the ior was run by the itc, or international technical committee, of the offshore racing congress, chaired between 1979 and 1987 by the late gary mull of san francisco. as with all published handicapping formulae, there was an ongoing game between the designers finding ways of designing boats that took advantage of shortcomings in the measurement system and handicapping formulae, and the rule makers closing the loopholes to ensure fair racing and a reasonable competitive life for the boats. as the racing became more competitive, the rate of change in the rule accelerated, and also the boats at the top of the fleet became stripped out racing machines that performed well but were expensive and also difficult to sail, and this resulted in a loss of popularity. however even if club sailors could not compete against the top boats, the ior did generate a reasonably level playing field across the sailing spectrum, with club sailors buying production race boats or custom boats past their prime, and moving up to more competitive boats as they wanted to sail up the fleet. towards the end of its life the ior had become a stable rule, but by then it had a reputation of changing too often, and this sowed the seeds for its successors. ims was introduced as a more "scientific" rule for racing yachts, driven by the usa, whereas channel handicap was introduced in 1983 by the rorc as a simple club level rule that would hopefully feed people into ior racing - though in fact it proved to be the final nail in the coffin for the ior rule.