interesting quote from the Q&A..
"The sport of sailing is made up of a wide range of sailors. From kiteboarding, frostbiting, team or match racing to PHRF/IRC/ORR, offshore one design, windsurfing, and cruising to high-performance skiffs, and many more; US SAILING is expected to serve each and every single one of these categories."

No catarmaran sections mentioned. So guess you aren't expected to join.. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />