The Courageous class comprised three battlecruisers built for the Royal Navy during World War I. Nominally designed to support Admiral of the Fleet Lord John Fisher's Baltic Project, which was intended to land troops on the German Baltic Coast, ships of this class were fast but very lightly armoured with only a few heavy guns. To maximize their speed, the Courageous-class battlecruisers were the first capital ships of the Royal Navy to use geared steam turbines and small-tube boilers. The first two ships, Courageous and Glorious, were commissioned in 1917 and spent the war patrolling the North Sea. Their half-sister Furious was designed with a pair of -inch (mm) guns, the largest guns ever fitted on a ship of the Royal Navy, but was modified during construction to take a flying-off deck an