SM U-31 (Germany)

SM U-31 was a German Type U-31 submarine built for the Imperial German Navy (Kaiserliche Marine) during World War I. She was one of 31 submarines of the U-31 class, a class of submarines that proved to be highly successful in commerce raiding.

U-31 was launched on 24 September 1914 from the Germaniawerft in Kiel and commissioned on 14 November 1914 under the command of Kapitänleutnant Gustav Niemeyer. Throughout her service, U-31 primarily operated in the waters around the British Isles and the North Sea, targeting Allied merchant shipping.

She is credited with sinking 35 ships, totaling 83,756 gross register tons (GRT), and damaging three more. Her targets included merchant vessels from various Allied nations, playing a significant role in the German U-boat campaign aimed at disrupting Allied supply lines.

On 13 January 1915, U-31 torpedoed and sank the British pre-Dreadnought battleship HMS Formidable in the English Channel. This was one of her most notable successes.

U-31 was sunk on 13 January 1919, a year after the end of World War I, at the Barrow Deep, following her surrender to the Allies. The circumstances surrounding her final sinking are generally attributed to an accidental explosion, possibly due to mines laid during the war or the unsafe handling of remaining munitions aboard.