I can confirm what Pepin said. At the A-class worlds last Feb. It was determined that mounting the footstrap with the tab on the rear off the hull constituted part of the hull length and violated the class rule regarding hull length. Everyone had to move their strap forward to comply with the class rules. Rudders and their hardware are excluded, provided the leading edge of the rudder is no more than 3" of the transom. If the leading edge of the rudder is more than 3" of the transom, then the rudder is considered part of the hull measure meant, and the trailing edge is used to determine the 18' max hull length.