My two cents worth on hull blisters and repair. My 1975 M-17 hull developed blisters after a full year ( 1983-84) in Folsom Lake, CA. There were literally hundreds, perhaps a thousand but they were very small. While on vacation, I checked with two boat repair yards in Marian and Mattappoisett, Mass. and they recommended, cleaning, sanding and application of Interlux Interprotect 1000 and 2000. Both were unanimous in this recommendation. Naturally, at that time, I didn't know from squat. In a New Bedford Boat US store I picked up a Interlux pamphlet entitled, " Boater's Painting Guide and colorchart". It explained the process for applying the barrier coat s ( 1000 & 2000) which I followed to the letter. Fortunately once the sanding was done ( nasty job with a lap strake hull) I found that the blistering was superficial and did not penetrate to the base. I then applied the barrier coats with small roller and brush and the two coats of Micron CSC anti fouling paint. All this in 1998 and so far no problem. The boat is moored in summer in fresh water. In 2000 I removed the cast iron centerboard and followed their instructions to the letter, sandblasting and coating with Interlux 2000 plus anti foul paint. Again, at this time, no problem. No sticky board, no problemo, works great. Not knowing anything different, I would suggest that one obtain a similar Interlux brochure ( www.Interlux.com) if still available or similar product with comprehensive instructions. My goodness, sailboats really need TLC! For what it's worth. Bill K M-17 Half Monty ( #55 )