Chances are, if you own a GRP boat at some point you’re going to have a ding, resulting in scuffs, scrapes and dents. Or in the case of Maximus, our PBO Project Boat, you might inflict gouges yourself with some over-eager paint scraping! Don’t panic, the beauty of composite hulls is they’re easy to repair – although getting a smooth finish and the correct colour does require precision. Before starting a gelcoat repair it’s worth understanding how GRP boats are made, and why gelcoat is so important.
Hull construction
Composite hulls are made from two or more materials with different chemical properties which, when combined, create new characteristics. This may be resin combined with glass fibres (GRP) but there are other types too, such as carbon fibre and ferrocement, or wood combined with epoxy resin.
Sandwich construction, which you find in Sadlers and Etap yachts, is also considered composite. Here you might have a balsa or foam core sandwiched between skins of GRP. These hulls are well insulated and unsinkable as their foam core provides buoyancy.
Osmosis
GRP layers are known
