German submarine U-31 (1936)
U-33, a typical Type VIIA boat
|Ordered:||1 April 1935|
|Builder:||AG Weser, Bremen|
|Laid down:||1 March 1936|
|Launched:||25 September 1936|
|Commissioned:||28 December 1936|
|Recommissioned:||30 July 1940|
|Decommissioned:||24 March 1940|
|Class and type:||Type VIIA submarine|
|Height:||9.50 m (31 ft 2 in)|
|Draught:||4.37 m (14 ft 4 in)|
|Complement:||4 officers, 40–56 enlisted|
|Sensors and |
|Identification codes:||M 28 961|
German submarine U-31 was a Type VIIA U-boat of Nazi Germany's Kriegsmarine during World War II. She was laid down on 1 March 1936 as yard number 912, launched on 25 September and commissioned on 28 December 1936.
As one of the first ten German Type VII submarines later designated as Type VIIA submarines, U-31 had a displacement of 626 tonnes (616 long tons) when at the surface and 745 tonnes (733 long tons) while submerged. She had a total length of 64.51 m (211 ft 8 in), a pressure hull length of 45.50 m (149 ft 3 in), a beam of 5.85 m (19 ft 2 in), a height of 9.50 m (31 ft 2 in), and a draught of 4.37 m (14 ft 4 in). The submarine was powered by two MAN M 6 V 40/46 four-stroke, six-cylinder diesel engines producing a total of 2,100 to 2,310 metric horsepower (1,540 to 1,700 kW; 2,070 to 2,280 shp) for use while surfaced, two BBC GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 17 knots (31 km/h; 20 mph) and a maximum submerged speed of 8 knots (15 km/h; 9.2 mph). When submerged, the boat could operate for 73–94 nautical miles (135–174 km; 84–108 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 6,200 nautical miles (11,500 km; 7,100 mi) at 10 knots (19 km/h; 12 mph). U-31 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), eleven torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and an anti-aircraft gun. The boat had a complement of between forty-four and sixty.
On 11 March 1940 U-31 was sunk in the Schillig Roads near buoy 12 (53°37′N 08°10′E / 53.617°N 8.167°E) by four bombs from a Bristol Blenheim, O of No. 82 Squadron RAF, with the loss of 58 lives . The U-boat had been on trials and carried eleven workers from the shipyard and two assistants to the flotilla engineer in addition to her regular complement.
In U-31's entire career she sank eleven ships, totalling 27,751 gross register tons (GRT), and one auxiliary warship of 160 GRT. A mine laid by U-31 damaged the British battleship HMS Nelson of 33,950 tons.
Summary of raiding history
|Date||Name of Ship||Nationality||Tonnage||Fate|
|16 September 1939||Aviemore||United Kingdom||4,060||Sunk|
|24 September 1939||Hazelside||United Kingdom||4,646||Sunk|
|1 December 1939||Arcturus||Norway||1,277||Sunk|
|3 December 1939||Ove Taft||Denmark||2,135||Sunk|
|4 December 1939||HMS Nelson||Royal Navy||33,950||Damaged (mine)|
|4 December 1939||Primula||Norway||1,024||Sunk|
|6 December 1939||Agu||Estonia||1,575||Sunk|
|6 December 1939||Vinga||Sweden||1,974||Sunk|
|23 December 1939||HMS Glen Albyn||Royal Navy||82||Sunk (mine)|
|23 December 1939||HMS Promotive||Royal Navy||78||Sunk (mine)|
|22 September 1940||Union Jack||Faroe Islands||81||Sunk|
|27 September 1940||Vestvard||Norway||4,319||Sunk|
|29 October 1940||Matina||United Kingdom||5,389||Sunk|
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- Kemp 1999, p. 67.
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- 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). IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
- Helgason, Guðmundur. "The Type VIIA boat U-31". German U-boats of WWII - uboat.net. Retrieved 8 December 2014.
- Hofmann, Markus. "U 31". Deutsche U-Boote 1935-1945 - u-boot-archiv.de (in German). Retrieved 7 December 2014.