redoing floor in bow rider

Hello all
Im new to the actual hands on baot building, Im in the midst of removing the entire floor of my 20 foot bow rider and replacing it with a fresh new one, the problem im having is the original joists inside are a little weak and arent holding the the new wider joists ive inlaid to hold the new plywood. Any suggestions? Also After I get the ne floor down, should I be using laminating resin or poly resin, and cloth or mat. I will be putting carpet over it on a further note. Oh and one more thing, on the new joist, should they be glassed as well before the plywood goes down.
Thanks.

 

Laminating polyester resin typically will not cure in the presence of air (it's air-inhibited) so when laying up a hull one layer remains tacky until after the next layer is applied - so you want a normal resin not a laminating resin. Polyester and Vinylester resins are best for adhering fiberglass to fibreglass whereas epoxy has a better bonding strength adhering fiberglass to wood.

 

I'm not picturing the problem you're facing, but can't you brace up the weak joists or laminate reinforcing joists next to them? Or is the problem in the connection between new and old? Can you use fillets made with pieces of fiberglass cloth and possibly a layer of roving to reinforce the joints?

 

I bet someone will disagree with me saying that you should leave one side open to let any water that comes in come out, but I would personally encapsulate all the wood structural members with epoxy. Be sure not to create any voids where water can accumulate - it will always find a way into a compartment where that you think is 100% sealed. If you put in drain holes, be sure to coat them very well with epoxy or use an inset of pvc to make sure moisture doesn't wick into the wood. I usually hate the idea of using mat - and you have to be careful using epoxy with mat because most mat is made so the binder dissolves with polyester resin but not epoxy. But you are on the right track using a resin rich layer to seal the deck prior to the carpet.

 

Here is what i have, now the old joints are a little weak, and when i goto screw the new joist on, it feels as though it doesnt grap, but the screws do go in the old joists, should i be putting epoxy in between and on the front of the joists.