HMS C7

HMS C7 was one of 38 C-class submarines built for the Royal Navy in the first decade of the 20th century. The boat survived the First World War and was sold for scrap in 1920.

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
C7 was built by Vickers at their Barrow-in-Furness shipyard, laid down on 9 December 1905 and was commissioned on 23 May 1907. The boat is often mistakenly credited with sinking SM UC-68 on 5 April 1917 off the coast of The Netherlands. However, this attack was made against SM UB-10, which survived. C7 was sold on 20 December 1919.