Throughout your salon, you have floor access panels. After years of walking on them, some of the panels may feel spongy at the edges. If the panels and floor are in otherwise good condition, it might just be the panel supports that are weakening. The factory used small bolts on my panel support strips, but I felt they were spaced too far apart to maintain full support without flexing under foot. This is an easy fix, with a screw gun and some wood screws

The panel supports on my boat are wood strips that are bolted to the plywood subfloor. The panel supports hold the access panel. They just need a little more reinforcement.

If you have this issue, use a screw gun and some wood screws. I used Number 10, 1-1/2 inch screws. Screw up from underneath. See photos. It's a little bit difficult holding the screw gun and screw upside down, but it's achievable. You may not be able to reach around the entire panel opening, but any screws you can attach will greatly improve the floor.

I tackled this job today on sections of my floor panel, that I felt were flexing too much. Now the floor panels feel rock solid underfoot. Or just like new. Actually, better than new. No movement at all, which is what I prefer.