1975 GB32. Epoxy or Polyester?

Hello. Were the earlier fibreglass Grand Banks 32 laminated with epoxy or polyester resin?

I know of no production boats that were or are built with epoxy. They can be repaired with epoxy but it is my understanding that gel coat my not properly bond to it. You would be fine to paint over it.

At least some boats use vinylester in the outer layers to help resist blistering, but I would be surprised if a 1975 model year did that. I think that was still in the "Fiberglass! Beats wood! No maintenance" early days.

(GB went to fiberglass around 1973, at least in the sizes I have considered, 32'-36')

Perhaps some experts here know when the vinylester (in general) started to be used. I don't. But if I had to guess I'd say 1990-ish? (Obviously brand dependent as to if and when they started to incorporate it.)

During the 80’s we were heavily into whitewater paddling. I had two custom boats. One was a C1 (looks like a kayak but flatter, use a canoe paddle from a kneeling position); other was a 15’ open tandem slalom design. The C1 was laid up with S-glass (high tensile strength) and vinylester resin. The open canoe was of Kevlar and vinylester. Mostly for fun but paddled in some slalom races including regional and national open boat races.

Due to the oil crisis of the early 70s, boats were starting to use lighter layups and the search was on for better ways to balance glass and resin use in boatbuilding, at about the same time as GB moved from wood to FG in their boats. Hand layup was still the norm, resins were almost exclusively polyester. It wasn't till blisters became a pervasive problem that other resins were tried, such as vinylesters and, in high end shops only, epoxies. I don't know exactly when you could get a production boat built with epoxies instead of polyesters, but I am sure it never happened in GBs.