Sister ship Warrior. Iron hull. Built as the British answer on the French ironclad Gloire. Designed by Chief Constructor of the Navy Isaac Watts and Chief engineer Thomas Lloyd. Building ordered on 6 October 1859, laid down by Robert Napier and Sons, Govan, Scotland on 12 October 1859, launched on 27 February 1861, sea trials in September 1862, completed on 27 September 1862, commissioned in May 1862, refitted in 1874-1875, reclassified as training ship in 1896, hulked and became harbour training ship at Queenstown, renamed Emerald in 1903, renamed Impregnable III and stationed at Plymouth in 1910 and sold to be broken up on 21 February 1923.
With a displacement of 9.284 tons and as dimensions 128 (over all) x 17,8 x 8,2 metres or 420 x 58.4 x 26.10 feet. Machinery consisted of 1 5.772ihp 2 cylinder Trunk steam engine of John Penn and Sons and 10 rectangular boilers allowing with the single shaft a speed of 13 (under sail)-17,5 (sail+steam) knots. With a speed of 11 knots and a coal bunker capacity of 867 tons was her range 2.100 nautical miles. Ship rigged with a sail area of 4.497 square metres/48.400 square feet. Crew numbered 706 men. Armour consisted of a 11,4cm/4.5” thick belt and bulkheads. Armament consisted of 26-20,6cm/8.1”/58 pound smoothbore muzzle loading guns, 10-17,8cm/7”/110 pound rifled breech loading guns and 4-12,1cm/4.77”/40 pound rifled breech loading guns.
