Forget the affiliation with the ISAF then (they would appear from what you have shown us Wouter to be a bunch of money hungry, power hungry, megolamaniacs, so STUFF them you don't really need them anyway) But I think that the incorporation is vital (if for no other reason than to protect the name and to offer protection for the association officers) and it can do nothing but good to affiliate with the state yachting authorities for when it comes to conducting state and or national titles.
Darryl