The HMVS Cerberus is a breakwater shipwreck that served as part of the Victorian Naval Forces when Australia was still a British colony and also as part of the Royal Australian Navy until 1924. It now rests just off the coast as a rusting scrap.

Named for Cerberus, the ferocious three-headed dog that guards the entrance to Hades, this 225-foot-long warship was built for the colony of Victoria in 1870. It was the first “breastwork monitor,” an innovation of designer Edward James Reed. As such, the ship inclu ded a central, armored structure that contained rotating gun turrets, the bridge, funnels, and all other necessary operational pieces. This both lessened the chance that the ship would be sunk by breaking waves and placed its weapons at a strategically elevated height.

Those weapons were never tested however. Although the HMVS Cerberus was one of the jewels of the Royal Australian Navy, she never left her home port of Philip Bay or saw any action, even though she was on active duty for over half a century. By World War I, her status as a warship was revoked, and she became a guardship and munitions store. Before being permanently retired in 1924, she also had a brief stint supplying submarines. 

In 1924, the ship was sold for scrap at a price of £409. Her stripped-down hull was then resold for an entire £150. She was scuttled in Half Moon Bay in 1926 to serve as a breakwater, her mass reducing the intensity of the waves on the beach in front of the Black Rock Yacht Club. For many years, however, she remained valuable as an attraction. The wreck is only about 180 metres (200 yards) from the shore, so for the period of time when the upper decks remained exposed, visitors would come out for picnics, exploration, and scuba diving. Following a structural collapse in 1993, things are now more precarious. Although HMVS Cerebus has started to sink under the water, the tough old broad remains visible from shore. A flag on top of her smoke stack still proudly waves in the sea breeze.