Denise, I own a 31, which is basically the same boat you have with a longer tramson or swim platform. Your keel is not encapsulated, it is bolted on to the hull. If you lift the floor boards in your salon and look at your bilge you will see the bolts next to the bilge pump and float switch. And unfortunally it is not made out of lead, but it is cast iron, and therefore subject to corrosion unless is mantained properly. It seems that whomever painted your bottom, did a great job of fairing keel/hull joint, eventually you will see the joint develop again, the keel will move back and forth, through groundings and other motion of the boat, this is perfectly normal. You need to check the through bolts for corrosion and tightness once a season.