SM UB-20

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For other ships with the same name, see German submarine U-20.
SM UB 45.jpg
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: German Type UB II submarine
Displacement:
  • 263 t (259 long tons) surfaced
  • 292 t (287 long tons) submerged
Length:
Beam:
  • 4.36 m (14 ft 4 in) o/a
  • 3.85 m (12 ft 8 in) pressure hull
Draught: 3.70 m (12 ft 2 in)
Propulsion:
Speed:
  • 9.15 knots (16.95 km/h; 10.53 mph) surfaced
  • 5.81 knots (10.76 km/h; 6.69 mph) submerged
Range:
  • 6,450 nmi (11,950 km; 7,420 mi) at 5 knots (9.3 km/h; 5.8 mph) surfaced
  • 45 nmi (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth: 50 m (160 ft)
Complement: 2 officers, 21 men
Armament:
Notes: 45-second diving time
Service record
Part of:
  • Imperial German Navy:
  • Baltic Flotilla
  • 12 March 1916 – 26 March 1917
  • Flandern Flotilla
  • 26 March – 28 July 1917
Commanders:
  • Oblt.z.S. Max Viebeg[3]
  • 10 February 1916 – 31 January 1917
  • Oblt.z.S. Hermann Glimpf[4]
  • 1 February – 28 July 1917
Operations: 15 patrols
Victories:

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°25′N 3°20′W / 51.417°N 3.333°W / 51.417; -3.333Coordinates: 51°25′N 3°20′W / 51.417°N 3.333°W / 51.417; -3.333. Thirteen crew members died in the event.[2]

Design[edit]

A German 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 centimetres (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]

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 a 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[edit]

Notes[edit]

  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.
  2. ^ Tonnages are in gross register tons

Citations[edit]

  1. ^ a b c d e Rössler 1979, p. 64.
  2. ^ a b c d e f Gröner 1991, pp. 23-25.
  3. ^ 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. 
  4. ^ 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. 
  5. ^ Bendert 2000, p. 195.
  6. ^ 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. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4. 
  • Rössler, Eberhard (1979). U-Bootbau bis Ende des 1. Weltkrieges, Konstruktionen für das Ausland und die Jahre 1935 – 1945. Die deutschen U-Boote und ihre Werften (in German). I. Munich: Bernard & Graefe. ISBN 3-7637-5213-7.