The C class as designated in 1913 was a heterogeneous group of torpedo boat destroyers (TBDs) built for the Royal Navy in the late-1890s. They were constructed to the individual designs of their builders to meet Admiralty specifications. The uniting feature of the class was a top speed of 30 knots, a "turtleback" forecastle and that they all had three funnels. The funnels were spaced equidistantly and were of equal height, but the central one was thicker.

The B class as designated in 1913 was a heterogeneous group of torpedo boat destroyers (TBDs) built for the Royal Navy in the late 1890s. They were constructed to the individual designs of their builders to meet Admiralty specifications, the uniting feature being a specified top speed of 30 knots (56 km/h) and four funnels, although the funnel spacings differed between ships. All "30 knotter" vessels with four funnels were classified by the Admiralty as the B class in 1913 to provide some system to the naming of HM destroyers. At the same time all "30 knotter" vessels with three funnels were classified by the Admiralty as the C class and those with two funnels became the D class.