Like the cliche made famous by Field of Dreams, "If you build it, they will come."
Often the problem is finding a place in the schedule to fit in a new event. And maybe the turnout will be small the first time. But if everyone has a good time, the word will spread, and it will grow each year.
You need an interesting name for it and maybe a theme of some kind that makes it identifiable and different from the other regattas in your area.
Let me know if there is anything I can do to help through Catamaran Sailor.