Ask Jack: Did the defender cheat to retain the America’s Cup?

Published on December 17th, 2013

Questions whether Oracle Team USA had a secret (and illegal) foil control system in their AC72 followed their defense of the America’s Cup. Jack Griffin of says no, and shares his findings…

“OTUSA has released drawings and photos of their system, which used a simple ‘mechanical feedback’ loop to allow precise control of the daggerboard rake. Helmsman Jimmy Spithill had buttons on the wheel to rake the daggerboard fore and aft in precise increments of 0.5° giving him better control over lift for hydrofoiling.

“OTUSA designers Dimitri Despierres (mechanical systems) and Eduardo Aldaz Carroll (electronic systems) began work in late June 2013 to help the team gybe better. The goal was to reduce distance lost in a gybe from 150 meters to 30 meters. To do this the engineers needed to deal with the problem that board movement varied depending on hydraulic pressure, making it impossible to control lift. What they needed was a way to move the board a fixed amount independent of the pressure and drag load on the board.”

Click here for the full report, photos, and diagrams.

Jack has also produced a video that demonstrates how Oracle Team USA turned its upwind deficiency into its greatest strength:

If you like this information, we encourage you to support a Kickstarter “crowdfunding” project for the production of a multimedia eBook on AC34. The pledge period ends this week and a major donor has offered a “challenge pledge” to match all pledges made this week, up to $3,000. Click here to make a pledge.

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