I will be attempting to spray paint my hull this spring. Black hull with silver stripe. Any one with experience in two part spray painting of hulls - do you have any do and do-not's to watch out for. I was going to use the Interlux barrier coat first, BUT I have just been told by a paint contractor that the barrier coat is largely a matter of marketing hype. If the hull is older than four years and has had no blisters. A hull properly prepared and painted with a two part polyurethane is all the protection you will ever need. (UNLESS THERE IS HULL DAMAGE, like a gouge or deep scratch that is not repaired) The use a good quality two part paint eliminates 99.99 % of any problems. But here's the what????? part. He claims that he as a chemical engineer and a professional coating expert, the truth about blisters is that the blame really is both the resin manufacture, trying the sell cheaper resins that has been cut with solvents to thin for manufacturing speed and to max profits and the boat builder who did not properly squeegee the resins into the cloth to properly saturate the cloth and eliminate the air in the glass fibers, there by a wicking of any moisture from outside the hull or from inside would be the natural step. But "liabilities" you know, the insurance/lawyers claims prevent the truth from being clearly faced up to.