Category: ww2 warships

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

Construction

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

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.

Protection

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.

Armament

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

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.

Modernizations

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.

Author illustration 2 views, Katori in 1944

Specifications

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

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 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 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.

Resources

Links

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
http://combinedfleet.com/ships/katori

Books

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

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.

Powerplant

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.

Armament

Main

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.

Secondary

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.

Mines

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.

Modifications

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.

Radars:
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

Read More

Books

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

Links

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
wikipedia

Model Kits

3D reconstruction by the Warthunder Team
On artstation

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 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

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 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.

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.

Development

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.

Construction

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.

Design

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.

Propulsion

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).

Performances

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.

Citadel
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.

Armament

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 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

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.

Author’s profile illustration Oyodo 1944

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

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

Books

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.

Links

http://www.combinedfleet.com/oyodo_t.htm
https://ru.wikipedia.org/wiki/%D0%9E%D1%91%D0%B4%D0%BE_(%D0%BA%D1%80%D0%B5%D0%B9%D1%81%D0%B5%D1%80)
https://reviews.ipmsusa.org/review/japanese-light-cruiser-oyodo-super-drawings-3d
https://en.wikipedia.org/wiki/Japanese_cruiser_%C5%8Cyodo

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.