Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I don't see any indication that it has any barrier coat on it. The white areas appear to be the original gel coat. Don't be aggressive in your sanding. You should avoid sanding away any of the gel coat. Catalinas built in 1989 and thereafter had factory applied barrier coat. If a pre-1989 boat has no significant blisters after 35+ years, it might not need a barrier coat.
Steve Milby J/24 "Captiva Wind" previously C&C 35, Cal 25, C25 TR/FK, C22 Past Commodore
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.