Keel Bolt question
I am under contract, pending survey, to purchase a 25-year old boat with a lead fin keel bolted on with stainless steel bolts. I didn''t count but there are probably about ten 3/4" bolts holding the 5000-lb keel on the boat. Inside the boat, the bolts and nuts appear to be in great condition, and they certainly don''t "sound" punky. The washers are well-bedded with polysulfide inside the boat, so leaks at the joint don''t show up inside the boat. Outside, there is a small amount of rust that weeped from the small crack at the keel-to-hull joint on the starboard side. The crack is probably within the realm of what would be considered normal for a bolted-on fin keel. When the current owner bought the boat in 1986, his survey report indicated the same problem on the port side, and called for re-bedding of the keel bolts, which apparently was done.
Obvioiusly, since then the joint has opened up enough to allow seawater into the bolts again, which have corroded some more to produce the rust. So how worried should I be about the integrity of the keel bolts? Could I sail this boat from the Chesapeake up to New England before undertaking further work?
If I brought the boat home, what would be the best course of action: (1) caulk the joint from the outside and forget about it; or (2) drop the keel to inspect the bolts and re-bed the whole joint?
Presumably these are "J" bolts cast into the lead, but since lead and stainless shrink differently, should I be worried about corrosion of the bolts down in the keel, and not just at the joint?
If I do drop the keel to inspect and rebed and the bolts look scary, then I guess I could sister them. Or should I just go ahead and sister them anyways?
If the decision is to drop the keel, how do I do that with the boat on blocks and jackstands in my backyard? Do I jack up the hull rest of the boat (~5000 lbs), or do I lower the (5000 lb) keel on jacks? Or do I hire a crane to come by for 1/2 a day?