Lead Keel Reinforcement

[Francisco Silva]

I am preparing for casting a lead keel for a 19' sailboat (Golant Gaffer) which has 630 Kg and is aprox. 2.3x0.12x0.2 meters. Talking with the foundry man, he suggested to include, in the casting, somekind of reinforcement, something like 3 or 4 lengths of stainless steel rods, which would act in a way similar to the steel rods in a reinforced concrete beam. Can anyone tell me if this is standard practice, why would this be necessary...

He also suggested including stainless steel tubes for the required keelbolts, as an alternative to drilling afterwards. Is this ok and are there special precautions and dangers in this method? He indicated that a tube of sufficient thickness should be used, so as to be able to create some grooves on the tube for a better "grip" to the lead. What would be the correct type of stainless steel for this usage?

Another question: is 0.5% the correct shrinkage ratio ?

[Thaddeus J. Van Gilder]

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I have been told that lead with about 3% antimony acts just like white oak when bolted to a keel, so I would have to say the reinforcement is not needed, beside they would be a b$*ch when you are drilling for your keelbolts if you were (when you are) to hit one.
This leads me to the next point, In a wooden boat, stainless isn't really an exceptable material for keelbolts, so, the bronze you would use(or monel) might electrolytically react with the stainless tubes inbedded in the lead as sleaves. These seem as though they would be a (first class) pain in the tail to line up, so I wouldn't bother. Lead really isn't that tough to drill anyway, as long as you lubricate the hole.
I say skip the whole stainless thing, skip the foundry, and cast it yourself. I've done it, I'll do it again; It's really not that rough.

[TomRobb]

Rebar would be distinctly non standard and unnecessary. It's not a beam holding up a load. It is the load. And since the several keel bolts that carry that load will be finest-kind bronze,(or have you scored some real wrought iron ones?) why not use copper tubes to cast in the holes for the bolts. Of course you could drill them, but why not avoid the tedium and seized drill bits. Your foundryman probably has the straight scoop on the shrinkage number. That's his bailywyck.

[RGM]

Francisco, you probably don't have a copy of "How to Build a Wooden Boat" by Bud McIntosh. There's good information on pouring a lead ballast keel in his book. I recommend that you get hold of a copy of it. It contains alot of other useful information also. Since you are in Portugal I don't know how easy it is for you to obtain a copy of it. As Thad and Tom stated don't use any reinforcement, or stainless steel (that would be a disaster). If you end up drilling the lead, try regrinding your drill flat (square up, the entry angle of the cutters so it doesn't dive into the lead) and use liquid dish soap as a lubricant. Good luck.

[Ross Faneuf]

The reinforcement is completely unncecessary and would be very unusual.

Including tubing to avoid the difficulties of drilling lead works well; I did it for my boat. I used copper water pipe, rather than stainless; stainless and lead are a poor galvanic pairing. Whatever you use, it is a good idea to plug the bottom of the tubing and fill it with well-packed sand; crimp or plug the top as well. Otherwise, if any lead leaks into the tube (a likely occurrence), you will be faced with the same drilling job. It's fairly easy to remove the sand afterwards; if a little lead intrudes, it will still be porous and the sand can still be driven out.

p.s. the usual shrinkage allowance for lead is 1%.

[This message has been edited by Ross Faneuf (edited 11-14-2001).]

[Paul Brooks]

Hi Francisco

Let me know how you get on - I think I may have to cast the same keel in a bit as the quote for a foundry casting is very high.

A question on the copper tubes. Is this really necessary as it is only 8in deep? It seems that it would be hard to set them up exactly to match the holes in the floors. Or perhaps I've missed something.

A question on stainless steel keel bolts. Is this a problem if the bolts are pre-coated in epoxy? Or are bronze the safest bet anyway

Best regards
Paul

[Dave Fleming]

Fransico, you are in Portugal?
Bom Tarde!
There are some damn fine boatbuilders there and in the Azores! I have worked with quite a few and live in the Point Loma section of San Diego, USA.. It has a large Portugese community involved in boat building and fishing. I would ask a boat builder who he uses for such work and pass on that foundry.
As has been said here, SS does not do well incapsulated and in water. Stick with Bronze, Silicon Bronze, or Monel preferably a 90/10 alloy.

[This message has been edited by Dave Fleming (edited 11-14-2001).]

[Peter Jacobs]

Francisco: Wooden Boat magazine #89 has a 12 page article on casting lead keels. I'm going to be casting a 1300 lb one in the future, so I'll be interested in how you make out.

I looked at the Golant Gaffer plans too. I like the looks of it, and the construction method sounded very interesting. How far along are you?

Regards,
Peter Jacobs

[Bob Cleek]

What they said... do NOT try to cast holes in your lead keel. That technique is for iron keels, not lead. You will never get the tolerances necessary to obtain a tight keel bolt fit in lead except by drilling. It is easily worked with woodworking tools. The idea of putting reinforcing bar in it is about as harebrained an idea as I've ever heard! As they said, how are you going to drill straight through the rebar if you hit it? There is no need to reinforce the ballast. If it is narrow and skinny, it may bend when lifted if not fully supported. If so, lift it the other way and bend it back... or use care and avoid the problem entirely. Your keel is not so large that it could not be done yourself at a lot less cost. I'd seriously consider finding another foundryman. This guy may know foundry work, but he is no marine engineer, that's for sure!

[Zane Lewis]

Well I'm going to disagree with everyone. I think a length of lead 2.3x0.12x0.2 unsurported would be inclined to bend in transporting and during the process of lifting etc. Given the dimensions I think that some form of reinforcing could be good. Given that it will be encapsulated in lead you could probably get a way with SS rod. Once it is in place any reaction that do take place will have no effect. The SS rod would allow you to spead the fasenings further appart. Think of the load on the lead strip if the boat is moving around on the bottom.

It is common for people to put in some locators for the keel bolts. This means that there is no risk of having to drill though the SS rod. ( You would not want your Keel bolts to be in contact with the SS.) Wood dowl can be used. Make sure it is dry and then the lead chars it leaving a char coal drill line.

As the others have said stay away from SS in any location where it will be imersed. We had a Trailer yacht that over a 4 month stay in the water every year would have to have the SS bolts on the lower rudder gudgin replaced every year.
(No electrical system at all)

[gashmore]

I agree with Zane. For us English measureres we are looking at a 1,400 pound ballast keel 7'6" long by about 7 3/4" by 4 5/8". Even with 3% antemony it will bend if it is not very carefully handled and fully supported. With 4% it will break.

As we are talking about totally incased reinforcement, stainless would be fine. In fact, a couple of lengths of plain old 12 mm mild steel re-bar set about 2 cm up from the bottom might even be better. That is unless Dave Connell finds out that lead is permiable to water.<g>

For the bolt holes, I used white oak dowels coated in sodium silicate. They worked great.

[Ross Faneuf]

If you're worried about the keel deforming during shipment, carefully strap it to a piece of timber or plywood box to support it. Same for installation. Once it's bolted in place you will have no problems. Note that the ballast is NOT a strength member of the boat's structure; except that it is a good shock absorber if you hit something with it (voice of experience http://media5.hypernet.com/~dick/ubb/smile.gif)

Bob has a point about a tight fit of the bolts to the keel. In my case the ballast is about 45 cm thick, and drilling through that much lead accurately is something I just didn't want to do. The fit I have is plenty good enough; with a much thinner section you have more options.

[Syd MacDonald]

Unless the lead bonds to the stainless steel, which I don't think it will, it will not do any good. Use rebar, which has a rough surface to prevent slippage and put one at the top and one at the bottom and you have something resembling an I-beam. It will not bend in the verticle plane. It will still bend in the horizontal plane unless you now put a rebar on either side in a horizontal plane. Now try drilling the holes for the keelbolts without hitting the rebar. Cut one rebar and your whole effort is wasted.
Check out the books written by the experts and see how many of them have put rebar or anything else in their keels. In all the literature I have read , including this forum, a bent lead keel is one problem I have never come across. Take the advice of the experts in this forum(not me) and forget the rebar.

[Eb]

I'm curious, if you did use the rebar or the stainless rods, how would you keep them from floating during the pour?

Eb

[Paul Brooks]

Hi
With this particular keel design (Golant Gaffer) I don't know of anybody who has had problems with it being structurally strong enough - though checking with Roger (the designer) would confirm this. (This is not to say that other keels don't need support, though).

Best regards Paul

[rbgarr]

Ross' suggestions make the most sense to me. I don't see any advantages to adding reinforcing bar given the cost and potential troubles. Drilling through such a shallow lead shoe won't be any real trouble anyway.

[Francisco Silva]

Dear all, thanks a lot for the many answers. This forum really is something wonderful. I feel as if this were a family or a worldwide group of friends, always ready to help oneanother. Wouldn't it be nice if we all were to meet one day, somewhere...

Dave, yes i am in Portugal, but there aren't many boatbuilders here anymore, or at least I don't know any. Nor homebuilders either.

Paul, I am still very far away from the moment where I will be needing to install the keel in the boat. But the lead keel is one of those things that I wasn't sure how I'd have it done, so I want to get it done and out of my mind (even though I might need it only some two years from now).

I'm going to start building a plug for the casting and I'm planning to have it cast sometime in January. The quote I got from the foundry is aprox. 1400 Euro plus VAT. Is that comparable to what you got?

To those favourable to drilling, what kind of drilling equipment does one use for boring 19 mm diameter holes in lead. I don't suppose a normal handheld powerdrill would do it...

For the keel bolts, is it acceptable practice to use a piece of rod, threaded on both ends, and then washers and nuts, or should it be a bolt with hexagon head?

Keep coming with the recomendations. I haven't quite made up my mind, but Im leaning towards, no reinforcement at all, bronze keel bolts, and drilling the holes afterwards.

I have just checked. I do have the book "How to build a wooden boat" by David MacIntosh, as well as few others. I now gonna look into it. Thanks a lot to all of you.

Francisco

[gashmore]

A dollar a pound is about what Mars Metals charges, plus shipping and hazzardus waste charge plus some other things. so the price is about right. I don't know what the wheel weight situation is in Portugal so I will stay away from any suggestion of casting your own.

I would still put some cores in for the bolt holes. I had to drill a 30 mm hole in my bulb and it was not fun. Especially counter boring to 60 mm for the washer and nut.

[Wilson]

Hello fellas. When I pour concrete bases for machinery, I set up the anchor bolts into the cement during the pour.

Is it a bird brain idea that the same could be done with your keel bolts?.

Some of the difficulties that I,ve thought of...

Placing the bolts accurately to match the flooring holes, Two solutions might be to wait until the holes are drilled down through the boat so that you can get some definate measurments). Or drill the holes down thru the hull/flooring, pass your bolts down thru and while they are in place , make up your "template" to hold them in place over your mold for the pour

All thats left to do is to push the keel up thru the boat...Yeh I know, my better half wonders at my intelligence,or lack thereof... tell me what you think.
Wilson