Just read the stupidest article in BOAT US magazine about hull blisters saying you should immediately repair osmotic hull blisters. BS, almost all "repairs" make things worse and the effect of blisters on performance is so small you'll never notice it There is not ONE documented case of normal osmotic blistering leading to any hull failures. It is nothing more'n a way to sell expensive "repairs" that do nothing. I know, I been there'n and done that and wasted the money.
My advice, ignore em and put on new bottom paint and go sailing secure in the knowledge that anything you do will make it worse and achieve nothing. My 1981 S2 has gazillions of blisters that do not affect her at all.