retapping bolts into cast iron keel

[floatingkiwi]

Just thought I would start a short thread to attract some info as quick as possible to ascertain the correct way to fix new bolts into the keel. I thought thet went right through,Yhe old ones), but they come out about halfway with about an inch of rusty thread left on them. They were surprisingly easy to extract. What shall I do to the keel to rethread new bolts into it.Drill deeper. Use bolts bigger than 3/4. Yikes.Thanks.
Kerry

[Bob Cleek]

Something's not right here. Never heard of iron bolts threaded into an iron keel, particularly not as you describe. I would expect the likelihood of threads corroding and losing their grip in tension would be a strong likelihood, then... bye, bye... ballast keel. Are you SURE that someone didn't just use threaded rod for keel bolt material and the bolt broke?

[John Meachen]

I have seen bolts tapped into blind holes in cast iron keels and while it may not be common it works.It helps if the bolts are galvanised properly and a little grease on the threads does no harm.Without understanding more about the state of the holes from which the keelbolts were removed it is difficult to make suggestions.It also makes a difference if the keel is still attached to the boat.You would probably begin by trying to identify the thread form originally used and establishing how much depth of thread was tapped into the keel.

[bruce w]

cast iron can turn into black sludge in tapped holes if the studs are at all a slack fit in sea water, usualy cast iron is easy to drill ,i would feel tempted to poke a drill through make a deep countersink in the bottom of the keel and through bolt .The thought of pulling the thread out in a seaway would make me ill a ease,on a dark wet cold night in a steep sea ,it would be bound to cross my mind.

[Gary E]

Agree with Bruce and only make one change..
I'd make the CoBore square about an inch or 1 1/4 deep, and the nut square also about 1 inch thick and Bronze...
Put it together with Never-Seez.. and cover the intire area with roofing tar...
This way it wont ever come apart, untill you unscrew it.

And yes, it's a lot of work, but I'd only do it to the bolts on each end...
So if you have 3 or 4 or more, just put them together with the Never-Seez

http://www.neverseezproducts.com/?gclid=CM6msZT9zZcCFQpxHgodrk7DCw

[LakeErieSailor]

I too have a Folkboat, like Kerry (floatingkiwi), and, yes, the forward three or four keelbolts are tapped into the keel. The remaining six have nuts on their lower ends. I don't know if this was the practice on Nordic Folkboats; mine was built by Abbott in Sarnia, Ontario, Canada.

Bronze nuts on steel/iron bolts?

[Noah]

My Folkboat keel had pockets cast into the keel about half way through the keel. There was just enough room to get a nut on the end of the bolt in the pocket - no room for a wrench though - you tighten from the top.

The fun part of my Folkboat was that the pockets in the keel were filled with concrete. Jesus...what a job it was chipping the concrete out of those 3X2 holes...

[floatingkiwi]

Wow it seems there have been as many ways to put a keel together than there are folkboats.
OK. On completion of extraction, one 3 inch bolt at the foremost end, reached the bottom side .There are 7 bolts . 4 were completely rusted away to nothing but dust, where they travelled through the oak floors.The three middle bolts were still retaining over half their girth and were all that was holding the keel on .
Now for the bit that pleasantly surprises me. Every single one of the 7 bolts are wound 6 or 7 full turns into the centre of the steel monolith. and the threads on the end of the bolts and inside the holes are completely intact with no rust. I'm talking shiny full sharp ridged fat threads that look like they were put in a week ago.I am assuming the reason for their preservation was perhaps a lack of oxygen down there. Thread some new stock, spray with cold galv, grease and in, and It'll be good for another 50. What'ya reckon about that guys? thanks for your input all.
Kerry

[eleventhirtyfour]

Good news about the freshness of those threads! At the start of the thread it loomed like the elephant in the room...

[John Meachen]

I will try really hard not to say "I told you so".It would seem that the tannic acid in the oak did more damage than a not too dis-similar metal.I would suggest a good dollop of mastic under the bolt head when the new blots go in.

[floatingkiwi]

Thanks, John. Your reply made the most sense to me and your following addition gives me the confidence I was looking for. Good on ya, mate. Kerry

Say, where does one acquire a "blot"?

[floatingkiwi]

I too have a Folkboat, like Kerry (floatingkiwi), and, yes, the forward three or four keelbolts are tapped into the keel. The remaining six have nuts on their lower ends. I don't know if this was the practice on Nordic Folkboats; mine was built by Abbott in Sarnia, Ontario, Canada.

Bronze nuts on steel/iron bolts?


Hey Manny.you aren't mistaking bolts holding the timber together for keel bolts, are you. If not , I'm jealous you have more than me.
Remember,the plan on "a folkboat found me"? Those drawings are accurate, to the detail. At least with my hull they are. I redrew them bigger and I'm using them for my rebuild.