Or the Nacra 20's will get a modern chute and decent main sail from a quality sailmaker.
The F18's should only have an advantage when it's blowing 15 or more.... the problem is the rig is just dated.
both boats weigh about 400 lbs carry crews of 340 to 400 lbs and are 8.5 feet wide. The 20's should have an advantage in the light stuff... but they can't sail the same angles up the coast.
Before I get a "modern chute" I'd just like a chute that doesn't fall apart twice in one friggin race.