Can someone please explain just what is the advantage, if any, of building a sailboat with a steel keel? I know that the damn thing will outlast me, but what in gods name would be the purpose of making it out of steel. You see, every spring it blooms beautiful marigolds and I grind the spots off, fill the holes with a two part expoxy sand and then sand some more. I slap on a coat of VC17 and pray that I hit something really hard and dislodge it so bad that it drops off. There must be a really good reason...possibly it cost less to build. Comments?
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C
Cliff
F
Franklin
Steel or Iron?
From what I remember of metal class a good 25 years ago, Cast Iron isn't steel. Steel is a mix of Iron and something else and that's what makes it strong.
From what I remember of metal class a good 25 years ago, Cast Iron isn't steel. Steel is a mix of Iron and something else and that's what makes it strong.
Iron Keel
I'm no engineer, but this is why I think some fiberglass boats have iron keels. It's part of the overall design. Most lead keels are bolted to a fiberglass stub molded into the bottom of the hull. This gives you a nice deep bilge, but is complicated to build and in some boats, prone different types of failure. The iron keels I've seen are attached to a relatively large section of the bottom of the hull providing support for the keel and strength to the hull at the same time. This is a very strong design concept and one for which lead would be too soft. As with most things, there is always some sort of trade off.
I'm no engineer, but this is why I think some fiberglass boats have iron keels. It's part of the overall design. Most lead keels are bolted to a fiberglass stub molded into the bottom of the hull. This gives you a nice deep bilge, but is complicated to build and in some boats, prone different types of failure. The iron keels I've seen are attached to a relatively large section of the bottom of the hull providing support for the keel and strength to the hull at the same time. This is a very strong design concept and one for which lead would be too soft. As with most things, there is always some sort of trade off.
They were thinking about money
like what Cliff said. Money. Iron is cheaper than lead. If they used lead, then they would have to add the structural integrity (fiberglass). In the mid-1980's boat companies started to make the switch over from iron keels to lead/fiberglass keels to better serve their consumer.
like what Cliff said. Money. Iron is cheaper than lead. If they used lead, then they would have to add the structural integrity (fiberglass). In the mid-1980's boat companies started to make the switch over from iron keels to lead/fiberglass keels to better serve their consumer.
definately $$$$$$$$$$
scrap iron is worth about $15/hundred lbs.--lead is about $100. pick a number, 4000# of iron vs. 4000# of a lead alloy. do the math.
scrap iron is worth about $15/hundred lbs.--lead is about $100. pick a number, 4000# of iron vs. 4000# of a lead alloy. do the math.
Dollars and environmental Issues
First of all the keels are cast iron not steel. Cast iron has a high carbon content (2%+), is very hard, difficult to machine and weld, cast iron also expant as it solidifies so there are no issues of poroity. Steel has a carbon ontent below around 1.4% (normally below .5% and alloyed with Mn plus other metals (Cr, Ni, Mo ... as needed) is machinable and weldable in the lower carbon ranges. Steel also shrinks as it solidifies so porosity is a large problem. Very difficult to heattreat something that size. The issue with lead, beyond the $ is environmental regulation. Melting lead is a nasty problem for the workers. (Used to work for a Swedish Steel company and it was impossible to produce leaded steels in most of Europe) That may be why the French boats had iron keels. Russell Who ever thought a degree in Metallurgy would be so helpful in sailing.
First of all the keels are cast iron not steel. Cast iron has a high carbon content (2%+), is very hard, difficult to machine and weld, cast iron also expant as it solidifies so there are no issues of poroity. Steel has a carbon ontent below around 1.4% (normally below .5% and alloyed with Mn plus other metals (Cr, Ni, Mo ... as needed) is machinable and weldable in the lower carbon ranges. Steel also shrinks as it solidifies so porosity is a large problem. Very difficult to heattreat something that size. The issue with lead, beyond the $ is environmental regulation. Melting lead is a nasty problem for the workers. (Used to work for a Swedish Steel company and it was impossible to produce leaded steels in most of Europe) That may be why the French boats had iron keels. Russell Who ever thought a degree in Metallurgy would be so helpful in sailing.
S
Steve O.
rust never sleeps...
I'm on my third boat with a cast iron keel and never had rust problems. It's all in the original (factory) prep job, the keel must be primed immediately after sandblasting.
I'm on my third boat with a cast iron keel and never had rust problems. It's all in the original (factory) prep job, the keel must be primed immediately after sandblasting.
Iron is OK
Iron has a tensile strength about 50 times that of lead. Also, the environment is a major factor. In addition to lead keels, fishermen drop/loose millions of pounds of pure lead into the oceans and waterways every year. It leaches into the marine environment, the water and into the fish we eat. Lead is not good for living things. As far as the "salvage value"... if the lead is the most valuable part of my boat that is left after an accident, the insurance company can have it!
Iron has a tensile strength about 50 times that of lead. Also, the environment is a major factor. In addition to lead keels, fishermen drop/loose millions of pounds of pure lead into the oceans and waterways every year. It leaches into the marine environment, the water and into the fish we eat. Lead is not good for living things. As far as the "salvage value"... if the lead is the most valuable part of my boat that is left after an accident, the insurance company can have it!
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