Here a trick I havent told anyone yet...Ok on new fiblerglass and new plastics parts.. I use etching primer..its a pea green color..It bites into any surfaces to help prime or paint adhears to the surface...I would use the etching spray can primer for Dupi-Color..works great..First I would use a wash it with prepsol/tar&wax&grease remover or wash the boat hull with dishwashing soap.....Then use a red scotchbright pad to scuff the hull down with....then etch prime it then if there no dirt?Then use a tac cloth to wip the hull with to take any dust off the hull....Then you can start painting the hull...