I would point out that there is an alternative sailing association that has both an international and US class and following. That is the International DN Ice Yacht Racing Association. This group has no affiliation with US sailing and holds its own events at, local, national and international levels. Last years worlds had 213 registrants from ~ 16 countries. Multihulls can go their own way also but only with a lot of effort.

Sail Fast,
Take chances,
Eric Anderson
IDNIYRA US 5193