Grampus class submersibles (1932-36)

The first British internwar minelaying submersibles: The 1,800-tons Grampus-class were derived in 1936-38 from the single prototype HMS Porpoise launched 1932. Five of a modified design were built therefore after years of testing and improvements. They shared the same marine mammals names, and paid a dearly price to world war two with just one surviving: HMS Porpoise was sunk by Japanese aircraft in 1945, Grampus by Italian torpedo boats in 1940, Narwhal by the Luftwaffe near Norway Cachalot by Italian TBs in 1941, and Seal was captured in the Kattegat…

HMS Porpoise Prototype

HMS Porpoise was long-derived from a German Coastal Minelayer UC-5 obtained as war reparation, scrapped in 1923. The numerous reports helped settting a working base that was later refined in 1929.
Eventually the final designs was approved and voted for contruction in 1930, attributed to Vickers Armstrong, Barrow, laid down in 1931. HMS Porpoise was launched on 30 August 1932.
As designed she was a saddle-tank type submersible for which Vickers just enlarged their existing Parthian class. The hull shape and internal arrangement was essentially the same, but of course with a provision in th ballast to fit the torpedo wells.
The deck gun 4.7in was replaced by a 4in/40 QF Mk XII in 1934. Mines were carried in the superstructure on an endless chain, which in general layout resembling that of the converted M3, but the excessively slow diving of the latter was avoided by careful design of the mine casing. Designed diving depth was 300ft and test depth 200ft, whilst the fuel was mainly in external welded tanks. In addition to the 50 mines of conventional type, 12 M2 mines could later be carried in place of the 12 torpedoes.

HMS Porpoise in Service: A remarkable career

HMS Porpoise was commissioned on 11 March 1933. Her early career is in research. In 1938 she had a new commander, George Walter Gillow Simpson, RN, from 21 September to the next 15 Nov 1939.
On 25 Aug 1939 she departed Portsmouth for Gibraltar to join the 1st Submarine Flotilla, but departed for Malta the following day. On 19 Sept. 1939 she was conducting exercises with HMS Otway (Cdr. H.R. Conway) off Malta with also HMS Cachalot (Lt.Cdr. S.W.F. Bennetts). On 11 October she was scheduled to return hom, via Gibraltar (15 Oct) and made it to Portsmouth 5 days later.

On the 24th, she departed for Sheernes and Chatham Dockyard for a refit. It was completed on 18 Jan 1940 and with a new commander, P.Q. Roberts, RN she returned from the yard to to Sheerness and after trials on the 21th, she returned to Portsmouth and after exercises, including conducted mine laying exercises off Portmouth on the 25th, on 7 Feb 1940 she proceeded to Yarmouth Roads, Isle of Wight followed by exercises off Yarmouth and returned to Portmouth, alternating between the two until 12 March 1940 when she departed Portsmouth escorted by HM yacht Sona, to cover the convoy FN.20 for Rosyth.
On 16 March 1940 she arrived there, and departed three days after for her 1st war patrol, escorting convoy ON 21 to Bergen and on the way back HN 21. She was back on 25 March and departed again on 27 March for her 2nd war patrol, escorting convoy ON 23 to Bergen and HN 23 back. Nothing happened for her during the trip.
On 13 April under Cdr. P.Q. Roberts she made her 3rd war patrol, relieving HMS Clyde off Egersund, Norway.
On the 16th at 21:36 she spotted the surfaced U-3 (Type IIA U-boat) and fired from 2000 yards six torpedoes at her, 10 nautical miles south-west of Egersund, but they all missed. U-3 manoeuvered towards her and fired one torpedo, passed overhead Porpoise as she was diving. Her 3rd war patrol ended on the 29th. After a maintenance and crew’s rest, she returned for her 4th patrol after exercizes on 8 May with HMS Tetrarch in the Firth of Forth. Her patrol started on 12 May, ordered to lay a minefield off Norway.

This minefield would later claim the German minesweeper M 5. She reported on 16 april firing on an U-Boat which disappeared and later was probably U-1, which hit a mine laid by HMS Narwhal.
On 15 May 1940, under command of P.Q. Roberts, she lays minefield FD 11 (48 mines) off Kalvag, Norway. It claimed the Swedish merchant Sonja (1828 GRT, built 1923) with a german prize crew.
On 9 June 1940 she left Immingham for her 5th war patrol and laid a minefield off Smøla, Norway. On the 12th she spotted a torpedo wake but was not hit.

On the 14th she laid minefield FD 18 (50 mines) off the Ramsoyfjord, Norway. It claimed on the 18th German minesweeper M 5 (682 tons). On the 19th while charging her batteries north of Halten she was attacked by the luftwaffe, took a bomb near-hit and made a crash dive to escape. On 4th july she made her 6th war patrol, and on the 9th was attacked by aircraft underway. On the 25th, she departed Immingham for her 7th war patrol, laying a minefield off the west coast of Denmark after patrolling off Lister, Norway. This was minefield FD 23 (50 mines with flooders set for 28 August 1940). She started her 8th patrol in August, 5, nothing to report. On 13 September, 9th patrol, she laid now under command of Lt.Cdr. J.G. Hopkins, the minefield FD 26 (48 mines) in the Bay of Biscay north-west of La Rochelle, France.
On 16 Sept. 1940 at 0047 hours, she spotted and launched six torpedoes on what was believed to be a surfaced U-boat south of the Penmarch peninsula, but more likely a trawler.
On 20 Sept. 1940 she was ordered to Falmouth and Holy Loch for her Passage north through the Irish Sea. After attack exercises in the Clyde area she departed for her 9th patrol in the Bay of Biscaye, but missed the only U-Boat signalled bound for Lorient.
On 30 Nov 1940 HMS Porpoise departed Holy Loch for Halifax in Canada. She departed Halifax for her 10th war patrol, escorting convoy HX 99 on 26 December. She was back on 13 Jan 1941. On the 26th she departed Halifax for her 11th war patrol, escorting convoy HX 105 home this time. She however soon departed Holy Loch back for Canada. On 7 March while underway she made a torpedo attack on a submarine, likely German U-boat U-A which was in the area at the time, but she missed. She escorted convoy SC 26 and later SC 29. On 20 May 1941 she sailed to Troon for a refit. It ended on 1st September. Later after post-refit trials she proceeded to gunnery and torpedo exercises with HMS La Capricieuse, and was sent to Govan’s No.2 dock for preparations for her Mediterranean service.

Mediterranean Service

From late 1941 to late 1942 HMS Porpoise operated in the Mediterranean:
Under command of Lt.Cdr. E.F. Pizey, DSC, she departed Holy Loch for Gibraltar, escorted in Irish Sea by HMS White Bear and later the German B-Dienst intercepted a signal giving her exact route, but failed to spot her. On 11 October she departed Gibraltar for Malta, unloading cargo and passengers and later more to Alexandria, including personal from Malta. Axis activity on the eastern Mediterranean was so fierce this was seen as a safer way than regular warship. In november she made two more trips between Malta and Alexandria. On 28 November 1941 she was based in Alexandria, departing for her 14th war patrol, and 1st in the Mediterranean, ordered to patrol the south-west approaches to the Anti-Kithera Channel in Greece.

On 9 December a few miles south of Navarino area where she patrolled newt, in the Peloponnese, she spotted, torpedoed and badly damaged the German passenger and cargo ship Sebastiano Veniero (Jansen), carrying 2,000 UK, South African and other Commonwealth POWs from Benghazi to Taranto, 300 being killed but the rest survived as the ship was beached at Methoni. The TB Centauro was escorting her. Later the destroyers Ascari and Carabiniere arrived and the hospital ship Arno to rescue more. Despite of this, on 11 December, she surfaced and fired two torpedoes at the beached wreck but made no hit. On the 17th, while passing north of Crete for home, at 13:11 hours, she sighted a German U-boat surfaceed, but it was out of range (this was U-652 en-route to the Dardanelles and black sea).

On 2 Jan 1942 she departed Alexandria for Haifa, embarked 12 dummy mines and laid this dummy minefield off the harbour as a test then on the she embarked 46 mines in her 15th war patrol, laying them off Suda Bay, Crete. It will claim on 14 Jan the German auxiliary vessel 11 V 1 (former Greek Palaskas) and on the 18th, she torpedoed the Italian merchant Città di Livorno (2471 GRT, 1930) 15 nm NE of Cape Maleka in Crete. On 7 February she departed Alexandria for her 2nd cargo trip to Malta and a third from 3 March. Experiencing engine problems she was docked in Alexandria on 31 March (Gabbari dock) until the 9th. She departed for Port Said and back. On 18 April she started her 4th trip to Malta.
On 2 May, 20:50 she sighted an ‘U-boat’ based on a report, but she was 50 miles behind her and ciuld not attack. She was in fact the Italian Nereide.
On 23 May this tume under orders of Lt. L.W.A. Bennington, DSC, she departed Alexandria for her 5th trip.

On 7 June, she departed Malta for her 16th war patrol and escorting convoy operations to Malta as part of Operation VIGOROUS. She also patrolled off the Gulf of Taranto.
On 15 Juned, 19:35 about 140 miles west of Crete she was attacked by aviation, had ner-missed by small bombs and dived to 60 feet. At 20:25 she was attacked again, and dived too, no damage.
On 1st July she was overhauled at Port Said. On she departed Haifa for her 17th war patrol and to lay a minefield off Ras el Tin, Libya, also patrolling Cyrenaica. One mine will later claim the Italian torpedo boat Generale Antonio Cantore.

Later, a westbound convoy with Albachiara (1245 GRT, built 1904) and Sibilla (1077 GRT, built 1900) escorted by the sub-chaser Selve crossed it, but the mines had not time to be armed. She tried to torpedo Sibilla but missed. However she later sank the Italian transport Ogaden (4553 GRT, built 1905) off Ras el Tin. She was transporting 200 POWs from Benghazi to Tobruk, escorted by Generale Carlo Montanari (another “Generali” vintage WW1 destroyer). MAS 561 came to pick up survivors but was soon chasing Porpoise.

On 15 August, she spotted, torpedoed and sank the Italian merchant Lerici (6070 GRT, built 1941), 120 nm north of Ras Amir while in convoy with Ravello (6142 GRT, built 1941) and escorted by the destroyer Nicoloso Da Recco and TBs Polluce, Calliope and Castore. Hit by two torpedoes she was abandoned. Polluce made three runs with 38 depth charges, claimed Porpoise sunk and returned to pick a survivor. Bersagliere and Mitragliere finished off the wreck by gunfire and rescued more survivors, but twenty-one were missing. on the 19th however she was off Tobruk detected and depth charged by the TB Lince escorting the transport Iseo (2366 GRT, built 1918) to Benghazi. She claim having damaged her, which was true. She stayed under until not hearing anything and surfaced to depart for home, escorting on her way on 20 August by Beaufighters in escort and later two Hunt-class destroyers. While she was in repairs in Port Said, one of her mines claimed Generale Antonio Cantore off Tobruk.
She departed Haifa for her 18th war patrol on 28 September, laying a minefield off Tobruk and proceed to Malta to unload cargo aboard. Once done on 10 October she was ordered to the Ionian Sea, with just four torpedoes aboard. On the 13th afternoon, she was informed of a convoy of two merchant ships proceeding from Brindisi to Benghazi but she missed the convoy which passed a little further east. She proceeded to Beirut next, and on the 29th departed to unload cargo to Malta. On 18 November she spotted an unidentified U-Boat about 3 miles away which was Pietro Micca on a transport mission to Tripoli. In fact the latter also spot her ahd stayed distant as ordered. The following day Porpoise spotted and fired a torpedo at the auxiliary patrol vessel F39/Fertilia off the Libyan coast but missed. However later that day she torpedoed and sank the Italian tanker Giulio Giordani (10,534 GRT, 1939) 45 nm NE of Misurata, Libya (she had been torpedoed and damaged earlier by British aircraft, abandoned). On the 21th she was ordered to return to Malta via Kerkenah and two days later, spotted, torpedoed and sank thesame Italian auxiliary patrol vessel F39/Fertilia she previously missed. On 4 December she left Malta for Gibraltar.

Pacific Service

On 14 Dec 1943 HMS Porpoise departed Gibraltar for Portsmouth. She conducted exercises off Portsmouth and transited to the Holy Loch. In February 1944 she trained in the Clyde area and alternated with Campbeltown. They went on until 17 Apr 1944, when she departed with Lt.Cdr. H.A.L. Marsham as new commander Holy Loch for Gibraltar. She was ordered for the Far East, assigned to the 4th Submarine Flotilla based at Trincomalee. She was escorted in the Irish Sea by HMS Telemachus and HMS Flint Castle. On 6 May she departed Gibraltar with HMS Telemachus and HMS Clyde for Malta, escorting underway convoy KMS 49. From there, she transited to Alexandria, Suez, Aden and on in June, Trincomanlee.
The Malacca Minefield
On 1st Jul 1944, she departed Trincomalee for her 20th war patrol and 1st in the Far East, ordered to lay mines in the Malacca Strait. She laid 30 mines (minefield ML 014) off the mouth of the Deli River, Sumatra, Netherlands East Indies. Her mines would claim Cha-8 (100 tons), the freighter Bukun Maru and Special Minelayer No.1 in March 1945.

Operation Rimau (attack on Singapore)
On 27 Jul 1944 she departed Trincomalee for Fremantle in Australia assigned to the 8th Submarine Flotilla. On the 11th she departed Fremantle for her 21th war patrol to conduct Special Operation Rimau, launching fifteen one-man submersible canoes (‘Sleeping Beauties’) against the naval base of Singapore. In all, she carried 96 passengers and crew members. The canoe were presumably carried inside the mine wells. 17/18 saw her passing Lombok Strait and on the 23th close to midnight she launched a folbot manned by Lt.Cdr. Donald Davidson, RNVR, and Corporal Clair Stewart in reconniasance of the island of Merapas usable as an advance base. The following day they were back confirming it was emtpy and safe as base. On the 28th, 13:59 HMS Porpoise captured the Malay junk “Mustika” later used for the operation, sneaking in with canoes aboard. The Malay crew was kept hostage in the submarine as the boarding party and the junk was in tow. On 29-30 September she transferred the Canoes to the Mustika and sailed away. This was a suicide mission as none of the 23 men which entered the harbor, apart three ships rumoured sunk they were all killed or executed by the Japanese.

The loss
Not waiting for the special operatives, she departed on 4 October for Lombok and returned to Fremantle. On the 30 she was sent back to Colombo, and later Trincomalee. She proceeded to various exercizes and on 2 December
under command of A/Lt.Cdr. H.B. Turner, departed Trincomalee for her 22th war patrol and to lay a minefield off Penang as well as patrolling the Nicobar Islands. The minefield ML 019 had 46 mines in two rows but claimed no victim. She ended her patrol and spent the rest of the year in Trincomanlee.

On 3 Jan 1945 she departed Trincomalee for her 23th war patrol, ordered to lay another minefield off Penang. Once done, she departed for a patrol while at 13 January, 01:01 hours, HMS Stygian received Captain S.4’s signal about the submarine being in trouble 17 miles northwest of Pulo Perak, via an Ultra decrypt. It established that on 11 January she had been attacked by a Nakajima B6N2 Tenzan heavy bomber from 331 Air Group based at Penang. One of the two closest 60kg bombs missed her port bow but the other was a direct hit. Unable to dive she was attacked again by another Tenzan at 11:45 off Perak Island while she managed to submerged but was leaking oil as reported by the Japanese. At 20:57 hours she had a third attack with six 60kg bombs falling and again at 10:00 hours the following morning. IJN aviators just had to follow the leaking oil tray.
HMS Stygian arrived and tried to contact Porpoise by radio, searched the area but found nothing. She sank at an unknown location with all hands: Her wreck had never been discovered yet. As sad end for probably one of the most succesful allied submarine of world war two.
Nevertheless, her minefield claimed on 15 January the Japanese auxiliary minesweeper Kyo Maru No.1, on 27 March the Japanese auxiliary minelayer Ma 1 and on 18 May the Japanese submarine chaser Ch 57.

The Grampus class

Usually assimilated with the Porpoise, but of a later, improved design, these five boats approached the double-hull type, with a pressure hull shaped to include the principal tuel tanks. They were laid down in 1933-36 and completed in 1936-39, while P411-P413, which would have differed io having a circular section pressure hull, ordered from Scotts on 13 January 1941 but cancelled in September. Stability was increased from that of Porpoise, as was the reserve of buoyancy, and armament was the same apart from the later addition of a 20mm gun in HMS Rorqual. Diving depth figures remained the same but fuel capacity was reduced. Grampus and Cachalot were sunk by Italian Torpedo Boats, Narwhal presumably by the Luftwaffe, Seal damaged by a mine before capture and integration in the Kriegsmarine (see later).

Author’s old illustration

General assessment

As seen above, these were the only and last minelayers submarines deployed by the RN in WW2, and they were globally successful. Their large size guaranteed long range, and they were roomy enough to be used as cargos and carry special operations with teams and their equipments. HMS Porpoise was by far the most successful, perhaps of all British submarines of the war. The top ten (yet to document and create) often includes HMS Splendid (P228, 9 kills), HMS Upholder (U-class) sinking four Italian warships, and HMS Trident operating from a Soviet base which sank the Ostpreufen, Donau II, Bahia Laura, UJ-1213, damaged Levante (4769 GRT) and sunk UJ-1201. Both captains, Geoffrey Mainwaring Sladen and Malcolm david Wanklyn became “aces”, which was rare. The captain turnover was such that not many could stay in place. Also the practice of “aces” in submarines was more sketchy, and not well established in the RN. Was there a difference between trade ships and warships ?
Nevertheless, while combining three main theaters of operations from 1939 to 1945, and with the capacity of laying mines in addition to their torpedo and deck gun, the class had the potential to have the best kill/tonnage ratio.
HMS Porpoise based on this was certainly in that top ten, but her sad end was caused by her leaky fuel tanks, an issue detected and solved by the following Grampus class. She indeed combined direct hits with indirect ones through her minefields.
The Grampus class were less successful (see later).

Read More

Books

Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN 1-904381-05-7.
Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-962-6.
Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
Chesneau, Roger, ed. (1980). Conway’s All the World’s Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 0-85177-146-7.
McCartney, Innes (2006). British Submarines 1939–1945. New Vanguard. Vol. 129. Oxford, UK: Osprey. ISBN 1-84603-007-2.
Caruana, Joseph (2012). “Emergency Victualling of Malta During WWII”. Warship International. LXIX (4): 357–364. ISSN 0043-0374.
Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
Frampton, Viktor & Domenico, Francesco de (2015). “Question 13/51: British Submarine Actions of WW II”. Warship International. LII (2): 116–118. ISSN 0043-0374.
Napier, Christopher (2017). HMS Rorqual: Commanded by Lennox Napier DSO DSC: June 1941–December 1943. Friends of the Royal Navy Submarine Museum.

Links

https://en.wikipedia.org/wiki/Grampus-class_submarine
https://en.wikipedia.org/wiki/HMS_Porpoise_(N14)
https://uboat.net/allies/warships/ship/3415.html
https://www.aidmen.it/forums/topic/250-sommergibile-hms-rorqual/
https://uboat.net/allies/warships/ship/3416.html
No model kit found yet.

3D

The Porpoise/Grampus class in action:

HMS Grampus (N56) was the lead ship of her class of mine-laying submarine of the Royal Navy. She was built at Chatham Dockyard and launched on 25 February 1936. She served in World War II off China before moving to the Mediterranean Sea. She was sunk with all hands by the Regia Marina on 16 June 1940.
On 16 June 1940, under the command of Lieutenant Commander C. A. Rowe, Grampus laid mines in the Syracuse and Augusta, Sicily area. She was seen by the Italian torpedo boat Circe, which was on anti-submarine patrol with Clio, Calliope, and Polluce. Within a very short time, Grampus was destroyed. Wreckage came to the surface along with air bubbles and oil. Polluce was credited with the kill. There were no survivors. Some sources give the date of this action as 24 June 1940. See the details on uboat.net

HMS Narwhal short but well filled wartime career. In 1939 she spent her time conducting exercises off Portland. On 15 Nov 1939 under command of Lt.Cdr. E.R.J. Oddie, she departed Portsmouth for her 1st war patrol, ordered to proceed to Halifax while escorting convoy OA 36 in part. On 2 Dec 1939 she departed Halifax with her sister HMS Seal, proceeding back home while escorting convoy HXF 11.
On 14 Jan 1940 she conducted exercises in the Firth of Forth and soon after departed to escort a Convoy to Norway, Bergen, which was formed to carry back steel as HN8 on the 20th.
In February 1940 she escorted the largest convoy yet with 29 ships escorted by five destroyers and her. She escorted back from Bergen the back Convoy HN 10 and later the Convoy ON 11 to Bergen. Next were the convoys ON 12 and and ON 14. With HN 14, on 25 Feb 1940, she helped HMS Imogen and HMS Inglefield to sink U-63, south east of the Shetland Islands. After ON 17 she was back in exercizes in March, at Scapa Flow, notably direction finding trials.
On 13 Mar 1940 under command of Lt.Cdr. R.J. Burch, she was sent to Rosyth and assigned to operation R.3 (assistance to Finland by the occupation of Norwegian key points), her 7th war patrol. But this was curtailed by the Finnish armistice, the subs were recalled on 16 March. Bu she was bombed and had to dive escaping a Do 17 aircraft on the 17th.
In 1-5 April 1940 she departed Blyth for Immingham, embarking 50 mines as her 8th war patrol, laying a minefield in the Heligoland Bight (F.D.1).
On 10-17th for her 9th war patrol she laied minefield (F.D.5) off Skagen. It will claimed the German auxiliary minesweepers M 1302/Schwaben, M 1102/H.A.W. Möllerthe, Gnom 7, Kobold 1 and Kobold 3, the German minesweeper M 11, German auxiliary submarine chaser UJ D/Treff VIII, the armed trawler V 1109/Antares and Swedish merchant Haga.
On 1st May after laying the minefield F.D.6 (50 mines) in the Kattegat she attacked a German convoy, torpedoed/sank the troop transport Buenos Aires (6097 GRT, 1912) and torpedoed, damaged (constructive loss) the troopship Bahia Castillo.
Ships damaged by mines laid by Narwhal also included the armed trawler V 403/Deutschland, and the German merchant Togo (later converted as a fire direction ship) on May, 20, and Clara M. Russ. The auxiliary minesweeper M 1101/Fock, Hubert and merchant Palime were also damaged, beached but total losses. They were sunk by later minefields at Feistein Island/Bud, Jaerens, also in Norway (south of Stavanger) in June, Haugesund and kristiansund.
Narwhal may also have sunk U-1 noted in the Kriegsmarine as disappeared on patrol, on 6 April 1940, it is likely she ran into a minefield from Narwhal although Porpoise reported firing upon an unknown submarine, which may be her.

Sinking
HMS Narwhal left Blyth on 22 July 1940 in what was her last war patrol. On the afternoon of 23 July, an aircraft reported attacking a submarine in her presumed area, believed by the Germans to be HMS Porpoise and assumed sank. Nevertheless, no new camed from Narwhal. She was presumed lost by unknown causes. In 2017, a Polish expedition in search of ORP Orzel found an unknown wreck, identified to be most likely HMS Narwhal, based on sonar data. On most publications she is reported “sunk, 30 July”.
See the details on uboat.net

Far East Campaign

HMS Rorqual was Commissioned on 10 Feb 1937. She conducted her sea trials, and post-fixes in a dockyard before being assigned t the 4th sub squadron in the far east. Nothing is known about her early months in fall 1937 up to late 1939 (nearly two years), probably aletrnating between her Shanghai and Hong Kong station, ports visits and exercizes. On 6 September 1939 under command of Lt.Cdr R.H. Dewhurst, she conducted exercises off Singapore notably with HMS Grampus and on the 13th she departed for her 1st war patrol off Sabang. On 14 October she made her second in the Sunda Strait followed by exercises off Singapore in November. On the 7th, she was again patrolling off Sabang, until the 26th. On 5 December, she was in exercises with HMS Tenedos followed by a refit on the 20th, leaving on 13 April 1940 Singapore Navy Yard. After trials and fixes she departed on the 28 April forr Colombo and proceeded on orderes to the Mediterranean via Aden, Port Said and her first hole port of Alexandria (16 May) before departing for Malta.

Mediterranean Campaign

On 27 May 1940 HMS Rorqual laid a practice minefield off Malat, and was soon ready for her first wartime patrols in the Med. She multipled operations of minelaying, claiming the Italian merchant vessels Loasso, Celio, Leopardi, and Salpi, the water tankers Verde and Ticino and pilot vessel F 34/Rina Croce. But her more covered kills were the Italian torpedo boats Calipso, Fratelli Cairoli, Generale Antonio Chinotto, Altair and Aldebaran as the Italian auxiliary submarine chaser AS 99 Zuri and German troop transport Ankara. They also sank the former French merchant P.L.M. 24 and armed fishing vessel Coligny. By mines laid she also claimed damaged the Italian merchants Caffaro, Ischia and Carbonello A.

With her own torpedoes, Rorqual sank the Italian tanker Laura Corrado, submarine Pier Capponi, merchants Cilicia and Monstella, German tanker Wilhemsburg, ex-French merchant Nantaise. She also badly damaged the Italian auxiliary cruiser Piero Foscarin but missed and Italian submarine and the merchant Securitas. By Gunfire she sank two Greek sailing vessels, presubamy used by the Germans. By August 1940 she attacked an Italian convoy but missed with her spread the merchants Verace and Doris Ursino. She was chased off and depth charged by the Generale Achille Papa, but escaped.

In January 1941, HLS Rorqual attacked the tug Ursus and a floating battery dealt with with her single 4-inch gun surfaced at about 500 yards. The tug put up a firce response so Rorqual shifted fire to silenced her, before finishing off Ursus, until her fire became dadly accurate, forcing the submersible to dive. The only torpedo she fired had a gyro malfunction, returning straight at her ! She had to dive deeper to avoid it. But Ursus sank anyway as the battery, on fire, was evacuated but later towed to Dubrovnik.

Rorqual like her other sister ships was operfectly apt at carrying stores in her mine wells. On 19 January 1941 in fact she demonstrated this capability first: She loaded her cargo in Alexandria, and was the first doing this cargo trip to Malta. In all she would made five such runs to Malta in 1941. Later that year by June 1941 she fell under command of Lt. Lennox William Napier. She made more missions but with nothing notable, and a refit and more runs from Alexandria and in 1942 from Beirut, the British “magic carpet runs”. They notably carried avgas drum tanks (well suited for her mine wells) for the local Hurricane fighters and kerosene for cooking. Passengers were also carried in both ways. By October 1943 she carried from Beirut to Leros an entire battery of 40mm Bofors guns and their towing jeep to boot. The isolated island was indeed attack by the German air force.

Operations for 1943-44:
On 21 Nov 1943 after departing Beirut for hr last trip to Malta she was ordered to return to the U.K. for a refit and on 2 December under command now of Lt. G.S.C. Clarabut she transited at Gibraltar and escorted the convoy GUS-23 back home. Clarabut took command as Lt. Cdr. Napier was ill with jaundice and just now a passenger. On 11 December as she sailed, a German U-boat was reported in the Straits and this delayed her trip to the following day. On the 19th she met off Bishops Rock HMS Patti escorting her surfaced to Falmouth later in the evening.
On 20 December, she departed Falmouth for Portland escorted by Vichy French submarine chaser Chasseur 5. The following day she arrived in Portsmouth when Chasseur 5 suddenly capsized with 22 aboard and she picked up three survivors. While off Portsmouth she met the destroyer Blyskawica and started her refit at the Portsmouth Dockyard from 28 December to 6 August 1944.
Based in Yarmouth and proceding to the Holy Loch escorted by HMS Cutty Sark she started trials and training, notably in the Clyde area and at the torpedo firing range of Arrochar, noise trials at Loch Goil., mine detection) trials off Fairlie and attack exercises, radar drills off Campbeltown, D/G tials off Helensburgh and log calibration, engine trials in Loch Long.on 19 October she was docked in AFD 20, Holy Loch and 4 days later departed again for Gibraltar intended for the Far East. From March 1944 she was under command of Lt. John Philip Holroyde Oakley, DSC, RN.
She escorted underway convoy KMS-67 and arrived on 2 Nov 1944 to Gibraltar, proceeding to Malta, Port Said, Aden, Trincomalee in December arriving on the 14th.

Return to the Far East

HMS Rorqual started operations against the Japanese as part of the British Pacific Fleet (BPF), laying minefields which claimed three Japanese sailing craft, also blasting three coasters with gunfire, damaging a fourth one. This was all in the east Indies. For example on 22 January she laid 50 mines (minefield ML 026) in Nancowry Strait, NE of Port Blair, Andaman Islands.
Later this month she is ordered to conduct air/sea rescue duties in the Andaman Sea. On 18 March she departed Trincomanlee for her 32th war patrol off the West coast of Sumatra and conducting the special operations Meridian and Caprice. Notably on 2 April 1945 she sank two sailing vessels with demolition charges off the west coast of Sumatra. She sailed to Fremantle and on 30 April departed Fremantle for her 33th war patrol, laying a minefield of Batavia (10 May).
On 20 May she was back at Fremantle and on 3 June departed for home, the only surviving ship of the Grampus class. He trip via Trincomalee, Port Said, Gibraltar, Portsmouth was followed on 28 July by her placement in reserve, under nominal command of John Philip Holroyde Oakley up to that date. She was later sold off, BU off Cashmore, Newport from 17 March 1946.
More details on Uboat.net

Cachalot entered service under command of Lt.Cdr. Sydney William Floyd Bennetts from 26 Aug 1937 (he stays her captain until 15 Jun 1940). In 1937-39 she was presumably in British waters (no logs). On 1st September 1939 she departed Britain for Malta. She conducted exercizes with notably HMS Porpoise and Otway, and later Sealion and Oswald. In October she returned home via Gibraltar.
On 29 Oct she departed Portsmouth for her 1st war patrol in the North Sea. He second patrol started on 11 November, escorting a convoy to Halifax, Canada. She trained there in Demeber with HMS Hunter and HMCS Restigouche. She escorted a large convoy back home from 29 December 1939 to 12 January 1940.

She had later a refit at Chatham Dockyard, and exercizes off Portsmouth in April. On 13 April she departed Blyth for Immingham to embark mines but collided at 21:25 off Whitby (rammed by accident) by the Italian merchant Beppe. She was sent for repairs to the Tyne, Devonport Dockyard and Sheerness. On 15 August now under command of Lt.Cdr. J.D. Luce, departed Rothesay for her 4th war patrol, 1st time in the Bay of Biscay, and she had to lay a minefield off the Gironde estuary. She torpedoed and sank German submarine U-51 on the 20th in the Bay of Biscay.
Her minefield would later claim in September the German auxiliary minesweeper M1604. On the 24th she spotted and attacked a submarine with torpedoes in the Bay of Biscay, which was almost certainly U-48 (KL Heinrich Bleichrodt), but missed.

She served from the Holy Loch in December. For her 7th war patrol she was sent off Punta Delgada in the Azores, as a German invasion of the Azores was feared at the time.
On 26 Jan 1941 she laid minefield FD 28 (50 mines) off Bud, Norway. On 5 February she departed Holy Loch for her 9th war patrol, and to lay a minefield off Norway, which happened to be signalled later as Vest Fjord (which claimled the Norwegian merchant Huldra). On 28 March, now under command of Lt. H.R.B. Newton, DSC, RN, she laid minefield FD 32 (50 mines) off the Gironde estuary. By late April she was ordered to Plymouth and from there to Gibraltar to commence Mediterranean operations.

She transited via Malta to Alexandria and Port Said and started a serie of storage trips to the beleaguered Malta. Cachalot left Malta on 26 July bound for Alexandria when at 2:00 on 30 July she was spotted by the Italian destroyer Generale Achille Papa, and she had to crash dive. When resurfacing she was attacked by her. While attempting to dive again her upper hatch jammed, and she was rammed. The crew had to scuttle and abandon her. Apart the Maltese steward all were picked up by the Italians. See the details on uboat.net

After her commission, HMS Seal performed her sea trials at Dartmouth-Torbay and made a first successful deep dive on 1st June 1939 when leaning of the loss of HMS Thetis that same day. Many of the crew had friends in this boat. She perform her torpedo trials at Gosport.
On 4 August 1939, she sailed to the far east squadron (in Shanghai), joining HMS Grampus and Rorqual via Gibraltar, Malta and Suez, but as the war broke out she stayed at Aden. She immediatelt started a round of patrols watching Italian activity in the area, fearing some help to German submarines. Back home, she escorted a damaged destroyer in the Mediterranean before reaching the North Sea for her first war patrol near the Dogger Bank, attacked by the Luftwaffe. Her second patrol show her escorting a convoy escort to Halifax in a 14-day crossing. Next she was assigned to Elfin, Blyth, in Northumberland. She made more war patrols in the North Sea, as part of the Norwegian campaign, after relocation to Rosyth.

Norway Operations
By February 1940, HMS Seal received commandos aboard (a boarding party) intended for the German tanker Altmark (which resupplied Graf Spee and was last spotted in a Norwegian fjord -still neutral). But the show was stolen by HMS Cossak but Seal was later visited by an admirative Admiral Horton in Rosyth for the general state of the boat and crew. In April 1940 the invasion of Norway had the submersible ordered even close to the Norwegian coast. Captain Lonsdale decided to enter Stavanger fjord, to reach Stavanger harbour, guided by his new precision Asdic to avoid being grounded along the narrow way.
Once arrived, he spotted four merchant ships under neutral flags, requesting to attack, having the personal to launch a strike on a seaplane base and land a shore party to sabotage the railway. But this was refused by Horton to not create another displomatic incident after the capture of the Altmark. There was also a shallow-draft German naval craft which he declined to hit by torpedoes, so the disappointed crew had to make the dangerous trip back through the fjord and proceed to Rosyth. HMS Seal narrowly escaped a torpedo attack underway and also later rammed and scrapped by a merchant vessel.

Dry-docked at Chatham, HMS Seal as HMS Cachalot were repaired, completed at Blyth and she replaced Cachalot for minelaying missions, notably Operation DF 7, a dangerous minelaying in the Kattegat, preventing the kriegsmarine to pass through Denmark and Sweden. Captain Bethall at the head of the flotilla, failed to persuade Admiral Horton to send her due to the numerous hazards of the place and narrow shoals, making the large subersible rather cumbersome in these waters. This was partly due to the exploit of Seal, navigating with Asdic through Stavanger fjord.

The Suicide Skagerrak minelaying Mission
On 29 April 1940, Seal left Immingham with 50 mines and entered the Skagerrak, meeting HMS Narwhal leaving, having just scoring six hits with six torpedoes, a rare feat of markmanship. This no doubt pimped up the crew’s resolve. Seal was maintained at shallow depth, maintaining speed lopw to spare fuel. But at this low depht she was spotted by a German Heinkel He 115 on 4 May, at about 02:30. She had to dive to the bottom, circa 90 feet (27 m) after being slightly damaged by a bomb. Lonsdale later detected German anti-submarine trawlers looking for them as he reached his initial minefield area, and diverted to the secondary target area. Her started to lay down these at 09:00, completing it 45 minutes later.

Mission accomplished, Londsdale ordered to turnback and head for home, with the trawlers still overhead. He tried an evasive course using Asdic to detect the pauses made by the trawlers to listen. At 3:00 pm, he spotted nine MTBs heading from a different direction but is was still daylight, and the Kattegat was still too shallow, but he evaded detection by zig-zaging. At 18:00 hiowever as he started to surface after such a long underwater crossing, he unwillingly entered an uncharted minefield. His two hydroplanes caught a mine stay-cable. At 06:30 pm the attached mine attached itself ot his stern, and scraped until one of the detonators hit, trigerring the mine’s explosion: HMS Seal was severely damaged and started to flood in.

The crew’s miraculous escape
All watertight doors were quickly sealed, and miraculously all but two of the crew were still alive. Even those, trapped in the after end, later managed to make their way to the control room. The German ship apparently assumed her sunk or never heard the explosion and left the area. Emergency repairs were done and at 22:30 Londsdale ordered to surface at last.
At 10:30 pm as the boat was emerging her stern stayed stuck on the sea bed until the bow made sharp angle which made work inside impossible. Even air quality deteriorated much, and attempt was made to blow air into the rear trimming system and for the second attemptn the 11-ton drop keel was released. After using even more compressed air to blow the remaining tanks, this was still unsuccessful. The third attempt also failed while oxygen ran out.

At 01:10, Lonsdale called to prayer with his crew moving as far forward as they could to rebalance, many fainting in the process. The captainalso thought to use the Davis escape gear but it needed hours to escape while flooding was a risk. Engineers managed to open a salvage-blow for a 4th and final attempt which saw the diesels, pushed to the absolute limit, catching fire, soon dyring out due to the lack of oxygen. Batteries were also nearly empty while high pressure air was not exhausted. While all seemed lost for good, one engineer realised there was still one air pressure group left, reached and opened the valve, and all that were still aware at the time felt the boat raising again, and this time, the stern followed.

Seal eventually surfaced at 01:30 and immediately with their last strenght men present managed to open the hatch. Fresh air usehed inside, causing blinding headaches as the crew had been so deprive from oxygen for so long. But all ultimately survived. Lonsdale arrived on the bridge and started to scan the horizin, sighting land. He decided to make it for neutral Swedish waters. Confidential papers were thrown overboard as the cipher books, Asdics were destroyed and also thrown overboard. He sent a message to the Admiralty “Am making for the Swedish coast”. He would receive “Understood and agreed with. Best of luck”, “Safety of personnel would be your first consideration after destruction of the Asdics”. However after some well-needed rest and restoration, engineers started to reports the rudder was damaged beyond repair. Still the boat could go in reverse but the only working engine was barely in shape and soon died out, leaving the boat stranded.

At 02:30, Seal unfortunately, now surfaced and unable to dive or move again, was spotted and attacked by two German Arado Ar 196s and a Heinkel. Lonsdale stayed the bridge under fire using a Lewis gun, which jammed, then another, which jammed too. Considering all his option, Londsdale decided to surrender. He had the white messroom table-cloth quickly hoisted on the mast. Leutnant Schmidt of one of the Ar 196 landed alongside and asked in english the captain to swim to him for a parley. Lonsdale, aged 35, made it so, and shortly after the enterview, the chief petty officer swam to the other Arado that also landed. The crew waited as the armed trawler UJ-128 arrived at 06:30. The crew attemped to scuttle their boat, but failed as a German boarding party took the crew in custody. Although leaking and patrly flooded, the crew saw in horror their submarine being towed to Frederikshavn.

Under the svatiska: The short career of “UB”
They would learn after the war that their mine belt sank the German freighter Vogesen (4241 BRT) and three Swedish ships until 5 June. But their story ends there. They became POWs until the end of the war. As for their submarine, it was the only British sub in this war to be captured and reused by the Kriegsmarine. It was no long to realize its potential as a minelayer indeed, as there were none (yet) in the Kriegsmarine. She was simply named “UB”.
She had temporary repairs at Frederikshavn, then was towed to Kiel and was completely refurbished under supervision of Admiral Rolf Carls which saw her usefulness. Her insisted to have her operational at any cost. This was long, complicated and went on until the spring of 1941. UB made her sea trials and first dive under command of Fregattenkapitän Bruno Mahn, aged 52, a trusted veteran and oldest German submarine commander in this war.

The boat was naturally showcased propaganda exhibit and acted as training boat until by late 1942 Krupp was able to deliver the brand new tailored minelaying mechanical system. The boat made minelaying runs which revealed so many issues left to solve, with cost soaring sky high. Dönitz ultimately pull the plug. In mid-1943 he decided to retire her for good (the dedicated Type XB – A dedicated post on them is in writing). She was paid off, stripped and left in Kiel dockyard but later hit and sunk as Admiral Hipper. For all what she costed, the only gain retired from this all was the British contact pistol torpedo detonator judged of superior design and subsequentely adopted.
On 3 May 1945 UB was scuttled in Heikendorf Bay and her wreck demolished by explosives.

Fate of the crew:
The crew was interrogated by the Kriegsmarine (meaning in a fair way, not Gestapo methods). Officers and ratings were separated and sent to several POW camps until April 1945. The crew had been adopted by the village of Seal which sent considerable gift packages to the crew until then. Two managed to escape, Petty Officer Barnes in poland which later made contact with the Polish underground. They reached the Soviet border, but the latter shot Barnes dead while his companion Briggs was emprisoned into Butyrka prison in Moscow. Engineer Don “Tubby” Lister also managed to escape many times until confined in the Oflag IV-C, Colditz Castle, built on a rocky hilltop. Relocated by a ruse in an open camp, he escaped in late 1942 to Switzerland and later arrived home at last. The rest of the crew was mostly detained in Marine-lager Westertimke, well treated. By April 1945, the Allies were at Bremen, 15 nautical miles (28 km) away, and they were marched off to Lübeck. During the journey, the column came under attack from Allied Spitfires. For surrendering his boat Both Londsdale and Lt. Trevor Beet faced court-martial in 1946, but given testimonies and report of his conduct in the circumstances, he was honourably acquitted. Personal note here: This story is too good not to be made into a movie.