I had the floor in my boat replaced a few years ago. It was 3/4 plywood , but was beginning to get bad. The guy that replaced it, ripped out the wood and got 1/2" x 4' x 8' sheets of PVC. It had a special name, but I can't remember what it is. There were framing boards which he first put glue on and then cut to fit and screwed the material and counter-sunk the screws. Then I put a heavy indoor/outdoor carpet down. Be sure to get waterproof carpet cement/glue. It was as solid as a rock. Worked really great. The floor would never wear out.

Garry-

Why would you want carpet in a fishing boat in the first place. Use vinyl

It is special and made for boats very easy to work with compared to carpet and last long no hooks getting caught in it and cleans very easy. Will never go back to carpet unless I go back to 21 and have a bevy of sweeties in a private yacht.