Details of how Oracle Team USA used their foil control system in their America's Cup victory against Team New Zealand have been released.
The details suggest the system employed by Oracle was legal, using a simple "mechanical feedback" loop to allow precise control of the daggerboard.
This system also gave the team added stability with skipper Jimmy Spithill using buttons on the AC72's steering wheels to rake the daggerboards in 0.5 degree increments forwards and backwards.
The precise nature of the movements meant Oracle had an advantage over Team New Zealand's manual system. Team New Zealand had to deal with variations in hydraulic pressure which came from their grinders.
Oracle admitted their upwind foiling at the start of the regatta was inferior to Team New Zealand however, once they understood their system, their upwind foiling became more effective than the Kiwis.
The full extent of the developments was posted on the Cupexpereince.com website.