I just replaced the pivot bolt for my centerboard (I have a 17' sailing dinghy), and I put new neoprene washers on both sides of the bolt, and I'm still getting a little water leaking in. How do I seal it? Would 3M 4200 work on the neoprene?
Perhaps the rules are referring to a seal/flap where the hull meets the trunk? My 420 had that. I kept splashing to a minimum and reduced drag(5) Centerboard flaps or gaskets shall not be permitted owner to race the boat in class races. If racing is not in your future, then you are able to create just about anything you desire to make your boat sail the way you desire. It would help us creative boat owners who work on older boats, to see some images of the problem you have and how you have tried to resolve it.