As one of my first projects, I'm planning on tearing out the old painted patchwork of plywood (nice alliteration, hey?) with planks - probably VG fir to match some of the other work done by a previous owner. My current plan is to try and run full lengths (no butt joints) leaving an opening for bilge access, and create a simple removable hatch (from the same strip planks) that spans maybe two floor timbers at the deepest area (near the companionway steps). I'm tempted to use standard 1x3 CVG tongue-groove fir typically used for residential flooring, but I could just use regular planks (non T&G). I wonder if the natural gaps (although small) of the non T&G would be better to help the bilge "breath" and manage the dampness better.