HMS Black Prince H.M.S. Black Prince was a Glasgow built ironclad frigate. Once in service, Black Prince was assigned to the Channel Fleet until 1866, then spent a year as flagship on the Irish coast.

Overhauled and re-armed between 1867 and 1868, she became guardship on the Clyde river. The routine of that duty was interrupted in 1869 when she and HMS Warrior towed a large floating dry-dock from the Azores to Bermuda.

Black Prince was again refitted between 1874 and 1875 and rejoined the Channel Fleet for a tour as flagship of that force's second-in-command. Later in the decade she crossed the Atlantic to visit Canada. In reserve from 1878, and reclassified as an armoured cruiser during much of that period, she was reactivated periodically to take part in annual fleet exercises.

Black Prince became a harbour training ship in 1896, stationed at Queenstown, Ireland. She was renamed Emerald in 1903. In 1910 she was taken to Plymouth for use in the training facility there under the name Impregnable III. The old ship was sold for scrap in 1923.