Let me guess, you own a late 1970''s early 1980''s Ericson?
Ericson, like a small number of other builders experimented with a technique for building their boats that resulted in the problem that you are facing. To explain the cause of the problem first, Polyester resin will not completely harden in the presence of air. This is very handy because it means that boat builders can lay up a boat without having to sand between laminations and still end up with a chemical, rather than a physical bond between the layers. There are two kinds of resins, laminating resins (used for the various layers)and finishing resins.
Finishing resins are used in the last lamination. It contains a small quantity of wax and that the heat of catalyzation causes to float to the surface. The wax forms an thin airtight layer and in the absence of air the resin cures.
Ericson experimented with only using laminating resins because they thought they could save labor installing bulkheads and other glassed in items.They built the boat and then sprayed the boat with a paint
that was supposed to seal out air. The problem was that paint
was too pourous and so the resins never really cured properly. Years later this uncured resin was still seeping through the paint
So how to cure the problem. I am not really sure but I would try spraying a parafin wax on a test area and letting it sit for a little while. Perhaps with a little heat on the area.(Was I right that you own an Ericson?)