Antifouling Peels Off

My son discovered some small white spots on the port side next to the keel. A closer inspection showed that the antifouling is peeling off. Fortunately, only the small area next to the keel seems to be affected. But I don't know what the reason could be. I will investigate it the next days.

Area where the antifouling peeled off, after cleaning with a steel brush and washing with salmiak-water

 

Subsequent entry:
The reason for the poor adhesion of the antifouling is probably moisture from condensation or very humid conditions during curing. Thus a waxy film appeared on surface of cured epoxy.