The C-class boats of the 1907–08 and subsequent Naval Programmes were modified to improve their speed, both above and below the surface.

[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.

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).

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.

During World War I, the boat was generally used for coastal defence and training in home waters.