODO launches a single floatplane which spots USS BASHAW (SS-241) on the surface, soon attacjed by HYUGA, having a 14-inch shell near-miss. On 15 February at 19:00, the Force arrived at Matsu Island Anchorage in Fukien Province (China) and the folling day, they depart via the Formosa Strait for Kure, close to Korean coast (which provides air protection), heading for Shimonoseki Strait. On their way they are met by USS RASHER (SS-269) alerted by “Ultra”. At 05:07 the latter spotted them by radar off Wenchow and surfaced in the driving rain, spotted one ship, firing six Mk.18 electric tprpedoes from 1,800 yards but misses as the Force changes course. The forces arrives at 21:06 at Chusan (Zhoushan) Island off Shanghai.
They depart against on the 18 to deop anchor at Shozen-To island in South Korea, departs the following day for Mutsure Jima and at last arrived at Kure on 20 February.
On the 25th Captain Matsuura Yoshi (on IJN IBUKI before)is the new captain of Oyodo.

Back in Japan (March-June 1945)

On 1 March 1945 Oyodo is assigned to Kure Training Force with her floatplane crew and service personnel transferred to IJN YAHAGI. On the 19th, TF 58 carriers USS ESSEX, INTREPID, HORNET, WASP, HANCOCK, BENNINGTON and BELLEAU WOOD made their first air attack one Kure Naval Arsenal with 240 aircraft between SB2C Helldivers, F4U Corsairs and F6F Hellcats armed with rockets and bombs rampaged the fleet at anchor. OYODO is hit three times with 500-lb bombs and perhaps ten near misses. One bomb weht through her port engine room (fire started) and damaged nearly all boilers. She had her starboard hull plating ruptured and start flooding, sinking by the bow with a 15° list. She is latter towed to Etajima, beached before any repairs could take plane. That day she fired her AA with little results and lost 52 sailors.
On 23 March she was drydocked, until 4 May. She then departs Kure for Etajima and the Inland Sea to be moored in Etauchi Bay, less exposed, off the western shore of Etajima. Fault of oil, she is stationed there as a floating battery and until mid-July partially camouflaged (unfortunately no record of this camouflage pattern exists), probably completed by netting. On 15 May Captain Taguchi Masaichi takes command, he would be the last.

The end

Under attack on 28 july
On July 24, 1945, a massive carrier-based air raid from the 38th operational formation (VADM McCain) hit targets of oppurtunities in the area. They soon spotted IJN Oyodo at 06:00. from there, and until 17:00 she is attacked by successive waves of about 50 Helldivers and Hellcats all armed with 500-1000 Ib HE bombs. Oyodo soon takes five direct hits of 500 Ibs bomns, two hitting the upper deck, close to the port side catapult, creating large entry holes, another two the central part, starboard, damaging the engine rooms and destroying a 100-mm mount. Another wen through the middle deck close to the forward superstructure, ravaing the encryption room and starting a firrce fire, ragung untik the 26th. She also had near-misses on her port side, holing her hull above the waterline. She was not flooded.

On the morning of July 28, she is attacked again by TF 38, this time, by 40 Helldivers from USS WASP and SHANGRI-LA. She taks several nar-misses on her starboard, close to the forward engine room and 5th boiler room, bursting the plating out and flooding. Counter-flooding had no effect so 25 minutes later by 12:00, she capsizes to starboard, listing at 80°. It was in shallow water so yhis left her port side over the water, by about 7.5 m. 300 drawn when she sank, the rest on orders of Commander Taguchi left her later in the afternoon. They had time to check for possible trapped survivors. Hellcats from USS MONTEREY came back layer and went to fire their rockets on the overturned cruiser. She is hit by two, creating holes and internal damage.

The end. Photo taken by a US plane in August 1945.

The war ended with Oyodo still in this position. On November 20 she at last is written off from the lists. She would stay her, a problem for merchant traffic, into 1946 and more of 1947. At last on September 20, 1947, she is reloated, towed to dry dock No. 4, Harima shipyard in Kure to be scrapped, from January 6 to August 1, 1948. As the the last survivors of the Imperial Navy’s cruiser, the modern JMSDF took inpiration of her design for large cold war ASW helicopter destroyers of the 1970-90s.

Oyodo’s scrapping in 1948

About the rest of the class

Cruiser C N°137

Cruiser C No. 137 was planned to be laid down at Kure in September 1941 and commissioned in March 1944. However, the keel laying was delayed until Cruisr No.136 (Oyodo) was out of the slipway. Moreover, after a meeting on November 6, 1941, due to incoming operation against Pearl Harbor, priority in shipbuilding changed. After Oyodo was launched on April 4, 1942, cruiser No.300 (the future Ibuki) was laid down in her place in the slipway on April, 24. Cruiser No.137 was suspended.

Cruiser C No. 137 was planned initially to be laid down at Kure in a separate slipway by September 1941 then operational by March 1944. However the yard objected to find a free slipway for her and so she had to be laid down in the same on dedicated to N°136. Both had their fate sealed when the first was delayed herself. As the launching of No. 136, was suspended after a meeting on November 6, 1941, pushed back to April 4, 1942, decision was made instead to prioritize cruiser No. 300 (IJN Ibuki), laid down on April 24. And so No.137 having little chances to be laid down before 1944, she was finally canceled.

Construction of Cruiser C N°137 (possibly named IJN “Niyodo”, the river in Kochi Prefecture) was indeed suspended on 6 November 1941, wating for her sister ship to clear the slipway. This played against her as the war changed drastically priorities and the prewar concept of Submarine Sentai soon proved irrelevant: IJN Niyodo was finally cancelled on 3 August 1942.
Thus cancellation came in accordance with an earlier proposal by the State School of Civil Engineering on June 30. She never got an official name.
It was not long before the remaining six of the 1939 plan were cancelled as the six of the 1942 plan.

Read More

Kawanishi “Shiun”, an interesting high speed two prop model that never was mass produced


Bob Hackett, Sander Kingsepp. CombinedFleet.com IJNMS OYODO: Tabular Record of Movement.
Eric Lacroix, Linton Wells II. Japanese cruisers of the Pacific war. Annapolis NIP
Campbell, John (1985). Naval Weapons of World War II. Annapolis NIP
Jentschura, Hansgeorg; Jung, Dieter & Mickel, Peter (1977). Warships of the Imperial Japanese Navy, 1869–1945. NIP
Lengerer, Hans (2018). “The IJN Light Cruiser Oyodo”. In Jordan, John (ed.). Warship 2018. Osprey.
Polmar, Norman & Genda, Minoru (2006). Aircraft Carriers: A History of Carrier Aviation and Its Influence on World Events.
Stille, Mark (2012). Imperial Japanese Navy Light Cruisers 1941–45. Osprey.



Model Kits

You can trust Aoshima, Tamiya and Hasegawa to procure this segment in 1:700 and 1:350

First published on Jun 20, 2018.

Swordfish (S) class submersibles (1931)

Swordfish class submarines (1931)

Royal Navy Flag Patrol Submersible 1930-1945:

HMS Swordfish, Sturgeon, Seahorse, Starfish.

WW2 British Submersibles:
X1 | Odin | Parthian | Rainbow | Thames | Swordfish | Porpoise/Grampus | Shark | Triton | U class | T class | S class | A class

Birth of a great standard: The S-class (1930-1980s)

HMS Seawolf (cc)

The S-class submarines of the Royal Navy were were planned to patrol the restricted waters of the North Sea and Mediterranean. They were also scheduled as replacments for replacing the vintage WWI British H-class submarines. It started with a modest class in 1930-33 called Swordsfish, and later the Shark class (8 boats). Given the ensemble performances of this design it was judged satisfactory enough to decline a whole mass-construction programme in wartime, with the 1941 “repeat S”. This cheap and all-around efficient type soon became the staple of the British submarine force duting the Second World War: The single largest group of submarines ever built for the Royal Navy, with 62 made total over 15 years, including the 50 “improved” S delivered until 1945. Many would gain fame with their “special operations” together with their patrol duties.

hms sealion
HMS Sealion camouflaged during the war (Shark class).

The S class never were intended for the Far East, but went there from 1944 after being fitted with extra tank capacity. In addition the S-class went on to serve in the Royal Navy until the 1960s, the last retired being HMS Sea Devil, sold for BU in February 1966. Some also changed flags and gained an extra mileage: HMS Springer was sold to Israel and became INS Tanin, eventually decommissioned in 1972. The Netherlands acquired one, Portugal three, France four (fighting in WW2 as well), and Turkey, through a modified version ordered in 1939: The Oruç Reis class.
Both the Shark and repeat S will be the object of their own standalone post. This one is dedicated to the original serie: The Swordfish.

About the Swordfish class (group I)

The start of this serie was a clear and simple specification of 1929 advocating a small, simple and chap patrol submarine tailored for “restricted waters” service, the North Sea and Mediterranean being prime examples, although they could have been sent to operate from South Africa and in the Indian Ocean as well. But the standard rotation was between Malta (which from they controlled both the western and eastern Mediterranean), and Portsmouth or any north sea port along the british Coast, up to Scapa Flow. Emphasis was not put on any particular design trait, rather for a good balance of every of these. Note that there was also an experimental HMS Swordfish in 1916.

⚠ Note: This is a starter article, to be Completed at a later date.

Design of the class

S-Class plans
S-Class plans (wartime)

Hull and general design

The S-class submarines were designed as successors to both the mass-produced H class and the late WW-I L class. Their area of operation dictated their range, tanks size and thus size and displacement. Thus compared to all previous submarines built since 1923 they were “only” 202 feet 6 inches (61.7 m) long overall, combined with a beam of just 24 feet (7.3 m), which left a rather narrow inner hull. Mean draught was established at 11 feet 11 inches (3.6 m) for a grand total of 730 long tons (740 t) surfaced, 927 long tons (942 t) submerged. They were not only cheap in construction but also in maintenance, as they only needed a complement of 38 officers and ratings. Their max diving diving depth was “in the norm” for the time, calculated to be at 300 feet (91.4 m). From this, no aircraft would ever be capable of spotting them.


For surface running, the boats were powered by two 775-brake-horsepower (578 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 650-horsepower (485 kW) electric motor. They could reach 13.75 knots (25.47 km/h; 15.82 mph) on the surface and 10 knots (19 km/h; 12 mph) underwater.[4] On the surface, the first-batch boats had a range of 3,700 nautical miles (6,900 km; 4,300 mi) at 10 knots (19 km/h; 12 mph) and 64 nmi (119 km; 74 mi) at 2 knots (3.7 km/h; 2.3 mph) submerged.[3]


The Swordfish class were given only an armament in the bow, not the stern, with six 21-inch (533 mm) torpedo tubes and six reload for each so twelve torpedoes carried in one go. This was quite acceptable in peacetime, but even before the war brok out, the Royal Navy ordered a serie of dedicated submarines depot ship (notably the Medway class), to assist them while deployed four from home. In addition to the tubes, they carried a 3-inch (76 mm) deck gun and nothing else.


HMS Swordfish (61S) was ordered on 2 July 1930 at Chatham Dockyard, laid down on 1 December, launched on 10 November 1931, commissioned on 28 November 1932.
HMS Sturgeon (73S) was laid down at Chatham Dockyard in January 1931, launched on 8 January 1932, commissioned on 27 February 1933.
HMS Sealion (72S) order on 23 December 1932 at BuilderCammell Laird, Birkenhead and laid down on 16 May 1933 was launched on 16 March 1934 and completed on 21 December 1934.
HMS Starfish (19S) was ordered on 16 March 1931 at Chatham Dockyard, laid downon 29 September 1931, launched on 14 March 1933 and commissioned on 27 October 1933.

⚙ specifications

Displacement 730 long tons surfaced, 927 long tons submerged
Dimensions 202 ft 6 in x 24 x 11 ft 11 in (61.7 x 7.3 x 3.6 m)
Propulsion 2 shafts diesels 1,550 bhp (1,160 kW), 2 electric motors 1,300 hp (970 kW)
Speed 13.75 knots (25.47 km/h; 15.82 mph) 10 knots submerged
Range Range: 3,700 nmi (6,900 km; 4,300 mi) at 10 knots surface; 64 nmi at 2 knots submerged
Test Depht 300 feet (91.4 m)
Armament 1x 3 in deck gun, 6× 21-in (533 mm) TTs
Crew 38

The Swordfish class in action

Royal Navy ww2 HMS Swordfish

At the start of the second world war, all four served with the 2nd sub flotilla ain home waters. HMS Swordfish was missed with three torpedoes by her sister ship HMS Sturgeon, mistaken for a U-boat while in Norwegian waters. On 20 April 1940, she attacked a German convoy but failed to hit anything. Two days later she spotted another convoy, but dropped the attack due to the ship’s shallow draught. On 26 April, avoided drifting mines, bumping into one which was a dud. Her sixth war patrol was another “blue on blue” incident, when she was targeted hy British aircraft. Lost in ther 12th patrol, at firsdt presumaby sunk by German destroyers off Brest but she hit a mine when her wreck was rediscoreded in June 1983 off the Isle of Wight.

Royal Navy ww2 HMS Sturgeon

HMS Sturgeon was assigned to the 2nd Submarine Flotilla during her interwar service. From 6 September 1939 she conducted patrols in the North Sea but was bombed by British aircraft like her sisters, an error quite common at the time. In her 2nd patrol three torpedoes at an unidentified submarine later to be HMS Swordfish, and missed. Her 3rd patrol saw her spotting but missing the German U-boat U-23, which replicated and she made a crush dive, hitting the bottom. She was later repaired and back in her 4th patrol on 20 November sank the German armed trawler V-209. It became the first British sub success of the war, quite a morale boost.

Her 5, 6, 7th patrols saw her sighting/sinking several ships notably the German troop transport Pionier, Danish merchants SS Sigrun and SS Delfinus. In 1941 she was reassigned to the Bay of Biscay, and in October 1942, reaffected to Operation Torch, used as beacon with the 8th Submarine Flotilla. Reassigned to the northern convoy route afterwards to Mursmansk, she was damaged by Allied (Russian) aircraft while escorting the Arctic Convoys PQ 15 and PQ 17.
In May 1943, she was loaned to the Royal Netherlands Navy as HNLMS Zeehond, returne din 1945 and sold for scrap in 1946. She became the only one of her class to survive the war.

Royal Navy ww2 HMS Seahorse

After an uneventful interwar service, HMS Seahorse made a first patrol southwest of Stavanger but when returning to port was mistaken by an U-Boat and attacked by British planes, with depth charges and sustained damaged. Repaired she was back for a second war patrol, spotted U-36 on 13 November 1939, fired but missed. On her 3rd patrol on 30 October, she spotted U-21, but the latter submerged before she launches.

On 18 November, HMS Seahorse spotted two destroyers, likely Z21 Wilhelm Heidkamp and Z19 Hermann Künne, but they were too fast for her to manoeuver in a suitable firing spot. On 26 December, she was making her sixth and last patrol off Heligoland Bight, with orders to latter enter the mouth of the Elbe on 30 December. But on 9 January 1940 she still did not returned, and it was speculated she had struck a mine. German records showed that she was sunk by the German First Minesweeper Flotilla reporting an attack on an unidentified submarine on 7 January 1940. Another hypothesis is that she was rammed and sunk by the German Sperrbrecher IV/Oakland, southeast of Heligoland, on 29 December 1939.

Royal Navy ww2 HMS Starfish

After an uneventful interwar carrer, Starfish like her sister took part in north sea patrols with the 2nd Submarine Flotilla. She made five uneventful war patrols spotting ships were never in position to attack or judging the target not worth her torpedoes. On 9 January 1940, her sixth patrol had her sent in dangerous waters, off Heligoland. She spotted and attacked a German minesweeper off Heligoland Bight but missed. Attacked in return, depht-charged, her diving planes jammed, and the captain eventually decided to surface. Her crew was rescued by the German ships and she was sunk for good. She was one of the rare British subs which crew was captured entirely by the enemy, ending in a POW until the end of the war.

Read More


Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press.
Colledge, J. J.; Warlow, Ben (2006). Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing.
Chesneau, Roger, ed. (1980). Conway’s All the World’s Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press.
Harrison, A. N. (January 1979). “The Development of HM Submarines From Holland No. 1 (1901) to Porpoise (1930) (BR3043)”.
McCartney, Innes (2006). British Submarines 1939–1945. New Vanguard. Vol. 129. Oxford, UK: Osprey.
Rohwer, Jürgen (2005). Chronology of the War at Sea 1939–1945: The Naval History of World War Two (Revised & Expanded ed.). Annapolis, Maryland: Naval Institute Press.



Model Kits

Birinci İnönü class submersibles (1927)

Birinci İnönü class submersibles (1927)

Turkish Navy Turkish Navy

Introduction on Turkish Submarine 1923-1935

The development of Turkish submarines went on a long way. The very first ones, Abdülhamid and Abdülmecid, were commissonned in 1886 and 1887, at a time more Navies considered them experimental and little else. A cooperation between Sweden and British Yards, they were based on the Nordenfelt design, brought to Turkey in pre-manufactured parts, assembled in great secrecy behind closed doors, at the Tersane-i Âmire dry dock.

They stayed in service for a few years, showing the limits of the steam engine concept, but also what the future could look like. The experience served to put the basis of a submarine corps, train personal, but technology went a long way until WWI. At the time, Turkey had no submersible in service to oppose to the entente. The young turks movement and revolution that followed plus the war with Greece and the new Republic changed all this.
Therefore this history could be separated unto several periods: Following the early beginnings in 1885-1918, it’s the Republican Period (1923-1935) which prepared the way, with acquisitions, followed by WW2 (1936-1943) and the cold war era from 1944 to 1967 and from 1968. About the latter topic, see the dedicated Cold war Turkish Navy Page.

The first modern Turkish Submersibles

The first two “modern” submarines since 1885 were so during the Republican period. They had been ordered in 1925, completed and commissioned in 1928. In between was a long process. Turkey at the time had no expertise in such construction and the question was who to ask them to built them, knowing that at the time as now, this has an impact on geopolitics and state relations (notably alliances and neutrality stance). Contencious relations with the former entente (France and UK in particular) precluded orders there, as for Italy, it’s stance with Greece before WWI was something to consider. USSR, like Imperial Russia before still was still seen as a potential threat, having close borders and relations would only warm up in the 1930s. That left only Germany, the natural WWI ally for such endeavour, but after a regime change and now under the yaw of the Versailles draconians limitations, was forbidden to built any submarine. Nevertheless, through the German attaché in Istanbul, a prospect soon emerged:

The choice of Ingenieurskantoor voor Scheepsbouw

In 1919 the Versailles treaty imposed that all German U-Bootes would be delivered or dismantled to Britain as approved by Articles 188, 189 and 191, as prepared on 28 June 1919, entered into force on 10 January 1920. The entente nations was then free to pick up existing U-Bootes of their choice (and obviously some were more prized than others), leading to sometimes tense discussions and arbitrations between England, France, USA, Japan and Italy.
The Treaty of Versailles though its Article 191 in addition forbade Germany of the construction or purchase of any submarine even for purely commercial purposes. However the entente ignored the entire infrastructure of technical expertise still there, inherited from German submarine industry. It was requested to hand over existing plans and documentation, but it seems this was never carried out. Not only that, personal employed in these design bureau, now back from military duty, were seen as wasted potential by the new head of the Reichsmarine, Admiral Von Trotha. This, Germany started various activities in order not to lose this expertise, experience and knowledge. Admiral Paul behncke which replaced him and retired from the navy in 1924 setup a complete organization in order not only to no loose this precious potential, but creating an export product that could benefit the country by generating resources and keeping the expertise alight until Germany wouls restart its own submarine production.

To avoid the political troubles by acting against provisions of the Versailles treaty, the Netherlands were chosen to settle a covert German company N.V. or Ingenieurskantoor voor Scheepsbouw (IvS for short) which meant “Engineering Bureau for Shipbuilding Inc.” Basically all engineers that counted in former design bureaus settled there to resume work in 1922, with documentation of former WWI submersible models. They setup an entirely new submarine technology development and application program, completely outside the territory of Germany and the peering eye of French or British inspectors. Once all was ready, a small commercial team started to contact naval attachés in Japan, Argentina, Italy, Sweden, Spain, Finland, Romania, the USSR, China and Turkey, always in a top secret fashion. Since the former entente countries had no spies in neutrals, nothing came out of it.

An order that arrived just in time

Three shipyards were owned by two German companies Vulkanwerft (Hamburg) and A.G.Weser/Krupp (Bremen) as well as Germaniawerft/Krupp (Kiel) with top secret support of the German government, all had invested in the Hague facility by in July 1922 and went over some legal issues causing delays. Thus, IvS started to market its first product by 1925. The design team called “Inkavos” was led by Dr. Hans Techel, and its financial support provided in complete secrecy by the German navy, eager to retain its abilities. Secretly financed, IvS could thank Turkey for its first orders, with the intermediary of Admiral Ernst von Gagern, making this sale happen.

The two Turkish submarines were ordered for one million marks just when the economic conditions of the country started to balance themselves, and it became vitally important for allowing IvS a first sale, enabling more trust from future customers. This was also a was for Turkey to came to the aid of its old ally. But it was not for certain at first, as the IvS sales team had its own priority countries: Argentina, Spain and Italy where they determined a need. When proposals met some resistance at first, IvS entered a financial stalemate to the “Turkish Connection” went at a perfect timing. With this support, Germany at least could see its whole enterprise succeed.
Tractations were all done in pure secrecy, with front companies established for the order, concealing communication between IvS and the German navy such as First Mentor Bilanz GmbH, and from 1927 Igewit 1 GmbH and Tebeg GmbH. Fijenoord received the order, and plans from IvS as a Dutch legitimate business whereas it was fully controlled by Krupp. Ths whole scheme was fully uncovered during the Nuremberg hearings after the war. Part of this operation still had not been fully clarified today.

Development of requirements

Fijenoord shipyard in the Netherlands was to be responsible for this construction. And we can only wonder how Dutch engineers looked at the blueprints that were showing a good old WWI design, UB-III class (see WWI German Uboats).
Lieutenant Atâulllah (Nutku) was one of the important personalities in Turkish shipbuilding industry later, which at the time mentioned in this memoirs some training on construction of future submarines with national designs and requirements. Via contacts at the Hague’s NV Ingenieurskantoor voor Scheepsbouw just opened in 1922, this project, also assisted by other Turkish engineers authorized to draft a basic adaptation of Germany U-Boat designs. This led in 1923 to a set of requirements to be submitted to IvS.
Lt. Nuktu worked at the Fijenoord Shipyard trained by German engineers and technicians from IvS. He also had the opportunity to apply theoretical knowledge acquired later, performing various navigational and diving missions on location. It was not a coincidence he was chosen for this task as an engineer with a German education (spoke fluently German and a bit of Dutch). However once on site he was kept largely in the dark, only taking part to the sea trials and cruise back to Turkey as observer. As he declared at the time:

… me and my friends have not been subjected to any questions, interrogations or examinations since we returned from our studies in the Netherlands, and we have been kept waiting for five months without taking part in any duty…

The fact this order was placed in 1925 reveals possibilities of secret negotiations between Germany and Turkey starting perhaps even after the proclamation of the republic. Werner Fürbinger was assigned to Turkey as a technical attaché as early as 1920 but no heavy equipments could be ships at the time due to the economical conditions of the young republic.
It seems the Turkish requirements were simple and straighforward: Two patrol submarines intended to have the range to criss-cross the Black sea, meaning going from Istanbul to Odessa, Sevastopol, the Kerch strait or as far east as Batumi, and stay on station. In case of war with USSR, at least three large rivers ended there, with the associated merchant traffic. The rest were common specifications for such type of submarine, and Krupp (pardon, IvS) engineers just exhibited the UB-III design which seemed perfectly tailored for the Job (and spared them a lot of efforts):

About the UB-III design

The UB-III were the most produced, last and best “medium” German submarines even developed to that point. The type is frequently cited as the start of a long lineage culminating with the legendary Type VIII when from 1933, all experts were repatriated to Germany and IvS almost took a secondary role. The UB-III was not large, with just 555 t surfaced and up to 684 t submerged, 57.80 m long (189 ft 8 in) with a 40.10 m (131 ft 7 in) pressure hull, 5.80 m (19 ft) wide and 3.85 m (12 ft 8 in) deep. It was powered by 6-cylinder diesel engines developing 1,100 PS (809 kW or 1,085 shp) and electric motors rated for 788 PS (580 kW or 777 shp) on two propellers. Speed was not stellar, just 13.9 knots surfaced and 8 knots submerged.

But they had a range of 9,090 nmi (16,830 km or 10,460 mi) at 6 knots surfaced in the last version (late production boats) or 55 (102 km/63 mi) submerged. They did not dive deep, tested at just 50 m (160 ft), but this was largely enough for the Black sea, which was not that deep either. Armament was classic for the time with a deck 105 mm (4-in) gun, four 50 cm (19.7 in) bow torpedo tubes, one stern of the same and just 10 torpedoes. Just like other countries, Turkey envisioned to acquire also a submarine depot ship or tender.

Design of the Birinci İnönü class

The general scheme of the UB-III type. By default of blueprints, we can guess that the İnönü class was virtually identical, with some minor dimensions changes, new interior detailed fittings, and a different conning tower, which formed the base for all German U-Boats designs to follow.
These first two submarines ordered were called the “First” and “Second” (Birinci, Icinci) battle of İnönü in 1921 which sealed the victory over the Greeks and sealed the fate of the Republic. (and not “number one”, “two” as stated in conways) The UB III class in its final (third planned) evolution in 1918, formed indeed the perfect basis with little revisions if any, ensuring the Turkish admiralty to have these in no time, despite their objections.

The first Turkish submarine therefore pioneered, from a never built planned type, and with the addition of engineering studies made in between, inclusion of recent scientifical and technological progresses, formed the first link in the long lineage that was the Type VII.
Still, these were also prototypes, full of recent R&D not completely created according to exacts demands of the Turkish Naval Forces. We can see here a political good will gesture going over the heads of the latter as it enabled the German Navy to examine design variables for their own future needs, all graciously paid for by Turkey…

Hull and general design

Interior design and top view of the UB-III. Again, we shall see the İnönü class as a faithful repeat, with some adjustments. The torpedo tubes room takes almost 1/3 for the pressure hull’s lenght, separated fro the main (crew) compartment amidships, the crews quarter, central operation room in the middle with the strong conning tower above and built-in periscopes, an its sail on deck. Behind, the galley, the small officers quarter and more crew quarters. Then the third compartment, separated by a watertight bulkhead like the torpedo room, containing the MAN diesels and batteries.

The hull of the İnönü class was 58.68 m long, 5.80 m wide and 3.50 m deep, so the Turkish design was longer by a 80 cm, same beam, and less deep (the original was 3.85 m) to better cope with shallow waters. After all for WW2 standards, these were coastal submarines. The only really distinctive piece (since original blueprints are lost) shows a slightly different conning tower. This had some importance (see later). The structuration was about the same as the UB-III again, with a central inner hull ending with a rectangular section running from the bow, which had moderate flare and was more rounded to improve seaworthiness, and sloped down almost to waterline level. The top of the presure hull was almost flat and covered with anti-stripping serrations.


There was little innovation on this: These had the usual solution of two MAN diesels, rated for 1,100 bhp combined, and two Siemens electric motors for 700 shp resulting in a top speed of 13.5 kts surfaced and 8.5 kts underwater. This was barely an improvement over the UB-IIIs, which reached up to 13.9 knots surfaced and 8 knots underwater.


It must be said that for treaty-bound peacetime regulations, these submarines had not been commissioned yet when undertaking the long trip to Istanbul. They were armed with was was available in Turkey.
Torpedo Tubes:
The Birinci İnönü class had six tubes, versus five on the UB-III: Four forward, but two aft. We can suppose for the models used that Turkey had no problem picking one of its regular 450 mm (17.7 in) models in the fleet, although there is not much info on that topic. Given the space aboard the torpedo compartment, they had likely ten torpedoes in storage, like for the UB-III. This only authorized for a short campaign, unless there was a supporting tender. Of course by WW2 standard this was a caliber considered completely obsolete. The next Dumlumpinar, Sakarya, and the “Ay” serie were all armed with 21-in tubes. In the 1920s, this caliber was still quite common for submersibles.

Birinci Inonu
Birinci Inonu, date unknown, showing its deck 75 mm gun in maximal elevation. The CT seems rigid, and there is no trace of the aft 20 mm AA gun.

Guns & AA:
The main deck gun was probably an Italian Ansaldo dual purpose, high elevation 75mm gun (3-in) or the original Vickers model.
The AA consisted in a 20mm autocannon (Oerlikon or Hispano) setup on deck, on a pintle mount aft of the conning tower, as shown in this photo.
Here lays the main difference and innovation of this design compared to the UB-III, which missed an AA gun, and which CT was a bit different.
It must be added that like WWI models, both has a net-cutter installed forward. Two communication cables were hanging from its base, up to the Conning Tower and aft to the poop. Barriers were fitted on each side of the central structure of the inner hull, rectangular with a simple bump to accomodate for the larger stepping platform of the forward deck gun.

Conning Tower:

According to rare photos of the İnönü class, the conning tower design changed over time. This photo allegedly in 1928, shows it only with the lower part of the kiosk, integrating a small chadburn and wheel, when surface navigating, but others shows at least a canvas or metal sheeting above, to protect the crew from the elements, which is found in most photos. It was the same as for the late UB-III type, minus the inclusion of a 20mm AA gun aft, but the latter is little documented, as there are no photos shing the rear part of the CT. In any case, this CT integrates for the forward part a wave breaker and had a flange on top to deal with heavy weather. There were two apertures at the back of the upper portion of the CT for conventional navigation lights (green and red). This photo and this one also shows apparently a “rigid” CT but this one and this one shows rather a white canvas instead, so likely an earlier date. It is true also these “canvas” versions of the CT are associated with a tricolor flag which more resemble the Dutch one than Turkish. Which goes into the hypothesis early tests were done with a canvas-covered CT, which became rigid after they entered service with Turkey, either because the parts to complete the CT were sent in between, or gathered from Germany, or both were refitted in the late 1930s or possibly WW2.

⚙ Birinci İnönü class specifications

Displacement 505t surface, 620t submerged
Dimensions 58.68 x 5.80 x 3.50 m (192.6 x 19 x 11.6 ft)
Propulsion 2x MAN diesels 1,100 bhp + 2x Siemens electric motors 700 shp
Speed 13.5/8.5 kts surface/submerged
Range 9,090 nmi/6 knots surfaced, 55nm submerged
Armament 6x 450mm (18-in) TTs (4 bow, 2 stern) 75mm gun (3-in), 20mm AA
Diving depth (max) 60m (196 ft)
Crew 29

Birinci İnönü’s class career

The Purchase, Construction and Delivery Process of the 1st and 2nd Inonu was done in the context of a Power Struggle over the Turkish Navy, founded over continuous wars since the Tripoli War, by a newly established Republic of Turkey to cope with immediate geopolitical threats, inherited from the Ottoman Empire. A naval armaments program and large-scale renovation and modernization of existing, “legacy” warships idling in ports for years became priorities. The rivalry between naval and land forces recurred in the Republican Era unfortunately.

The army emerged victorious from the War of Independence and with Kemal Ataturk at the head of state, became the sole authority in the modernization of the armed forces, it therefore shaped the naval program in accordance to their own needs. General Chief of Staff Fevzi Pasha wanted a limited naval program oriented towards coastal defense, with submarines and small ships. Its first traduction were the 1st and 2nd İnonu submarines, largely the product of a land forces-oriented perspective.

Turkish Navy Birinci and Ikindci İnönü in service

Type VII
Even before completion, and even long before sporting the red and crescent flag of the young republic, the two submersibles carried an all-German personal aboard to make an extensive serie of close to shore sea trials and navigational tests in the North Sea, testing cruising performances generating extensive reports, all later carried via diplomatic briefcases to Krupp.

At completion, these submarines left Rotterdam on 25 May 1928 for their cruise to be be delivered to Turkey. That cruise was carried out under the Dutch flag, and with a the German crew, plus a few few Turkish observers on board which were just there as passengers. Neither France or Britain had any idea that a German submersible with its German crew and bogus flag were cruising along their coast, from the Netherlands through the channel and to the Gulf of Gascony, the Spanish coast, strait of Gibraltar, coasts of North africa and strait of Messina, up to the Aegeans and Greek coast, and the Dardanelles…

Nothing can be found on the service logs of these submarines, were are left in the dark here, apart the fact they were almost always seen together in photos, and likely based at the Istanbul naval base.
We also know these submarines were modernized in 1940-1941 with German help, allowing them to last a few more years (hence the new style CT shown in some photos). By September 1948 they were outdated and Birinci Inönü was lost on October 17, 1951 in the Black Sea for unknown reasons. Her sister-ship was withdrawn from service on March 14, 1954 due to a fire which wrecked her to such a point the examination team reported the dmage was too extensive at this point to make any repairs worthwile.
At the time, MDAP programs soon procure a new generation of GUPPY types to the naval forces in the frame of NATO. Thus, Ikindci İnönü was broken up soon after. Conways is quite vague on the subject, just telling they were “discarded circa 1950”.

Conclusion: A crucial first step… paid by Turkey

IvS engineers after this well timed Contract for Turkey prove it was able to the task, and soon, Finland, the USSR, Spain, Sweden, Japan, Romania, Argentina and even indirectly Italy looked forward the small Netherlands Company for their own design, with the conditions they would be built in the respectuive customer’s countries. The sum of the knowledge gained in the next submarine types, looely based on customer’s specification sometimes, fit the future Kriegsmarine’s specifications, and gave birth to the coastal Type IIA, the oceanic Type VII and long range Type IX based on all these IvS prototypes. Germany later signed an agreement on 29 June 1935 with Britain to loosen the Versailles conditions, and the first German submarine was built on German soil just five weeks afterwards, all thanks to the ground work made by the Dutch design bureau, which closed its doors before an enquiry could be done.

By allowing Germany to have a new-built UB-III and test limited innovations, the Turkish order enable a long lineag that went through approximately 1,150 U-Boats by 1945. The “numbers” were also probably the most direct ancestors of the Type VII (500-tonnes class). Despite officially Finland was a customer in 1926, Spain in 1928, the sales followed always the same pattern, proposed but first adapted to German needs. The final customers were bacically forced to accept the deal and tone down their own requirements. The Finnish types were the prototypes of the U-Boat Type IIA and the U-25 and U-26 of the 1936 Spanish E1 and Turkish Gür class. The Type I U-Boat was in fact TCG Gür, and this classification was used the first time. Many more would follow until the Type XXI and beyond…

Read More


Conway’s all the world’s fighting ships
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pigboats.com on UB88
Google books – research on the interwar Turkish Navy
wiki German_Type_UB_III_submarine
On uskudar.biz
On dergipark.org.tr/
On bitmezat.com/
On wowturkey.com
On savunmasanayiidergilik.com

Model Kits

None found, but i presume any UB-III with some scratchbuilt work on the CT would do.
UB-III kits: Found only these small 1/700 3-D printed ones on shapeways.
There is however a paper kit from UBoatInfo (1:72 scale !) with 580 parts requiring, about 100 hours to build. It shows the interior structure, the machines, armament, crew and crew space. Full review and photos.

Summary of Turkish Submarines

Birinci İnönü class (Built in NL Fijenoord) launched 29 January 1927, comm. 9 June 1928 (stk 1948)
İkinci İnönü launched 12 March 1927, comm. 9 June 1928 (stk 1948)
TGC Dumlupınar: A version of the Italian Vettor Pisani-class submarine built in CRDA, Monfalcone, launched 4 March 1931, Commissioned 06 November 1931, stricken 1949
Italian modified Argonauta-class submarine built in CRDA, Monfalcone, launched 5 February 1931, comp. 6 November 1931, Decomm. 1949
Modified U-Boat Type IA built by proxy by the Yard Echevarrieta y Larrinaga, Cádiz, launched 22 October 1930, comm. 29 December 1936, Decomm. 1947
Ay class:
Modified version of the Type IXA submarine built in Germaniawerft Kiel:
-Saldıray: launched 23 July 1938, comm. 5 June 1939, Decomm. 1958
-Atılay: Launched 1938? Comm. 1939? Lost 14 July 1942
-Batıray: Launched 28 September 1938, seized, comm. 20 September 1939 as KMS UA, Scuttled 3 May 1945
-Yıldıray built in Gölcük Naval Shipyard, launched 26 August 1939, comm. 15 January 1946, Decomm. 1958
More on the following classes on the cold war Turkish Navy Page