My

is twenty years old. I am the original owner, and have never put a bottom paint on the hull. I did apply a good barrier coat.
A) For the first three or four years the boat was slipped in a fresh water marina. No exposure to a salt water environment.
B) The remaining years the boat was on a trailer, and slipped for only a couple of weeks.
Because of being in fresh water and not salt water, a bottom paint is not needed.
The worse bottom problem was green growth on the bottom. Oxalic acid removes this. (Very informative discussion on this forum, look it up)
Point of this is, whether to apply a bottom paint is determined by where and how your boat is used.
This has nothing to do with the original poster because his problem was (if I remember correctly) regular house paint being used on the bottom by a previous owner. As Catagale has pointed out: “If you are going to trailer sail, do nothing. Any blistering that might have happened has already happened, and epoxy won't fix blisters. If it hasn't blistered by now, it won't if you trailer sail.”