German submarine U-712

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.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-712 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-712 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and two twin 2 cm C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.

Service history
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 GS U-975. U-712's 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.

Fate
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.