J/30 Class Association Forums J/30 Forum One Design Class Rules Mainsail weight minimum

The class measurer I'm sure will weigh in here but it has always been based on the cloth weight, not the weight with the finishing coats. This provides a consistent baseline that all sailmakers may build to. Class rules specify dacron (or other trade name equivalents) so the associated cloth weights are very well defined for the sailmakers to build class legal sails.