were preceded by the shorter Type VIIB submarines. U-364 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 superchargeddiesel 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-364 was fitted with five torpedo tubes, fourteen torpedoes, one SK C/35 naval gun, 220 rounds, and two twin C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.
The boat was built in Flensburg in 1942 and 1943, U-365 was a Type VIICU-boat, with five torpedo tubes and a deck gun for smaller targets. She was captained by Kptlt.Haimar Wedemeyer, an efficient if slightly cautious officer, who worked his boat and crew up before being dispatched to the 9th Flotilla based at Bergen, Norway, from which she conducted her first three patrols.
War patrols
U-365s early operations were in support of clandestine operations in the North Sea and Arctic Ocean, in the course of which she saw no action against Allied shipping or positions. Not until her fifth patrol, following a shift in patrol zones to the frozen seas around Novaya Zemlya and transfer to the 13th U-boat Flotilla, that U-365 experienced success. In this region, on the 12 August, the boat spotted a small Soviet convoy and in rapid order sank a 5,000-ton freighter and the two 600-ton minesweepers intended to protect it. However, due to the remoteness of the U-365s patrol zones, the cautiousness of her commander and the efficiency of Allied submarine defences by the autumn of 1944, Wedemeyer was unable to score another victory for his boat in the next two patrols, and was eventually replaced by Kptlt. Diether Todenhagen, who had previously served on the enormously successful, and had a reputation as an aggressive submariner. This seemed deserved as on his first patrol, on the 6 December, he sank the tiny Soviet patrol shipBO-2 in the Barents Sea. This was followed five days later with a determined attack on an Allied convoy in which the British destroyer was seriously damaged. However, in orchestrating the attack the U-boat's position was revealed, and just two days later two Fairey Swordfish aircraft from 813 Squadron flying from the escort carrier spotted the submarine and sank her near the Lofoten Islands with bombs. All 50 of the U-boat's crew perished in the wreck.
