HMS C31

History
United Kingdom
Name	HMS C31
Builder	Vickers, Barrow
Laid down	7 January 1909
Launched	2 September 1909
Commissioned	19 November 1909
Fate	Sunk by mine, 4 January 1915
General characteristics
Class and type	C-class submarine
Displacement	290 long tons (290 t) surfaced 320 long tons (330 t) submerged
Length	142 ft 3 in (43.4 m)
Beam	13 ft 7 in (4.1 m)
Draught	11 ft 6 in (3.5 m)
Installed power	600 bhp (450 kW) petrol 300 hp (220 kW) electric
Propulsion	1 × 16-cylinder Vickers petrol engine 1 × electric motor
Speed	13 kn (24 km/h; 15 mph) surfaced 8 kn (15 km/h; 9.2 mph) submerged
Range	910 nmi (1,690 km; 1,050 mi) at 12 kn (22 km/h; 14 mph) on the surface
Test depth	100 feet (30.5 m)
Complement	2 officers and 14 ratings
Armament	2 × 18 in (450 mm) bow torpedo tubes

HMS C31 was one of 38 C-class submarines built for the Royal Navy in the first decade of the 20th century. She struck a mine in 1915 and sank with the loss of all hands.

The C-class boats of the 1907–08 and subsequent Naval Programmes were modified to improve their speed, both above and below the surface. The submarine had a length of 142 feet 3 inches (43.4 m) overall, a beam of 13 feet 7 inches (4.1 m) and a mean draft of 11 feet 6 inches (3.5 m). They displaced 290 long tons (290 t) on the surface and 320 long tons (330 t) submerged. The C-class submarines had a crew of two officers and fourteen ratings.^[1]

For surface running, the boats were powered by a single 12-cylinder^[2] 600-brake-horsepower (447 kW) Vickers petrol engine that drove one propeller shaft. When submerged the propeller was driven by a 300-horsepower (224 kW) electric motor.^[1] They could reach 13 knots (24 km/h; 15 mph) on the surface and 8 knots (15 km/h; 9.2 mph) underwater. On the surface, the C class had a range of 910 nautical miles (1,690 km; 1,050 mi) at 12 knots (22 km/h; 14 mph).^[3]

The boats were armed with two 18-inch (45 cm) torpedo tubes in the bow. They could carry a pair of reload torpedoes, but generally did not as they would have to remove an equal weight of fuel in compensation.^[4]

HMS C31 was built by Vickers, Barrow. She was laid down on 7 January 1909 and was commissioned on 19 November 1909. The boat was sunk by a mine off the Belgian coast on 4 January 1915 while patrolling off Zeebrugge. There were no survivors.

• Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN 1-904381-05-7.
• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
• Gardiner, Robert & Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 0-85177-245-5.
• Harrison, A. N. (January 1979). "The Development of HM Submarines From Holland No. 1 (1901) to Porpoise (1930) (BR3043)". RN Subs. Retrieved 27 September 2022.

• HMS C31 Roll of Honour
• 'Submarine losses 1904 to present day' – Royal Navy Submarine Museum Archived 25 September 2015 at the Wayback Machine