![]() SM UB-45, a U-boat similar to UB-21
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History | |
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Name | UB-21 |
Ordered | 30 April 1915[1] |
Builder | Blohm & Voss, Hamburg[1] |
Yard number | 251[1] |
Launched | 26 September 1915[1] |
Completed | 18 February 1916[1] |
Commissioned | 20 February 1916 |
Fate | Sunk as target 30 September 1920 |
General characteristics [2] | |
Class and type | Type UB II submarine |
Displacement | |
Length |
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Beam |
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Draught | 3.70 m (12 ft 2 in) |
Propulsion |
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Speed |
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Range |
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Test depth | 50 m (160 ft) |
Complement | 2 officers, 21 men |
Armament |
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Notes | 45-second diving time |
Service record | |
Part of: |
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Commanders: | |
Operations: | 26 patrols |
Victories: |
SM UB-21[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 20 February 1916 as SM UB-21. The submarine sank 33 ships in 26 patrols for a total of 36,764 gross register tons (GRT).[7] Surrendered to Britain in accordance with the requirements of the Armistice with Germany, UB-21 was sunk as a target by HMS Terror in the Solent on 30 September 1920; the wreck was sold in 1970 and most had been cleared by 1998, although some remnants survive.[8]
Design
[edit]A Type UB II submarine, UB-21 had a displacement of 263 tonnes (259 long tons) when at the surface and 292 tonnes (287 long tons) while submerged. 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 producing a total of 280 metric horsepower (280 shp; 210 kW), two Siemens-Schuckert electric motors 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). 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-21 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-one crew members and two officers and a 45-second dive time.[2]
Summary of raiding history
[edit]Date | Name | Nationality | Tonnage[Note 2] | Fate[9] |
---|---|---|---|---|
5 May 1916 | Harald | ![]() |
275 | Sunk |
20 October 1916 | Lekna | ![]() |
204 | Sunk |
20 October 1916 | Randi | ![]() |
467 | Sunk |
20 October 1916 | Svartvik | ![]() |
322 | Sunk |
21 October 1916 | Fritzöe | ![]() |
641 | Captured as prize |
21 October 1916 | Grönhaug | ![]() |
667 | Sunk |
22 October 1916 | London | ![]() |
184 | Sunk |
22 October 1916 | Thor | ![]() |
372 | Sunk |
3 November 1916 | Pluto | ![]() |
1,148 | Captured as prize |
16 February 1917 | Lady Ann | ![]() |
1,016 | Sunk |
17 February 1917 | Excel | ![]() |
157 | Sunk |
22 February 1917 | John Miles | ![]() |
687 | Sunk |
29 March 1917 | Bywell | ![]() |
1,522 | Sunk |
31 March 1917 | Norden | ![]() |
776 | Captured as prize |
29 April 1917 | Victoria | ![]() |
1,620 | Sunk |
2 May 1917 | Rikard Noordrak | ![]() |
1,123 | Sunk |
5 May 1917 | Edith Cavell | ![]() |
20 | Sunk |
6 May 1917 | Harold | ![]() |
1,679 | Sunk |
8 May 1917 | Batavier II | ![]() |
157 | Captured as prize |
6 June 1917 | S.N.A. 2 | ![]() |
2,294 | Sunk |
7 June 1917 | Sir Francis | ![]() |
1,991 | Sunk |
21 July 1917 | Trelyon | ![]() |
3,099 | Sunk |
22 July 1917 | Glow | ![]() |
1,141 | Sunk |
23 July 1917 | Vanland | ![]() |
1,285 | Sunk |
24 August 1917 | Springhill | ![]() |
1,507 | Sunk |
18 October 1917 | Amsteldam | ![]() |
1,233 | Sunk |
19 October 1917 | Gemma | ![]() |
1,385 | Sunk |
23 November 1917 | Ocean | ![]() |
1,442 | Sunk |
29 December 1917 | Inverness | ![]() |
3,734 | Damaged |
29 December 1917 | Patria | ![]() |
838 | Sunk |
30 December 1917 | Hercules | ![]() |
1,295 | Sunk |
25 March 1918 | Hercules | ![]() |
1,095 | Sunk |
8 May 1918 | Constantia | ![]() |
772 | Sunk |
10 May 1918 | Anboto Mendi | ![]() |
2,114 | Sunk |
11 May 1918 | Gothia | ![]() |
1,826 | Sunk |
12 May 1918 | Haslingden | ![]() |
1,934 | Sunk |
4 July 1918 | Mentor | ![]() |
539 | Sunk |
26 September 1918 | Paul | ![]() |
659 | Sunk |
References
[edit]Notes
[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 Gröner 1991, pp. 23–25.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Ernst Hashagen (Royal House Order of Hohenzollern)". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Franz Walther". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Walter Scheffler". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Bruno Mahn". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 29 January 2015.
- ^ Bendert 2000, p. 195.
- ^ Dodson, Aidan; Cant, Serena (2020). Spoils of War: the fate of enemy fleets after the two World Wars. Barnsley: Seaforth. pp. 49, 129. ISBN 978-1-5267-4198-1.
- ^ Helgason, Guðmundur. "Ships hit by UB-21". 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.