German submarine U-713 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 21 October 1941 at the H. C. Stülcken Sohn yard at Hamburg, launched on 24 September 1942, and commissioned on 29 December 1942 under the command of Oberleutnant zur See Henri Gosejacob.
Attached to 8th U-boat Flotilla based at Danzig, U-713 completed her training period on 30 June 1943 and was assigned to front-line service.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-713 had a displacement of 769t when at the surface and 871t while submerged. She had a total length of 67.1m (220.1feet), a pressure hull length of 50.5m (165.7feet), a beam of 6.2m (20.3feet), a height of 9.6m (31.5feet), and a draught of 4.74m (15.55feet). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of NaNPS for use while surfaced, two Garbe, Lahmeyer & Co. RP 137/c double-acting electric motors producing a total of 750PS for use while submerged. She had two shafts and two 1.23abbr=onNaNabbr=on propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-713 was fitted with five 53.30NaN0 torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.82NaN2 SK C/35 naval gun, 220 rounds, and two twin 2sp=usNaNsp=us C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.
U-713 was missing since 24 February 1944 in the Norwegian Sea north-west of Narvik.[1]
While operating against convoy JW 57 on 24 February 1944, U-713 was spotted by a Swordfish from . The destroyer HMS Keppel was directed towards the U-boat and attacked with depth charges, sinking U-713 in position 69.45°N 57°W.