Design of a Foiling Optimist
Journal article, 2018

Because of the successful application of hydrofoils on the America's Cup catamarans in the past two campaigns the interest in foiling sailing craft has boosted. Foils have been fitted to a large number of yachts with great success, ranging from dinghies to ocean racers. An interesting question is whether one of the slowest racing boats in the world, the Optimist dinghy, can foil, and if so, at what minimum wind speed. The present paper presents a comprehensive design campaign to answer the two questions. The campaign includes a newly developed Velocity Prediction Program (VPP) for foiling/non-foiling conditions, a wind tunnel test of sail aerodynamics, a towing tank test of hull hydrodynamics and a large number of numerical predictions of foil characteristics. An optimum foil configuration is developed and towing tank tested with satisfactory results. The final proof of the concept is a successful on the water test with stable foiling at a speed of 12 knots.


Wind tunnel


Optimist dinghy

Towing tank



Anton Andersson

Shipping and Marine Technology

Anton Barreng

Shipping and Marine Technology

Erik Bohnsack

Shipping and Marine Technology

Lars Larsson

Shipping and Marine Technology

Linus Lundin

Shipping and Marine Technology

Gustav Olander

Shipping and Marine Technology

Robert Sahlberg

Shipping and Marine Technology

Erik Werner

Shipping and Marine Technology

Christian Finnsgård

SSPA Sweden AB

Adam Persson

SSPA Sweden AB

Matz Brown

SSPA Sweden AB

John McVeagh

SSPA Sweden AB

Journal of Sailboat Technology

Vol. 2018 1-24 06

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