Glass reinforced plastics, GRP, are a form of fiber reinforced plastics, FRP, which were introduced for marine structural applications in the 1940's in the form of Navy personnel boats. Since that time fiberglass have found widespread acceptance for yachts and small boats such as fishing trawlers up to 34 m in length. Although the future of glass reinforced plastics for larger ship structures is very promising, economic factors, and to some degree, questions of durability, limit their applicability.