: comments.........
My chance to be overly opinionated! Look, I've got enough to worry about in my life without the dreaded fear of polyester microfracturing in my boats. Going to bed at night realizing that every time someone let's a fart loose there may be another fracture in the hull structure is just too much to bear. You can SCRIMP it, vacuum bag it, apply it as carefully as you want, it's still not worthy of wasting good glass or wood by using it. I've posted this before . . . this, George, is the engineering.
http://web.usna.navy.mil/~phmiller/

And then there's the dreaded osmosis blisters that are caused by water penetration and delamination of the hull structure. There are armies of wetbacks making their livings in Florida grinding the bottoms off polyester boats that have been attacked by this boat plague. And what do you think the cure for this attack is? Why it's the application of an "epoxy barrier coat!"
Even the good glass builders haven't faced up to the problem yet.

TPI feels that its SCRIMP process which assures high glass to resin ratios is the answer. Yet, they still use a vinylester barrier coat so they can offer a 10 year no blister warranty. If you price vinylester you will note that it's about the same price as epoxy. Other builders make similar claims. But the truth is nobody knows if polyester can ever be made to work in a marine environment.

If you go up market, Carrol Marine and a few others will build you a boat with epoxy resin, but the rest of the fiberglass boatbuilding industry is addicted to using polyester because it's cheap.

Well, got that off my chest! Now I've got to go out and grind the bottom off my pimpled '69 Boston Whaler and I'd better barrier coat the J/24 before it gets infected.

All this is enough to give traditional wooden boats a good name.