HMS C11 was one of 38 C-class submarines built for the Royal Navy in the first decade of the 20th century. The boat was lost after being rammed in 1909.

Design and description

The C class was essentially a repeat of the preceding B class, albeit with better performance underwater. The submarine had a length of 142 ft overall, a beam of 13 ft and a mean draft of 11 ft. They displaced 287 LT on the surface and 316 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 16-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 12 kn on the surface and 7 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

C11 was built by Vickers at their Barrow-in-Furness shipyard, laid down on 6 April 1906 and was commissioned on 3 September 1907. The boat was sunk in a collision with the collier Eddystone in the North Sea south of Cromer, Norfolk on 14 July 1909. There were only three survivors. Attempts were made to salvage the stricken submarine but they were abandoned in September 1909, after only a single body had been recovered. The wreck was rediscovered in the late 1990s.