SM UC-31
SM "UC-31" was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy () during World War I. The U-boat was ordered on 29 August 1915 and was launched on 7 August 1916. She was commissioned into the German Imperial Navy on 2 September 1916 as SM "UC-31". In 13 patrols "UC-31" was credited with sinking 38 ships, either by torpedo or by mines laid. "UC-31" was surrendered on 26 November 1918 and broken up at Canning Town in 1922. Design. A German Type UC II submarine, "UC-31" had a displacement of when  at the surface and while submerged. She had a length overall of , a beam of , and a draught of . The submarine was powered by two six-cylinder four-stroke diesel engines each producing (a total of ), two electric motors producing , and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of . The submarine had a maximum surface speed of and a submerged speed of . When submerged, she could operate for at ; when surfaced, she could travel at . "UC-31" was fitted with six mine tubes, eighteen UC 200 mines, three torpedo  tubes (one on the stern and two on the bow), seven torpedoes, and one Uk L/30 deck gun. Her complement was twenty-six crew members.