HMS C4

HMS C4 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 1922.

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
C4 was built by Vickers at their Barrow-in-Furness shipyard, laid down on 13 November 1905 and was commissioned on 13 March 1907. In 1917 C4 was converted by the secret D.C.B. Section of the Royal Navy's Signals School, Portsmouth into an unmanned remotely operated D.C.B. controlled by an operator in a ‘mother’ aircraft. The boat was the only C class submarine not to be scrapped at the end of World War I, instead she was used for trials and sold on 28 February 1922.