in 1859, which was installed in the ironclad floating battery, HMS ''Trusty'', for trials in 1861, becoming the first warship to be fitted with a revolving gun turret. Coles's aim was to create a ship with the greatest possible all round arc of fire, as low in the water as possible to minimise the target.

The Admiralty accepted the principle of the turret gun as a useful innovation, and incorporated it into other new designs. Coles submitted a design for a ship having ten domed turrets each