She was a steam-powered ironclad of revolutionary design, mounting four guns in two large turrets to the fore and aft of her superstructure. This was a drastic break with the traditional design of wooden warships and pointed the way forward to twentieth-century warship design. She was the first British warship to be powered entirely by steam.
The Cerberus was made the flagship of the Victorian Navy and patrolled Melbourne's Port Philip Bay for many years. In 1901, after the federation of the Australian colonies, she was incorporated into the Commonwealth naval forces, and then into the Royal Australian Navy when it was founded in 1911. By this time, however, she was already in poor condition. Her boilers had been condemned in 1906 and her main armament condemned in 1908. She was now used as a floating explosives store until 1921 when she was renamed HMAS Platypus and used for a while as a supply store for Australia's submarine fleet.
In 1924 she was finally sold off and two years later was scuttled in 3 metres of water at Half Moon Bay to act as a breakwater, where she still remains. She is now badly corroded and in very poor shape.
In 1993, during a large storm, the hulk suffered a major collapse. Various plans have been put forward to save her on account of her historical significance, but none have been pursued.
''Length: 225 feet. Displacement: 3,340 tons. Top Speed: 9 knots. Main armament: 4 x 10-inch RML guns''