Ship model no 6672 Keel IV Rudder I
Designer
Ben Lexcen
(1936 - 1988)
Datec 1980
Object numberANMS1543[340]
NamePlan
MediumPaper
DimensionsOverall: 2680 x 825
Copyright© Ben Lexcen
ClassificationsMaps, charts and plans
Credit LineAustralian National Maritime Museum Collection purchased with USA Bicentennial Gift funds
DescriptionBen Lexcen designed, ‘lines plan & ballast keel’ of AUSTRALIA II the successful 12 metre challenge yacht which won the 1983 America’s Cup race for Australia. HistoryThe ’12 metre International Rule’ for racing yachts, participating in the America’s Cup, started in 1958 and ran up to 1987 when the International Americas Cup Class (IACC) was introduced. During this period, Australian yacht designer Ben Lexcen, designed seven America’s Cup challenge yachts. Australia’s quest for the coveted America’s Cup began in 1962 with GRETEL. In 1974 Australian businessperson, Alan Bond hired Lexcen, (then Bob Miller) to design the 12 metre challenge yacht SOUTHERN CROSS (KA-4). Based on his lifelong experience designing, building and racing, fast sailing yachts, Lexcen, was the obvious choice for Alan Bond. A successful small boat designer and international sailor, Lexcen had designed many successful ocean racing yachts including: PLUM CRAZY, MERCEDES 111, APOLLO, GINKGO, BALLYHOO and CEIL II.
The 1974 Australian challenge was not successful, but he went on to design and build AUSTRALIA (KA-5) for the 1977 and 1980 races. For the design of AUSTRALIA in 1977, Ben Lexcen teamed up Johan Valentijn, an experienced Dutch naval architect, who had worked for ‘Sparkman & Stephens’ in the US. The designers worked together on a number of yachts, including the 45-foot IOR yacht GUIA V in 1976, for the experienced Italian ocean racing yachtsman, Giorgio Falck. Interestingly, Lexcen and Valentijn 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 future design work on AUSTRALIA II (KA-6).
The America’s Cup trophy was held by the NYYC, successfully defending twenty-four challenges for 132 years, until 1983, when the Australian yacht AUSTRALIA II designed by Lexcen and representing The Royal Perth Yacht Club of Australia, beat the American yacht LIBERTY.
SignificanceWith an indicated load water line length of 13.47 metre, the advanced shape of the rudder and the distinctive wings and bulb of the ballast keel, indicates the drawing was made well into the design program. The tandem keel concept would have been the logical choice to test at the time, and the data gained from the test tank used to make an overall evaluation. The eureka moment came by inverting the ballast keel and maintaining a full keel profile.
