J/30 Class Association Forums J/30 Forum One Design Class Rules Max Luff of Blade

Just curious if anyone knows the background of why the maximum luff on the blade is a full 6" shorter than the max luff on the genoa. Seems odd since most if not all competitive boats have done away with the #2, why the class rules would limit the potential size of the #3 creating a larger span in sail area from the #1 to #3.