some clubs here us the "different starting time" for different boats based on their yardstick or handicap. but it is only used once a year as a novelty/fun race as the rsults that are obtained are anything but realistic. There have been times in such races where a small 10' dingy has started first due to its rather "slow" rating and yet it has still finished before the faster Tornado (starting time based on its yardstick/handicap) has even started.
That sort of "delay" starts in yacht racing never seems to work.