A27 Hull/Deck Joint

[Ambler27FC]

Lining up some winter/spring projects. I have a minor leak that I am now convinced is the hull/deck joint. I have sealed all of the ports and there are no deck fixtures nearby. Plus there was a missing rivet or two right where you would hit a dock on parallel approach - which I had ignored because it had already been a brutal maintenance season and we had to float.

This is a common subject, and I think I've read all of the posts. The most common fix seems to be 5200 at any gaps and re-riveting. If anyone has done this, I was curious on the process. Separating large sections to put 5200 between the layers seems risky - specifically lining up the sections so that the rivets go back in with no gaps. Is the adhesive only applied to the surface? Hoping to do this right and only once.

I've been debating fiber-glassing over the whole seam and making it bullet-proof. Cracks develop in the toe rails at the sharp corners, which have excessive gelcoat and a mystery white/tan filler. No fault on the manufacture - those sharp corners are tough and building up the glass would fix this. But their don't seem to be any good alternative for the rub-rail. Increase the flange thickness and the existing rub-rail will not fit.

[Ambler27FC]

With some wonderful fall weather this year I was able to start removing the rub rail and vinyl U-channel. Solved the leak(s), but the fiberglass was a bit of a mess. The gelcoat was up to 1/8" thick and had allot of cracks, so it was ground off. There were some cracks in the proper fiberglass as well - probably from unfortunate docking encounters. It was obvious this was not the first-time repairs had been attempted.

I fixed the leak issue with 4200, new rivets, and a few layers of CSM over the joint. But I think thin layer of fiberglass will crack over time. I really want to thicken the joint with bi-axial cloth, but if you thicken this joint at all the current rub-rail will not fit. And there are no substitutes - all larger rub-rails are surface mount. Removing the existing rub rail was a destructive process (the vinyl U-channel was adhered and came off in pieces) so I would like to solve this once and for all.

So I am thinking of going to crazy town (pictured below). I call it that because I can't find another example of someone else doing this. Fiberglass completely over the joint then adhere a 1/2" piece of coring material to the bottom of the flange, and then adding another 1/8" of fiberglass over the whole joint. After that you have a thick flange and solid hull-deck joint. With a thick flange you can mount many types of rub-rail. And I am painting the hull next year, so this is the best time to fair in a new joint.

This is an extreme solution, are there any better alternatives? I don't want to just smear more goop of the problem.