German submarine U-431

German submarine U-431 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 4 January 1940 by Schichau-Werke in Danzig as yard number 1472, launched on 2 February 1941 and commissioned on 5 April 1941 under Kapitänleutnant Wilhelm Dommes (Knight’s Cross).

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-431 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 460/8-276 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-431 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 an anti-aircraft gun. The boat had a complement of between forty-four and sixty.

Service history
The boat's service began on 5 April 1941 for training as part of the 3rd U-boat Flotilla. Afterwards she transferred to the 29th flotilla operating in the Mediterranean on 1 January 1942. In 16 patrols she sank or damaged 12 ships in total.

Wolfpacks
She took part in one wolfpack, namely,
 * Brandenburg (15 September – 1 October 1941)

Fate
She was sunk on 21 October 1943 in the Mediterranean off Algiers at position 37.38333°N, 0.58333°W by depth charges dropped from a RAF Wellington bomber of 179 Squadron, operating out of Gibraltar. All hands were lost.