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Lure of The Wooden Folkboat



Maintenance Topic - Keelbolts


Swapping out the keelbolts is a thankless job.  They don't make the boat faster, or even prettier.  They just hold the keel on, and after 56 years, maybe it is time for Shanty (#56) to get some new ones.  It also is a very frightening job, a Folkboat keel weighs a ton, literally, 2200 pounds and held on by some rusty old bolts that somehow have to come out.  This is not a job for the faint of heart, so Fred Anderson has been kind enough to do the job. 
Keelbolts are mysterious too.  No one can tell you how long they last.  In Svendsen's yard they have keelbolts from hell mounted on the boatyard's wall, they changed them out just in time.  You hear about the ocean racers who lose their keels and now that is one of my fears.  To be sailing along in the bay and oops, there goes the keel.  Fred Andersen told me at least you won't sink in a wood Folkboat.  Fred has Filur (#74) in the shop being polished and varnished and I asked him just how old are the bolts?  He said Dan, the previous owner, changed them and was pretty upset because the old ones were perfect.  That is where the mystery lies.  Brandt-Moeller built Filur, and there was another Brandt-Moeller of the same age a few years ago that lost her keel while in her berth.  
    This is a job I've been putting off, not because of the expense, but because sometimes wood Folkboats don't survive.  I sail on Scout (#115) often and while she is a fiberglass boat, she has the soul of a wood one.  She was a wood Folkboat that was never the same after the bolts were changed.  A couple industrious folkboaters cast a fiberglass hull and used everything else from the wood boat.
    We replaced the front keelbolt and the bolts for the stem on Shanty last haulout.  The second keelbolt was replaced some time ago.  I suspect the other bolts are not quite up to snuff and here is why.

Here is a picture of the keel, just washed off and you can see where the wood stops and iron keel begins.  Only in the back, the front is perfect.  It appears that the rear keelbolts may be a little loose.  OK, so here we go, how to replace keelbolts
Step One, set the boat almost on the ground to make it easy to work on.

Step Two, open up the pockets in the keel where the end of the bolts are.  Small problem, no pockets on this keel, Fred doesn't seem quite so happy......

Here is one pocket (upper left), but that is it.  If you look lower down the keel, next to the chain, is another keelbolt.  The bolt comes all the way through the keel, yes, this one is perfect, only a few years old.  The rest are still a mystery.

Step three, since you can't get at the bottom part of the keelbolts, undo the upper keelbolt nuts.  Then raise the hull a little on the stands to take some load off the keel, and with a sledge, hit the top of the bolts.  Fred made the point that you only want to pound on keelbolts with the keel attached.  The shockload is absorbed by the keel and is relatively gentle to the hull.

Success, an air gap between the keel and hull, not much less than 1/4 inch.  Now time to crack a beer and leave it to dry out overnight and let the wood shrink a little.

Step four, after drying out for the weekend, Fred got the keel to separate a little more, chocked the keel and then cut off what keelbolts were left.  He raised up the boat up on the stands and lowered them down onto the blocks and the keel to support the hull.  Turns out the rear keelbolts were indeed bad.  

Here is what the rear keelbolt looked like, it was corroded down to a pencil point.  The keelbolt just  forward of this one was gone completely.  Now the difficult part, getting the remains of the keelbolts out of the keel and floor timbers so new ones can be put in.  The remains of the bolts in the floor timbers can't be driven down, so Fred has some special hydraulic tool to pull them up and out.
Once the keel is off, the bolts can be taken out, the keelbolt portion inside the iron keel are perfect.  At the bottom of the keelbolt, the square end of the bolts are hand forged steel.  This picture also gives you an idea of the size of the keelbolts.  Now is a good time to clean the corrosion from the iron.
  It is easy to forget how much of the hull is iron.  Looks pretty funny without the keel.  Now it is time for rebuilding, Fred is off to pick up some oak to build some floor timbers.  The new keelbolts out of 316 Stainless are ordered.  If the old mild steel keelbolts lasted 56 years, stainless keelbolts should last even longer.  Now, what to do until the new bolts arrive next week, bad weather for varnishing. 

Here is the new lower section of a floor.  The upper section is in very good condition but the lower section was damaged.  When steel rusts it expands and this was strong enough to break the old floor section.  Roger Rapp was here today and said that many old time boatbuilders would make the floor timbers in two sections for just this reason.
Fred repaired the floors by making two thin sections because the access is so difficult.  Once in place, he combined the two with screws and glue.  Once painted they will match perfectly.
 The new keelbolts in 316 stainless steel.  The old steel keelbolts lasted 50 years, these should last even longer.
Fred raised up the boat on the stands and moved the keel roughly into position using a forklift.
  Now the job of lining up the keel so the bolt holes line up.  The question is how do you move a 2200 pound keel?  Turns out, you don't, you move the boat.

Fred was able to move the boat by adjusting the stands.  The keel was a little over one inch forward of the boat so here you see Fred lifting the bow to make the rear keelbolt holes line up.  Easy, right? maybe if you have done it before.

Did I mention that everything is set in 5200 adhesive.  Here is Fred caulking the rear bolt before setting it in position.

Keelbolts in position.  Fred added a nice touch, notice the inserts at the top of the floors.  They were beat up from the old bolts.  I'm thinking I should varnish them to showcase the craftsmanship.  
    Next step, we wait for a day to tighten up a little more, a week for the 5200 adhesive to set up, then add water.

With the keel now on, time to fair the keel, turns out to be quite time consuming.  First, the rudder could use some attention.
 The rudder is old fashioned with the lower pin using the keel as a pivot point.  Trouble is, the keel is being used as a bearing but in salt water there is no way to protect from corrosion.  A big chunk of the keel under the rudder broke off and the hole has become so large, the bottom of the rudder wasn't supported well.
The solution came to me while I was in the dentist's chair.  Drill down into the keel and build it back up.  Here I have drilled a 3/4 inch hole about three inches deep.

I inserted a stainless steel sleeve in the hole and will fill around it with an epoxy filler.  This way the iron keel will no longer be a bearing surface and the stainless steel will be able to handle salt water better.
    Now that the the boat has a keel again, there is still plenty of work to do.  The keel looked like the surface of the moon, with a lot of rust and craters from 56 years in salt water.  The first job is to blast off all the rust, the best way is to sandblast, but that is out of the question in a boatyard.  Airtools will work, I used an air chisel to get at all the deep stuff and a tool called an needle gun to get the smaller stuff and pound the rust into submission.  Even after all this, the keel still rusts on its own, the iron is porous and has water trapped inside.  The only way to counter this is to keep the oxygen away and paint is the best way to accomplish this.  I first coated the keel with three coats of a thin, etching primer (the green in previous pictures), this was followed by three coats of an underwater primer.  The undercoats filled the pores but not the craters, that is where fairing compound comes in.  I used a vinylester fairing compound in various shades of blue.

This is what a keel looks like in the process of being faired, splotchy and multi-colored.  It is a rather simple process of filling the low parts and sanding flush.  This will get it close, sure you can get it perfect by using long sanding boards but this is a time consuming process.  I think time is better spent painting a couple coats of epoxy barrier coats to keep the water out so blisters and rust pockets will not form.

Almost done and starting to look good, the keel is pretty well faired into the hull.  One fellow at the yard asked me if it was a new keel, little does he know what it looks like under all the fairing compound.

Ready to go back in the water, I found some really old fashioned antifouling paint, so she looks very traditional and ready to sail for another 60 years.

This is a nice surprise, the bilge after one day in the water.  Fred said I should paint the bilge, but it is always full of water, no one ever sees it, so I blew him off.  I need to listen.  Thanks Fred, it was a pleasure from start to finish.  Now let's go sailing, no more blogging, Spring Keel is next weekend, and 56 is signed up.