Australia (yacht)

Australia docked in Sydney in her current livery
Yacht club	Sun City Yacht Club (1977)  Royal Perth Yacht Club (1980)
Nation	Australia
Class	12-metre
Sail no	KA–5
Designer(s)	Ben Lexcen
Builder	S. E. Ward
Launched	1977
Racing career
Skippers	Noel Robins (1977) James Hardy (1980)
America's Cup	1977

Australia (KA–5) is an Australian 12-metre-class America's Cup racing yacht that twice challenged unsuccessfully for the America's Cup in 1977 and 1980. Designed by Ben Lexcen in association with the Dutch designer Johan Valentijn for Alan Bond, Australia failed to win a single race against the 1977 defender, Courageous (US-26), but managed to win one race against the 1980 defender, Freedom (US-30). Australia resides in Sydney, Australia.

Australia was designed during 1976 by Ben Lexcen in association with the Dutch designer Johan Valentijn. Both men spent seven months experimenting with 1/9th scale models in the University of Delft test tank in the Netherlands.

Australia is a conventional design and has been described as a "Courageous-style boat". It has v-shaped mid-ship sections, a low freeboard, large bustle and a low aft run finishing in a wide U-shaped transom. Its fore overhang is very narrow and round shaped in its lowest part. The cockpits are shallow, keel is thin and the ballast is placed very low. The elliptical mast is made in extruded aluminium.Australia was approximately 1,500 kilograms (3,300 lb) lighter than Courageous and it was hoped that by lowering the freeboard and taking a penalty on length, Australia would prove faster than the US boat.

Australia was built by Steve Ward in Perth and launched in February 1977. Australia then sailed in sea trials against Alan Bond's 1974 challenger, Southern Cross (KA-4), off Yanchep in Western Australia. The older boat remained a trial horse for Australia during the 1977 America's Cup series.

For the 1977 America's Cup, Australia went to Newport and raced against the 1970 Australian challenger, Gretel II (KA-3), the Swedish entrant, Sverige (S-3), and the French challenger, France (F-1), led by Baron Bich. Eventually, Australia won the right to challenge for the Cup by defeating Sverige 4–0.