What would cause the keel to drop a half inch on a 2 ft section towards the stern pn a 76 huntet 30
Are you saying that the cost of drilling out the old bolts will likely be more than the cost of hauling the boat & dropping the keel? Or are you saying that the cost of the replacement bolts is very high?Changing the bolt will be quite a job. First you will have to drop the keel entirely.
Then you will inspect all keel bolts for deterioration. Then you will decide if the cost of drilling out all affected bolts and replacing each (expensive) is the way to go, or if there is an alternative for your situation.
I suggest you google "replacing keel bolts" for a lot of experiences with this problem.
Welcome the world of sailing old boats.That's ok but thanks for getting back. The boat is a learning curve for me as something different seems to become an obstacle for enjoyment.