SM UC-51

SM UC-51 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy (Kaiserliche Marine) during World War I. The U-boat was ordered on 20 November 1915 and was launched on 5 December 1916. She was commissioned into the German Imperial Navy on 6 January 1917 as SM UC-51. In seven patrols UC-51 was credited with sinking 28 ships, either by torpedo or by mines laid. UC-51 was mined and sunk in the English Channel on 17 November 1917.

The wreck was located and identified by marine archaeologist Innes McCartney close to the official sinking position in 2001.

Design
A Type UC II submarine, UC-51 had a displacement of 434 t when at the surface and 511 t while submerged. She had a length overall of 52.69 m, a beam of 5.22 m, and a draught of 3.64 m. The submarine was powered by two six-cylinder four-stroke diesel engines each producing 290 - 300 PS (a total of 580 - 600 PS), two electric motors producing 620 PS, and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of 50 m.

The submarine had a maximum surface speed of 11.8 kn and a submerged speed of 7.2 kn. When submerged, she could operate for 56 nmi at 4 kn; when surfaced, she could travel 8820 to 9450 nmi at 7 kn. UC-51 was fitted with six 100 cm mine tubes, eighteen UC 200 mines, three 50 cm torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 8.8 cm Uk L/30 deck gun. Her complement was twenty-six crew members.