# SM UC-51

SM UC-51 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy (German: 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 tonnes (427 long tons) when at the surface and 511 tonnes (503 long tons) while submerged. She had a length overall of 52.69 m (172 ft 10 in), a beam of 5.22 m (17 ft 2 in), and a draught of 3.64 m (11 ft 11 in). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 290–300 metric horsepower (210–220 kW; 290–300 shp) (a total of 580–600 metric horsepower (430–440 kW; 570–590 shp)), two electric motors producing 620 metric horsepower (460 kW; 610 shp), and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of 50 metres (160 ft).
The submarine had a maximum surface speed of 11.8 knots (21.9 km/h; 13.6 mph) and a submerged speed of 7.2 knots (13.3 km/h; 8.3 mph). When submerged, she could operate for 56 nautical miles (104 km; 64 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,820 to 9,450 nautical miles (16,330 to 17,500 km; 10,150 to 10,870 mi) at 7 knots (13 km/h; 8.1 mph). UC-51 was fitted with six 100 centimetres (39 in) mine tubes, eighteen UC 200 mines, three 50 centimetres (20 in) torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 8.8 cm (3.5 in) Uk L/30 deck gun. Her complement was twenty-six crew members.

## Summary of raiding history

| Date | Name | Nationality | Tonnage | Fate |
| 16 April 1917 | Amanda | Sweden | 232 | Sunk |
| 16 April 1917 | Polycarp | Norway | 509 | Sunk |
| 17 April 1917 | Atalanta | Sweden | 1,091 | Damaged |
| 4 May 1917 | Marie | Denmark | 772 | Sunk |
| 5 May 1917 | Segovia | Norway | 1,394 | Sunk |
| 18 June 1917 | Kangaroo | United Kingdom | 84 | Sunk |
| 18 June 1917 | Violet | United Kingdom | 158 | Sunk |
| 22 June 1917 | Miami | United Kingdom | 3,762 | Sunk |
| 24 June 1917 | Hilversum | Netherlands | 1,505 | Sunk |
| 26 July 1917 | Ludgate | United Kingdom | 3,708 | Sunk |
| 11 August 1917 | Gloriosa | United Kingdom | 23 | Sunk |
| 12 August 1917 | Eleazar | United Kingdom | 111 | Sunk |
| 14 August 1917 | N. Verberckmoens | France | 1,353 | Sunk |
| 14 August 1917 | Wisbech | United Kingdom | 1,282 | Sunk |
| 8 September 1917 | Ezel | United Kingdom | 163 | Sunk |
| 8 September 1917 | Laura | United Kingdom | 104 | Sunk |
| 10 September 1917 | Jane Williamson | United Kingdom | 197 | Sunk |
| 10 September 1917 | Mary Orr | United Kingdom | 91 | Sunk |
| 10 September 1917 | Mary Seymour | United Kingdom | 150 | Sunk |
| 10 September 1917 | Moss Rose | United Kingdom | 161 | Sunk |
| 10 September 1917 | Water Lily | United Kingdom | 111 | Sunk |
| 11 September 1917 | Luxembourg | United Kingdom | 1,417 | Sunk |
| 11 September 1917 | Rosy Cross | United Kingdom | 25 | Sunk |
| 11 September 1917 | William | United Kingdom | 78 | Sunk |
| 14 September 1917 | Zeta | United Kingdom | 2,269 | Sunk |
| 15 September 1917 | Saint Jacques | France | 2,459 | Sunk |
| 9 October 1917 | Poldown | United Kingdom | 1,370 | Sunk |
| 15 October 1917 | HMD Active III | Royal Navy | 81 | Sunk |
| 20 October 1917 | Ionian | United Kingdom | 8,268 | Sunk |
| 17 November 1917 | David Lloyd George | United Kingdom | 4,764 | Damaged |