Ship Model no. 5854B Keel VA with winglets IIA
Designer
Ben Lexcen
(1936 - 1988)
Date1980 - 1983
Object numberANMS1543[356]
NamePlan
MediumFilm copy
DimensionsOverall: 2210 x 865
Copyright© Ben Lexcen
ClassificationsMaps, charts and plans
Credit LineAustralian National Maritime Museum Collection purchased with USA Bicentennial Gift funds
DescriptionA Ben Lexcen ‘lines plan’ section view of the lead ballast keel developed in The Netherlands in 1982 while tank testing scale models of the 12 metre AUSTRALIA II for the 1983 America’s Cup race.
The drawing, marked ‘Keel 5A and winglets II’, is the finalisation of several months design and development of the revolutionary hull and ballast keel of AUSTRALIA II in 1982. The effort, time and considerable costs, all proved to be worthwhile when the computer analysis clearly indicated AUSTRALIA II would be 5% more efficient when sailing to windward compared to rival yachts. HistoryFollowing the failure of the Australian team to win the coveted America’s Cup Race in 1974, Alan Bond and the Australian Syndicate immediately made plans for the next challenge in 1977. Prominent Australian yacht designer Ben Lexcen, teamed up with Johan Valentijn, a young but experienced Dutch naval architect, who had worked for ‘Sparkman & Stephens’ in the US. Together they designed the 12 metre yacht AUSTRALIA (K-5) which raced in the 1977 and 1980 challenge races in the United States. The two designers spent seven months in 1976 testing 1/9th scale models of AUSTRALIA at the University of Delft test tank in the Netherlands. This period of on-site design and tank testing scaled models in the water, proved vital for later design work on AUSTRALIA II (KA-6).
Lexcen spent four months at Netherlands Ship Model Basin in Wageningen during early 1982, designing and developing the hull and ballast keel of AUSTRALIA II assisted by the test tank staff. The drawing, marked ‘Ship Model No. 5854B’, was made towards the end of this design and testing program, indicated by the keel and winglet design numbers. Bond, the chairman of the Australian challenge syndicate, together with John Bertrand, the yachts captain, travelled to the Dutch water tank testing facility at Wageningen in mid-summer 1981. Initially sceptical of the revolutionary design of AUSTRALIA II, when the computer analysis clearly indicated the yacht would be 5% more efficient when sailing to windward compared to rival yachts, Bertrand famously said: “I had to agree that the results of these tests were so overwhelming that we would be crazy not to build this boat.”
AUSTRALIA II was built in aluminium by ‘Steve E. Ward & Co.’ boatyard in Perth, Western Australia and launched in 1982 and the famous inverted wing keel was cast by the Western Australia at the ‘State Engineering Works’. At the time it was the largest lead casting of its kind in the world.
The America’s Cup trophy had been held by the New York Yacht Club since 1851, successfully defending twenty-four challenges for 132 years. In September 1983, representing the Royal Perth Yacht Club, the Australian yacht AUSTRALIA II designed by Lexcen and captained by Bertrand beat the American yacht LIBERTY captained by Dennis Conner.
SignificanceLexcen's revolutionary inverted ballast keel with additional wings, was a remarkable change of tradition, so typical of the designers ‘out of the box thinking’. Always searching for ways to make a boat lighter, sail faster and perform better than its rivals, Lexcen was one of the great innovators of modern yacht design. His inverted ballast keel with wings, lowered drag, made the yacht more stable and maneuverable and faster when tacking. From then on, the design of modern, highly competitive racing yachts, would never be the same again. 
