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).
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-431 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged.[2] She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two AEG GU 460/8-276 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).[2]
The submarine had a maximum surface speed of 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph).[2] When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-431 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and a 2 cm (0.79 in) C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.[2]
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 11 ships in total.[1]
She took part in one wolfpack, namely:
She was sunk on 21 October 1943 in the Mediterranean off Algiers at position 37°23′N 00°35′E / 37.383°N 0.583°E / 37.383; 0.583 by depth charges dropped from a RAF Wellington bomber of 179 Squadron, operating out of Gibraltar. All hands were lost.[1]