The D class as they were known from 1913 was a fairly homogeneous group of torpedo boat destroyers (TBDs) built for the Royal Navy in the mid-1890s. They were all constructed to the individual designs of their builder, John I. Thornycroft & Company of Chiswick, to meet Admiralty specifications. The uniting feature of the class was a top speed of and they all had two funnels. In 1913 the nine surviving "30 knotter" vessels with two funnels (all ten had been built by Thornycroft, but Ariel was lost before their renaming as "D" class) were retrospectively classified by the Admiralty as the "D" class to provide some system to the naming of HM destroyers. In the same way those with three funnels were classified as the "C" class and those with four funnels as the "B" class. All these vessels had