Yes Simon, I did say SOME classes. The 5.9 was not eligible to race as an iF20, I think mainly due to the fact it had carbon stringers. It was shorter, narrower, no daggerboards, no kite! Just as the 5.9 slogan reads 'when the fast isn't fast enough'
Wouldn't a fleet of 5.9s, Nacra 6.0s, Prindle 19s have given better racing? particularly with 'open' sails. Yes the F18s and the reformatted tornado have affected the 5.9s, but look at the age of the competitive 5.9s, they last,so are great value second hand boats, and now have a great 3 sail option. Buy an iF20? I think not.

Cheshirecatman