I took the centerboard off last spring and when i went to fair and paint it i found that there was water inside it. This water intrusion was no doubt the reason for the gelcoat blisters. I drilled about 20 holes all the way through and let it sit in the florida sun for days, changing its orientation often. Eventually, it dried out enough that i didnt hear it swishing around anymore. It was faired, the wing shape was improved and all remaining damage from use was repaired. The deep repairs were a combo of marinetex and the west system activity kit. The remaing pits were filled with a bondo product for very tiny pinholes. It came out really good and had fun working with the different products to get a feel for what works. Since i used bondo i thought i would use some black automotive filler primer and then apply marine topcoat. So far so good. I added about 5 layers of paint, sanded, then polished. The shell was perfect and upwind performance was much better than before. Been sailing regularly since the repair and admit that we grind on the sandy bottom. The centerboard shows some battle scars on the bottom edge. Well, last week in my excitement of a great sail and concerns of the new tow vehicle pulling up the ramp i did the unthinkable. I loaded the boat on the trailer with the centerboad down. The sound.... Might as well been my shin. The new suv got us out no prob and i was able to check out the damage. About 18 inches of paint scraped off the leading edge and one good ding. It's a leading edge so i knew i had to lay some new paint there. I pulled the centerboard out and figured this would be easy. Nope. Every time i went to sand the paint edge it was still loose enough to flick off a piece. I started sanding the whole paint job off but got lazy and tried a chisel. It was so easy my son asked if he could try it. It was almost satisfying watching the chips explode off as he scraped 1 inch wide swaths of destruction from one end of board to another. Even after chiseling the underlying primer coat was flawless. It had a cool carbon fiber look to it. I figured paint failure was due to an incompatible primer so sanded that off. It was very easy and so now were back to a mix of factory gelcoat, west system, layup, marinetex, and bondo. The base is in really good condition, even the deep red bondo. This time I'm going to gelcoat/flowcoat/hotcoat the whole thing like a surfboard. As I'm washing with soap i turn the centerboard and i hear it. Water swishing inside. Sounds like 8 oz worth. Unbelievable. So now im trying to drain it. I think the water is coming in at the screw hole that locks the centerboard to the hinge pin. The pin is underwater the whole time the boat is off the trailer. Trying to think of how to seal the hole for the screw so that i can undo the screw and centerboard for future repairs. Here are some pictures. On one you can see the sanded topcoat, primer, the fairing. The circular sharpie marks where fairing compound was needed are still visible. At this point in time i was thinking a couple coats of paint and be done. The bottom of the centerboad shows the notch for hinge pin. A screw goes through the protruding bit then into the core. Just blast it with 4200 sealant next time?