Alright, I own a 1981 Morgan 382 with a mild case of blistering on the starboard side of the hull. There are several dozen dime sized blisters scattered about - primarily on the starboard side. Before I purchased the boat last spring, the boat had been kept in the water year-round for 20 years in the Baltimore, MD region of the Chesapeake.
Post survey, I hired a gent named Mike Previti out of Solomons, MD to assess the extent of the problem. Mike apparently opened the first Osmotech blister repair facility in this area and was in the business for some time. He eventually got out of the blister repair business to start his own surveying company. I figured that he would know blisters pretty well, and, since he was no longer in the repair business, he wouldn't try to sell me something that I didn't need. I was pretty pleased with Mike's thoroughness, and her certainly seemed to know what he was talking about.
Mike sounded the entire hull with a hammer (inside and out) as well as investigated with a moisture meter. In addition, he opened one blister to see the extent of the damage. The blister that we opened up was affecting the first layer of CSM. It didn't appear to affect the mat or roving. His assessment was that I shouldn't do anything to repair them... just monitor the blisters for a few seasons to see if they progressed. He rationalized that, since the boat was over 30 years old and had been kept in the water for at least 20, the problem was about as advanced as it was going to get.
Here is my question... is Mike nuts?
I'm getting ready to go cruising for several years starting next season. We're heading to the warm waters of the Caribbean, and I've read that warm waters make blister problems worse. If I need to fix the blisters, I'd rather do it now while I'm still employed. However, I don't want to waste precious time and money on a problem that may not really be a problem.