but they proved to be significantly lighter as built, displacing at normal load and fully loaded. The ships had an overall length of and a length between perpendiculars of . They had a beam of and a deep draught of forward and aft. The class was over longer overall than the Devonshires and displaced over more. The ships' complement was 769 officers and enlisted men. They rolled quickly with a metacentric height of at deep load and their six-inch guns were as wet as predicted. The cruisers were powered by two 4-cylinder triple-expansion steam engines, each driving one shaft, which produced a total of and gave a maximum speed of . The engines were powered by 20 Babcock & Wilcox water-tube boilers and six cylindrical boilers. The ships carried a maximum of of coal and an additional of fuel oil that was sprayed on the coal to increase its burn rate. At full capacity, they could steam for at a speed of . Armament The Duke of Edinburghs main armament consisted of six 45-calibre BL 9.2-inch Mk X guns in single-gun turrets, a much more powerful gun than used in the Devonshires. The guns were distributed in two centreline turrets, one each fore and one aft of the superstructure, and four wing turrets disposed in the corners about the funnels. The centreline turrets could traverse a total of 285° while the wing turrets were limited to about 120° on the broadside due to muzzle blast. The gun had an elevation range of −5° to +15°. The shell weighed and was fired at a maximum muzzle velocity of . This gave it a range of at maximum elevation. The gun's rate of fire was about three rounds per minute and the ships carried 100 rounds for each gun. Their secondary armament of ten 50-calibre BL 6-inch Mk XI guns was arranged in single embrasures. They were mounted amidships on the main deck and were only usable in calm weather. The guns could only traverse about 120° on the broadside. They initially had a maximum elevation of +13°, but this was later increased to +20°. This gave them a range of at an elevation of +15° with their shell. Each gun was provided with 150 rounds. Twenty Vickers quick-firing (QF) 3-pounder guns were fitted for defence against torpedo boats, six on turret roofs and fourteen in the superstructure, all on pivot mounts.