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.

Along with her sisters C36 and C37, C38 was transferred to Hong Kong in February 1911 to operate with the Royal Navy's China Squadron.