America's Cup: Oracle's foiling secrets revealed

Oracle Team USA skippered by James Spithill celebrates after they beat Emirates Team New Zealand. Photo / Getty Images.

Details revealing how Oracle Team USA used the foil control system in their America's Cup victory over Team New Zealand have been released.

This report from Cupexperience.com suggests the system employed by Oracle was legal, using a simple "mechanical feedback" loop which allowed them to have precise control of the daggerboard rake, bringing added stability.

The changes allowed Oracle skipper Jimmy Spithill to push buttons on the AC72's steering wheels to rake the daggerboards in 0.5 degree increments forwards and backwards.

These automatic movements gave Oracle an advantage over Team New Zealand who continued with a manual system which meant dealing with variations in hydraulic pressure which came from their grinders.