SM U-31 (Germany)

History
German Empire
Name	U-31
Ordered	29 March 1912
Builder	Germaniawerft, Kiel
Yard number	191
Laid down	12 October 1912
Launched	7 January 1914
Commissioned	18 September 1914
Fate	c. 13 January 1915 – Mined in the North Sea; all hands lost.
General characteristics
Class and type	Type U 31 submarine
Displacement	685 t (674 long tons) (surfaced) 878 t (864 long tons) (submerged)
Length	64.70 m (212 ft 3 in) (o/a) 52.36 m (171 ft 9 in) (pressure hull)
Beam	6.32 m (20 ft 9 in) (o/a) 4.05 m (13 ft 3 in) (pressure hull)
Draught	3.56 m (11 ft 8 in)
Installed power	2 × 1,850 PS (1,361 kW; 1,825 shp) diesel engines 2 × 1,200 PS (883 kW; 1,184 shp) Doppelmodyn
Propulsion	2 × shafts 2 × 1.60 m (5 ft 3 in) propellers
Speed	16.4 knots (30.4 km/h; 18.9 mph) (surfaced) 9.7 knots (18.0 km/h; 11.2 mph) (submerged)
Range	8,790 nmi (16,280 km; 10,120 mi) at 8 knots (15 km/h; 9.2 mph) (surfaced) 80 nmi (150 km; 92 mi) at 5 knots (9.3 km/h; 5.8 mph) (submerged)
Test depth	50 m (164 ft 1 in)
Boats & landing craft carried	1 dinghy
Complement	4 officers, 31 enlisted
Armament	four 50 cm (20 in) torpedo tubes (2 each bow and stern) 6 torpedoes
Service record
Part of:	IV Flotilla 18 September 1914 – 13 January 1915
Commanders:	Oblt.z.S. Siegfried Wachendorff[1] 1 August 1914 – 13 January 1915
Operations:	1 patrol
Victories:	None

SM U-31^{[Note 1]} 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 but disappeared shortly thereafter. It was assumed, correctly, she had struck a mine, and sunk with all hands somewhere in the North Sea.

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