Help me decide - do I NEED to paint the hull?

This is a little long but please bear with me. A little history and background. 1970 15ft fiberglass boat that has been stored in a garage since 1987.

The are many little blisters covering what would be the wet surface of the hull if it was in the water. The blisters are small, up to about 1/8" diameter and barely raised but you can feel them if you run your hand over the hull. Osmosis I believe. The hull is DRY since it hasn't been in the water in over 20 years.

At some point in the past the hull has been finished in an antifouling paint that is now mostly worn or flaked off. I found that paint stripper works good at removing the antifouling.

The boat will be trailered when not in use so will spend relatively little time sitting in the water.

I experimented on the transom as follows; Power sanded with 320 grit to remove oxidation, staining etc and also to knock the tops off the blisters. Next wet sanded with 400 then 600 grit to bring the gloss back up. Turned out pretty good so far. Plan on finishing with rubbing them polishing compounds then a good waxing.

So here is the question. Is it necessary or recommended to paint the hull? If I just complete the sanding and buffing process, can I just go ahead and use the boat as is? Will the blisters reappear, and if they do, do I really have to worry about them? Will painting prevent the blisters from coming back?

This is an old boat and I don't expect it to look like new, but I also don't want it to be destroyed thru negligence.

Comments and suggestions very much appreciated.

Re: Help me decide - do I NEED to paint the hull?

You can use an epoxy barrier coat after sanding the hull then repaint, it'll be a little expensive, but on a small boat it won't be too bad.

OR, you can just continue what you're doing and may last for a while at least.

Either way there's no guarantee they won't come back. On bigger boats they'll strip all the gel coat off plus a layer or two of mat and use epoxy to rebuild the surface, this doesn't work all the time either. When the boats in the water you're the only one that knows they're there, so it just depends on how much work and money you want to put into it for you to feel better about it.