I'm going to be looking for a new boat next year. In looking around, I see both lead and cast iron keels used on new mid-sized cruisers. While I can think of some advantages of having either a lead or cast iron keel I was wondering what some you more experienced sailors might feel are the advantages of one over the other and why. Last summer I was on a friend’s boat that had a cast iron keel when it ran aground on rocks. We really banged around for a while till we got pulled off. After he pulled the boat out for the season I asked what shape his keel was in - he replied that it only had the paint rubbed off. My boat has a lead keel and in similar circumstances it would have received much more damage. I offer this as only one area of difference between the two, and no I don't want to buy a boat just on the basis of keel construction but would like to consider all the factors (durability, maintenance, functionality, performance, longevity etc). Gary
Merits of lead vs cast iron keels
- Thread starter GKuffner
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First off a ton of ballast is a ton of ballast
that said, a ton of cast iron is larger than a ton of lead. During world war 2 thousands of private yachts were broken up for the lead in their keels. Look for the shape that you want and don't worry about whether the keel is iron , lead or depleted uranium. The designer knows how much ballast the boat needs and usually gets it right.
that said, a ton of cast iron is larger than a ton of lead. During world war 2 thousands of private yachts were broken up for the lead in their keels. Look for the shape that you want and don't worry about whether the keel is iron , lead or depleted uranium. The designer knows how much ballast the boat needs and usually gets it right.
Iron is stronger so keel is thinner...better point
,,,some say it points better and less resistance in the water. Hunters are lead, Jeanneau are iron. Iron rusts but they are well encapsulated in modern boats. Personaly, I agree with the first post....get the boat you want and don't worry about if its iron or lead (assuming it is a newer boat) abe
,,,some say it points better and less resistance in the water. Hunters are lead, Jeanneau are iron. Iron rusts but they are well encapsulated in modern boats. Personaly, I agree with the first post....get the boat you want and don't worry about if its iron or lead (assuming it is a newer boat) abe
Iron will rust and lead will deform.
Gary: Some of this conversation can be determined by where you live. If you reside in fresh water the arugments against cast iron are not very important. If you are in salt water then there can be an arguement for lead. If you hit something with a cast iron keel there will probably be little if any damage. If you hit something with a lead keel there will probably be at least a dent that can be repaired (if necessary). Go with the boat and do not worry about the keel. There are several coatings on the market to protect an iron keel. That with general maintenace will keep you iron keel in good shape. If you never did anything to an iron keel for 100 years it will still be around.
Gary: Some of this conversation can be determined by where you live. If you reside in fresh water the arugments against cast iron are not very important. If you are in salt water then there can be an arguement for lead. If you hit something with a cast iron keel there will probably be little if any damage. If you hit something with a lead keel there will probably be at least a dent that can be repaired (if necessary). Go with the boat and do not worry about the keel. There are several coatings on the market to protect an iron keel. That with general maintenace will keep you iron keel in good shape. If you never did anything to an iron keel for 100 years it will still be around.
If you hit something with..
If you hit something with lead it will give slightly and potentially cause less damage to the hull than cast iron will. I'd rather put some filler on a lead keel that absorbed some of the blow than sand, wire brush and re-barrier coat an iron keel that had no give when my boat hit a rock. Yes a ton is a ton above water but cast iron has more encapsulate air trapped in it by nature so while both the lead and cast iron are lighter under water, than above, the iron ton weighs less than the lead ton when underwater. Keep in mind were not even talking 5% differences in underwater weght but you asked about the differences between lead and iron. Another point is that an iron keel needs to be significantly larger than a lead keel to be the same weight. A Larger keel means more surface area and thus more drag. Manufacturers that use iron are doing it for one reason only and that reason is to keep costs down. Lead keels are very costly compared to iron. I've only ever owned one boat with an iron keel and it was a nightmare maintenance wise even with barrier coat. If you get any moisture between the keel and the hull, which happens on most all boats eventually, you can't stop the rust from creeping out of the joint unless you do a complete keel re-set. The bottom line is they both work but lead is more expensive at the manufacturing end but is considered the preferred tool for the job. Iron is a cost saver but it does work...
If you hit something with lead it will give slightly and potentially cause less damage to the hull than cast iron will. I'd rather put some filler on a lead keel that absorbed some of the blow than sand, wire brush and re-barrier coat an iron keel that had no give when my boat hit a rock. Yes a ton is a ton above water but cast iron has more encapsulate air trapped in it by nature so while both the lead and cast iron are lighter under water, than above, the iron ton weighs less than the lead ton when underwater. Keep in mind were not even talking 5% differences in underwater weght but you asked about the differences between lead and iron. Another point is that an iron keel needs to be significantly larger than a lead keel to be the same weight. A Larger keel means more surface area and thus more drag. Manufacturers that use iron are doing it for one reason only and that reason is to keep costs down. Lead keels are very costly compared to iron. I've only ever owned one boat with an iron keel and it was a nightmare maintenance wise even with barrier coat. If you get any moisture between the keel and the hull, which happens on most all boats eventually, you can't stop the rust from creeping out of the joint unless you do a complete keel re-set. The bottom line is they both work but lead is more expensive at the manufacturing end but is considered the preferred tool for the job. Iron is a cost saver but it does work...
The main problem comes with swing keels.
The 70's versions of many boats had cast iron keel/centerboard housings that a fiberglass centerboard would swing into. The iron rusts and swells only to bind the centerboard into the trunk. The is typical of some of the smaller O'Day and Paceship Yachts. It is an easy fix if there was a lift available. O'Day changed it's design to an encapsulated keel trunk ( it was part of the hull) to accomodate the fiberglass center board. I have seen major rust on some cast iron swing keels (some catalinas) but also some pretty good dings in lead keels. Most of my experience is fresh water. r.w.landau
The 70's versions of many boats had cast iron keel/centerboard housings that a fiberglass centerboard would swing into. The iron rusts and swells only to bind the centerboard into the trunk. The is typical of some of the smaller O'Day and Paceship Yachts. It is an easy fix if there was a lift available. O'Day changed it's design to an encapsulated keel trunk ( it was part of the hull) to accomodate the fiberglass center board. I have seen major rust on some cast iron swing keels (some catalinas) but also some pretty good dings in lead keels. Most of my experience is fresh water. r.w.landau
Maine sail,, There is NO AIR encapsulated in cast
iron. Iron weighs less per cubic foot than lead because of its place on the atomic scale. Aluminum weighs less than iron for the same reason. lead weighs 708 pounds per cuft. Iron weighs 450 pounds per cuft. Bronze weighs 509 pounds per cuft. Aluminum weighs 165 pounds per cuft. A 14 inch cube of cast iron will weigh slightly more than a 12 inch cube of lead. So the difference in size of the ballast is not very significant.
iron. Iron weighs less per cubic foot than lead because of its place on the atomic scale. Aluminum weighs less than iron for the same reason. lead weighs 708 pounds per cuft. Iron weighs 450 pounds per cuft. Bronze weighs 509 pounds per cuft. Aluminum weighs 165 pounds per cuft. A 14 inch cube of cast iron will weigh slightly more than a 12 inch cube of lead. So the difference in size of the ballast is not very significant.
Ross...
With all due respect, cast iron, depending on the foundry, certainly does have minute amouts of air traped in it from the pouring process. I sold cast iron as a broker between the foundry and the manufacturer for a number of years. A good deal of my time was spent dealing with porosity issues. High quality foundry's pour better quality castings such as engine blocks although most have now gone to aluminum due to consistently better quality castings on the first try. Repeatablity is key in the foundry business. Low quality foundry's, such as those pouring mushroom anchors and keels, pour relatively low quality and thus more air is trapped. Think of it as a HQ pour as not being very porous where as a cheap pour using up to 40% recycled product as being more porous. again we're talking minute amounts. I can almost guarantee there is NO keel made today with 100% virgin iron. Every day in just about every factory milling cast iron there are hundreds of thousands of pounds of castings sent back to me re-melted and re-poured due to porosity issues it's just the nature of cast iron. For some strange reason this does not happen with aluminum aluminum/alloys or lead lead/alloys as much as it happens with cast iron. The good foundrys employ a vibrating mold to purge the tiny bubbles out of the pour. Many of this porosity can be attributed to "polution" of the batch from the recycling process. Note that I also said it made little to NO difference as iron weighs less anyway. Iron weighs a lot less, approx 40% less, by volume so an iron keel to match a lead keel would have to be approx 40% bigger. Like I said it's no big deal as they both work..
With all due respect, cast iron, depending on the foundry, certainly does have minute amouts of air traped in it from the pouring process. I sold cast iron as a broker between the foundry and the manufacturer for a number of years. A good deal of my time was spent dealing with porosity issues. High quality foundry's pour better quality castings such as engine blocks although most have now gone to aluminum due to consistently better quality castings on the first try. Repeatablity is key in the foundry business. Low quality foundry's, such as those pouring mushroom anchors and keels, pour relatively low quality and thus more air is trapped. Think of it as a HQ pour as not being very porous where as a cheap pour using up to 40% recycled product as being more porous. again we're talking minute amounts. I can almost guarantee there is NO keel made today with 100% virgin iron. Every day in just about every factory milling cast iron there are hundreds of thousands of pounds of castings sent back to me re-melted and re-poured due to porosity issues it's just the nature of cast iron. For some strange reason this does not happen with aluminum aluminum/alloys or lead lead/alloys as much as it happens with cast iron. The good foundrys employ a vibrating mold to purge the tiny bubbles out of the pour. Many of this porosity can be attributed to "polution" of the batch from the recycling process. Note that I also said it made little to NO difference as iron weighs less anyway. Iron weighs a lot less, approx 40% less, by volume so an iron keel to match a lead keel would have to be approx 40% bigger. Like I said it's no big deal as they both work..
I was concerned
about the iron keel on my H28.5 prior to buying it. After doing some research, I bought the boat anyway and have not regretted it. I suppose Hunter used iron in this, and some other models, to save costs. I would have preferred to have a boat with a lead keel as there is almost no maintenance with lead. If I were buying the boat new, I would have gladly paid the price differential to have lead keel, if that were an option. Yet after 3 seasons with this boat, I have found the additinional maintenance required for the iron keel to be truly minimal and really no big deal. The use of POR-15, or other products that chemically bond with rust and make it inert, have really minimized yearly keel maintenance for me to no more than an hour. As such, I would not base a boat buying decision on the composition of the keel. I would base it on the condition of the keel and keel joint, whether iron or lead.
about the iron keel on my H28.5 prior to buying it. After doing some research, I bought the boat anyway and have not regretted it. I suppose Hunter used iron in this, and some other models, to save costs. I would have preferred to have a boat with a lead keel as there is almost no maintenance with lead. If I were buying the boat new, I would have gladly paid the price differential to have lead keel, if that were an option. Yet after 3 seasons with this boat, I have found the additinional maintenance required for the iron keel to be truly minimal and really no big deal. The use of POR-15, or other products that chemically bond with rust and make it inert, have really minimized yearly keel maintenance for me to no more than an hour. As such, I would not base a boat buying decision on the composition of the keel. I would base it on the condition of the keel and keel joint, whether iron or lead.
Main sail, Those holes are gas pockets
commonly called blowholes. In iron pigs they are common. But entraped gases cannot account for any significant change in weight. Otherwise it would be used as a quality control check before castings were shipped.
commonly called blowholes. In iron pigs they are common. But entraped gases cannot account for any significant change in weight. Otherwise it would be used as a quality control check before castings were shipped.
Right..
I never said it was a significant weight difference. I was not going to get into the why's and how's of the trapped air/gas just that it's there..
I never said it was a significant weight difference. I was not going to get into the why's and how's of the trapped air/gas just that it's there..
Ross?
Surely if a cu ft of lead in air weighs 708lb and of iron 450lb the corresponding weights in water will be 646lb and 388 lb - water weighing 62 lb per cu ft. This means lead is 66% heavier so, for the same righting power, lead will give a slimmer, lower drag and hence faster keel. Lead for keels has small amounts of other metals added to make it strong enough. I had my last boat with an iron keel for 18 years. Every winter one patch about 6" square ALWAYS bubbled up and rusted underneath. Every year it was scrape scrape, fill fill, paint paint. I even had the whole keel sandblasted and gave it 8 coats of epoxy and rubbed rubbed, filled filled and paint paint etc. Next season just as before. NO IRON KEELS FOR ME - EVER AGAIN.
Surely if a cu ft of lead in air weighs 708lb and of iron 450lb the corresponding weights in water will be 646lb and 388 lb - water weighing 62 lb per cu ft. This means lead is 66% heavier so, for the same righting power, lead will give a slimmer, lower drag and hence faster keel. Lead for keels has small amounts of other metals added to make it strong enough. I had my last boat with an iron keel for 18 years. Every winter one patch about 6" square ALWAYS bubbled up and rusted underneath. Every year it was scrape scrape, fill fill, paint paint. I even had the whole keel sandblasted and gave it 8 coats of epoxy and rubbed rubbed, filled filled and paint paint etc. Next season just as before. NO IRON KEELS FOR ME - EVER AGAIN.
Donalex, a little phosphoric acid on that rust
spot would have been a big help. There is no debate concerning the fact that lead ballast requires less volume per unit weight than iron but properly configured the difference in sailing qualities would not be significant outside of the international racing circuit.
spot would have been a big help. There is no debate concerning the fact that lead ballast requires less volume per unit weight than iron but properly configured the difference in sailing qualities would not be significant outside of the international racing circuit.
Should not be a major decision maker
The only disadvantage I can think of with a lead keel is the initial purchase price of the boat when new. As for your statement...."My boat has a lead keel and in similar circumstances it would have received much more damage"., that may not necessarily be so. The softness of the lead has much greater impact resistance and shock absorbancy. Lead is soft as a general rule, but it doesnt dent quite as easily as some would expect, and is sooooooo easy to repair. Anyway, I would not let that be the determining factor in purchasing a boat, unless of course, the cast iron was in really bad condition. I have seen many 30 and 40 year old boats with what looks like severe keel corrosion, patched up and like someone else mentioned, will probably last another 30 or 40 years. Biggest problem would be with a cast iron 'swing' keel at the pivoting points. Tony B
The only disadvantage I can think of with a lead keel is the initial purchase price of the boat when new. As for your statement...."My boat has a lead keel and in similar circumstances it would have received much more damage"., that may not necessarily be so. The softness of the lead has much greater impact resistance and shock absorbancy. Lead is soft as a general rule, but it doesnt dent quite as easily as some would expect, and is sooooooo easy to repair. Anyway, I would not let that be the determining factor in purchasing a boat, unless of course, the cast iron was in really bad condition. I have seen many 30 and 40 year old boats with what looks like severe keel corrosion, patched up and like someone else mentioned, will probably last another 30 or 40 years. Biggest problem would be with a cast iron 'swing' keel at the pivoting points. Tony B
Ross 2
LOTS of phosphoric acid in proprietary products didn't help a bit carried out over several winters. I think makers claims are exaggerated for seawater use. I tried zinc in a rubberoid paint base without success so eventually I had the whole keel flame sprayed with zinc and then with aluminium over that to try to seal it all in but these coatings are porous so the corrosion still came through. It was only this one patch which gave trouble, the remainder of the keel was perfect and Primocon would have been enough.
LOTS of phosphoric acid in proprietary products didn't help a bit carried out over several winters. I think makers claims are exaggerated for seawater use. I tried zinc in a rubberoid paint base without success so eventually I had the whole keel flame sprayed with zinc and then with aluminium over that to try to seal it all in but these coatings are porous so the corrosion still came through. It was only this one patch which gave trouble, the remainder of the keel was perfect and Primocon would have been enough.
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