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Dave
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Dan Ebert
Lead weights more
Lead weights 710 lb./cu.ft. Average iron weights 473 lb./cu.ft. Source: The Engineers' Manual ~Hudson 2nd Edition
Lead weights 710 lb./cu.ft. Average iron weights 473 lb./cu.ft. Source: The Engineers' Manual ~Hudson 2nd Edition
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Mark Johnson
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MArk
Depends or other uses
Hey Joe, If formed into a bulb or billet and not under any stresses other than its own weight, for a non-trailerable boat, lead is usually a better choice. If the keel is shaped into a thin fin that needs to resist lateral pressure, lead will bend or break, so you better use iron. An iron fin ending with a lead bulb may be the best choice. My answer would have been different if your question was "Which is the better ballast?". For a non-trailerable boat, lead is the best ballast because it takes up less space for the same weight and won't rust, On the down side, it may be hazardous if improperly handled and disposal is a concern. My choice for ballast in a trailerable boat is water. It's free and you can leave it for others to enjoy when you take your boat home. Weight comparision: 1LB lead weighs 1LB 1LB iron weighs 1LB 1LB water weighs 1LB Happy (fusion powered) sails *_/), MArk
Hey Joe, If formed into a bulb or billet and not under any stresses other than its own weight, for a non-trailerable boat, lead is usually a better choice. If the keel is shaped into a thin fin that needs to resist lateral pressure, lead will bend or break, so you better use iron. An iron fin ending with a lead bulb may be the best choice. My answer would have been different if your question was "Which is the better ballast?". For a non-trailerable boat, lead is the best ballast because it takes up less space for the same weight and won't rust, On the down side, it may be hazardous if improperly handled and disposal is a concern. My choice for ballast in a trailerable boat is water. It's free and you can leave it for others to enjoy when you take your boat home. Weight comparision: 1LB lead weighs 1LB 1LB iron weighs 1LB 1LB water weighs 1LB Happy (fusion powered) sails *_/), MArk
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Don Evans
Depends
Oxidation and thus constant maintenance is the main drawback if the iron keel is exposed. If it is encapsulated and the fiberglass is not punctured either could be satisfactory. Some boats have even used concrete. However, since lead is denser it allows more flexibility to the designer with regards to keel size (smaller keel relative to equal weight of iron). It is more expensive though. Don
Oxidation and thus constant maintenance is the main drawback if the iron keel is exposed. If it is encapsulated and the fiberglass is not punctured either could be satisfactory. Some boats have even used concrete. However, since lead is denser it allows more flexibility to the designer with regards to keel size (smaller keel relative to equal weight of iron). It is more expensive though. Don
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Ken
Rust & Forgiving
Lead doesn't rust and is more forgiving in a hard grounding. Lead being much softer that steel does forgive some during a hard grounding. Making the difference in many situations between severe structural damage and minor. Being softer it is also easier to work with when repairing.
Lead doesn't rust and is more forgiving in a hard grounding. Lead being much softer that steel does forgive some during a hard grounding. Making the difference in many situations between severe structural damage and minor. Being softer it is also easier to work with when repairing.
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Tom
Every one pretty much hit the highlights
Lead - ** Doesn't rust - easier maintenance ** "softer" grounding ** All things being equal need less for same ballast which equals less draft for same righting arm -- Easier to make shallower draft boat with same sailing properties ** relatively easier to repair Iron - ** cheaper ** rusts & constant maintenance (eventually even with epoxy coatings will get nicked and need repaired) ** Thinner fin profile more capable of handling higher stresses than lead... might be important for pure racering boats with deep keels and very think keels. All in all Lead is superior to iron in almost all respects, other than costs and ultra race boats. Now why in the heck doesn't Jenneau offer Lead Keel boats -- to me thats a downfall.
Lead - ** Doesn't rust - easier maintenance ** "softer" grounding ** All things being equal need less for same ballast which equals less draft for same righting arm -- Easier to make shallower draft boat with same sailing properties ** relatively easier to repair Iron - ** cheaper ** rusts & constant maintenance (eventually even with epoxy coatings will get nicked and need repaired) ** Thinner fin profile more capable of handling higher stresses than lead... might be important for pure racering boats with deep keels and very think keels. All in all Lead is superior to iron in almost all respects, other than costs and ultra race boats. Now why in the heck doesn't Jenneau offer Lead Keel boats -- to me thats a downfall.
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Peter J. Brennan
Lead, hands down
Our first boat had an iron swing keel. I probably spent more time and effort trying to maintain that keel than all the rest of the boat and swore: Nevermore! When we went lookng for our present boat, an O'Day 37, we heard there had been a couple of years when O'Day used iron keels. Lead prices had gone through the roof. And indeed, the manual has instruction on how to maintain the iron keel. But we specifically instructed the surveyor to ensure that our keel was lead. It is, encapsulated. No problems. I would never buy a boat with an iron keel.
Our first boat had an iron swing keel. I probably spent more time and effort trying to maintain that keel than all the rest of the boat and swore: Nevermore! When we went lookng for our present boat, an O'Day 37, we heard there had been a couple of years when O'Day used iron keels. Lead prices had gone through the roof. And indeed, the manual has instruction on how to maintain the iron keel. But we specifically instructed the surveyor to ensure that our keel was lead. It is, encapsulated. No problems. I would never buy a boat with an iron keel.
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Kevin
One advantage of iron
The other posts have covered all of the pluses of lead. Here is one for iron. Since iron is so hard it isn't as easy for the keel bolts to wiggle loose. I saw a boat last year at my club where the "J" end of a keel bolt had turned and torqued itself right through the side of the lead keel. Kevin
The other posts have covered all of the pluses of lead. Here is one for iron. Since iron is so hard it isn't as easy for the keel bolts to wiggle loose. I saw a boat last year at my club where the "J" end of a keel bolt had turned and torqued itself right through the side of the lead keel. Kevin
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Dave
Lead Versus Iron Weight
Lead and Iron weigh exactly the same amount!!! One pound of lead is exactly the same as one pound of iron! They both weigh exactly the same as one pound of goose down!!! Now you might have said one pound of lead has less VOLUME than one pound of iron because the MASS of each is different. Thus the lead keel will have less wetted surface and presumably less drag as a result. Dave
Lead and Iron weigh exactly the same amount!!! One pound of lead is exactly the same as one pound of iron! They both weigh exactly the same as one pound of goose down!!! Now you might have said one pound of lead has less VOLUME than one pound of iron because the MASS of each is different. Thus the lead keel will have less wetted surface and presumably less drag as a result. Dave
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Tom
G
Gerry
Combination keel
Everyone I've read so far has been talking about a pure material keel. Pure lead although heavy is very malleable and easily malformed. Carbon steel more readily accepts oxygen molecules or rusts faster, this does not mean that lead does not. Lead too will oxidize just at a slower rate due to its density. Most keels are a lead over stainless covered with a fiberglass jacket combination. The stainless skeleton provides stress strength and having a minimum of 10% chromium slows the corrosion process. The lead on top of the stainless adds the weight and can be shaped more easily . The fiberglass jacket just makes it smoother for less drag and resists “gouging” by smaller debris in the water where lead would become more easily damaged. So my answer is a combination of several materials taking advantage of particular strengths of each.
Everyone I've read so far has been talking about a pure material keel. Pure lead although heavy is very malleable and easily malformed. Carbon steel more readily accepts oxygen molecules or rusts faster, this does not mean that lead does not. Lead too will oxidize just at a slower rate due to its density. Most keels are a lead over stainless covered with a fiberglass jacket combination. The stainless skeleton provides stress strength and having a minimum of 10% chromium slows the corrosion process. The lead on top of the stainless adds the weight and can be shaped more easily . The fiberglass jacket just makes it smoother for less drag and resists “gouging” by smaller debris in the water where lead would become more easily damaged. So my answer is a combination of several materials taking advantage of particular strengths of each.
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Tom
Yeah, its usually not 100% lead. There is
other things in there. Its just easier to say Lead. Typically a lot of these keels are Lead alloy with Antimony for just your reasons.(Usually about 4% antimony for the correct hardness) BTW another (what I think big!) advantage of lead is that you can use a stainless steel Keel Bolts. With lron keel you "must" use carbon steel which will rust much faster if not 100% totaly isolated from water.(And what keel bolts really are out there.....even the ones that are epoxy encapsulated) Here is a link of someone who was making his own boat AND smelting down his own lead/antimony keel from automotive batteries....very cool!
other things in there. Its just easier to say Lead. Typically a lot of these keels are Lead alloy with Antimony for just your reasons.(Usually about 4% antimony for the correct hardness) BTW another (what I think big!) advantage of lead is that you can use a stainless steel Keel Bolts. With lron keel you "must" use carbon steel which will rust much faster if not 100% totaly isolated from water.(And what keel bolts really are out there.....even the ones that are epoxy encapsulated) Here is a link of someone who was making his own boat AND smelting down his own lead/antimony keel from automotive batteries....very cool!
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Al
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Kevin
Tom, No stainless steel with iron???
Tom, I have an iron keel and I am sure the keel bolts are SS. Its a 1975 CS27 and the keel bolts look brand new. Same for other CS27s at my club from the late '70s and early '80s. If not SS,what else could of lasted this long sitting in water in the bilge? Kevin
Tom, I have an iron keel and I am sure the keel bolts are SS. Its a 1975 CS27 and the keel bolts look brand new. Same for other CS27s at my club from the late '70s and early '80s. If not SS,what else could of lasted this long sitting in water in the bilge? Kevin
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Tom
I'll ask other knowledgable people to chime in
But when I was looking at the Jenneaus last year, they have fully encapsulated Keel Bolts in epoxy. (Didn't even ask how I was supposed to retighten the bolts with epoxy on them) I asked why they did that and they told me its because they have an iron keel and they needed to use carbon steel bolts . Then again he was a salesman telling me this (albeit very informative on many subjects). This is a very complex subject and a lot has to do with the different type and alloy of metals. In your case it makes sense that the stainless steel bolts still look good, because stainless steel is a much more noble metal than your iron keel. But the more noble something is relative to the other metal the more likely there might be corrosion. But the real issue is with regular steel keel bolts. But I have heard that stainless steel is not perfect, and that there is such a thing as crevice corrosion. I think if you have a well engineered and designed keel bolt it will be fine. A lot of these are also "dipped" to mitigate any corrosion factors. And it really depends on the type of stainless steel and "iron" keel you have. There are advantages to carbon steel bolts (corrosion is not one of them), for instance, it has a much better strength properties than 316 stainless steel (which is considerably more "brittle"). But 304 stainless seems to do ok, although it is less "stainless" . Sorry I don't have the answers - Here are some links to peruse http://mcnallyinstitute.com/04-html/4-1.html http://www.ocean.udel.edu/mas/masnotes/corrosion.html http://www.corrosionsource.com/handbook/galv_series.htm http://www.weirmaterials.com/galvanic_corrosion.htm
But when I was looking at the Jenneaus last year, they have fully encapsulated Keel Bolts in epoxy. (Didn't even ask how I was supposed to retighten the bolts with epoxy on them) I asked why they did that and they told me its because they have an iron keel and they needed to use carbon steel bolts . Then again he was a salesman telling me this (albeit very informative on many subjects). This is a very complex subject and a lot has to do with the different type and alloy of metals. In your case it makes sense that the stainless steel bolts still look good, because stainless steel is a much more noble metal than your iron keel. But the more noble something is relative to the other metal the more likely there might be corrosion. But the real issue is with regular steel keel bolts. But I have heard that stainless steel is not perfect, and that there is such a thing as crevice corrosion. I think if you have a well engineered and designed keel bolt it will be fine. A lot of these are also "dipped" to mitigate any corrosion factors. And it really depends on the type of stainless steel and "iron" keel you have. There are advantages to carbon steel bolts (corrosion is not one of them), for instance, it has a much better strength properties than 316 stainless steel (which is considerably more "brittle"). But 304 stainless seems to do ok, although it is less "stainless" . Sorry I don't have the answers - Here are some links to peruse http://mcnallyinstitute.com/04-html/4-1.html http://www.ocean.udel.edu/mas/masnotes/corrosion.html http://www.corrosionsource.com/handbook/galv_series.htm http://www.weirmaterials.com/galvanic_corrosion.htm
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