




jm,
Polyester resin is micro porous. Epoxy resin is a little better. If your boat had no gelcoat coating to seal the resin/glass hull it would sink like a rock.
You can build a resin-coated mdf box and run a hose over it continuously with no problem....IF drainage is part of the equation and if the box execution is perfect, ie; no seams, no staple/nail/screw depressions, radiused edges, etc. But a boat is a little different. It's a sauna under cover with a little moisture in the bilge. With a rare roller over the bow water gets everywhere. If the box sits on carpet you have a mold and mildew trap that will wick up moisture through any coating and will eventually delaminate even the best grade of solvent based ply. Don't use automotive carpet in any case as it will hold moisture. If carpeting use only a marine grade mildew resistant rubber-backed carpet. Again, the materials are important but the construction and installation details are critical in any case.
David
Earmark Marine