HMS Acheron was to have been a screw sloop. She was laid down in 1861 but she was cancelled in 1863 before her launch.
HMS Northumberland was an ironclad frigate launched in 1866. She became a base ship in 1898 and was renamed HMS Acheron in 1904. She was hulked as C8 in 1908, renamed C68 in 1926, was sold in 1927, and resold as the hulk Stedmound.