German submarine U - 755 German submarine " U - 755 " was a German Type VIIC submarine U - boat built for the German Kriegsmarine for service during World War II . Under the command of Kapitänleutnant Walter Göing " U - 755 " served with 9th U - boat Flotilla in the Atlantic , and later with 29th U - boat Flotilla operated in the Mediterranean . Record . Work on " U - 755 " began on 11 January 1940 at werk 138 of the Kriegsmarinewerft in Wilhelmshaven . She was commissioned on 3 November 1941 , under the command of Kapitänleutnant Walter Göing and trained with 5th U - Boat Flotilla until 31 July 1942 . Serving with 9th U - boat Flotilla , she served in two patrols . On 9 September 1942 – thirty - four days into her first patrol - " U - 755 " sank her first ship . At 15 . 16 hours on 9 Sep 1942 , she fired a spread of three torpedoes at the USS Muskeget , two hits were reported . Of the 121 onboard , all were killed . U - 755 docked at Brest on 6 October , after sixty - four days at sea . On 1 November , " U - 755 " began travelling from Brest to La Spezia in Italy , after a further twenty - two days at sea . On 1 December 1942 , " U - 755 " was transferred from 9th U - Boat Flotilla , to 29th U - Boat Flotilla . She began her twenty - five day long third voyage on 27 January 1943 . She returned to La Spezia from Algeria on 20 February . " U - 755 " set out on her fourth patrol on 21 March , where she was to head to Morocco , and then head off to Toulon in Vichy France . At 02 . 07 hours on 26 March , " U - 755 " fired three torpedoes at a convoy north of Ceuta and confirmed a hit in the bow of FFL " Sergent Gouarne " ( P - 43 ) , which broke in two and sank in approximately ninety seconds , killing five of its nineteen - man complement . The U - boat attacked the same convoy with another spread of three torpedoes at 04 . 13 hours and reported a hit after 12 minutes , but this was probably an end - of - run detonation . On 2 April , the French trawler " Simon Duhamel II " was spotted off Cape d´Alboran , some time after 06 : 00 , after straggling from convoy TE - 20 due to a problem with her engines . " U - 755 " fired at the trawler at 06 : 24 , with one confirmed hit to the midship . This hit caused an explosion that broke the vessel apart , sinking in a mere four minutes . Only one man of her fifty - three - man crew survived , being rescued two days later . On 18 May , " U - 755 " set sail from Toulon on her fifth , and last patrol . Two days in , she was attacked by the British submarine HMS " Sickle " , but the fired torpedoes missed . Eight days in , at 06 . 26 hours , " U - 755 " was attacked by a British Lockheed Hudson aircraft of No . 500 Squadron RAF , flown by pilot S / L H . G . Holmes , DFC , thirteen miles north of Alboran Island . The aircraft was hit in the port engine by AA fire during the first attack run , but dropped three depth charges . The Hudson then made two dive - bombing attacks and dropped first two and then one A / S bomb , one of them exploding just five yards off the port beam . The damaged engine then forced the pilot to return to base . Strafing had killed one crewman and wounded two others on " U - 755 " , which was forced to return to port due to heavy damages but was sunk in another air attack only 2 days later . Of her complement of forty , only nine crewmen survived , her commander was not one of them .