Abrasive paint stripping is the preferred method of professionals who make their livings fairing hulls for racers. Yes, it can be hard on gel coat, but what it is really doing is taking out weaker material which might otherwise cause problems under fairing/filler compound. I just recently sand blasted the hull of my 1982 Hunter 33 using a $100.00 Harbor Freight blaster and 00 graded SAND. Note: My 1982 Hunter had not one blister. NOT ONE! Does that blow the theory that ALL hulls get blisters? Yet I saw a recently stripped Marine Trader who's hull was entirely covered with blisters. More in a square foot than I could count. Go figure. Having previously stripped a hull using chemical stripper, I can say unequivocally that sand is the way to go, does less damage than chemical, and is certainly a lot less work. I didn't have enough air pressure to take best advantage of the machine so it took me about a day and a half of actual work to blast my hull. Worst part was sweeping up the 800 pounds or so of used sand and chucking it. Yes, the process left small pock marks. I just spent a few hours filling them with epoxy putty. No big deal at all. Barrier coat? Plain and simple; If your older hull is clean and you don't barrier coat you should be committed! Especially if evidence of blistering has been found. $13.00 per foot of water line length is a good price. In my area the price appears to be $16.00/foot. The professional jobs I've seen look great and show minimal damage to gel coat. Have it blasted!