HMS/M Undine pre-war (All photographs courtesy Cyberheritage)

UNDINE, 7th January 1940, Western Europe, 20 miles SW of Heligoland island off German North Sea coast - by depth charges of German minesweepers M.1201, 1204 and 1207. Attacking minesweepers while on Heligoland patrol (German North Sea coast patrol)

UNITY, 29th April 1940, Western Europe off Blyth, NE England in North Sea (c 55-15'N, 1-15'W) - by collision with Norwegian steamship 'Atle Jarle'. Sailing from Blyth for Norwegian patrol during the German invasion (Norwegian Campaign patrol)

Surviving boat - URSULA (Russian 'V.4' from 1944)

War Programmes - 540/740 tons, 11/10 knots, 1-12pdr or 3in/4tt, 30 crew, 1940-45, 68 boats completed by war's end, 17 lost

HMS/M United 1944

P.32, 18th August 1941, Central Mediterranean, off Tripoli, western Libya - by Italian mines. Attacking Italian convoy heading into Tripoli (Tripoli patrol)

P.33, August 1941, Central Mediterranean - 'overdue, presumed lost'. On patrol off Tripoli, eastern Libya and reported overdue on 23rd August. Presumed lost on Italian mines in her patrol area. Italians claim she was sunk by torpedo boat 'Partenope' off Pantelleria island on the 23rd; lost with all hands (Tripoli patrol)

P.36, 1st April 1942, Central Mediterranean, at Malta - by German or Italian bombers. In harbour after covering Alexandria/Malta convoy (MW.10?) at time of Second Battle of Sirte (Malta convoys)

P.38, 23rd February 1942, Central Mediterranean, east of Tripoli, western Libya (c 32-45'N, 15-00'E) - by Italian torpedo boat 'Circe' and destroyer 'Usodimare'. Attacking Italian convoy bound for Tripoli (Tripoli patrol)

P.39, 26th March 1942, Central Mediterranean, at Malta - by German bombers. In harbour following a patrol in the area east of Tunisia. Previous bomb damage being repaired (Defence of Malta)

P.48, 25th December 1942, Central Mediterranean, off northern Tunisia in Gulf of Tunis (c 37-15N, 10-30'E) - by depth charges of Italian destroyer escorts 'Ardente' and 'Ardito'. Attacking Italian convoy making for Tunis; lost with all hands (Gulf of Tunis patrol)

UMPIRE (Lt Mervyn Wingfield), 19th July 1941, Western Europe, NW of Cromer, eastern England in North Sea (c 53-00'N, 1-00'E) - rammed in error by RN armed trawler 'Peter Hendriks'. Working up and on passage with northbound East Coast convoy EC.4; 22 men lost. One of the few survivors was Lt Edward Young, first RNVR officer to command a submarine.

UNBEATEN, 11th November 1942, Western Europe, in Bay of Biscay (47-00'N, 7-00'W) - sunk in error by RAF Wellington. On patrol in Bay of Biscay for German raiders, supply ships and U-boats on passage (Bay of Biscay patrol)

UNDAUNTED, May 1941, Central Mediterranean - 'overdue, presumed lost'. Failed to return to Malta on 11th May from patrol off Tripoli, eastern Libya, presumed lost on mines. Italians claim she was sunk by torpedo boat 'Pleiade' off Tripoli on 13th during attack on Axis supply ship; lost with all hands (Tripoli patrol)

UNION, 20th July 1941, Central Mediterranean, 25 miles SW of Pantelleria island in Strait of Sicily - by Italian torpedo boat 'Circe'. Attacking Italian convoy and presumed lost in counter-attack (Strait of Sicily patrol)

UNIQUE, October 1942, eastern area of North Atlantic - 'overdue, presumed lost'. Carrying out Bay of Biscay patrol while on passage from Britain to Gibraltar. Reported off Lands End on the 9th and not heard from again. Cause of loss unknown, but possibly around the 24th October, west of Gibraltar; lost with all hands (partly Bay of Biscay patrol)

UPHOLDER (Lt Cdr Malcolm Wanklyn VC +), 14th April 1942, Central Mediterranean, NE of Tripoli, western Libya (c 35-00'N, 16-00'E) - by depth charges of Italian destroyer escort 'Pegaso'. Attacking Italian convoy and presumed lost in counter-attack; lost with all hands (Tripoli patrol)

URGE, April/May 1942, Central or Eastern Mediterranean - 'overdue, presumed lost'. On passage from Malta to Alexandria at time of withdrawal of 10th Submarine Flotilla from the heavily bombed island. Sailed on 27th April, but failed to arrive on 6th May. Probably lost on Italian mines, with all hands (Defence of Malta)

USK, April/May 1941, Central Mediterranean - 'overdue, presumed lost'. Sailed from Malta on 19th April for patrol off NW Sicily and later the Cape Bon, Tunisia area in the Strait of Sicily. Failed to return on 3rd May and presumed lost on Italian mines. Italians claim sunk by destroyers 'Pigafetta' and 'Zeno' on the 4th May, west of Sicily during a convoy attack; lost with all hands (Italian NW Sicily patrol)

USURPER, September/October 1943, Central Mediterranean - 'overdue, presumed lost'. Sailed from Algiers on 24th September for Gulf of Genoa patrol. Failed to answer signal on 11th October. Possibly mined or. sunk by German anti-submarine vessel UJ.2208 in the Genoa area on the 3rd; lost with all hands (Italian Gulf of Genoa patrol)

UTMOST, 24th November 1942, Central Mediterranean, off NW Sicily in Tyrrhenian Sea (c 36-30'N, 12-00'E) - by depth charges of Italian destroyer escort 'Groppo'. On patrol off Marittimo island (Italian NW Sicily patrol)

VANDAL, February 1943, Western Europe in Mull of Kintyre/Arran area, west coast of Scotland - 'overdue, presumed lost'. Left Holy Loch on the Clyde on 22nd February for working-up exercises in the Firth of Clyde. Failed to return on 24th, cause of loss unknown; lost with all hands.

Plus lost while manned by an Allied Navy - UREDD, Norwegian Navy, 24th February 1943, off Norway

Boats completed by war's end and surviving - P.47 (Dutch 'Dolfijn'), P.52 (Polish 'Dzik'), ULTIMATUM, ULTOR, UMBRA, UNBENDING, UNBROKEN (Russian 'V.2' from 1944), UNISON (Russian 'V.3' from 1944), UNITED, UNIVERSAL, UNRIVALLED, UNRUFFLED, UNRULY, UNSEEN, UNSHAKEN, UNSPARING, UNSWERVING, UNTIRING (Greek 'Amfitriti' from 1945), UPRIGHT, UPROAR, UPSHOT, UPSTART (Greek 'Xifias' from 1945), URCHIN (Polish 'Sokol'), URTICA, UTHER, VAGABOND, VAMPIRE, VARANGIAN, VARIANCE (Norwegian 'Utsira'), VARNE (Norwegian 'Ula'), VARNE (2), VELDT (Greek 'Pipinos'), VENGEFUL (Greek 'Delfin'), VENTURER, VIGOROUS, VIKING, VINEYARD (French 'Doris'(2)), VIRULENT, VIRTUE, VISIGOTH, VITALITY (ex-UNTAMED), VIVID, VOLATILE, VORACIOUS, VORTEX (French 'Morse' 2), VOTARY, VOX (French 'Curie'), VOX(2), VULPINE 

77. 'A' class - 1,120/1,620 tons, 18/8 knots, 1-4in/10tt, 60 crew, 1945, 2 boats, AMPHION, ASTUTE, completed by war's end

HMS/M Astute post-war

FOREIGN & CAPTURED BOATS

78. ex-American 'R' class - 570/680 tons, 14/10 knots, 1-3in/4tt, 30 crew, 1918, 3 boats transferred 1941-42, 1 lost

P.514, 21st June 1942, North Atlantic off east coast of Newfoundland - rammed in error by Canadian minesweeping sloop 'Georgian'. On passage around Newfoundland from Argentia to St Johns for anti-submarine training duties.

Surviving boats returned in 1944 - P.511, P.512  

79. ex-American 'S' class - 850/1,060 tons, 14/11 knots, 1-4in/4tt, 40 crew, 1919, 6 boats transferred 1941-42

Lost while manned by an Allied Navy - JASTRZAB, Polish Navy, 2nd May 1942, Arctic

Surviving boats returned in 1944 - P.552, P.553, P.554, P.555, P.556 

80. ex-Turkish boats - 680/860 tons, 14/10 knots, 1-3in/5tt, 35 crew, 1941-42, 4 boats building in Britain and acquired by Royal Navy, 1 lost

 P.615, 18th April 1943, Central Atlantic Ocean, south of Freetown, Sierra Leone, West Africa (c 7-00'N, 13-00'W) - by torpedo from German U.123. On passage to South Atlantic Station for anti-submarine training duties.

Surviving boats transferred to Turkey in 1942 and 1945 - P.611, P.612, P.614 

81. ex-German & Italian boats - 570/680 tons, 14/10 knots, 1-3in/4tt, 30 crew, 1918, 4 boats, captured and commissioned into Royal Navy, 1 lost

GRAPH (ex-German U.570), 20th March 1944, Western Europe, on Islay island, west coast of Scotland (55-48'N, 6-27'W) - driven aground and wrecked. On tow from Aberdeen to the Clyde for experimental purposes and broke adrift.

Surviving boats - P.711 (Italian 'Galileo Galilei' captured 19th June 1940), P.712 (Italian 'Perla' captured 9th July 1942, Greek 'Matrozos' from 1943), P.714 (Italian 'Bronzo' captured 12th July 1943, French 'Narval' from 1944)

MIDGET SUBMARINES

 82. 'X' classes - c 30/33t, 6/6 knots, 2-2 ton side charges, 4 crew, launched 1942-45. Miniature submarines with full diving capabilities, equipped with periscope etc. and able to drop side charges beneath the target after being towed to vicinity by ocean-going submarines. XT boats were for training and not equipped with side charges; XE boats were more habitable and designed for Far East operations. XE's also had a diving compartment to allow divers to leave the boat and attach limpet mines. On the 31st July 1945, XE3 sank Japanese heavy cruiser "Takao" in the Johore Strait off Singapore. 31 boats, X3-X10, X20-X25, XT1-XT6, XE1-XE9, XE11-XE12, 8 lost

X5, X6, X7, 22nd September 1943, Northern Europe, Altenfiord, Norway - Lost in attack on German battleship "Tirpitz" at anchor in Kaafiord. "X6" and "X7" laid their charges under or near "Tirpitz" badly damaging her

X8, 17th September 1943, Northern Europe - Lost in attack on German battleship "Tirpitz" at anchor in Kaafiord.

X9, 15th October 1943, Northern Europe - Lost in attack on German battleship "Tirpitz" at anchor in Kaafiord.

X10, 3rd October 1943, Northern Europe - Lost in attack on German battleship "Tirpitz" at anchor in Kaafiord.

X22, 7th February 1944, Western Europe, Pentland Firth, off N Scotland - lost in collision with submarine "Syrtis"

XE11, March 1945, Western Europe, Loch Striven, Scotland - lost in collision with trawler

HUMAN TORPEDOES

83. 'Chariots' - weight 1000lb with charge, length 20ft, 3-4 knots, 1 bow charge with 590lb of Torpex, 2 crew, built from 1942. Electrically powered submersible with crew of two equipped with diving suits and breathing apparatus sitting astride the torpedo-shaped hull. Armed with detachable bow charge. Developed by the Italian Navy and nicknamed "Maiale" or pig, their greatest triumph was the sinking of "Queen Elizabeth" and "Valiant" in Alexandria harbour on the 19th December 1941, although both British battleships were raised and put back into service. Design of captured craft developed by the Royal Navy and named "Chariots". 28 lost, losses in date order

No. VI and VIII, 31st October 1942, Western Europe, off Trondheimfiord, Norway - broke away in rough weather. Being towed below Norwegian fishing boat "Arthur" on final approach for attack on German battleship "Tirpitz" (Operation "Title") in Fottenfiord well inside Trondheimfiord. Tow broke in bad weather.

No. X and XVIII, December 1942/January 1943, Central Mediterranean, Maddalena, Sardinia area - lost with submarine "P.311". Being carried in watertight deck containers mounted on "T" class submarine "P.311" for attack on Italian cruisers at Maddalena, NE Sardinia (Operation "Principal"). Last signal from "P.311" on 31st December. Probably sunk by Italian mines in the approaches to Maddalena. Italians claim sunk by torpedo boat 'Partenope' on 29th - two days before her last signal. One source dates the loss of the Chariots on the 8th January 1943.

No. XV, XVI, XIX, XXII and XXIII, 2nd/3rd January 1943, Central Mediterranean, Palermo, northwest coast of Sicily - scuttled. Launched from watertight deck containers on submarines "Thunderbolt" (two Chariots) and "Trooper" (three Chariots) for attack on Palermo Harbour - Operation "Principal". After two Chariots successfully penetrated the defences, charges are laid which severely damage Italian light cruiser "Ulpio Traiano" then being fitted out before completion and transport "Viminale" early on the 3rd. The Palermo attack was part of the same operation, which led to the loss of "P.311" and Chariots No.X and XVIII above

No. XII and XIII, 19th January 1943, Central Mediterranean, Tripoli, Libya - scuttled. Two weeks after the Palermo attack, submarine "Thunderbolt" carried two Chariots for an attack on Tripoli Harbour (Operation "Welcome"). The operation failed.

No. LII and LVII, 22nd November 1943, Western Europe, Norway - scuttled in heavy weather. Taking part in attack on German shipping in Norwegian fords

No. LVIII and LX, 21st/22nd June 1944, Central Mediterranean, La Spezia, NW Italy - scuttled. A joint British-Italian operation mounted from Italian destroyer "Grecale" and MTB "MS.74", the Chariots were launched for an attack on Italian warships under German control in La Spezia harbour on the NW coast of Italy (Operation "QWZ"). Heavy cruiser "Bolzano" had been torpedoed and damaged by submarine "Unbroken" in 1942 and taken to La Spezia for repairs. Later plans to convert her to a cruiser-aircraft carrier came to nothing and she was captured when Italy surrendered. In the attack "Bolzano" was sunk.

No. LXXIX and LXXX, 28th October 1944, South East Asia, Phuket, SW coast of Thailand in Andaman Sea - scuttled. Transported to Phuket by submarine "Trenchant", penetrated harbour and sank transport "Sumatra Maru", badly damaging another ship.

No. V, XXIX, XXXI and XXXIV, 1945, Western Europe, west Scotland. Loss reported in June 1945

No. XI, XIV, XVII, XX, XXI, XXIV and XXV, 1945, Central Mediterranean, Malta. Loss reported in June 1945 

ONE MAN MIDGET SUBMARINES

84. Welman Craft - weight 5,750lb with charge, length 20ft, 3 knots, 1 bow charge with 425lb of Torpex, 1 crew, built 1943. Small one-man operated submarines with limited range and no periscope. Navigated on the surface through window in small conning tower. Declared unsuitable for operations in late 1943 and scrapped 1944. Approximately 100 craft, 5 lost

No. 10, 9th September 1943, Western Europe in Loch Cairnbawn (Locha Chairn Bhain?) NW Scotland - by accident. Sank alongside depot ship "Bonaventure".

No. 45, 46, 47 and 48, 22nd November 1943, Western Europe, Bergen, SW Norway - captured/scuttled by their crews. Carried by MTB's across the North Sea for attack on Bergen Harbour. Failed to reach target area with one Welman captured by the Germans and three scuttled