How the J class became the wartime design baseline

Henderson pressed for destroyers with enough firepower to make the fleet screen harder to penetrate. The J, K and N classes developed features of the Tribal design and earlier destroyers, continuing a line of development that began with the late-1920s A class. The J-class hull and machinery arrangement became a pattern for the emergency ships. The tally here is 114 emergency hulls derived from that pattern. The design reflected the Royal Navy's operating areas and doctrine.