SM UB-31

SM UB-45 a u-boat similar to UB-31
History
German Empire
Name:	UB-31
Ordered:	22 July 1915
Builder:	Blohm & Voss, Hamburg
Cost:	1,152,000 German Papiermark
Yard number:	255
Launched:	16 November 1915
Completed:	24 March 1916
Commissioned:	25 March 1916
Fate:	sunk 2 May 1918 by British warships
General characteristics
Class and type:	German Type UB II submarine
Displacement:	274 t (270 long tons) surfaced 303 t (298 long tons) submerged
Length:	36.90 m (121 ft 1 in) o/a 27.90 m (91 ft 6 in) pressure hull
Beam:	4.37 m (14 ft 4 in) o/a 3.85 m (12 ft 8 in) pressure hull
Draught:	3.69 m (12 ft 1 in)
Propulsion:	1 × propeller shaft 2 × 6-cylinder diesel engine, 270 PS (200 kW; 270 bhp) 2 × electric motor, 280 PS (210 kW; 280 shp)
Speed:	9.06 knots (16.78 km/h; 10.43 mph) surfaced 5.71 knots (10.57 km/h; 6.57 mph) submerged
Range:	7,030 nmi (13,020 km; 8,090 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 depth:	50 m (160 ft)
Complement:	2 officers, 21 men
Armament:	2 × 50 cm (19.7 in) torpedo tubes 4 × torpedoes (later 6) 1 × 8.8 cm (3.5 in) deck gun
Notes:	42-second diving time
Service record
Part of:	Imperial German Navy: Baltic Flotilla 16 May 1916 – 24 February 1917 Flandern Flotilla 24 February 1917 – 2 May 1918
Commanders:	Oblt.z.S. Karl Vesper 18 March – 11 August 1916 Oblt.z.S. Thomas Bieber 12 August 1916 – 31 January 1918 Oblt.z.S. Wilhelm Braun 1 February – 2 May 1918
Operations:	25 patrols
Victories:	26 merchant ships sunk (72,684 GRT) 8 merchant ships damaged (34,699 GRT)

SM UB-31 was a German Type UB II submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The U-boat was ordered on 22 July 1915 and launched on 16 November 1915. She was commissioned into the German Imperial Navy on 25 March 1916 as SM UB-31.

The submarine sank 26 ships in 25 patrols. UB-31 was depth charged and sunk by British warships HMS Lord Leitrim, HMS Loyal Friend, and HMS Ocean Roamer in the English Channel on 2 May 1918.

A German Type UB II submarine, UB-31 had a displacement of 274 tonnes (270 long tons) when at the surface and 303 tonnes (298 long tons) while submerged. She had a total length of 36.90 m (121 ft 1 in), a beam of 4.37 m (14 ft 4 in), and a draught of 3.69 m (12 ft 1 in). The submarine was powered by two Benz six-cylinder diesel engines producing a total 270 metric horsepower (270 shp; 200 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).

The submarine had a maximum surface speed of 9.06 knots (16.78 km/h; 10.43 mph) and a maximum submerged speed of 5.71 knots (10.57 km/h; 6.57 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 7,030 nautical miles (13,020 km; 8,090 mi) at 5 knots (9.3 km/h; 5.8 mph). UB-31 was fitted with two 50 centimetres (20 in) torpedo tubes, four torpedoes, and one 8.8 cm (3.5 in) Uk L/30 deck gun. She had a complement of twenty-one crew members and two officers and a 42-second dive time.