Structural and marine grade silicone is better for top cap separations, and rub rail leaks I'm thinking? I've got "CRL-RTV {structural construction, aircraft, and marine grade} silicone", I'm going to use for the same thing. I bought 5200 too but after more research I learned it doesn't flex as much which is what's needed between hull cap, and also for rubrail bonding and fasteners. I've seen videos of people removing 5200 and it peels the fiberglass right off. 5200, seems to me, like it's as strong as epoxy. Even though I believe it's considered a polyurethane.