# SM UC-20

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For other ships named German submarine U-20, see [German submarine U-20 (disambiguation)](/source/German_submarine_U-20_(disambiguation)).

**SM *UC-20***[Note 1] was a German [Type UC II](/source/Type_UC_II_submarine) [minelaying](/source/Minelayer) [submarine](/source/Submarine) or [U-boat](/source/U-boat) in the [German Imperial Navy](/source/German_Imperial_Navy) (German: *Kaiserliche Marine*) during [World War I](/source/World_War_I). The U-boat was ordered on 29 August 1915 and was [launched](/source/Ceremonial_ship_launching) on 1 April 1916. She was [commissioned](/source/Ship_commissioning) 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](/source/Naval_mines) laid. *UC-20* was surrendered on 16 January 1919 and [broken up](/source/Ship_breaking) at [Preston](/source/Preston,_Lancashire) in 1919–20.[1]

## Design

Like all pre-*UC-25* [Type UC II submarines](/source/Type_UC_II_submarine), *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](/source/Beam_(ship)) of 5.22 m (17 ft 2 in), and a [draught](/source/Draught_(ship)) 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 hp) (a total of 500 metric horsepower (370 kW; 490 hp)), two [electric motors](/source/Electric_motor) producing 460 metric horsepower (340 kW; 450 hp), and two [propeller shafts](/source/Propeller_shaft). She had a dive time of 35 seconds and was capable of operating at a depth of 50 metres (160 ft).[8]

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](/source/Torpedo_tube) (one on the stern and two on the bow), seven torpedoes, and one [8.8 cm (3.5 in) Uk L/30](/source/8.8_cm_SK_L/30_naval_gun) [deck gun](/source/Deck_gun). Her [complement](/source/Ship's_company) was twenty-six crew members.[8]

## Summary of raiding history

Date Name Nationality Tonnage[Note 2] Fate[9] 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

## References

### Notes

1. "SM" stands for "Seiner Majestät" (English: *His Majesty's*) and combined with the *U* for *Unterseeboot* would be translated as *His Majesty's Submarine*.

1. Tonnages are in [gross register tons](/source/Gross_register_tons)

### Citations

1. UC+20. Retrieved 22 February 2009.

1. Tarrant, p. 173.

1. 18. Retrieved 10 February 2015.

1. 188. Retrieved 10 February 2015.

1. 167. Retrieved 10 February 2015.

1. 165. Retrieved 10 February 2015.

1. 270. Retrieved 10 February 2015.

1. Gröner 1991, pp. 31–32.

1. uc20. Retrieved 10 February 2015.

### Bibliography

- Bendert, Harald (2001). *Die UC-Boote der Kaiserlichen Marine 1914-1918. Minenkrieg mit U-Booten* (in German). Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0758-7.
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). *U-boats and Mine Warfare Vessels*. Vol. 2. German Warships 1815–1945. Translated by Thomas, Keith & Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
- *Conway's All the World's Fighting Ships 1906–1921*. [Annapolis, Maryland](/source/Annapolis,_Maryland): [Naval Institute Press](/source/Naval_Institute_Press). 1985. ISBN 978-0-87021-907-8. [OCLC 12119866](https://www.worldcat.org/oclc/12119866)
- Tarrant, V. E. (1989). *The U-Boat Offensive: 1914–1945*. Annapolis, Maryland: Naval Institute Press. ISBN 978-0-87021-764-7. [OCLC 20338385](https://www.worldcat.org/oclc/20338385)

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Adapted from the Wikipedia article [SM UC-20](https://en.wikipedia.org/wiki/SM_UC-20) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/SM_UC-20?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.