HMS Hercules was a central-battery ironclad of the Royal Navy in the Victorian era, and was the first warship to mount a main armament of 10-inch (250 mm) calibre guns.

She was designed by Sir Edward Reed, and was in all significant factors an enlarged version of his earlier creation HMS Bellerophon with thicker armour and heavier guns.

She had a pointed ram where previous ships had sported a rounded one; she was built with a forecastle, but had no poop until fitted with one as preparation for her role as Flagship, Mediterranean Fleet.

Paid off at Portsmouth, she was re-commissioned as Flagship of the Particular Service Squadron formed under the command of Admiral Astley Cooper Key at the time of the Russian war scare in 1878.

From March to June 1902 she served temporarily as port guard ship at Portland with the crew of the permanent guardship HMS Revenge, which was in for a refit.

[4] In July the same year she was temporarily commissioned by Captain John de Robeck, who transferred to HMS Warrior when it had finished a refit to become depot ship.

In July 1914 she arrived at Devonport in tow of the old cruiser HMS Sutlej,[6] Calcutta's engines being by this time inoperable, and in April 1915 she became an artificers' training establishment at Portsmouth under the name of Fisgard II.

With the Morecambe facility to close in April 1923, only limited demolition was carried out there, and on 1 December 1922 the hulk was towed to Wards' Preston yard where breaking up was completed.