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The Development of the Flying Fifteen

The Flying Fifteen/Flying Fifteen Development
How the concept of the Flying Fifteen keelboat came to Uffa Fox

The Development of the Flying Fifteen

Uffa Fox photoThe legendary Uffa Fox designed the Flying Fifteen in England in 1947, and his vision of a high performance planing keelboat continues to flourish around the world, thanks to some judicious and intelligent class management. By embracing and carefully controlling the use of modern materials, the Fifteen has maintained its exhilarating performance without becoming too expensive to build or maintain.

The original design of Uffa Fox in the late 1940’s occurred when small sailing boats were normally built at home by amateurs from timber or marine plywood, around stringers. Uffa allowed a one inch (25mm) tolerance either side of the median plan lines to comply with the measurement needsIn the early years, the fleet expanded rapidly and by 1964, 700 boats had been built with boats being registered in a number of countries including United Kingdom, Ireland, Australia, Canada, USA, Guatemala, Venezuela, Iraq, Qatar, Aden, Hong Kong and Rhodesia.

As time passed the hulls were made of fibreglass using a mould which allowed for tighter tolerances. Some builders using this new construction medium exploited the original tolerances and several designs were marketed, some suited to sea conditions and others more adept on inland waters. Carbon fibre is now common in hull construction.

In the late 1970’s the National Flying Fifteen Owners’ Association moved to have the Class designated as an ‘International Class’ affiliated with the IYRU, and on 1 January 1981 officially became an ‘International Class”. As such all National Class Associations were federated under Flying Fifteen International.

In the UK in the late 1970’s and early 80’s, British boat builders and designers developed moulds over a number of years which exploited the use of the hull tolerances to extend the waterline length of the boat. Such boats were clearly faster than the standard hull design.

Flying Fifteen International then resolved to tighten hull tolerances and in 1984 reduced the hull tolerances from +/-25mm to +/-15 mm and introduced hull measurement templates. This was progressed in 1993 to a reduction to +/- 7mm of the median lines of the hull, and at the same time the median being was adjusted to take in the most popular new design – the Windebank Mould IX. This has achieved the goal of a truly “one design hull” as envisaged by Uffa Fox. At this time there were 14 production moulds in use around the world. With the change in tolerances this has now been reduced to six.

Older boats built to the original design are known as "Classics" . By definition these are boats with a sail number below 2700 and have not been modified. Some boats with a number over 2700 also qualify due to a quirk in the way numbers were allocated in the past. A definition of Classic boats is available here.

To maintain a market for “in between” boats FFI introduced a “Silver” category and some clubs have built their fleets on Silvers. FFI defines boats between 2701 and 3200 to be Silvers.

Read more about the history of the various moulds

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