 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.In 1913 all "30 knotter" vessels with 3 funnels were classified by the Admiralty as the "C" class to provide some system to the naming of HM destroyers (at the same time, the 4-funnelled, "30 knotters" became the "B" class and the 2-funnelled ships the "D" class).