Some of first polyester resin boats used cotton as a substrate, not fiberglass. Some of these boats were still in use in the '60s. Polyester resin was invented by Dupont in the '30s but perfected by the Germans. The Brit's stole the formula for the improved Polyester Resin from the Germans and gave it to the US who began manufacturing it in 1942. Fiberglass was also invented in the '30s with Owens Corning filing the first patent for fiberglas in 1938. Fiberglas reinforced polyester plastic parts
soon went into production for aircraft parts
after 1942. There were many pioneers in fiberglass boat production and date from the late '40s. by the '50s, fiberglass outboard
boats were beginning to replace wooden runabouts. Our neighbor bought a fiberglass boat with an unheard of powerful 35hp Johnson outboard
around 1956-58. We used to scrape up all the nickels we could to buy gas and ski befhind the boat. Our 18hp Mercury
powered wood skiff that we bought in '57 had the bottom sheathed in fiberglass by the builder, but was marginal for skiing. Mercury
and Evenrude/Johnson were soon in a hp war breaking the 50hp barrier by the end of the 50's.
became a problem with the OPEC fuel
embargo in 1973-4. The boat builders became desperate to get resin and began importing a lot of it from the far east. That resin had issues with blisters. Remember seeing a boat in around 1975 that almost totally blistered below the water line. Uniflite built river boats for the Navy
out of a fire resistant resin. They put their FRP boat production expertise to work making civilian powerboats as the Navy
contracts began to dry up in the early '70s. They made a big deal about the fire resistant qualities of their boats and the hulls and decks they layed up for Valiant. Severe blistering problems of that fire resistant resin soon raised it's ugly head
and put Uniflite out of business. Valiiant lived on after dropping the Fire Resistant Resin for standard Polyester Resin. About the only real fix for boats built with that resin was to grind the below water line hull
down to a thin male mold
and laying up a new hull on to it.