I think the topic here is an eventual international F-20 class, not a Nacra/Inter-20 US based one-design class who allows other 'stray dogs' to race with them? We can always discuss philosophy and one-design vs. formula racing, but humor me and lets discuss true formula.

There are many other 20 footers than the Nacra/Inter-20, you will have to document 98% before I belive that. There have been buildt several thousand T's up trough the years, then there are M-20's, Eagle 20's, Taipan 5.7's, Ventilo's etc. The rules found at http://www.f20.nl are probably tailored for the Nacra/Inter-20, but if they are opened up a bit, many other boats can compete.

I guess the Formula 16's met many of the same arguments in the start. After all, the Hobie 16 is probably the largest catamaran class out there, but they seem pretty successful in their class building.