Fibreglass, or GRP as it is often known, is made from polyester resin reinforced with chopped or woven glass fibres. Once the resin sets to a hard matrix the resulting laminate is strong and rigid. The smooth external appearance is due to a protective gelcoat, made from polyester resin. Despite its obvious advantages, experience has shown that glass fibre is susceptible to the effects of sunlight and the marine environment.

There are two problems to be aware of:

1. Fibreglass is prone to osmosis
2. Gelcoats fade

Eventually the gelcoat will begin to fade as a result of exposure to UV (Ultra Violet) light in sunlight. Polishing with wax may delay this, but eventually a coat of paint will be needed to restore colour and protect the surface.