Intumescent paint

A paint which protects glass-reinforced resin (‘fibreglass’) against fire. The polyester resin of which most modern boats are built will burn merrily, so it is wise to protect the galley and engine areas with intumescent paint. When heated, this paint swells up into a crust, not unlike meringue, cutting off the oxygen supply to the resin, and to some extent insulating it from heat.