See main article: Fremantle-class patrol boat. Starting in the late 1960s, planning began for a new class of patrol boat to replace the Attack class, with designs calling for improved seakeeping capability, and updated weapons and equipment.[1] The Fremantles had a full load displacement of, were long overall, had a beam of, and a maximum draught of .[2] Main propulsion machinery consisted of two MTU series 538 diesel engines, which supplied to the two propeller shafts.[2] Exhaust was not expelled through a funnel, like most ships, but through vents below the waterline. The patrol boat could reach a maximum speed of, and had a maximum range of at .[2] The ship's company consisted of 22 personnel.[2] Each patrol boat was armed with a single 40 mm Bofors gun as main armament, supplemented by two .50 cal Browning machine guns and an 81 mm mortar,[2] although the mortar was removed from all ships sometime in the late 1990s. The main weapon was originally to be two 30-mm guns on a twin-mount, but the reconditioned Bofors were selected to keep costs down; provision was made to install an updated weapon later in the class' service life, but this did not eventuate.[3] [4]
Warrnambool was built by NQEA, Cairns.[2] The ship was laid down on 30 September 1978, launched on 25 October 1980, and commissioned into the RAN on 14 March 1981.[5]
Warrnambool was decommissioned on 29 November 2005.
The patrol boat was broken up for scrap in Darwin during 2006 and 2007, at a cost of $450,000 to the Australian government.