German submarine U-712 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. Commissioned on 5 November 1942, she served with the 8th U-boat Flotilla until 31 October 1943 as a training boat, and as a front boat in the 3rd U-boat Flotilla under Oberleutnant zur See Walter Pietschmann until 14 December, before being replaced by Oberleutnant zur See Walter-Ernst Koch.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-712 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 AEG GU 460/8–27 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-712 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.
Built as yard number 778 at the HC Stülcken & Sohn shipyard in Hamburg, U-712 was launched on 10 August 1942. After the completion of system checks and crew training, U-712 was transferred to the 3rd Flotilla on 1 November 1943. On 1 January 1944, she was reassigned to the 21st U-boat Flotilla as a training boat. On 3 July 1944, Oberleutnant zur See Koch handed over to Freiherr Eberhard von Ketelhodt, leaving to command .[1] U-712s purpose was succeeded by a similar function with the 31st from 1 March 1945.
In the rest of her career under Walter-Ernst Koch and Freiherr Eberhard von Ketelhodt, she served as a training vessel, never having made a single patrol.
After Germany's surrender in May 1945, U-712 was surrendered at Kristiansand on 9 May 1945 in Norway. She was later taken to Loch Ryan in Scotland, where the British used her bulk for testing before breaking her up at Hayle in 1950.