River-class torpedo-boat destroyer

The River class was a class of six torpedo-boat destroyers operated by the Royal Australian Navy. Three were ordered for the Commonwealth Naval Forces (the post-Federation amalgamation of the Australian colonial navies) in 1909; two were built in the United Kingdom, while a third was partially built, disassembled, then transported to Australia for reassembly. Another three ships were later ordered. All six ships were operated during World War I, but were disposed of during the late 1920s and early 1930s. Three were sunk as target ships, while the other three were used as accommodations ships, but later ran aground or sank.

Design and construction
Three ships, HMAS Parramatta (D55), HMAS Yarra (D79) and HMAS Warrego (D70), were ordered on 6 February 1909; the first ships to be ordered for the Commonwealth Naval Forces, the post-Federation amalgamation of the Australian colonial navies. Another three ships, HMAS Huon (D50), HMAS Swan (D61), and HMAS Torrens (D67), were ordered later. All six ships of the class were named after Australian rivers (one from each state), starting a tradition in the Royal Australian Navy of naming ships after the rivers of Australia.

Based on the British Acheron class, these destroyers had a displacement of 750 tons. The first three had a length overall of 246 ft, while the second three were longer at 250 ft. They were powered by three Yarrow oil-burning boilers connected to Parsons turbines, which delivered 10000 shp to three propeller shafts. Cruising speed was 11.5 kn, giving the ship a range of 2690 nmi, and maximum speed was 26 kn. Each ship's company consisted of between 66 and 73 personnel, including five officers.

The destroyers' main armament consisted of a single BL 4-inch Mark VIII naval gun, supplemented by three QF 12 pounder 12 cwt naval guns. They were also fitted with three .303-inch machine guns and three single 18-inch torpedo tubes.

Parramatta and Yarra were built in the United Kingdom, and were the first new ships launched for the Australian navy. After completion, the two vessels were temporarily commissioned into the Royal Navy for the delivery voyage to Australia, although they reverted to the control of the Commonwealth Naval Forces on arrival in Broome. Warrego, however, was built up to launch condition, then disassembled, transported to Australia by ship, and rebuilt at Cockatoo Island Dockyard: the reasoning behind this was to raise the standard of the Australian shipbuilding industry by giving Cockatoo Island hands-on experience in warship construction. The second batch of three warships were all built at Cockatoo Island.

Operational history
In May 1917, the six River-class ships were ordered to Malta. On arrival, they were to undergo anti-submarine training, but were immediately deployed as escorts for a convoy. After completing the convoy run, the Australian warships completed the training, and were assigned to patrols of the Adriatic. The six destroyers returned to Australian waters in March 1919.

Decommissioning and fate
After decommissioning, Parramatta and Swan were stripped down and sold to the NSW Penal Department for use as prisoner accommodation on the Hawkesbury River. The two hulks were then sold into private hands; after plans to use them as fishers' accommodation, they were used to transport metal to islands along the river. In 1934, Swan and Parramatta were being towed along the river to the ship breakers when heavy weather caused the hulks to break free of their towing vessel; Swan sank, and Parramatta ran aground. The two ships were abandoned, although in 1973, the bow and stern of Parramatta were salvaged for use as memorials.

Warrego was used as accommodation at Cockatoo Island. She sank at her berth, and was later demolished. Yarra, Torrens, and Huon were all scuttled outside Sydney Heads after being used as target ships.