I am in the final stages of rebuilding a O'Day 25. The boat we taken off the trailer for the 1st time to get the bottom barrier coated. We discovered that the centerboard had been glassed in; barnacles and centerboard. After cutting it free, the centerboard was removed and is being treated with barrier coating. Now i need to know what should be done with the 2cavity. How can that narrow be properly prepped for barrier coating and anti-fouling?