During last week’s training session in San Francisco, ORACLE TEAM USA sailors were learning to fly on hydrofoils. An L-shaped daggerboard and T-shaped rudders were fitted to one of the team’s AC45s and the platform took flight. Foiling is not a new phenomenon. Many high-speed ferries rely on hydrofoils for a smooth ride for their passengers. In sailing, the Moth class has experimented with foils since the early 1970s, about the same time that experimental foiling boats were attempting to set the first officially observed speed trials at Weymouth Speed Week. In 2009 the 60-foot foiling trimaran l’Hydroptere set the record at 51.36 knots.
Foils help reduce draft and increase speed. They are a very cost efficient way to gain performance. You can research them extensively in the computer before you build them, and they are small scale, compared with a wing. The foil project is a continuation of one started on USA 17, the team’s 90-foot trimaran that won the 2010 America’s Cup.