J/30 Class Association Forums J/30 Forum One Design Class Rules Class Rules & #1 Genoa Size Limits

Class rules state for the #1 genoa state:

5.12.5.1 The length of LP shall not exceed 5665 mm nor be less than 5250 mm.

The max is a 163% LP - minimum is closer to 155% (roughly, I didn't do the math). The 415mm range allowed within the rules is not insignificant.

So, if you want a smaller sail, it's allowable within the rules -though you would have to stick with the sail you start with throughout a regatta.