Restoring the Shine to Fiberglass, The outer surface of a fiberglass boat is normally a special resin called gelcoat. Gelcoat has little structural value–the underlying laminates of resin-saturated glass fabric provide that–but gelcoat protects the hull and gives it its color and shine. When the gelcoat was originally sprayed into the hull mold, it–like all gels–took on the shape and texture of the mold surface. The ultra-high gloss, most new boats, exhibit is due entirely to the highly polished, mirror-like surface of the mold used in the original construction of the boat. Time and exposure eventually erode the relatively soft surface of gelcoat, leaving it dull and chalky. Normally called oxidation, fortunately, the gloss usually can be restored.