Oracle Racing shook thing up Monday when they released a photo of one of their AC45s “flying” on San Francisco Bay using an “L” shaped hydrofoil.
KTVU-TV quotes an Oracle spokesman as saying the tests are “encouraging”… but there was no comment on how the foil is controlled, or what’s inside the bulb located toward the base of the mast.
It doesn’t appear the foils can be used in the World Series races on board AC45s – which means they’re for the AC72s only and the smaller boats are serving as test beds. Whatever they’re making the “L” joint out of has got to be some sort of miracle material – the entire boat is balanced on it, along with all the pressure from the sails and water.
Here’s the Oracle release:
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 designers such as Rod Macalpine-Downey were experimenting with foils 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.