Re: Replacing lead Keel bolts
GeneT has the best advice here IMHO but I'd add one other choice. Your keel is only 1200 Lbs or so - not a huge lump. There is a type of fastener called a "Hanger Bolt" that has conventional threads on 1/2 of it and lag type threads on the other 1/2. If you got some good big ones in good metal, carefully drilled new boltholes, no larger than the minor axis of the lag threads and wrenched them down into the lead it should be adequate.
I believe Catalina advises this type of repair on one or more of their smaller boats. It's called "sistering" the bolts.
I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.