Sketch Keel drawing
Designer
Ben Lexcen
(1936 - 1988)
Date1936-1988
Object numberANMS1543[359]
NamePlan
MediumPencil on film
DimensionsOverall: 1010 x 570
Copyright© Ben Lexcen
ClassificationsMaps, charts and plans
Credit LineAustralian National Maritime Museum Collection purchased with USA Bicentennial Gift funds
DescriptionAn early Ben Lexcen hand drawn sketch, showing his ideas during development of his revolutionary inverted winged ballast keel, fitted to the 12 metre Americas Cup challenge yacht AUSTRALIA II in 1983.
HistoryAustralia’s quest for the coveted Americas Cup began in 1962 with the Alan Payne designed GRETEL. This was followed in 1966 with the Warwick Hood yacht DAME PATTIE and by GRETEL II in 1970. In 1973/74 entrepreneur Alan Bond, hired Ben Lexcen, (then Bob Miller) to design the 12 metre challenge yacht SOUTHERN CROSS (KA-4). Based on a lifelong experience designing, building and racing, fast sailing yachts, Lexcen, was the obvious choice for Bond. A successful small boat designer and international Olympic sailor, Lexcen had designed many successful ocean racing yachts including: PLUM CRAZY, MERCEDES III, APOLLO, APOLLO II, 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, Lexcen teamed up Johan Valentijn, an experienced Dutch naval architect, who had previously 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. Lexcen and Valentijn spent seven months in 1976 testing 1/9th scale models of AUSTRALIA (KA-5) 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). With considerable experience in tank testing 12 metre racing yachts, using the Netherlands Ship Model Basin in Wageningen was an obvious choice for Lexcen. Many design drawings were produced, and scaled models built and tested. A computer analysis was made at each design change, using tank testing software and collaboration with the ‘National Aerospace Laboratories of the Netherlands’ (NLR).
SignificanceA seemingly simple, but important sketch, by Ben Lexcen showing his early ideas and plan for the revolutionary inverted winged ballast keel which was fitted to the winning Australia 12mR yacht ‘AUSTRALIA II’ in 1983. His remarkable ‘out of the box’ thinking, and uncanny ability to understand the fluid dynamics around a yachts hull, changed the design of all future America Cup boats and influenced racing yacht design around the world. 
