We just hauled our boat
to apply new bottom paint
for the first tome since purchased. We also had blisters
that looked similar to what you are dealing with. It’s a simple fix, but loads of work
Grind them out, leave them be to dry for a month or so, fill and fair, barrier coat, paint
. That’s all there is to it. If some of them are particularly deep, add a few new layers of glass before fairing.