Keels: Lead v Iron?

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Ric

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I'm a bit surprised to read a thread about the Sirius 310 which reveals that this quality boatyard uses rust-prone pig-iron for its keels. Are there any advantages of iron over lead (apart from cost)? If cost is no object, is there any reason not to use lead?
 
Ric said:
I'm a bit surprised to read a thread about the Sirius 310 which reveals that this quality boatyard uses rust-prone pig-iron for its keels. Are there any advantages of iron over lead (apart from cost)? If cost is no object, is there any reason not to use lead?
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Just looked it up as I hadn't heard of the boat.

Their own website says they use lead. http://www.sirius-werft.de/phpwcms/index.php?id=464,0,0,1,0,0


My own boat has an iron/lead keel. The light-weight iron is very useful as it keeps the lead well away from the bottom of the boat, which allows me to keep more sail up and go faster.

That's the only advantage I can think of other than cost. Maintenance of the iron part of the keel is a nightmare compared to the lead (will see how the epoxy has fared next time she is lifted).

My next boat will definitely have a lead keel.
 
No comparison go for lead anyday unless you can afford uranium(One of my compeditors in the 76 Transat had a uranium keel ).In the late 70's I delivered two Nic 32's(one lead one iron) just after Campers had changed from lead to iron,higher centre of gravity..more tender..possibility of rust.Also 40 years on the lead is worth a lot more!Sorry just saw the thing about fin keels...don't do those.Incidentally mine is Rock Elm and Lead.Questions on a postcard.
 
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Mad Pad said:
No comparison go for lead anyday unless you can afford uranium(One of my compeditors in the 76 Transat had a uranium keel )
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I seem to remember that Uranium burns quite readily in air - happens occasionally when drilling holes in it. Not sure how it would behave underwater, but I wouldn't like to try a grounding test.
 
Lead is great in a long keel, but adds complexity in a deep fin keel - it is far too soft to form the structure of the keel, so you still need to use some strong, rigid material and the overall result is complexity and expense.
 
maby said:
Lead is great in a long keel, but adds complexity in a deep fin keel - it is far too soft to form the structure of the keel, so you still need to use some strong, rigid material and the overall result is complexity and expense.
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Thanks - I did wonder about the structural integrity of deep fin keels in lead. I know the Elan boatyard used to make boats with deep lead keels - something like 2m on a 31ft boat - presumably they had some sort of iron internal support?
 
Ric said:
Thanks - I did wonder about the structural integrity of deep fin keels in lead. I know the Elan boatyard used to make boats with deep lead keels - something like 2m on a 31ft boat - presumably they had some sort of iron internal support?
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I was under the impression that most supposedly lead deep fin keels are actually iron keels with a hollow bulb that is filled with lead - it's more a performance thing than durability. Filling the bulb with lead allows you to get the balast weight lower and to reduce drag since a given weight occupies less volume.
 
maby said:
Lead is great in a long keel, but adds complexity in a deep fin keel - it is far too soft to form the structure of the keel, so you still need to use some strong, rigid material and the overall result is complexity and expense.
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Perhaps you should tell the Swedes then. Antimony is added to the lead to make it sufficiently stiff for the keel,with some residual softness, great for those Baltic rocks. Even Bavaria offer lead keels on some if not all models.
 
maby said:
Lead is great in a long keel, but adds complexity in a deep fin keel - it is far too soft to form the structure of the keel, so you still need to use some strong, rigid material and the overall result is complexity and expense.
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I believe the answer is a lead/antimony alloy. At least I hope it is, that's what hangs down beneath my boat.
 
Mad Pad said:
No comparison go for lead anyday unless you can afford uranium(One of my compeditors in the 76 Transat had a uranium keel ).In the late 70's I delivered two Nic 32's(one lead one iron) just after Campers had changed from lead to iron,higher centre of gravity..more tender..possibility of rust.Also 40 years on the lead is worth a lot more!Sorry just saw the thing about fin keels...don't do those.Incidentally mine is Rock Elm and Lead.Questions on a postcard.
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I was under the impression it was depleted uranium which if i can recall my school physics becomes lead when it has finished reacting. I would imagine it was just lead but more pure and dense. I would be interested in someone with a genuine understanding of the science's input.
 
wklein said:
I was under the impression it was depleted uranium which if i can recall my school physics becomes lead when it has finished reacting. I would imagine it was just lead but more pure and dense. I would be interested in someone with a genuine understanding of the science's input.
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Depleted uranium is highly radioactive and anyway, where did they get it from?
 
CAPTAIN FANTASTIC said:
Depleted uranium is highly radioactive and anyway, where did they get it from?
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A quick wiki suggests that the WHO disagree with you, and say there is no evidence of harm,except if you breathe the dust of exploded munitions.
The specific gravity of DU is about 19, compared to lead's 11.3, it sounds a brilliant material for yacht ballast if you can afford it!
 
wklein said:
I was under the impression it was depleted uranium which if i can recall my school physics becomes lead when it has finished reacting. I would imagine it was just lead but more pure and dense. I would be interested in someone with a genuine understanding of the science's input.
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DU is what you are left with after enriching uranium to make fissile material for reactors or bombs.
CAPTAIN FANTASTIC said:
Depleted uranium is highly radioactive and anyway, where did they get it from?
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DU is not highly radioactive, its heavy metal toxicity is far more of a concern than the radioactivity.
 
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