In Southern California most of the Formula 18 guys are members of Yacht Clubs. There are still a few taking advantage of not being asked for an affiliation but they are the exception. There are other fleets (monos) as well that take advantage of the situation. Here you do not even need to be a YC member there are sailing associations that qualify.

Yacht Clubs here are really friendly to allowing the Formula 18s to race in their events. We have many regattas and could put more on the menu if we needed.

Later,
Dan