wiki
Gelcoat (GRP yacht finish)
Defined term — gelcoat on polyester GRP hulls: cosmetic layer, osmosis blisters, repair scope and survey language.
Definition
Gelcoat is the outer cosmetic resin layer on most polyester GRP hulls — pigmented, smooth, and the first line of defence against water ingress. It is not structural; damage here still matters for osmosis and resale.
Survey language
Surveyors note pinholes, stress cracks, and blisters in gelcoat. Distinguish cosmetic gelcoat cracks from flexing laminate issues below.