Modern composites are considerably more durable than their predecessors. Isophthalic resins offer greater water resistance and tensile strength, while techniques such as performance-matching give a better bond between the gelcoat and the skin coat beneath. However, even the strongest carbon fibre and epoxy laminate can still be chipped, dented, scratched or cracked.
Repairing damage to fibre-reinforced plastic (FRP) laminates is important for structural as well as cosmetic reasons. Thanks to the advances in composites technology, there is now less likelihood of a boat developing osmosis – but any breach of the gelcoat must be viewed as potentially letting water into the substrate, which could ultimately lead to delamination of the hull or deck. This is particularly important with sandwich construction on older boats where, to keep the laminate light but strong, the builders included a reinforcing layer of plywood. If water is allowed to soak into the ply, it can swell up and eventually split the laminate.
Crazing of the laminate can be found on almost any older boat, particularly around highly-stressed areas of the deck such as stanchion bases. If the crazing is below the surface, the gelcoat integrity is probably unaffected – but keep an eye on the problem and, if it starts to spread, think about repair.
Glass fibre is not difficult to repair using proprietary kits, but repairing more advanced FRP laminates will need careful matching of materials.
If you find signs of osmotic blistering on the hull, get professional advice so that you know how far the problem extends. Unless it is very local, you will probably need to call in the experts to deal with it.
Wooden and steel boats should be protected from water by an impermeable skin of paint or plastic – so if the skin is chipped, rubbed or flaked off it should be repaired as soon as possible.
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