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Test T-1, Sparkman&Stephens Inc

Designer Ben Lexcen (1936 - 1988)

Date13 November 1973

Object numberANMS1543[153]

NamePlan

MediumPaper

Dimensions595 x 1800

ClassificationsMaps, charts and plans

Credit LineAustralian National Maritime Museum Collection purchased with USA Bicentennial Gift funds

Terms

designs

DescriptionINTREPID lines plan. A photo copy ‘study drawing’ from the Ben Lexcen collection, showing the original ‘lines plan’ for a 12-meter America’s Cup yacht. The drawing etiquette shows ‘Sparkman & Stephens’, dated November 13th.1973, but it is likely the 1967 12mR yacht INTREPID designed by Olin Stephens and winner of the 1967 and 1970 America Cup races. HistoryTank testing yacht designs has been an important tool for a yacht designer to assess changes in a yacht's proportions and their effects on its potential importance. For many years only smaller scale models could be tested because of the small size tanks available. Lexcen and his design team which included draughtsman and model builder Dennis Philips built and tested a small number of 1:13.3 scale models for the design of the yacht SOUTHERN CROSS in 1974 with the series number 71xx and 72xx. They were run in the small tank at the University of Sydney Engineering Department. Alan Bond, and the Australian challenge syndicate, commissioned Ben Lexcen (then Bob Miller), in 1973 to design an International 12mR yacht to challenge the Americas Cup in 1974. ‘SOUTHERN CROSS’, sail number KA-4, was the first 12mR yacht designed by Ben Lexcen for the Australian challenge. Designed according to the International Third Rule- America’s Cup, it was built in aluminium by ‘Halvorsen, Morson & Gowland’ boatyard, Sydney in 1974. The American yacht ‘INTREPID’ won the 1967 and 1970 America’s cup races, and following another design change by Olin Stephens, tried again in 1974 but lost in the trials to ‘COURAGEOUS’. During the design of ‘INTREPID’ in 1966/67, Olin Stephens carried out extensive tank testing of the hull, and included several innovative design features, which were used on all future 12mR yachts. He reduced the underwater area, included a short ballast keel, fitted with trim-tab on the trailing edge. It had a separate rudder well aft and ‘bustle’ just forward to the rudder as well as at the start of the waterline forward. Few changes had been made to 12mR yacht design prior to ‘INTREPID’ and these new features were then used on all future 12mR yachts up to 1983, when Ben Lexcen turned the world upside-down with his revolutionary and innovative design of ‘AUSTRALIA II’. Alan Bond made his second challenge for the America’s Cup in 1977 with his new yacht ‘AUSTRALIA’. For this design, Ben Lexcen teamed up Johan Valentijn, an experienced Dutch naval architect, who had previously worked for ‘Sparkman & Stephens’ in the United Stated. Lexcen & Valentijn, 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, Ben Lexcen and Johan 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. ‘AUSTRALIA’ failed in the 1977 challenge and was re-deigned for the 1980 race. It was not until Ben Lexcen decided on a complete rethink of the 12mR design, and ‘AUSTRALIA II’ finally won the Americas Cup in 1983. SignificanceThis drawing was probably used as a study work by Ben Lexcen, and his colleague Johan Valentijn, when they jointly designed AUSTRALIA the 12mR America’s Cup challenge yacht in 1977. The drawing was important as it contained all the latest features of a successful 12mR racing yacht at the time. The American yacht INTREPID was highly innovative in 1967, with a short keel, trim-tab on the ballast keel, separate rudder and bustle just forward to the rudder and at the start of the waterline forward. The yacht was re-designed by Britton Chance in 1970 and again in 1973 by Olin Stephens, but failed to win trials for the 1974 race.