Hydrofoils Applied to Canting-keel Yachts

Abstract

Hydrofoils have been applied to many different types of marine craft, including yachts. However, most of these have been for attempts at speed records or by inventors and, notably, the international Moth class, but so far not to modern racing yachts. They provide a number of advantages, and this project has investigated the feasibility of application to a modern canting-keel maxi yacht.The investigation began with drawing up a set of lines for a modern canting-keel maxi yacht. A resistance was then predicted, both with and without foils, using the Delft Systematic Yacht Series and a three-dimensional analysis of the foil-borne resistance. A towing rig was designed and constructed, and several models built and tested on open water and in a swimming pool to compare the resistance and performance, both with and without foils. Finally, a radio-controlled sailing model was constructed and tested, both with and without foils.The results showed a clear speed advantage for the foil-assisted maxi yacht. Just as with canting keels, fitting foils to an ocean-racing maxi will not be without its problems. However, the evidence is compelling, and it is considered only a matter of time before someone sets a precedent with a full-scale yacht, which others will follow.