The turrets were placed one at each end of this breastwork, with the funnels, ventilators, and so on, between them. The breastwork deck, as it was called, was strongly plated as compared with the main-deck plating of all existing ironclads, and the protective plating of the upper deck was from two to three inches thick. Above the turrets was the usual hurricane deck. She carried two 30-ton guns in each turret, the guns being of an Armstrong type improved upon at Woolwich, and throwing projectiles weighing 600 lb., and of the Palliser pointed type. Her two turrets gave her an absolutely all-round fire, a consummation which was impossible with any vessel depending at all upon sails. Her engines, which constituted her sole motive power, were the largest which had yet been applied to working twin screws and were each of 800 h.p. nominal, and gave her a speed of twelve and a half knots. [Illustration: H.M.S. “DEVASTATION.” _Photograph by Symonds & Co. Portsmouth._] She was 285 feet in length between perpendiculars, with an inside beam amidships of 58 feet, and an extreme beam of 62 feet 3 inches, with an average draught of 26 feet. The depth from the midship portion of the covering-in deck to the top of the keel was 18 feet. The double bottom contained the water-tanks, and above these were a series of watertight compartments containing the engines and so on, and above these again were another series of watertight compartments used as coal bunkers and lockers, and another series, formed of watertight bulkheads, enclosed the officers’ accommodation. They were said to be as strongly constructed as the strong room of a bank.