Gel coat

The g is soft, but the coat should not be. It is the glossy outer skin of a resinglass moulded hull which not only gives desired beauty but also protects the underlying laminate against ingress of water. It is between half and a quarter of a millimetre in thickness (up to a fiftieth of an inch, say) and should be treated with care. Scratches and cracks should be filled before water gets a chance to penetrate, for a subsequent frost would burst further areas of gel coat away from the laminate. Most of the troubles with resinglass hulls are related to the gel coat.