German submarine U-21 (1936)

German submarine U-21 was a Type IIB U-boat of Nazi Germany's Kriegsmarine. Her keel was laid down 4 March 1936, by Germaniawerft of Kiel as yard number 551. She was commissioned on 3 August 1936. During World War II, she conducted operations against enemy shipping.

U-9, a typical Type IIB boat
History
Nazi Germany
NameU-21
Ordered2 February 1935
BuilderGermaniawerft, Kiel
Yard number551
Laid down4 March 1936
Launched31 July 1936
Commissioned3 August 1936
FateDecommissioned on 5 August 1944 at Pillau and cannibalized for spare parts
General characteristics
Class and typeType IIB coastal submarine
Displacement
  • 279 t (275 long tons) surfaced
  • 328 t (323 long tons) submerged
Length
Beam
  • 4.08 m (13 ft 5 in) (o/a)
  • 4.00 m (13 ft 1 in) (pressure hull)
Height8.60 m (28 ft 3 in)
Draught3.90 m (12 ft 10 in)
Installed power
  • 700 PS (510 kW; 690 bhp) (diesels)
  • 410 PS (300 kW; 400 shp) (electric)
Propulsion
Speed
  • 13 knots (24 km/h; 15 mph) surfaced
  • 7 knots (13 km/h; 8.1 mph) submerged
Range
  • 1,800 nmi (3,300 km; 2,100 mi) at 12 knots (22 km/h; 14 mph) surfaced
  • 35–43 nmi (65–80 km; 40–49 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth80 m (260 ft)
Complement3 officers, 22 men
Armament
Service record
Part of:
Commanders:
  • Kptlt. Kurt Freiwald
  • 18 July 1935 – 3 October 1937
  • Kptlt. Werner Lott
  • September 1936 – 31 March 1937
  • Kptlt. Wilhelm Ambrosius
  • 1937
  • Kapt.z.S. Erwin Sachs
  • 1937
  • Kptlt. Fritz Frauenheim
  • 1 October 1937 – 6 January 1940
  • Wolf-Harro Stiebler
  • 6 January – 28 July 1940
  • Oblt.z.S. Hans Heidtmann
  • 1 August – 20 December 1940
  • Kptlt. Ernst-Bernard Lohse
  • 21 December 1940 – 18 May 1941
  • Oblt.z.S. Karl-Heinz Herschleb
  • 19 May 1941 – 3 January 1942
  • Oblt.z.S. Hans-Heinrich Döhler
  • 4 January – 24 September 1942
  • Lt.z.S. Hans-Ferdinand Geisler
  • 25 September 1942 – 28 January 1943
  • Oblt.z.S. Rudolf Kugelberg
  • 29 January 1943 – 11 May 1944
  • Oblt.z.S. Wolfgang Schwarzkopf
  • 12 May – 5 August 1944
Operations:
  • 7 patrols:
  • 1st patrol:
  • 25 August – 5 September 1939
  • 2nd patrol:
  • a. 9 September – 1 October 1939
  • b. 2 – 3 Oct 1939
  • 3rd patrol:
  • 22 October – 8 November 1939
  • 4th patrol:
  • 27 November – 5 December 1939
  • 5th patrol:
  • 17 – 24 December 1939
  • 6th patrol:
  • 27 January – 9 February 1940
  • 7th patrol:
  • a. 21 – 27 March 1940
  • b. 16 – 20 April 1940
Victories:
  • 5 merchant ships sunk
    (10,706 GRT)
  • 1 auxiliary warship sunk
    (605 GRT)
  • 1 warship damaged
    (11,500 tons)

U-21 went on seven war patrols, sinking five ships, one auxiliary warship and damaging one warship.

Design

German Type IIB submarines were enlarged versions of the original Type IIs. U-21 had a displacement of 279 tonnes (275 long tons) when at the surface and 328 tonnes (323 long tons) while submerged. Officially, the standard tonnage was 250 long tons (250 t), however.[1] The U-boat had a total length of 42.70 m (140 ft 1 in), a pressure hull length of 28.20 m (92 ft 6 in), a beam of 4.08 m (13 ft 5 in), a height of 8.60 m (28 ft 3 in), and a draught of 3.90 m (12 ft 10 in). The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700 metric horsepower (510 kW; 690 shp) for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460 metric horsepower (340 kW; 450 shp) for use while submerged. She had two shafts and two 0.85 m (3 ft) propellers. The boat was capable of operating at depths of up to 80–150 metres (260–490 ft).[1]

The submarine had a maximum surface speed of 12 knots (22 km/h; 14 mph) and a maximum submerged speed of 7 knots (13 km/h; 8.1 mph).[1] When submerged, the boat could operate for 35–42 nautical miles (65–78 km; 40–48 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 3,800 nautical miles (7,000 km; 4,400 mi) at 8 knots (15 km/h; 9.2 mph). U-21 was fitted with three 53.3 cm (21 in) torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a 2 cm (0.79 in) anti-aircraft gun. The boat had a complement of twentyfive.[1]

Operational history

First, second and third patrols

U-21's first patrol was relatively uneventful.

On her second foray, the boat was attacked by the British submarine HMS Ursula which fired six torpedoes at her in the North Sea northeast of Berwick-Upon-Tweed [On the English/Scottish border] on 17 September 1939. These were the first submarine weapons launched by the Royal Navy in the Second World War. They all missed.

On her third patrol, the U-boat also had torpedoes fired at her in the central North Sea by another British submarine, HMS Sealion. The result was inconclusive as well.

Fourth and fifth patrols

The boat's first success with a torpedo came on 1 December 1939 when she sank the Finnish-registered Mercator about 12 nmi (22 km; 14 mi) southeast of Buchan Ness (near Peterhead). She also damaged the British cruiser HMS Belfast with a mine.

On her fifth sortie, she sank Mars on 21 December 1939 and Carl Henckel (both from Sweden), on the same day. She also sank the British boom defence vessel HMS Bayonet in the Firth of Forth,[2] again with a mine.

Sixth patrol

Patrol number six saw her sink the Danish Vidar 100 nmi (190 km; 120 mi) east of the Moray Firth[3] on 31 January 1940.

Seventh patrol

She sank the British Royal Archer with a mine on 26 February 1940, but then it all went horribly wrong on 27 March when she ran aground off Oldknuppen Island after a navigational error. The boat was towed to Mandal in Norway where she was interned. She was then towed to Kristiansand for repairs and released on 9 April after the German occupation of the Nordic country.

Fate

In July she was transferred to the 21st U-boat Flotilla in Kiel as a training boat, with whom she remained for the rest of the war. U-21 was scrapped in February 1945.[4]

Summary of raiding history
Date Name Nationality Tonnage[Note 1] Fate[5]
21 November 1939 HMS Belfast  Royal Navy 11,500 Damaged (mine)
1 December 1939 Mercator  Finland 4,260 Sunk
21 December 1939 Carl Henckel  Sweden 1,352 Sunk
21 December 1939 HMS Bayonet  Royal Navy 605 Sunk (mine)
21 December 1939 Mars  Sweden 1,475 Sunk
31 January 1940 Vidar  Denmark 1,353 Sunk
24 February 1940 Royal Archer  United Kingdom 2,266 Sunk (mine)

References

Notes
  1. Merchant ship tonnages are in gross register tons. Military vessels are listed by tons displacement.

Citations
  1. Gröner 1991, pp. 39–40.
  2. The Times Atlas of the World – Third edition, revised 1995, ISBN 0 7230 0809 4, p. 10
  3. The Times Atlas of the World, p. 10
  4. Helgason, Guðmundur. "The Type II boat U-21". German U-boats of WWII – uboat.net. Retrieved 6 December 2014.
  5. Helgason, Guðmundur. "Ships hit by U-21". German U-boats of WWII – uboat.net. Retrieved 29 December 2014.

Bibliography
  • Busch, Rainer; Röll, Hans-Joachim (1999). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN 1-55750-186-6.
  • Busch, Rainer; Röll, Hans-Joachim (1999). Deutsche U-Boot-Verluste von September 1939 bis Mai 1945 [German U-boat losses from September 1939 to May 1945]. Der U-Boot-Krieg (in German). Vol. IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
  • 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.
  • Helgason, Guðmundur. "The Type II boat U-21". German U-boats of WWII – uboat.net. Retrieved 6 December 2014.
  • Hofmann, Markus. "U 21". Deutsche U-Boote 1935–1945 – u-boot-archiv.de (in German). Retrieved 6 December 2014.

41°10′N 30°47′E

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