German submarine U-391 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.
She carried out one patrol. She did not sink or damage any ships.
She was sunk by a British aircraft northwest of Cape Ortegal in Spain on 13 December 1943.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-391 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 Garbe, Lahmeyer & Co. RP 137/c 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-391 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.
The submarine was laid down on 9 January 1942 at the Howaldtswerke (yard) at Flensburg as yard number 23, launched on 5 March and commissioned on 24 April 1943 under the command of Oberleutnant zur See Gert Dültgen.
The boat was a member of three wolfpacks.
She served with the 5th U-boat Flotilla from 24 April 1943 and the 3rd flotilla from 1 October of the same year.
The boat departed Kiel on 23 October 1943. Passing through the gap that separates Iceland and the Faroe Islands, she was attacked by a Vickers Wellington of No. 179 Squadron RAF on 28 November.
On 13 December, she was attacked and sunk by depth charges dropped from a British B-24 Liberator of 53 Squadron on the western edge of the Bay of Biscay, northwest of Cape Ortegal in Spain.
51 men died in the U-boat; there were no survivors.
U-391 took part in three wolfpacks, namely: