Re: sailcloth: laminated or woven?
I don't think you can fault a laminated sail for coming unglued after 20+ years. Used or not used, it is still a flexible adhesive joining two flexible plastics, none of which really takes well to adhesives in the first place. And every time you bend or roll the cloth, each layer bends to a different radius and that pulls laminates apart as well.
After 20 years? The glue is probably coming undone, and the glues they had 20 years ago probably had nevr been tested, or intended for use, for that long.
No sail is really designed to be used that long.
Get a dacron sail, get good cloth with a heavy resin calendering, and HAVE IT RECOATED from time to time, before the original resin can wear off. Or, ignore that and put the money towards a new sail in ten years. Honestly, 20 years? As the man said, give it a good burial.