International America's Cup Class

IACC sail numbers were issued according to the date when the ACM measurement committee decided that the hull had reached a certain stage of completion.

Typical parameters of an IACC yacht were: The 2007 America's Cup saw the introduction of the ‘’Umpire Signaling System’’ (USS) which allowed the Umpires to notify the two boats regarding their position in relation to each other when overtaking and their position relating to a mark of the course when in close proximity of the mark.

On both the defender and the challenger there was a display unit with three LED lights coloured green, amber and white respectively.

The purpose of the USS is to remove doubt and associated protests caused by competitors having differing opinions of either their positions relative to each other or their distance from marks and then performing tactical maneuvers prohibited by the racing rules.

The feeling was that the existing IACC rule had evolved as far as was practical and that in the spirit of the America's Cup, a new design challenge was needed.