Fisher's 33-knot requirement and a builder competition

Fisher demanded oil-fired steam turbines and 33 knots from ships displacing under 1,000 tons, accepting limited fuel and armament to obtain speed. The target preserved roughly a six-knot margin over the planned cruiser line. Rather than impose one detailed design, the Admiralty issued specifications to Armstrong Whitworth, Cammell Laird, Hawthorn Leslie, J. Samuel White, and Thornycroft so that each yard could propose its own solution. Follow-on contracts were divided rather than awarded wholesale to a single winner, while yards such as Armstrong Whitworth soon received larger cruiser work. The resulting class functioned as a relatively inexpensive technology demonstrator whose machinery lessons could inform later destroyers and the oil-fired, turbine-powered Queen Elizabeth-class battleships.