I have about as many on my boat, but from the pictures, mine may be a bit smaller and not so promenent, but I do have three larger ones about the size of a 50cent piece.... in the research ive done, the bigger ones are the problem ones....
but its true that the resale value of the boat will be questionable.
from all I have read about the subject, what you have is not troubling, but more of a nuisance for a racing boat.
the yard I used to haul the boat when I had the survey done said about the same as all the experts who have done in depth studies and written books on the subject say... when the boat drys out, the small ones may disappear and are not a real problem at this time... but they can develop into a more serious problem at any time. rarely bad enough to put the safety of the boat in jeopardy, but severe problems are not unheard of some of the early built FRP hulls.
there is a lot of good reading on this subject, depending of course on how interested you are in it... after reading you will probably come to same conclusion the experts have, that the "repair" of the small blisters that dont grow very fast is not really necessary, but for vanity reasons people dont like their boats to have a "pox", or have any problem that may diminish the value of it...and so will spend thousands to repair it, if they can afford it.
a couple things the experts all agree on is, when a boat has a few small blisters, a "questionable" yard may use this opportunity to make clear the dangers of blisters in the hull, and in turn, make a lot of money from the fear factor that they have instilled in the customer.
the questionable/dishonest boat yard does not differentiate between the small gelcoat blisters and the big deep blisters that can be troublesome. and so after the education the boatyard just gave the customer, he/she will shun a boat with any sign of hull blistering in any future boat or discussion about it.
and another agreeable point is... if more people knew what they were seeing when looking at a blistered hull, there would be a lot less worry about the small blisters that most of the older boats have (or had) at least a few of...
what you show is not an immediate problem, so I would do exactly what Stu Jackson does and give it a new coat of paint, and in another 3-4 years, see if they are getting worse.... its really no more work to repair blisters that are twice that size later than it would be to try and "cure" the problem now... if they dont get worse, enjoy the boat and sell it when your done.
if putting 10-12,000 dollars into it isnt going to make it sail better, then whats the point, because you probably wont get the money back out out of it when or if you do decide to sell it. unless its a newer or high end boat..
here is another FACT... just because you repaired it with the latest and greatest technology available, there is no guarantee that it will keep it from happening again. it has been noted that after some attempted repairs,in a few years the blisters came back worse than before. money well wasted!
what I have wondered is,.... if a person let the hull dry out for a year so the small blisters had a chance to dry out, then bead blasted the the gelcoat to clean it and rough it up, and then painted it with a barrier coat of epoxy or vinylester resin, how would it hold up then?
if one is only trying to keep the non-waterproof/porous gelcoat from swelling as it soaks up water (and in turn creating a bubble behind it that holds water), then this procedure should be an affordable fix for most of us with gelcoat blisters (as opposed to the more serious deep hull blisters).
at the very least, it doesnt cost much to try and should be a smooth finish. and if the time ever comes to do the $12,000 repair, its easy enough to strip off with the gelgoat, and the foundation with be fresh and clean without previous attempts at grinding and filling.
this is what I plan to do to my boat when I get it home for a couple years...
