The turret was first used in naval combat on the USS "Monitor" in 1862, with a type of turret designed by the Swedish engineer John Ericsson. A competing turret design was proposed by the British inventor Cowper Coles with a prototype of this installed on HMS "Trusty" in 1861 for testing and evaluation purposes. Ericsson's turret turned on a central spindle, and Coles's turned on a ring of bearings. Turrets offered the maximum arc of fire from the guns, but there were significant problems with their use in the 1860s. The fire arc of a turret would be considerably limited by masts and rigging, so they were unsuited to use on the earlier ocean-going ironclads. The second problem was that turrets were extremely heavy. Ericsson was able to offer the heaviest possible turret (guns and armor protection) by deliberately designing a ship with very low freeboard. The weight thus saved from having a high broadside above the waterline was diverted to actual guns and armor. Low freeboard, however, also meant a smaller hull and therefore a smaller capacity for coal storage—and therefore range of the vessel. In many respects, the turreted, low-freeboard "Monitor" and the broadside sailer HMS "Warrior" represented two opposite extremes in what an 'Ironclad' was all about. The most dramatic attempt to compromise these two extremes, or 'squaring this circle', was designed by Captain Cowper Phipps Coles: HMS "Captain", a dangerously low freeboard turret ship which nevertheless carried a full rig of sail, and which subsequently capsized not long after her launch in 1870. Her half-sister was restricted to firing from her turrets only on the port and starboard beams. The third Royal Navy ship to combine turrets and masts was of 1876, which carried two turrets on either side of the centre-line, allowing both to fire fore, aft and broadside.