Hello everyone. I got this old 156 Sport-A-Bout tri hull from my dad and am wanting to fix it back up. Not really sure on the year model. The hull and transom is good and the motor runs great but the floor needs replacing. My dad knew it was weak but it had carpet in it and he thought it was just plywood under the carpet and maybe just a few week spots that could be patched. i have torn the carpet out and found fiberglass under the carpet and noticed the floor is spongy. I've been doing some searching and reading in the forums here trying to learn as this is my first time doing any work on a boat. Is there plywood under the fiberglass and what is the best way to start cutting the floor out?