Armament
The four 12-inch muzzle-loading rifles carried as main armament were housed in two pairs in two centre-line turrets on the upper deck, one on either side of the funnel. These guns, each of which weighed 25 long tons (25 t), could fire a shell weighing 600 pounds (270 kg) with a muzzle velocity of 1,380 ft/s (421 m/s). Being situated on the upper deck, at a height of seventeen feet above water, they were seven feet higher than any battery in the fleet, with significant advantage thereby accruing in terms of range and command. Unlike earlier turret-equipped coast-defence ships, training was by steam power.
A good gun crew could fire an aimed shell every two minutes.
To compensate for the inability of the main guns to train either fore or after, two smaller guns of 7 inch calibre were carried in the bow, and one in the stern.
Read more about this topic: HMS Monarch (1868)