I'm going to try Richards suggestion today regarding fin attachment. I'm scratch building my first dual deploy and today is fin mounting day. It's a 4" BT with a 54mm MMT so there's not a lot of room to lay up fiberglass - fin to MMT. (They will be glassed to the BT). So that I understand it correctly, I need to "notch or groove" the root edge of the fins many times aprox 1/8" deep? Thus sort of creating a serrated edge giving much more surface area for bonding. Thinking of just using a bench grinder (the edge of the grinding wheel) to make the notches. Is this the idea Richard? I've not epoxied the aft centering ring yet so I'm able to still apply fillets. Mike Ostby