SM UB-21

Last updated
SM UB 45.jpg
SM UB-45, a U-boat similar to UB-21
History
War Ensign of Germany 1903-1918.svg German Empire
NameUB-21
Ordered30 April 1915 [1]
Builder Blohm & Voss, Hamburg [1]
Yard number251 [1]
Launched26 September 1915 [1]
Completed18 February 1916 [1]
Commissioned20 February 1916
FateSunk as target 30 September 1920
General characteristics [2]
Class and type 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 (13 ft) pressure hull
Draught3.70 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 depth50 m (160 ft)
Complement2 officers, 21 men
Armament
Notes45-second diving time
Service record
Part of:
  • I Flotilla
  • 14 April 1916 – 1 February 1917
  • II Flotilla
  • 1 February – 10 September 1917
  • V Flotilla
  • 10 September 1917 – 29 April 1918
  • I Flotilla
  • 29 April – 7 October 1918
  • Training Flotilla
  • 7 October – 11 November 1918
Commanders:
  • Kptlt. Ernst Hashagen [3]
  • 20 February – 26 November 1916
  • Oblt.z.S. Franz Walther [4]
  • 27 November 1916 – 9 September 1917
  • Oblt.z.S. Walter Scheffler [5]
  • 10 September 1917 – 28 April 1918
  • Oblt.z.S. Bruno Mahn [6]
  • 29 April – 7 October 1918
Operations: 26 patrols
Victories:
  • 33 merchant ships sunk
    (36,764  GRT)
  • 1 merchant ship damaged
    (3,734  GRT)
  • 4 merchant ships taken as prize
    (2,722  GRT)

SM UB-21 [Note 1] was a German Type UB II submarine or U-boat in the Imperial German 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]

Contents

Design

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

DateNameNationalityTonnage [Note 2] Fate [9]
5 May 1916 Harald Flag of Sweden.svg  Sweden 275Sunk
20 October 1916 Lekna Flag of Sweden.svg  Sweden 204Sunk
20 October 1916 Randi Flag of Norway.svg  Norway 467Sunk
20 October 1916 Svartvik Flag of Sweden.svg  Sweden 322Sunk
21 October 1916FritzöeFlag of Norway.svg  Norway 641Captured as prize
21 October 1916 Grönhaug Flag of Norway.svg  Norway 667Sunk
22 October 1916 London Flag of Denmark.svg  Denmark 184Sunk
22 October 1916 Thor Flag of Norway.svg  Norway 372Sunk
3 November 1916PlutoFlag of Norway.svg  Norway 1,148Captured as prize
16 February 1917 Lady Ann Civil Ensign of the United Kingdom.svg  United Kingdom 1,016Sunk
17 February 1917 Excel Civil Ensign of the United Kingdom.svg  United Kingdom 157Sunk
22 February 1917 John Miles Civil Ensign of the United Kingdom.svg  United Kingdom 687Sunk
29 March 1917 Bywell Civil Ensign of the United Kingdom.svg  United Kingdom 1,522Sunk
31 March 1917NordenFlag of Norway.svg  Norway 776Captured as prize
29 April 1917 Victoria Civil Ensign of the United Kingdom.svg  United Kingdom 1,620Sunk
2 May 1917 Rikard Noordrak Flag of Norway.svg  Norway 1,123Sunk
5 May 1917 Edith Cavell Civil Ensign of the United Kingdom.svg  United Kingdom 20Sunk
6 May 1917 Harold Flag of Sweden.svg  Sweden 1,679Sunk
8 May 1917Batavier IIFlag of the Netherlands.svg  Netherlands 157Captured as prize
6 June 1917 S.N.A. 2 Flag of France.svg  France 2,294Sunk
7 June 1917 Sir Francis Civil Ensign of the United Kingdom.svg  United Kingdom 1,991Sunk
21 July 1917 Trelyon Civil Ensign of the United Kingdom.svg  United Kingdom 3,099Sunk
22 July 1917 Glow Civil Ensign of the United Kingdom.svg  United Kingdom 1,141Sunk
23 July 1917 Vanland Flag of Sweden.svg  Sweden 1,285Sunk
24 August 1917 Springhill Civil Ensign of the United Kingdom.svg  United Kingdom 1,507Sunk
18 October 1917 Amsteldam Civil Ensign of the United Kingdom.svg  United Kingdom 1,233Sunk
19 October 1917 Gemma Government Ensign of the United Kingdom.svg  United Kingdom 1,385Sunk
23 November 1917 Ocean Civil Ensign of the United Kingdom.svg  United Kingdom 1,442Sunk
29 December 1917InvernessCivil Ensign of the United Kingdom.svg  United Kingdom 3,734Damaged
29 December 1917 Patria Flag of Russia.svg  Russian Empire 838Sunk
30 December 1917 Hercules Civil Ensign of the United Kingdom.svg  United Kingdom 1,295Sunk
25 March 1918 Hercules Government Ensign of the United Kingdom.svg  United Kingdom 1,095Sunk
8 May 1918 Constantia Civil Ensign of the United Kingdom.svg  United Kingdom 772Sunk
10 May 1918 Anboto Mendi Flag of Spain.svg  Spain 2,114Sunk
11 May 1918 Gothia Flag of Sweden.svg  Sweden 1,826Sunk
12 May 1918 Haslingden Civil Ensign of the United Kingdom.svg  United Kingdom 1,934Sunk
4 July 1918 Mentor Flag of Norway.svg  Norway 539Sunk
26 September 1918 Paul Flag of Belgium (civil).svg  Belgium 659Sunk

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.
  2. Tonnages are in gross register tons

Citations

  1. 1 2 3 4 5 Rössler 1979, p. 64.
  2. 1 2 3 Gröner 1991, pp. 23–25.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. Bendert 2000, p. 195.
  8. 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.
  9. 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

50°44′28″N1°01′6″W / 50.74111°N 1.01833°W / 50.74111; -1.01833