Military Wiki
SM U-31 (Germany)
Career (German Empire)
Name: U-31
Ordered: 29 Mar 1912
Builder: Germaniawerft, Kiel (Werk 191)
Laid down: 12 Oct 1912
Launched: 7 Jan 1914
Commissioned: 18 Sep 1914
Fate: 13 Jan 1915 - Final fate unknown. Possibly mined off E coast of UK. 31 dead (all hands lost).
General characteristics
Class & type: German Type U 31 submarine
Displacement: 685 tons (surfaced)
878 tons (submerged)
971 tons (total)
Length: 64.70 m (overall)
52.36 m (pressure hull)
Beam: 6.32 m (overall)
4.05 m (pressure hull)
Height: 7.68 m
Draught: 3.56 m
Propulsion: Diesel (2 x 950 PS)
Electric (2 x 600 PS)
1850 hp (surfaced)
1200 hp (submerged)
Speed: 16.4 knots (surfaced)
9.7 knots (submerged)
Range: 8790 miles @ 8 kn (surfaced) 80 miles @ 5 kn(submerged)[1]
Test depth: 50 m
Complement: 4 officers
31 crewmen
Service record
Part of: 'Imperial German Navy'
Commanders: Siegfried Wachendorff 1 Aug 1914 - 13 Jan 1915
Operations: 1 patrol

SM U-31 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-31 was engaged in the naval warfare and took part in the First Battle of the Atlantic.

U-31 sailed from Wilhelmshaven on 13 January 1915, and disappeared shortly thereafter. It was assumed she had struck a mine and sunk with all hands, somewhere in the North Sea. But six months after her supposed sinking, she drifted ashore on the British east coast. The entire crew was dead. Upon inspection, it was determined that, while lying on the sea floor, the crew had been overcome by poisonous fumes, and the sub had floated to the surface after her ballast tanks had blown independently.[4]


  1. type U31
  2. Fitzsimons, Bernard, ed. "U-Boats (1905-18)", in The Illustrated Encyclopedia of 20th Century Weapons and Warfare, "(Phoebus Publishing, 1978), Volume 23, p.2534.
  3. Fitzsimons, p.2575; he mistakenly identifies it as 86mm p.2534.
  4. Gilbert, Martin. "The First World War: A Complete History" (Henry Holt & Co., 1994), p. 127.

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