German submarine U-646
German submarine "U-646" was a Type VIIC U-boat of Nazi Germany's "Kriegsmarine" during World War II. The submarine was laid down on 23 December 1941 at the Blohm & Voss yard at Hamburg, launched on 3 September 1942, and commissioned on 29 October 1942 under the command of "Leutnant zur See d.R." Heinrich Wulff. Attached to 5th U-boat Flotilla based at Kiel, "U-646" completed her training period on 31 March 1943 and was assigned to front-line service. Design. German Type VIIC submarines were preceded by the shorter Type VIIB submarines. "U-646" had a  displacement of when at the surface and while submerged. She had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of for use while submerged. She had two shafts and two 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-646" was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one SK C/35 naval gun, 220 rounds, and one twin C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty. Service history. While on patrol in the North Atlantic, "U-646" was detected by Hudson "J" of No. 269 Squadron RAF south-east of Iceland on 17 May 1943. In the subsequent attack, the U-boat was sunk and  all 46 crew members perished.