I have an old plywood rowboat which periodically is repaired with
fiberglass cloth. This has worked very welll- the boat is now about 70
years old!
I just did some minor repair work including bottom painting and
fiberglassing. The bottom is still quite rough as over the years there
have been many layers of paint which has peeled off unevenly.
Even heavy sanding won't fix it completely.
For years it has seemed to me that painting the entire bottom with
fiberglass resin (no cloth) would make an extremely durable and
water-resistant primer, to be painted over with polyurethane marine
paint.
Is there any reason this shouldn't work really well?
Thanks in advance!
Frank