SM UB-20[Note 1] was a German Type UB II submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The U-boat was ordered on 30 April 1915 and launched on 26 September 1915. She was commissioned into the German Imperial Navy on 10 February 1916 as SM UB-20. The submarine sank 13 ships in 15 patrols for a total of 10,230 gross register tons (GRT).[5] UB-20 was mined and sunk on 28 July 1917 at 51°21′N 2°38′E / 51.350°N 2.633°E. Fifteen crew members died in the event.
 SM UB-45, a U-boat similar to UB-20
| |
| History | |
|---|---|
 German Empire | |
| Name | UB-20 |
| Ordered | 30 April 1915[1] |
| Builder | Blohm & Voss, Hamburg[1] |
| Yard number | 250[1] |
| Launched | 26 September 1915[1] |
| Completed | 8 February 1916[1] |
| Commissioned | 10 February 1916 |
| Fate | Sunk by mine, 28 July 1917 |
| General characteristics [2] | |
| Class and type | Type UB II submarine |
| Displacement | |
| Length |
|
| Beam |
|
| Draught | 3.70 m (12 ft 2 in) |
| Propulsion |
|
| Speed |
|
| Range |
|
| Test depth | 50 m (160 ft) |
| Complement | 2 officers, 21 men |
| Armament |
|
| Notes | 45-second diving time |
| Service record | |
| Part of: |
|
| Commanders: | |
| Operations: | 15 patrols |
| Victories: | |
Design
editA Type UB II submarine, UB-20 had a displacement of 263 tonnes (259 long tons) when at the surface and 292 tonnes (287 long tons) while submerged.[2] She had a total length of 36.13 m (118 ft 6 in), a beam of 4.36 m (14 ft 4 in), and a draught of 3.70 m (12 ft 2 in). The submarine was powered by two Körting six-cylinder, four-stroke diesel engines each producing a total 284 metric horsepower (209 kW; 280 shp), a Siemens-Schuckert electric motor producing 280 metric horsepower (210 kW; 280 shp), and one propeller shaft. She was capable of operating at depths of up to 50 metres (160 ft).[2]
The submarine had a maximum surface speed of 9.15 knots (16.95 km/h; 10.53 mph) and a maximum submerged speed of 5.81 knots (10.76 km/h; 6.69 mph).[2] When submerged, she could operate for 45 nautical miles (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 6,650 nautical miles (12,320 km; 7,650 mi) at 5 knots (9.3 km/h; 5.8 mph). UB-20 was fitted with two 50 centimetres (20 in) torpedo tubes, four torpedoes, and one 5 cm (2.0 in) SK L/40 deck gun. She had a complement of twenty-three crew members and two officers and a 45-second dive time.[2]
Loss
editAt noon on 28.07.1917 UB 20 left Ostend for a four-hour sea trial in the area around West Hinder lightship. The boat did not return. (Pos. 51°21'N-02°38'E). The commander's body was washed up on the Jutland coast near Lodbjerg on 03.08.1917 and buried in the local cemetery.[5]
Summary of raiding history
edit| Date | Name | Nationality | Tonnage[Note 2] | Fate[6] |
|---|---|---|---|---|
| 2 August 1916 | Bror Oskar |  Sweden
|
368 | Sunk |
| 2 August 1916 | Commerce | Sweden
|
638 | Sunk |
| 2 August 1916 | Themis | Sweden
|
1,047 | Captured as prize |
| 2 August 1916 | Vera | Sweden
|
312 | Sunk |
| 2 August 1916 | Vermland | Sweden
|
213 | Sunk |
| 10 April 1917 | Pluto |  United Kingdom
|
1,266 | Sunk |
| 7 May 1917 | Martha Maria |  Netherlands
|
176 | Sunk |
| 7 May 1917 | Prins Hendrik De Nederlande | Netherlands
|
182 | Sunk |
| 16 May 1917 | Friso | Netherlands
|
171 | Sunk |
| 17 May 1917 | Kilmaho | United Kingdom
|
2,155 | Sunk |
| 18 May 1917 | Adventure | United Kingdom
|
50 | Sunk |
| 18 May 1917 | Primrose | United Kingdom
|
62 | Sunk |
| 19 May 1917 | Askild |  Norway
|
2,540 | Sunk |
| 20 May 1917 | Normand | Norway
|
2,097 | Sunk |
| 11 June 1917 | Knight Companion | United Kingdom
|
7,241 | Damaged |
References
editNotes
edit- ^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.
- ^ Tonnages are in gross register tons
Citations
edit- ^ a b c d e Rössler 1979, p. 64.
- ^ a b c d e Gröner 1991, pp. 23–25.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Max Viebeg (Pour le Mérite)". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Hermann Glimpf". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
- ^ a b Bendert 2000, p. 195.
- ^ Helgason, Guðmundur. "Ships hit by UB 20". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
Bibliography
edit- Bendert, Harald (2000). Die UB-Boote der Kaiserlichen Marine, 1914-1918. Einsätze, Erfolge, Schicksal (in German). Hamburg: Verlag E.S. Mittler & Sohn GmbH. ISBN 3-8132-0713-7.
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
- Rössler, Eberhard (1979). Die deutschen U-Boote und ihre Werften: eine Bilddokumentation über den deutschen U-Bootbau; in zwei Bänden (in German). Vol. I. Munich: Bernard & Graefe. ISBN 3-7637-5213-7.