German submarine U - 343 German submarine " U - 343 " was a Type VIIC U - boat of the German " Kriegsmarine " during World War II . The submarine was laid down in April 1942 at the Nordseewerke yard at Emden , launched in December and commissioned in February 1943 under the command of " Leutnant " Wolfgang Rahn . After training with the 8th U - boat Flotilla at Danzig , " U - 343 " was transferred to the 3rd U - boat Flotilla , based at La Pallice in France , for front - line service on 1 November 1943 , and then to the 29th U - boat Flotilla , based at Toulon on the Mediterranean coast , on 1 February 1944 . In March , " U - 343 " was sunk off Bizerte by depth charges from a British warship . All 51 of her crew members were lost with the U - boat . Construction and Design . " U - 343 " was ordered by the " Kriegsmarine " on 21 November 1940 . She was laid down about eight months later at the Nordseewerke yard at Emden , on 1 April 1942 . Just under eight months later , " U - 343 " was launched from Emden on 21 December 1942 . She was formally commissioned next year on 18 February 1943 . " U - 343 " carried 5 × torpedo tube s ( four located in the bow , one in the stern ) and had one C35 88mm / L45 deck gun with 220 rounds . She could also carry 14 G7e torpedo es or 26 TMA mines and had a crew of 44 - 52 men . Service history . 1st patrol . " U - 343 " sailed from Kiel under the command of " Oberleutnant zur See " Wolfgang Rahn on 16 October 1943 , stopping at Trondheim for three days before continuing out into the north Atlantic to join the " wolfpack s " ' Eisenhart 7 ' on 9 November and ' Schill 2 ' on 17 November . However , she made no successful attacks , before arriving at her new home port of La Pallice on 16 November after 26 days at sea . 2nd patrol . " U - 343 " left La Pallice on 26 December 1943 , sailed around the coast of Spain and Portugal and into the Mediterranean Sea , passing through the Strait of Gibraltar on 5 January 1944 . At 20 : 30 on 7 January the U - boat was attacked by a Wellington bomber from No . 36 Squadron RAF . After dropping five depth charge s , all of which missed , the plane was hit on the port wing by the U - boat ' s anti - aircraft fire and caught fire . The aircraft crashed into the sea , the pilot and navigator were killed . The remaining four crewmen were rescued by the Free Polish destroyer the next day . However , another Wellington of 36 Squadron arrived on the scene , and immediately attacked " U - 343 " . Its depth charges fell wide after the port engine was hit by the U - boat ' s AA fire , but it managed to reach Bône , Algeria , safely . The next day , 8 January , at 21 : 40 a third Wellington of 36 Squadron located " U - 343 " south - west of Cartagena , Spain , and brought two more Wellingtons from No . 179 Squadron RAF , based at Gibraltar , to attack . One aircraft dropped six depth charges , but was hit by AA fire on the port wing , which caught fire , and the aircraft crashed into the sea , killing five crewmen . Only the pilot survived , and was passed closely by the U - boat twice while in his dinghy . He was picked up by the destroyer the next morning . The attacks on the U - boat continued for several hours , and were augmented by the arrival of a Catalina flying boat from No . 202 Squadron RAF . It too was hit by AA fire , that damaged the port wing , fuselage and both fuel tanks , and wounded the flight engineer , forcing the aircraft to head for home . The aircraft finally broke off the attack at 23 : 00 as " U - 343 " , badly damaged and unable to dive , managed to escape into the darkness with only one crewman wounded by strafing . After making repairs she was able to reach her new base at Toulon on 19 January . 3rd patrol . " U - 343 " left Toulon on 4 March 1944 and headed for the coast of Tunisia . There on 10 March 1944 , north of Bizerte , in position , she was sunk by depth charge s from the British minesweeping trawler HMS " Mull " with the loss of all 51 hands .