Thanks Jim and Ron for the comments. I spoke to my original surveyor as well as a fiberglass "expert" who has done some work for me in the past. The surveyor thought it unlikely that their could be a "serious" blister problem based on his moisture test 1 1/2 years ago. The fiberglass guy examined the boat yesterday and said that the blisters were only involving the bottom paint not gel coat. I guess they formed outside of the barrier coat but inside the vc17. This seemed consistent with my own exam in that they only contained water under low pressure that did not smell. They both recommended carefully sanding with 80 grit and repainting in the spring. thanks for the assist.
FYI
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