 The foremost torpedo tube was sited between the second and third funnels, a distinctive feature of this class.There were twelve 'standard' vessels built to a common Admiralty design, and eight builders' specials that (except for "Garland") had a shorter, less beamy hull; five of the latter were from Thornycroft with (one of Thornycroft's ships, , was planned to diesel cruising motors, but these were not ready in time and "Hardy" was completed with Thornycroft's standard machinery).One by Parsons () had semi-geared turbines giving a speed of on trials, with a seventh from Fairfields had a clipper bow.