I'm getting ready to strip down my Fisher Netter 16 Deluxe. It has a factory floor and side walls. I need to remove them so I can strip the boat down for cleaning and paint. There are a few spots where the floor is riveted down to the bottom of the boat, and also some spots where the side walls are also riveted to the side walls of the boat. Any suggestions for removing this? How should I fill the holes? Also, It seems the boat has styrofoam underneath the floor and behind the walls, I noticed it while pressure washing the boat. Does that seem right?