I think I see what you are trying to do. You might have a J series and you want the bow of the D series. You should fiberglass that on.
You can work that glass smooth and gel coat your finished project. That's gonna be the best for being waterproof. Do this right and you will increase flotation as well!
For more technical info, consult the fiberglass forums. I used to do this, but I didn't write a book.
Gorilla Glue. Would you be serious, please? Gorilla glue is nothing more than a water activated polyurethane adhesive. POR 15 is not that far off chemically speaking, but lacks a foaming agent.
I can tear anything apart where Gorilla glue was used if it can be peeled. This is exactly the type of bonding he is looking for and it will fail. Gorilla glue may be water resistant, but it's not waterproof.