# SM UC-20

SM UC-20 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 29 August 1915 and was launched on 1 April 1916. She was commissioned into the German Imperial Navy on 7 September 1916 as SM UC-20. In 13 patrols UC-20 was credited with sinking 21 ships, either by torpedo or by mines laid. UC-20 was surrendered on 16 January 1919 and broken up at Preston in 1919–20.

## Design

Like all pre-UC-25 Type UC II submarines, UC-20 had a displacement of 417 tonnes (410 long tons) when at the surface and 493 tonnes (485 long tons) while submerged. She had a total length of 49.35 m (161 ft 11 in), a beam of 5.22 m (17 ft 2 in), and a draught of 3.65 m (12 ft). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 250 metric horsepower (180 kW; 250 shp) (a total of 500 metric horsepower (370 kW; 490 shp)), two electric motors producing 460 metric horsepower (340 kW; 450 shp), and two propeller shafts. She had a dive time of 35 seconds and was capable of operating at a depth of 50 metres (160 ft).
The submarine had a maximum surface speed of 11.6 knots (21.5 km/h; 13.3 mph) and a submerged speed of 7 knots (13 km/h; 8.1 mph). When submerged, she could operate for 55 nautical miles (102 km; 63 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 9,430 nautical miles (17,460 km; 10,850 mi) at 7 knots (13 km/h; 8.1 mph). UC-20 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 |
| 19 October 1916 | Frits Emil | Denmark | 194 | Sunk |
| 17 November 1916 | Emilia | Portugal | 1,159 | Sunk |
| 10 April 1917 | Abd Razik | Tunisia | 25 | Sunk |
| 11 April 1917 | Candia | Kingdom of Italy | 1,045 | Sunk |
| 14 April 1917 | Cinque Ottobre | Kingdom of Italy | 39 | Sunk |
| 14 April 1917 | Progresso | Kingdom of Italy | 31 | Sunk |
| 15 April 1917 | Alessio Cocco | Kingdom of Italy | 29 | Sunk |
| 18 May 1917 | Millicent Knight | United Kingdom | 3,563 | Sunk |
| 25 May 1917 | Argentina | Kingdom of Italy | 97 | Sunk |
| 25 May 1917 | Ida | Kingdom of Italy | 46 | Sunk |
| 26 May 1917 | Unione Salvatore | Kingdom of Italy | 57 | Sunk |
| 26 May 1917 | Abd es Salem | France | 25 | Sunk |
| 26 May 1917 | Dandolo | France | 50 | Sunk |
| 26 May 1917 | Manoubia | France | 50 | Sunk |
| 26 May 1917 | Messaouda | France | 50 | Sunk |
| 26 May 1917 | San Francesco | Kingdom of Italy | 47 | Sunk |
| 27 May 1917 | Boldwell | United Kingdom | 3,118 | Sunk |
| 26 August 1917 | Maurizio P. | Kingdom of Italy | 558 | Sunk |
| 4 January 1918 | Regina Elena | Kingdom of Italy | 7,940 | Sunk |
| 13 April 1918 | Giove | Kingdom of Italy | 5,037 | Damaged |
| 28 April 1918 | Verdun | France | 2,769 | Sunk |
| 4 May 1918 | Mergellina | Kingdom of Italy | 354 | Damaged |
| 4 June 1918 | Strombus | United Kingdom | 6,163 | Damaged |
| 12 June 1918 | Poincare | Tunisia | 35 | Sunk |