German submarine U-231
German submarine "U-231" was a Type VIIC U-boat of Nazi Germany's "Kriegsmarine" during World War II. The submarine was laid down on 30 January 1942 at the Friedrich Krupp Germaniawerft yard at Kiel as yard number 661, launched on 1 October, and commissioned on 14 November under the command of "Kapitänleutnant" Wolfgang Wenzel. After training with the 5th U-boat Flotilla at Kiel, "U-231" was transferred to the 3rd U-boat Flotilla on 1 May 1943 which was based at La Pallice in France, for front-line service. In three war patrols, the U-boat  sank or damaged no merchant ships. She was a member of eleven wolfpacks. "U-231" was sunk on 13 January 1944 in the North Atlantic northeast of the Azores by a British aircraft. Design. German Type VIIC submarines were preceded by the shorter Type VIIB submarines. "U-231" 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 AEG GU 460/8–27 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-231" 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 an anti-aircraft gun. The boat had a complement of  between forty-four and sixty. Service history. First patrol. "U-231" departed Kiel on 13 April 1943. On the 22nd, she was attacked on two occasions by Catalina aircraft of No. 190 Squadron RAF. Both attacks caused no damage, although a man was lost overboard during the first. She was then attacked on the 23rd (twice), the first of which resulted in a flooded conning tower. She was also attacked on 21 May by American Avenger aircraft from the carrier . The result was a chlorine gas leak and both radio transmitters being knocked out and the boat returned La Pallice in  occupied France on 31 May. Second patrol. This foray commenced from Bordeaux, took her to the middle of the Atlantic Ocean and terminated in La Pallice. Third patrol and loss. "U-231" was sunk northeast of the Azores by depth charges from a RAF Vickers Wellington of 172 Squadron on 13 January 1944. Seven men died, there were 47 survivors. Wolfpacks. "U-231" took part in eleven wolfpacks, namely: