I did not have leaks as such that I know of but when replacing a ceiling panel with insulation I noticed daylight through a myriad of imperfections and pinholes.
The roof was rubbed down clearing all bad points and old gel coat; Carefully so as not to go too far as the roof is very thin (2oz) layup. I then applied two separate coats of resin followed by a coating of Gel coat. Finally a primer of Nitrous Oxide followed by a standard synthetic coach paint primer, two coats of under-coat and a top coat mixed with liqueur.
It helps to remove the Moorlight and work from the opening rather than with step ladders. Chuck Berry