Body plan for model 7205

Designer Ben Lexcen (1936 - 1988)

Date17 October 1972

Object numberANMS1543[080]

NamePlan

MediumPencil on drafting film

Dimensions475 x 770

ClassificationsMaps, charts and plans

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

Terms

DescriptionA Ben Lexcen (formally Bob Miller) hull ‘Body Plan’, with hand-written calculations, for a proposed scale model of the 12mR America Cup challenge yacht SOUTHERN CROSS (K-4) designed in 1972 and 1973 for the 1974 Americas Cup races. HistoryIn 1973, during the design and development of the 12mR yacht SOUTHERN CROSS (K-4) for Alan Bond and the Australian challenge team, several hull designs were proposed, and scale models of the hull hulls built and tested. Model 7205 was one such model. This was important work as the America’s cup challenge yacht SOUTHERN CROSS represented Australia, its yacht design, build, management and above all, the skill and seamanship of the crew. The defending American design team had a large budget, as well as the best materials and resources to draw on, so carried out extensive design work and tank testing. Several scaled models of SOUTHERN CROSS hull and ballast keel were built, varying from 1.41 metre to 1.51 metre in length overall. When tank testing, an allowance is made for the actual weight, so they can be tested in the water to check the designed hydrostatics, pounds per inch of emission, hull resistance, wave making, overall displacement and so forth. These tests take place in large, purpose-built water tanks, which allows the vessel to be towed though the water and information gathered to fully optimise the hull shape. A self-taught naval architect, yacht designer and accomplished yachtsman, Ben Lexcen was born Robert Clyde Miller, on March 19th. 1936 at Boggabri, in New South Wales, Australia. He left school at fourteen, after only five years formal education, to become an apprentice machinist at the New South Wales locomotive works. In 1952, at the age of 16, Ben Lexcen (then Bob Miller) designed and built his first sailing boat ‘THE COMET’ with his friend William Bennett. He soon began to make a name for himself at local sailing competitions. In 1960 he entered his boat ‘TAIPAN’ in the 18-Footer World Championships, and later winning the World Championship in 1961 with his design, the 18-foot skiff ‘VENOM’. In 1962, together with his friend Craig Whitworth, he set up the ‘Miller & Whitworth’ sail making business in Sydney, while continuing to design sailing dinghies. An accomplished sailor, then Bob Miller represented Australia in the Soling class at the 1972 at the Olympic Games at Munich, West Germany. Bob Miller (later Ben Lexcen) soon became known for his fast, lightweight, racing yachts which included, PLUM CRAZY, MERCEDES III, APOLLO, APOLLO II, GINKGO, BALLYHOO and CEIL III. These early yacht designs were not tank tested as the process is costly and time consuming. It requires several different hull models to be designed, built, and tested in a purpose-built water tank facility. The costs involved would have been too high, and considered unnecessary, for owners of yachts of around 45-feet long. Alan Bond and Bob Miller (later Ben Lexcen) were together at Newport, Rhode Island in 1970 for the Newport to Bermuda race. Together with the Australin team, they were preparing Alan Bond’s racing yacht ‘APOLLO’, at ‘Bob Direcktor’s Shipyard, at Mamaroneck, Yew York. While visiting a boatyard together at City Island, New York, Alan Bond spotted a large sailing yacht alongside, which unusually, had all the deck winches and crew positioned below deck. Alan Bond wanted a closer look so wondered down the pontoon to study the boat and layout but one of the crew took offence and shouted for him to go away. This did not go well, and when asked what type of boat it was anyway, was told it was the America Cup yacht ‘VALIANT’. Still mystified, Bob Miller explained what the America Cup was and about the yachts involved. To which Alan Bond told Bob Miller. ‘You design me one of those 12-metre boats, and we’ll come back here and win their bloody America’s Cup.’ With a final overall length of 20.45 metres (67.09 feet) and beam of 3.71 metre (12.17 feet), SOUTHERN CROSS (KA-4) was built of aluminium at Terry Hills, Sydney by ‘Halvorsen Morson and Gowland’ of Mona Vale and launched in 1974. Following sea trials and crew training alongside the previous challenge yacht GRETEL II, SOUTHERN CROSS was shipped to the USA for the American elimination trials. The American 12mR yachts; INTREPID, MARINER, VALIANT and COURAGEOUS were all trying to be the defending yacht for the cup challenge. Skippered by talented Australian Jim Hardy, SOUTHERN CROSS did her best but ultimately lost to COURAGEOUS. SOUTHERN CROSS was not successful in winning the America Cup in 1974 but in 1983 Alan bond returned to Newport with the Ben Lexcen designed AUSTRALIA II. Captained by John Bertrand, the yacht beat the American yacht ‘LIBERTY’ and Australia finally won the America’s Cup.SignificanceThe hull ‘body plan’ is part of the overall hull ‘lines plan’, made by Ben Lexcen during early development work on Alan Bond’s first 12mR yacht ‘SOUTHERN CROSS in 1972/73. The work shows thirteen hull stations, or cross section views of the hull. It was made to build a scale model of the hull to tank test the design. It represents the start of Alan Bond and Ben Lexcen’s quest for the coveted Americas Cup, when advanced designed, purpose built 12-metre yachts, raced against each other.