the ior concentrated on hull shape with length, beam, freeboard and girth measurements, foretriangle, mast and boom measurements, and stability with an inclination test. additionally, the ior identified features which were dangerous, or it couldn't fairly rate, and penalized or prohibited them. the measurements and penalties were used to compute the handicap number, called an "ior rating", in feet. the higher the rating, the faster the boat was deemed to be able to sail. a typical ior 40 footer (a "one tonner") rated 30.55 feet.