
09-15-2006
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Join Date: Feb 2000
Location: Annapolis, Md
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I think that you are correct that these boats have an iron keel. What I can't recall is whether they have a flange or bolts directly into the iron casting. If the boat has a flange then the keel bolts are comapratively easy to replace.
BUT if the keel bolts go directly into the keel casting, you are looking at a massive and miserable job to do. I did this job on a Folkboat back in the 1970's and it was a real bear. If the bolts are in the keel rather than a flange, a Columbia 25 mk II is not valuable enough, and is not a good enough boat, that unless you got her free or already owned her, to be worth doing the job professionally.
The step by step job is first figure out whether you are dealing with a flange or not. In either case the first step is to carefully block up the boat and brace the keel, and then back off the existing nuts. With a flange mounted keel the boat is then lifted off of the keel and the stubs of the bolts driven out the bottom of the flange. Some may be bound in which case you, cut the bolt off flush, drill down the center of the bolt with increasingly large drill bits (5/16 in 1/8" increments on up to 3/4" or even 1") and then use a chissel to split the bolt so that you can drive out the pieces.
If you are dealing with internal bolts it gets much harder. Typicially, in that era there were bolt pockets in the side or bottom of the keel. You have to open the pockets, remove the nut, and with any luck at all extract or drive out the bolt. The times that I have been involved usually a few come out easy and then you go to war with the rest. You either end up drilling them out, or else drilling new holes into the iron, tapping them and then screwing in new bolts. This latter solution is a course of last resort as cast iron does not hold bolts very well. Boat building manuals discourage that as a rule and the only manual that I ever saw that recomemnded it as a suitable repair suggested that the threaded holes generally need to be 12 to 16 bolt diameters.
It is a much easier to this if you can drop the keel and if you have access to a good drill press and can set up some kind of portable boring rig. Working in the bilge, even with the industrial 3/4 chuck drill that I was using, was months of back breaking work. It was the worst job that I have ever done on a boat.
Jeff
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