German submarine U-100 (1940)
German submarine "U-100" was a Type VIIB U-boat of Nazi Germany's "Kriegsmarine" during World War II. Design. German Type VIIB submarines were preceded by the shorter Type VIIA submarines. "U-100" 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 BBC 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-100" 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 anti-aircraft gun. The boat had a complement of between forty-four and sixty. Service history. First patrol . The boat was launched on 10 April 1940, with a crew of 53, under the command of "Kapitänleutnant" Joachim Schepke. On her first active patrol, "U-100" came into contact with two Allied convoys, OA-198 and OA-204. She shadowed both convoys. Second patrol. "U-100" departed for her second active patrol on 11 September 1940, coming into contact with the Allied convoy HX 72. HX 72 lost 11 ships in total, with "U-100" accounting for 7 ships of 50,340 GRT. In the attack on this convoy, while other U-boats stood off to the side and fired their torpedoes to little or  no success, "U-100" penetrated inside the convoy before attacking, a tactic soon adopted by the C-in-C of U-boats, Admiral Karl Donitz. Third patrol. After resupplying, "U-100" departed for her third active patrol on 12 October 1940. She came into contact with two Allied convoys, HX 79 and SC 7. Fourth patrol. "U-100" departed on her fourth patrol on 7 November 1940. On 22 November she came into contact with the Allied convoy SC 11 and began to shadow it. Fifth patrol. "U-100" left for her fifth active patrol on 2 December 1940, sinking two vessels from Convoy  OB 256, then a third solo vessel. Sixth and final patrol. "U-100" departed on her sixth and what would be her final patrol on 9 March 1941. She approached convoy HX 112 from astern in the pre-dawn hours of 17 March, but was detected at a range of 1,000 meters by the Type 286 radar aboard . "U-100" was the first U-boat to be so discovered during World War II; she was rammed and sunk by "Vanoc" while attempting to submerge. Another destroyer, , was also present. Six of the boat's 53 crew members survived, spending the remainder of  the war as POWs. Schepke was not one of them.