HMAS Onslow - Decommissioning and Preservation

Decommissioning and Preservation

Onslow was decommissioned from service on 30 March 1999. While in service, Onslow travelled 358,068 nautical miles (663,142 km; 412,057 mi). On the same day, sister boat Otama was permanently reassigned to the submarine base at HMAS Stirling in Western Australia, clearing the way for the closure of HMAS Platypus.

On 3 May 1999, the submarine was towed from Platypus to the Australian National Maritime Museum at Darling Harbour. Onslow was docked next to HMAS Vampire, another warship belonging to the museum, and was officially opened to the public on 1 June 1999. Onslow is the second RAN submarine to be preserved as a museum ship; the first was sister submarine HMAS Ovens, which was decommissioned at the end of 1998 and installed at the Western Australian Maritime Museum. As of 2004, she is one of seven Oberon class submarines preserved in this manner.

On 22 November 2002, Onslow was taken by tugs to Garden Island for three weeks of maintenance in drydock. This included cleaning and repainting of the hull, replacement of the tributyltin coating used to prevent biofouling with a coating that was not harmful to marine organisms, and the sealing of several ballast tanks to improve the boat's stability and raise the aft section relative to the waterline. Onslow was returned to the museum on 11 December, and re-opened to the public three days later. In October and November 2008, Onslow returned to Garden Island for maintenance and upkeep. During this refit, an additional torpedo was loaded into the submarine's torpedo tubes and her hull was cleaned and painted. Another docking occurred on 18 May 2012, with hull cleaning, rust removal, repainting, and repairs to the boats aft torpedo tubes to occur before she returns to display on 6 June.