German submarine U-631

German submarine U-631 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 5 September 1941 by Blohm & Voss, Hamburg as yard number 607, launched on 27 May 1942 and commissioned on 16 July 1942 under Oberleutnant zur See Jürgen Krüger.

Service History
The boat's career began with training at 5th U-boat Flotilla on 16 July 1942, followed by active service on 1 January 1943 as part of the 9th Flotilla for the remainder of her service.

In three patrols she sank two merchant ships, for a total of.

Wolfpacks
U-631 took part in seven wolfpacks, namely
 * Falke (28 December 1942 – 19 January 1943)
 * Landsknecht (19–28 January 1943)
 * Stürmer (11–20 March 1943)
 * Seewolf 2 (21–30 March 1943)
 * Meise (11-27 April 1943)
 * Rossbach (27 September – 9 October 1943)
 * Schlieffen (14–17 October 1943)

Fate
U-631 was sunk on 17 October 1943 in the North Atlantic SE of Cape Farewell, Greenland, in position 58.21667°N, -32.48333°W, by depth charges from British corvette HMS Sunflower (K41). All hands were lost.