German submarine U - 42 ( 1939 ) German submarine " U - 42 " was a Type IXA U - boat of the Nazi German " Kriegsmarine " that operated during World War II . " U - 42 " was ordered by the " Kriegsmarine " in November 1936 . Her keel was laid down in December 1937 ; she was launched in February 1939 and commissioned in July 1939 . " U - 42 " had a very short career , being sunk while still on her first war patrol . During her service with the " Kriegsmarine " , the boat conducted only one training patrol and one war patrol . Over the latter she damaged one enemy vessel of . Both her patrols were as part of the 6th U - boat Flotilla . " U - 42 " was sunk southwest of Ireland on 13 October 1939 . Out of a crew of 46 , 20 survived and 26 went down with the submarine . Construction . " U - 42 " was ordered by the " Kriegsmarine " on 21 November 1936 ( as part of Plan Z ) . Her keel was laid down on 21 December 1937 by AG Weser of Bremen as " Werk 947 " . She was launched on 16 February 1939 and commissioned on 15 July of that same year under the command of " Kapitänleutnant " Rolf Dau . Like all other Type IXA U - boats , " U - 42 " had two MAN M9V40 / 46 supercharged 9 - cylinder diesel engines that put out , as well as two SSW GU345 / 34 double - acting electric motors that produced and allowed her to travel at up to while surfaced and submerged . She had a range of at while on the surface and at while submerged . " U - 42 " had six torpedo tubes ( four in the bow and two in the stern ) . She also carried a total of twenty - two torpedoes and had a Utof 105 mm / 45 deck gun with 110 rounds . She was equipped with 2 cm FlaK 30 anti - aircraft guns . " U - 42 " had a crew of 46 men . However , she could hold up to 56 crew members at any given time . After being commissioned and deployed , " U - 42 " was stationed in the German city of Wilhelmshaven . It was to be her home port for the rest of her fairly short career . Service record . Patrol . Following training exercises with the 6th Flotilla from 16 July 1939 to 1 October 1939 , " U - 42 " was moved into active service with the 6th Flotilla , ready for operations . The day after her training exercises ended , she left Wilhelmshaven on 2 October . On a 12 day journey , " U - 42 " traveled into the North Sea and circumnavigated the British Isles . She then entered the North Atlantic in search of any Allied convoys . During this operation , one enemy ship was damaged , the 4 , 803 ton British steam freighter " SS Stonepool " , which had become separated from Convoy OB 17 while sailing from Liverpool , England to North America . This was to be the boat ' s first and only attack on any Allied merchant vessel . Fate . While still on her first war patrol , " U - 42 " was sunk on 13 October 1939 by depth charge s from the British destroyers and . This attack took place off the southwest coast of neutral Ireland . Of the 46 man crew , 26 were killed in the depth charge attack , 20 crew members survived and were made prisoners of war by the British . The youngest crew member aboard " U - 42 " was Rudolf Nuggel who was born on 22 December 1919 and was among the 26 dead . He was 19 years old with his 20th birthday just over two months away . The captain , Rolf Dau , was the oldest known crew member of " U - 42 " . He was born on 1 April 1906 and was 33 years old at the time of the boat ' s sinking ; he survived . " U - 42 " was the fifth U - boat to be lost in World War II .