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.

Design and description

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 ft overall, a beam of 13 ft and a mean draft of 11 ft. They displaced 290 LT on the surface and 320 LT submerged. The C-class submarines had a crew of two officers and fourteen ratings. For surface running, the boats were powered by a single 12-cylinder 600 bhp Vickers petrol engine that drove one propeller shaft. When submerged the propeller was driven by a 300 hp electric motor. They could reach 13 kn on the surface and 8 kn underwater. On the surface, the C class had a range of 910 nmi at 12 kn. 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.

Construction and career

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.