Posted by wing15601 on 04/20/15 - 5:48 PM
#4
im not sure what chemical process causes osmotic blisters. Gelcoat is not waterproof though water migrating through is probably on the molecular level but something chemical happens between the gelcoat and fiberglass layup which causes the blisters. I have a 1984 Montauk 17 which has spent years in a slip in both fresh and salt water and there are no blisters. I wouldn't worry about it. If you can't help but worry, have an epoxy barrier coat applied to the bottom.