SM UB-31 was a German Type UB II submarine or U-boat in the German Imperial Navy () during World War I. The U-boat was ordered on 22 July 1915 and launched on 16 November 1915. She was commissioned into the German Imperial Navy on 25 March 1916 as SM UB-31.
The submarine sank 27 ships in 25 patrols. UB-31 was depth charged and sunk by British warships , , and in the English Channel on 2 May 1918. Alternatively she may have been sunk by a mine on that date.
Design A Type UB II submarine, UB-31 had a displacement of when at the surface and while submerged. She had a total length of , a beam of , and a draught of . The submarine was powered by two Benz six-cylinder diesel engines producing a total , two Siemens-Schuckert electric motors producing , and one propeller shaft. She 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, she could operate for at ; when surfaced, she could travel at . UB-31 was fitted with two torpedo tubes, four torpedoes, and one Uk L/30 deck gun. She had a complement of twenty-one crew members and two officers and a 42-second dive time.
Summary of raiding history DateNameNationalityTonnageTonnages are in gross register tonsFate9 April 1917Kittiwake1,866Sunk24 April 1917Saint Jacques415Damaged28 April 191712,350Sunk21 May 1917City of Corinth5,870Sunk15 June 1917Teesdale2,470Damaged17 June 1917Stanhope2,854Sunk5 July 1917Ocean Swell195Sunk6 July 1917Ariadne Christine3,550Damaged7 July 1917Bellucia4,368Sunk10 July 1917Hildegard622Sunk11 July 1917Brunhilda2,296Sunk1 August 1917Alcyone149Sunk1 August 1917Laertes4,541Sunk2 August 1917Newlyn4,019Sunk3 August 1917Renee Marthe49Sunk8 August 1917Algerie3,386Damaged8 September 1917Elizabeth58Sunk9 September 1917Pluton1,449Sunk19 October 1917Waikawa5,666Sunk20 October 1917Colorado7,165Sunk23 October 1917Lepanto6,389Damaged19 November 1917Farn4,393Sunk13 December 1917Britannic92Sunk15 December 1917Sachem5,354Damaged18 December 1917Riversdale2,805Sunk20 December 1917Alice Marie2,210Sunk20 December 1917Eveline2,605Sunk20 December 1917Warsaw608Sunk22 January 1918Admiral Cochrane6,565Damaged22 January 1918Greatham2,338Sunk24 January 1918Elsa3,581Sunk28 February 1918Heenvliet492Sunk20 March 1918Boorara6,570Damaged24 April 1918Agnete1,127Sunk25 April 1918Joseph42Sunk
References
Notes
Citations
Bibliography
External links Croche, Paulo (2014) 'UB-31 Folkestone, Kent: Archaeological Report', Wessex Archaeology Historic England project to research First World War submarine wrecks.