Keelbolt conundrum

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rjp

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Alysia, my wooden Buchanan 32, is just about ready for a survey so I contacted a surveyor to book a date. When was a keel bolt last drawn? - pretty much the first thing he asked. No idea says I, but they are bronze and every bronze bolt or fitting I've removed has been pristine. He then proceeds to tell me that he would be wasting his time and my money unless I remove a keelbolt before he comes. So I go poking around under the keel with a mirror looking to see where I need to dig a hole but can't see where the darn things come out. Bottom of keel is pretty pock-marked, looks like she's sat on more than the odd pebble during her life, but nowhere can I see anything that looks like a pocket that would take a keel bolt. Is it possible that they're cast into the lead keel rather than through bolts? If so what are my options - drop the keel, x-ray? Any other suggestions? I'm reluctant to start hammering unless there's some likelyhood of something actually coming out of the bottom.

John
 
The keel bolts being bronze, could be tapped into the top of the keel, that is holes drilled and threads tapped in them and the keel bolts/studs screwed into the keel, boat is then lowered over the keel, nuts put on inside the boat. The only way one could be "pulled" in that case is to slacken the nut, put another nut on the stud, lock the two nuts together and then unscrew the stud from the keel, otherwise, you would have to driop the keel to inspect them all. But of course there may be another way, I just dont know it.
 
If the keel is lead, then there may be bronze nuts cast into it, as the lead is not a really strong metal when threaded. An iron keel will almost certainly be tapped. The removal method outlined by CCScott is fine, provided that enough length of bolt protrudes above the nut to allow a second nut to gain a grip of the bolt. If there is not enough bolt for this, get another nut of the correct thread which can be sacrificed. Cut through one "corner" of the nut with a hacksaw so that the nut can be clamped onto the bolt with a pair of self-locking pliers when it is put on in lieu of the regular nut. Sometimes keelbolts can be under the engine, and an X-ray might save a lot of grief in this case. If you have to get the X-ray contractor in for this it would pay to do all of the other bolts at the same time. Try the simplest method first.
Peter.
 
I suspect that they will go all the way through. Most boats are built that way - but it is not uncommon to be unable to find the lower ends!

My boat has an iron keel and iron bolts and we can never find the heads of the bolts until we start bashing the other ends.

The bolts may have T heads or "upset" (cone shaped) heads.

When it comes to bashing the inboard ends of the bolts - ease the nut back far enough to protect the end of the thread and bash the nut hard with a very heavy hammer. 14lb sledge hammer is ideal. Tapping away with anything smaller just deforms the head of the bolt.

One thing that you should perhaps do anyway is to contact Alan Buchanan and buy a set of the drawings for your boat - nice to have and makes the surveyor's task much easier, but will also show where the bolts are and how they are driven.
 
I concur Mirelle, I'll bet at the bottom of the keel there are 2" square holes where the bolt heads reside, well recessed. They will be invisible under the accumulated paint, gunge etc. & filled with some sort of filler. A good scraping back to metal should reveal them in due course.

Bashing those lovely bronze bolts is most unpleasant, but the only way.
 
If you can not see any thing from underneath then I would look very carefully at the sides of the Keel for signs of square/rectangular blanking plugs. Not uncomon for lead keels to have pockets cast in to reduce the length of bolt needed. The bolts will then have nuts and large plate washers fitted.
 
Thanks all for the helpful suggestions. Being a first-timer at keelbolts I'm erring on the side of caution but it's reassuring to know from those with experience that I'm not the first person to have these problems! I wrote to Alan Buchanan this morning to seek his advice. I have a set of drawings for the boat but detail of the keel fixing is missing, just a set of centre-lines for the keelbolts shown on the general schematic. I've marked out where the bolts should come out approximately and cleared an area with the angle grinder but still nothing, so for now I'm biding my time getting on with other jobs in the hope that information/inspiration will make everything lucid. Have to go to foreign parts with work on Sunday for 10 days so will defer doing anything further until I return when I will attack the problem in earnest. Just a bit worried what the effect of beating a keelbolt with a sledge hammer might be if it ISN'T designed to pop out of the bottom. Obviously I'm hoping to reuse the keelbolt if I ever manage to get it out - is this wishful thinking? I'm assuming of course that there will be nothing wrong with it except the havoc I might wreak with sledge hammer. One alternative suggestion I've been given is to fabricate a 'bridge' which can be attached to adjacent keelbolts to allow a hydraulic jack to be applied to the top of a bolt. Anyone ever seen/used this method?

John
 
If the lower end of the bolts is contained within the ballast, you'll only deform the bolt by trying to move it independently to the others. If the bolt is waisted then it may fracture at the 'waist' and the upper taper would drive past the lower until the whole lot siezes up in the hole. Better to try to draw it out upwards by unscrewing until you know for certain how they are set up.
Peter.
 
I would NOT plan to replace a bolt that you have drawn.

You will find that bronze bolts are not quite as earth-shatteringly expensive as you may have supposed, and they are prone to going "crystalline" in their length - I don't pretend to understand the metallurgy of this, but it may be related to fatigue stresses - so that they break very easily after some years.

Pete Thomas is right - if no trace on the bottom of the keel, there MUST be rectangular pockets in the sides of the keel containing large nuts and washers, and these are usually filled with a fairly friable filler (typically just linseed oil putty) which can be scraped out without difficulty. Fairly easy to locate as the filler makes a dead sound when tapped - you can then scrape back the paint to find it.
 
When I removed Kestrel's bronze keel bolts they had been in place for probably 80+ years.

Although not as good as new there was at least annother 50 years life in them. Not so the large square nuts on the outside. If hit with a hammer they broke clean in two.

Incidently, a well meaning previous owner had been worried about the keel bolts condition and decided to double up with some steel ones. Not a good idea! All I found in the lead keel was the hole - no sign whatsoever of the bolt.
 
Bronze keel bolts should come out quite easily. Do NOT hit them too hard unless you are very sure about both ends of the bolts. NAB, Nickel Aluminium Bronze is about as good as you can get. Available in 10ft lengths. Extremly strong and shock resistant. The refrence code used to be ,CA103, though there are others .Composition 20% Aluminium 80%. Copper 5% Iron and 5% Nickel. You must use the same grade material for the nuts otherwise you will suffer corrosion problems. Check out Columbia metals.co.uk for availabilityof material.
 
Why would the surveyor want you to exract a keel bolt? He should be able to see if there is a need to do this from his inspection as there will be tell tell signs indicating any movement or leakage. A boat builder told me years ago that if the keel looks in perfect condition and the the keel bolts/nuts look in prestine condition then leave them alone.

Regards.

Peter.
 
Try another surveyor ?

Unless your insurance specifically requires taking the boat apart, or upon close inspection something looks iffy..... why do it?

I would expect the expert to come up with some blooming good reasons for this claptrap before I agreed to pay him to board my boat.

Ask him what type of boat is his speciality? Is your boat the type of thing he is really good at? If he is a plastic bred chap, good at osmosis and rigging, then perhaps he is not for you....... It could be a waste of your money regardless of whether you pull a keel bolt or not.

Good luck.
 
My boat is 53 years old. We had the bolts xrayed and ultrasound tested by Spree Engineering in Kent, and decided to leave them in situ. There appeared to be less than 10% wasting, so I think we're alright for a bit longer (fingers crossed, wood touched etc)
 
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