HMVS Cerberus
HMVS Cerberus (Her Majesty's Victorian Ship) is a breastwork monitor that served in the Victoria Naval Forces, the Commonwealth Naval Forces (CNF), and the Royal Australian Navy (RAN) between 1871 and 1924.
Built for the colony of Victoria under the supervision of Charles Pasley, Cerberus was completed in 1870, and arrived in Port Phillip in 1871, where she spent the rest of her career. The monitor was absorbed into the CNF following Federation in 1901, and was renamed HMAS Cerberus when the navy became the RAN in 1911. In 1921, the ship was renamed HMAS Platypus II.
In 1924, the monitor was sold for scrap, and was sunk as a breakwater off Half Moon Bay. The wreck became a popular site for scuba diving and picnics over the years, but there was a structural collapse in 1993. The upper part of the vessel is still visible. There have been several campaigns to preserve the ship. (one of which is ongoing), as she is one of the last monitors, the only surviving ship of the Australian colonial navies, and one of only two surviving ships in the world with Coles turrets.
Built by Palmers Shipbuilding and Iron Co at Jarrow shipyard on the Tyne. She was laid down on 1 August 1867, launched on 2 December 1868, and completed in August 1870. Engines by Maudslay, Sons and Field. The shortcomings of the ship in storms, heavy seas, and high temperatures became very apparent of her voyage to Victoria.
For the source of the above, and much more information, see Wikipedia entry.
The Friends of the Cerberus website has links to a wealth of information about the ship.