# SM UC-40

SM UC-40 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 September 1916. She was commissioned into the German Imperial Navy on 1 October 1916 as SM UC-40. In 17 patrols UC-40 was credited with sinking 30 ships, either by torpedo or by mines laid. UC-40 was being taken to surrender but foundered in the North Sea en route on 21 January 1919.

## Design

A Type UC II submarine, UC-40 had a displacement of 400 tonnes (390 long tons) when at the surface and 480 tonnes (470 long tons) while submerged. She had a length overall of 49.45 m (162 ft 3 in), a beam of 5.22 m (17 ft 2 in), and a draught of 3.68 m (12 ft 1 in). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 260 metric horsepower (190 kW; 260 shp) (a total of 520 metric horsepower (380 kW; 510 shp)), two electric motors producing 460 metric horsepower (340 kW; 450 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 11.7 knots (21.7 km/h; 13.5 mph) and a submerged speed of 6.7 knots (12.4 km/h; 7.7 mph). When submerged, she could operate for 60 nautical miles (110 km; 69 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 9,410 nautical miles (17,430 km; 10,830 mi) at 7 knots (13 km/h; 8.1 mph). UC-40 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 |
| 22 January 1917 | Kamma | Sweden | 1,516 | Sunk |
| 28 March 1917 | Hero | United Kingdom | 66 | Sunk |
| 1 April 1917 | Bergenhus | Denmark | 1,017 | Sunk |
| 6 April 1917 | Presto | United Kingdom | 1,143 | Sunk |
| 10 May 1917 | HMT Lord Ridley | Royal Navy | 215 | Sunk |
| 23 May 1917 | Gran | Norway | 1,153 | Sunk |
| 25 June 1917 | HMT Gelsina | Royal Navy | 227 | Sunk |
| 30 July 1917 | Amor | Denmark | 196 | Sunk |
| 6 August 1917 | Polanna | United Kingdom | 2,345 | Sunk |
| 8 September 1917 | Family’s Pride | United Kingdom | 39 | Sunk |
| 9 September 1917 | Swiftsure | United Kingdom | 823 | Sunk |
| 10 September 1917 | Margarita | United Kingdom | 2,788 | Damaged |
| 10 September 1917 | Parkmill | United Kingdom | 1,316 | Sunk |
| 12 September 1917 | HMT Asia | Royal Navy | 309 | Sunk |
| 12 September 1917 | Glenelg | United Kingdom | 4,160 | Damaged |
| 11 October 1917 | Voronezh | Russian Empire | 5,331 | Damaged |
| 19 October 1917 | Slavonic | Russian Empire | 3,604 | Sunk |
| 21 October 1917 | Anglo Dane | Denmark | 808 | Sunk |
| 21 October 1917 | Flynderborg | Denmark | 1,400 | Sunk |
| 24 October 1917 | Novington | United Kingdom | 3,442 | Damaged |
| 24 October 1917 | Woron | Russian Empire | 3,342 | Sunk |
| 8 December 1917 | HMS Grive | Royal Navy | 2,037 | Sunk |
| 12 December 1917 | Leonatus | United Kingdom | 2,099 | Sunk |
| 8 March 1918 | Corsham | United Kingdom | 2,760 | Sunk |
| 8 March 1918 | Intent | United Kingdom | 1,564 | Sunk |
| 10 March 1918 | HMT Columba | Royal Navy | 138 | Sunk |
| 14 March 1918 | Castleford | United Kingdom | 1,741 | Sunk |
| 28 April 1918 | HMT Emley | Royal Navy | 223 | Sunk |
| 28 April 1918 | Upcerne | United Kingdom | 2,984 | Sunk |
| 8 June 1918 | Eros | United Kingdom | 181 | Sunk |
| 12 June 1918 | Afrique | France | 2,457 | Sunk |
| 15 June 1918 | Cairnmona | United Kingdom | 4,666 | Damaged |
| 16 June 1918 | Melanie | United Kingdom | 2,996 | Sunk |
| 23 July 1918 | HMS Vanity | Royal Navy | 1,300 | Damaged |
| 26 July 1918 | Blairhall | United Kingdom | 2,549 | Sunk |
| 27 July 1918 | Crimdon | Sweden | 1,599 | Sunk |
| 30 July 1918 | War Deer | United Kingdom | 5,323 | Damaged |
| 3 August 1918 | Skjold | Denmark | 166 | Damaged |