The racing yacht Australia II, captained by John Bertrand, won the America's Cup and ended the New York Yacht Club's 132-year defence of the trophy.

Yacht racing is a sailing sport involving sailing yachts and larger sailboats, as distinguished from dinghy racing, which involves open boats. It is composed of multiple yachts, in direct competition, racing around a course marked by buoys or other fixed navigational devices or racing longer distances across open water from point-to-point. It can involve a series of races with buoy racing or multiple legs when point-to-point racing.

Australia II is an Australian 12-metre-class America's Cup challenge racing yacht that was launched in 1982 and won the 1983 America's Cup for the Royal Perth Yacht Club. Skippered by John Bertrand, she was the first successful Cup challenger, ending a 132-year tenure by the New York Yacht Club.

John Edwin Bertrand AO is a yachtsman from Australia, who skippered Australia II to victory in the 1983 America's Cup, ending 132 years of American supremacy, and the only time Australia has won. Bertrand won the bronze medal in the Finn competition at the 1976 Summer Olympics in Montreal. In 2010 and 2016, he won the world Etchells class sailing championships. He is a life member of both the Royal Brighton Yacht Club in Melbourne, and the Sorrento Sailing Couta Boat Club.

The 1983 America's Cup was a 12-metre class yacht racing series which pitted the defending New York Yacht Club's Liberty against the Royal Perth Yacht Club's challenger, Australia II. The September 1983 series of match races was won by Australia II, with four race wins to three, in the first successful challenge of the New York Yacht Club's 132-year defense of the Cup. The Australian syndicate's boat, skippered by John Bertrand, fought back from a 3–1 deficit to best the Dennis Conner-helmed defender, ending both the longest winning streak in sporting history and U.S. domination of the racing series.