[Barnsnake]

I spent 20 years in the service side of the marine industry and I've never seen "blistering" as you describe it in dry parts of a boat. I've seen delamination of the gel-coat (not referring to paint over the gel-coat) due to excessive catalyst in the first layer of structual glass. Admittedly, my experience is in the sunny south. I've never been around may boats that spent time in the Puget Sound area. Based on some of my trips up there it may be as wet above the water line there as it is submerged in Texas. :-) If the blisters are water-filled, that may be the difference.
In any case, gel-coat blisters are much larger that those TKing is describing. He shouldn't have to worry about grinding the gel-coat off.