Monitor's two guns stood up to a ship carrying ten despite a reload interval of about seven minutes. A revolving turret could serve both sides of a ship, reducing the number of guns needed for an equivalent broadside. Heavy armored mountings created stability problems, however, and masts and rigging obstructed their firing arcs. Cowper Coles had patented a turret in 1859 and promoted lower mountings after objecting to the high freeboard and restricted end-on fire of HMS Monarch. His HMS Captain combined low freeboard and heavy turrets with a full sailing rig, then capsized off Spain in September 1870 with all but 18 men lost, including Coles. Edward Reed's HMS Devastation removed the sailing rig and relied entirely on steam. She still had very low freeboard, with an armored breastwork protecting the central part of the ship and two turrets each carrying a pair of 12-inch muzzle-loading rifles. Up to 1,800 tons of coal supported her intended ocean-going role.
Chapter · 2:02:40-2:06:24
From Monitor's turret to HMS Captain and Devastation
Turret firing arcs promised fewer guns, while Captain's loss and Devastation's layout exposed the costs of combining armament with sail.