I am rebuilding a neglected catamaran
. The water tanks
are fibre-glass, roughly moulded to the shape of the hull
. They are installed under the beds, kept in place with partial bulkheads ( is there a term for a bulkhead that doesn't fill the whole space between the floor and the deck
? ). The bulkheads are ply, and they are glassed into the hull
. The ply has delaminated, and the bulkheads need replacing entirely.
I've removed the old bulkheads, but now I am thinking how they got damp enough for long enough for water
to penetrate. Perhaps they weren't epoxied carefully enough, so that water penetrated. Anyway, it seems to me that with such a system, condensation
around the tank is inevitable, whenever the air is warmer than the water in the tank. Water is bound to build up between the bulkheads.
How can I avoid a build up of condensation
? There isn't room with the tanks
I have to create much of an air gap, and ventilation under the beds is difficult anyway. I don't want to fill the space between the tanks and the hull with foam, in case I need to get the tanks out for any reason. I am thinking of laying polythene over the hull, then using foam around the tank. But does ordinary polyurethane
foam ( as sold in builder's merchants ) absorb water? If so, can anyone recommend another foam, or another solution?