GINKGO lines plan

Designer Ben Lexcen (1936 - 1988)

Datec 1970

Object numberANMS1543[006]

NamePlan

MediumPaper

Dimensions465 x 585

ClassificationsMaps, charts and plans

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

Terms

DescriptionAn early original design work by Bob Miller for the 45-foot IOR racing yacht GINGKO. The drawing has no scale or date, but likely dates from 1971 or early 1972, as the yacht was built and launched in July 1972. It is drawn on an irregular offcut of water proof drawing paper with no scale, date, company details or name of designer, so may be an early work or one made up later after the calculations have been made. The layout with the hull sections added at the centre of the drawing is often used in marketing or for a magazine article about the yacht. HistoryThe drawing gives the overall length of the yacht as 46 feet but GINKGO and the Miller & Whitworth Admiral Cup Series 45’ were 44.3 feet LOA with a 41-foot waterline. The drawing also gives GINKGO a 13-foot 6-inch beam, but the later boat was 12.47 feet. Also, the displaced weight is not the same: showing a displacement of 22,000 pound but the later boat was 23,000 pounds. This gives weight (no pun intended!) to the early design possibility. But the design does show the modern, unconventional thinking of the yacht designer at the time. The need for a low weight, an easily driven hull with low drag and the right amount of ballast and sail area. The ballast keel and rudder are shaped like a swept-backed jet aircraft wing in profile and the same in sectional view. A deep keel yacht will go to windward better than a shallow keel, and deeper keels get the ballast lower in the yacht, which in turn helps sail carrying ability. The early 1970’s saw the study of aircraft wing sections, understanding drag and lift, and optimum shapes for underwater parts, as all being necessary for a fast racing yacht. It is unsure the exact purpose of this small lines plan of the 45’ IOR Racing yacht GINKGO as it is drawn on an off-cut of draughting paper, with no date, description, or author, but the hand written notes at the bottom of the sheet are typical of Ben Lexcen with the slopping ‘L’ common on his drawing work. SignificanceThe lines plan for GINKGO clearly indicates Bob Miller's design ideas using a light weight, low wetted area hull, with reduced drag and aerodynamic ballast keel and rudder sections. The lines plan is the start of a successful design project, which started in late 1971 or early 1972 and continued to at least 1976, first with ‘Miller & Whitworth’ and later with ‘Miller & Valentijn’. Several successful racing yachts were later built to this design and Miller & Whitworth marketed the design as their ‘Admirals Cup Series’