In a message dated 6/10/03 12:02:44 AM, trawler-world-list-request@lists.samurai.com writes: << Looking at some websites I came across a cautionary word about older yachts having cheap wood core to strengthen the GRP decks. This then rots when teak decks previously screwed down come loose with age letting water in the screw holes. This rot can be very hard to pick up with a survey and not surprisingly repairing/replacing the deck would be hugely expensive if not impossible. Sounds like a potentially very valuable tip and makes me pretty nervous. I can't find any other info on it so seeing your list >> Neil, The use of wood or foam core decks and hulls is widespread in fiberglass boats. Fiberglass is very strong in tension but is not particularly rigid. The core between an inner and outer layer of fiberglass provides the required rigidity without unduly increasing the weight. Many respectable trawlers were and are still being made with glass over plywood topsides and decks. Unfortunately if water is allowed to penetrate a wood core structure the wood may eventually rot. Fittings to a wood deck must be properly caulked and the bolt holes pretreated with resin to prevent water penetration of the core. If rot is discovered it can be treated in several ways. Map out the area of rot by core drilling or sounding. If the area is small the easiest approach is to drill a grid of small holes over the rot area, let dry, and inject a low viscosity epoxy like Git Rot. Then patch the holes with epoxy putty and paint. If the area is large, and if the deck is cored with a lower layer of fiberglass, carefully cut off the upper layer with a contractor's saw or router set to just penetrate the thickness of the glass. Remove the fiberglass. Take out the rotted section. Scarf the edges of the plywood core and epoxy glue in a new piece. Replace the removed fiberglass section and resecure by use of fiberglass tape and resin. The job is time consuming but the material cost is low. It's messy but it ain't brain surgery. The reason it is expensive is that the process is labor intensive and boatyards charge by the man hour. But it is easy to do it yourself. All it takes is the courage to tear up your boat. Larry Z