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I recently purchased a 30 odd year old hartley queenslander ferro
cement sloop. I love it and so does my family and friends. Its a funny old thing, everything works, but all the know alls who own boats built of other materials look down their noses and all have some anecdotal story about the woes of ferro construction. It sails beautifully, motors with ease, is very comfortable. Could someone who has owned , or does own a ferro share with me their trials and tribulations. |
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On Thu, 16 Aug 2007 23:28:04 -0700, dave
wrote: I recently purchased a 30 odd year old hartley queenslander ferro cement sloop. I love it and so does my family and friends. Its a funny old thing, everything works, but all the know alls who own boats built of other materials look down their noses and all have some anecdotal story about the woes of ferro construction. It sails beautifully, motors with ease, is very comfortable. Could someone who has owned , or does own a ferro share with me their trials and tribulations. I don;t own one but have a mate that owns a 50 footer. He used to sail it to Perth every year and back to Thailand six months later. No problems with the hull. The reason that ferocement boats have a bad reputation is because people used to b build them in their back wards and when it came time to plaster them would get a bunch of beer and all their mates in. some of these were pretty horrible. Other people were smart enough to have a professional plasterer do the job and never have a problem. They are heavy for their length though and you'll probably find that you can carry a lot more sail then the fiberglass boats. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
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They are heavy for their length though and you'll probably find that you can carry a lot more sail then the fiberglass boats. But a LOT less than a cored glass boat of the same shape and equal displacement with the weight saved in the hull carried as ballast. The glass boat will also be much stronger if some of the weight savings is used to add material. I once figured out that a typical ferrocement hull was the material equivalent of 1/64 of an inch of steel on each side of a 1/2 inch concrete core. Does that sound like a way to build a boat? Worse the steel, which should be the tensile material on a thin shell, was on the inside and the concrete, a material most effective in compression, was on the outside. Strong as wood, heavy as steel, about sums it up. That doesn't mean you can't built a good boat out of it, just that it will not be as strong or well performing as other materials which are not significantly different in cost when you consider the full investment. -- Roger Long |
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"dave" wrote: I recently purchased a 30 odd year old hartley queenslander ferro cement sloop. I love it and so does my family and friends. Its a funny old thing, everything works, but all the know alls who own boats built of other materials look down their noses and all have some anecdotal story about the woes of ferro construction. It sails beautifully, motors with ease, is very comfortable. Could someone who has owned , or does own a ferro share with me their trials and tribulations. Basic problem with ferro is their is no non destructive test method to determine if you have a good hull, thus insurance companies are reluctant to insure them. Everything is dependant on the quality of the workmanship and there is no way to test it. If you get a poorly built one, chances are it will crack at the worst time. About 20 years ago here in Los Angeles, a ferro boat a guy had spent over 20 years building, fell off the truck on the way to inital launch and cracked. It had just become a worthless flower pot. If you are lucky enough to get a good one, you are a winner, because among other things, concrete gains strength as it ages. Years ago, there were some WWII ferro "liberty" ships they tried to break up and couldn't. Ended up sinking them to form a reef for fish, someplace off the Oregon coast if I remember correctly. Sounds like you may hace a good one, enjoy it. Lew |
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On Aug 17, 2:52 am, "Roger Long" wrote:
.... Strong as wood, heavy as steel, about sums it up. That doesn't mean you can't built a good boat out of it, just that it will not be as strong or well performing as other materials which are not significantly different in cost when you consider the full investment. .... Indeed, particularly with yachts where most of the total cost is in the fit-out. But that's new builds. From time to time there are some really good deals on the used market in fero and I know some folks who have cruised happily in big stone boats that cost them far less than an equivalent used boat in metal or plastic would have. I am aware of the many arguments folks make against fero and am not a big fan of it myself, but some cruisers have been very well served by their cement craft. -- Tom. |
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On Fri, 17 Aug 2007 12:25:38 -0700, "
wrote: Strong as wood, heavy as steel, about sums it up. Steel is lighter than wood. of equal strength. Aluminum is lighter than wood. For the same weight aluminum and steel are equally strong. |
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On Aug 18, 2:18 pm, (Richard Casady)
wrote: On Fri, 17 Aug 2007 12:25:38 -0700, " wrote: Strong as wood, heavy as steel, about sums it up. Steel is lighter than wood. of equal strength. Aluminum is lighter than wood. For the same weight aluminum and steel are equally strong. I didn't write that. I was quoting Roger. My feeling is that the word construction is implied in his statement. As built to typical scantlings wooden boat construction is lighter but weaker than steel construction. In small craft the difference is very significant because of minimum practical plate thickness. -- Tom. |
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"Richard Casady" wrote: Strong as wood, heavy as steel, about sums it up. Steel is lighter than wood. of equal strength. Aluminum is lighter than wood. For the same weight aluminum and steel are equally strong. Compared to an Airex cored hull with epoxy and knitted glass skins, all of the above are a joke. Lew |
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On Sat, 18 Aug 2007 17:45:11 -0700, "
wrote: As built to typical scantlings wooden boat construction is lighter but weaker than steel construction. In small craft the difference is very significant because of minimum practical plate thickness. Lots weaker. As I said, steel has a better strength to weight ratio than wood If you build similar boats, of equal strength, wood will be heavier not lighter. My experience with 16 foot boats is that wood is a lot heavier than riveted aluminum. Same with the canoe. No maintance whatever for fifty years, with the aluminum boats. It is true that welded construction does require a minimum thickness. Not so riveted, you get to use all of the weight, instead of unnecessarily strong and heavy steel. Aluminum is thicker than steel for equal strength, so it is stiffer, strength to weight ratio being the same as the steel. For equal strength wood is stiffer than metal, because it is thicker. I much prefer metal to wood or fiberglass. Light weight, zero maintance what more could one want? Metal is noisier. Wood is quieter, give or take the moaning and groaning, which the engine and/or wind will drown out. In conclusion, welded steel is not optinum for boats under about fifty feet. Steel tends to warp from the expansion when you weld it, so you have a minimum thickness and a minimum sized boat, assuming you want to use the strength of the steel efficiently. At one hundred feet, you can use 1/4 inch plate. That is much easier to weld than sheet metal. Casady |
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On Sat, 18 Aug 2007 20:19:58 -0700, "Lew Hodgett"
wrote: "Richard Casady" wrote: Strong as wood, heavy as steel, about sums it up. Steel is lighter than wood. of equal strength. Aluminum is lighter than wood. For the same weight aluminum and steel are equally strong. Compared to an Airex cored hull with epoxy and knitted glass skins, all of the above are a joke. The very best plastic may be stronger. I think if Boeing is using it that says something. Be interesting to see a table comparing the S/N for various materials. I know the latest fiberglass [and other plastic] is a lot better than it used to be. Been my experience that the older fiberglass boats are heavier than a comparable aluminum boat. In any case, I got a 22 foot aluminum boat, in the usual good shape, for two grand, instead. I laughed all the way to the bank. If the available steal had been a plastic boat I might well have bought that. It is well known that you can build a decent boat from any of the popular materials. That is why they are popular, after all. The family has a plastic boat that has been in use for fifty years. It is pretty heavy. A turbocraft, first of the jet boats, SN 10. It finally got painted after forty years. On the other hand, the local aluminum boats of that vintage are still doing fine with the original bare metal. We have a couple of neighbors with 1940's fiberglass sailboats. The material was not well understood, they used too much, and the boats are way heavy. They are, however, still in good shape. Something called Rebels, they are among the earliest of the production glass boats. Plastic [not necessarily glass], _is_ lighter than aluminum if it is done right, the aircraft industry is proving that. As for glass, it is heavier than graphite or kevlar, and you can get those materials in boats. Titanium is lighter than aluminum, for that matter. Ever hear of the Russian Alfa class subs? Titanium. They didn't build many of them. Where you really want the lightest construction is in canoes that are destined to be portaged. Early fiberglass canoes were way heavier than aluminum, and the wooden ones were heavy. While metal and wood haven't changed, the plastic is a lot better than it used to be. Casady |
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"Lew Hodgett" wrote in message ... "Richard Casady" wrote: Strong as wood, heavy as steel, about sums it up. Steel is lighter than wood. of equal strength. Aluminum is lighter than wood. For the same weight aluminum and steel are equally strong. Compared to an Airex cored hull with epoxy and knitted glass skins, all of the above are a joke. Lew wel my Zodiac..... |
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"Richard Casady" wrote: The very best plastic may be stronger. I think if Boeing is using it that says something. Be interesting to see a table comparing the S/N for various materials. I know the latest fiberglass [and other plastic] is a lot better than it used to be. Been my experience that the older fiberglass boats are heavier than a comparable aluminum boat. snip Most existing "fiberglass" boats are polyester resin with woven roving and mat. Woven roving is coarse compared to knitted material and requires the mat to retain the polyester resin. About the best glass/resin ratio you can expect is 35%Glass/65%resin which produces a heavy laminate. Polyester is also more brittle than epoxy resin. Polyester is also NOT an adhesive which is why you see holes thru the plywood used for bulkheads with the glass going thru the hole. It provided a mechanical means of bonding. OTOH, epoxy is an adhesive, can take advantage of knitted glass which means much higher glass content with less resin required. A 50%glass/50%resin ratio is easy to obtain with hand layup techniques, vacuum bagging can achieve even higher glass/resin ratios. The result is a much lighter as well as stronger laminate. Add Airex foam as a core material to the mix and it is a whole new ball game. You could build a dynamite hull for a 15'-20' boat using 1/2" thick Airex foam core(6.3lbs/ft^3), and 3 layers of 17OZ double bias(+/-45degree) glass. Translation: 3 layers of 17 Oz with a 50/50 G\R ratio= (17*3)*2=102 Oz for each laminate skin or 204 Oz/sq yard for both skins. The Airex: (1/2)(6.3*16*36*36)/1728 = 14.2 Oz/sq yard for 1/2" Airex. 204 + 14.2 = 216 Oz/Sq Yard = 216/9 = 24.0 Oz/Sq Ft = 1.5 Lbs/Sq ft. Pick a metal, you will need at least 1/4" plate to provide equalivant strength which means a lot more weight. BTW, add a layer of 17OZ glass, say 6"-8" wide along the keelson for a wear strip, and you are good to go. The only problem with epoxy is that it has no UV resistance so a coat of paint is required. Lew |
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On Aug 18, 5:44 pm, (Richard Casady)
wrote: .... As I said, steel has a better strength to weight ratio than wood If you build similar boats, of equal strength, wood will be heavier not lighter. My experience with 16 foot boats is that wood is a lot heavier than riveted aluminum. ... Volumes have been written on matteral's properties. It isn't a simple subject and I am not a master of it. The properties of complex structures in a complex environment are very, very difficult to grasp from first principles. The strength of a structure is only loosely connected to the strength of it's materials. Thus, comparing a single property of steel and wood isn't a great guide to that property in a complete boat. Cruising boats aren't 16 foot tinnies. Also, you are comparing a lightly built tin boat with a heavy wood one. Right up until the 70's racing dingies, rowing shells, unlimited hydroplanes &c. built of wood were lighter, stiffer and faster than glass, aluminum was not competitive and steel was never considered. In practice, boats built as lightly as permissible to any of the classification societies rules to a given service will be heaviest in steel and then aluminum and then solid fiberglass and then wood and lightest in cored glass or exotic fiber. So, while I will not argue that a steel boat couldn't be made as lightly as a wooden boat for a given service, such a craft would be revolutionary. In practice, steel boats are heavy but very durable and wood ones are light and less durable and in that context Roger's statement seems very reasonable to me. I don't mean to dis metal boats, many of them are great. I've got an aluminum RIB that I'm very fond of. Riveted aluminum can be very light and I know a guy who built a catamaran of cor-ten steel with an ingenious space frame system that was reasonably light. On the other hand, I remember a lovely evening in Apia Samoa when I shared dinner and a couple of jugs of wine with three world cruisers who had voyaged there on their steel boats. We got to talking horror stories and they each had one to tell about putting a finger or dropping a hammer through a bit of the hull or deck on their own boats. Localized corrosion can be a real problem for steel boats and thin plates will make it worse. Steel boats are always rusting and thick ones last longer too. A riveted thin skinned aluminum boat with an electrical system that was in the water full time is almost certain to have major electrolysis problems. So, I'd advise caution when you attempt to make a steel boat as light as a wooden one. Scantlings take into account mistakes other folks have made for you... -- Tom. |
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On Sun, 19 Aug 2007 14:03:55 -0700, "
wrote: Cruising boats aren't 16 foot tinnies. Also, you are comparing a lightly built tin boat with a heavy wood one. Why do you say that. I have seen boats of all kinds that have hit something, like rocks. The metal ones hold up better than wood. All the boats I have encountered, in fifty years at the same lake were strong enough. I don't remember with trouble with strength with any of them. None of the metal boats needed it, but you can drill out rivets to make repairs, and put in exact replacements for damaged parts, and have it end up exactly as it was. Exactly. Right up until the 70's racing dingies, rowing shells, unlimited hydroplanes &c. built of wood were lighter, stiffer and faster than glass, aluminum was not competitive Why then did they use aluminum to build all those airplanes? The brits built some wood bombers during WWII but none survive. They certainly were no better than metal. They got around an aluminum shortage caused by U-Boats. All of them rotted away over the years. They use aluminum for the floats on float planes, they are neither heavy or weak. And as for wood, the examples you pick are scarce, limited edition specialty boats. There are probably more than 100 metal boats for every one of the types you mention. How about a realistic comparison. There is a guy who who makes sports fishing boats. He molds the hull in plywood [more or less] and it is significantly stronger and lighter than something made from 4x8 sheets: they cost a lot. Wood is no better but it always seems to cost more.I read the writeups on the go fast boats, in Boating. The ones made from the very best plastic. Kevlar, stuff like that. You can get a go fast cruising boat that will cruise at 60MPH, with diesel engines and drink a reasonable ammount. Some of those boats are about as high tech as it gets. As for the ordinary wood boats, the ones I have seen in the real world are heavy. Lightweight construction may exist, but I have seen very little of it in the real world I do my boating in Iowa, and wood boats are very rare these days. My father's wood boat is in a museum. I would like some of that miracle wood. You know the stuff. 3/8 planking that is as strong as 1/8 inch aluminum. Wood was not only all there was not so long ago, it was actually affordable. Those who like wood can still get it, but it is far from cheap, unfortunately. The best plastic is much more expensive than metal. Where I come from nobody will do the maintainance that wood requires. The very best and most expensive aircraft grade sitka spruce is just about as strong as the very weakest aluminum available: pure aluminum, with no copper or magnesium to harden it. The stuff used for outboard engines for the corrosion resistance in salt water. And for beer cans. The cans are ..006 inch thick. You can't do that with fiberglass. Casady |
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On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote: Strong as wood, heavy as steel, about sums it up. My inland lake fishing boat is 22 feet of riveted aluminum. It has a bow locker with two tiny bunks. Too thin to weld. It is both strong and light and I love it. It cost two grand, and if the available steal had been glass, I would have that. Steel is either too thin for good welding, or too heavy, in anything smaller than maybe seventy five feet. You can perhaps rivet that stuff too. Aluminum killed the wood boats before there even was glass. Where I do my boating there are a bunch of aluminum boats mostly fifty years old, no maintainence ever, and lighter than the wood they replaced. Aluminum is good, but it is a bit noisy in the sheet metal type thicknesses. Of course, destroyer hulls were famous for noisy oil canning. Why they called them tin cans. Quarter inch plates. |
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"Richard Casady" wrote in message ... On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long" wrote: Strong as wood, heavy as steel, about sums it up. My inland lake fishing boat is 22 feet of riveted aluminum. It has a bow locker with two tiny bunks. Too thin to weld. It is both strong and light and I love it. It cost two grand, and if the available steal had been glass, I would have that. Steel is either too thin for good welding, or too heavy, in anything smaller than maybe seventy five feet. You can perhaps rivet that stuff too. Aluminum killed the wood boats before there even was glass. Where I do my boating there are a bunch of aluminum boats mostly fifty years old, no maintainence ever, and lighter than the wood they replaced. Aluminum is good, but it is a bit noisy in the sheet metal type thicknesses. Of course, destroyer hulls were famous for noisy oil canning. Why they called them tin cans. Quarter inch plates. What is this repeated comment about "steel...too thin for good welding"? Unless we're talking about foil, thinner guage steel (16 or even 18 ga) is entirely weldable. I should think 1/4" steel would be excellent for below-the-waterline on a 35 footer, perhaps going to 1/8th or 3/16ths above the waterline and for decks. Frames could be trussed to achieve strength without excessive weight. I believe that the biggest reason for having extreme thickness in steel hulls is to provide more material that can be lost to corrosion before compromising the hull. But with modern epoxy coatings, perhaps overlaid with glass or some other material for abrasion protection (to protect the epoxy barrier), this could be made unnecessary. Just thinking aloud. |
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On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote: Does that sound like a way to build a boat? Worse the steel, which should be the tensile material on a thin shell, was on the inside and the concrete, a material most effective in compression, was on the outside. That is why they invented prestressed concrete. Tension on the steel keeps the concrete in compression. The design allowance for tensile strength of concrete is zero. Opposite of chain, which has no compressive strength. Materials science is a facinating field of study. They generally cover steel building framing with concrete, but it is just fireproofing for the metal. On the other hand, they do use actual reenforced concrete for similar structures, and they can look similar on the outside.reenforced concrete that looks about like the covered steel. For something more efficient consider the submarine, with two concentric shells and all the frames between. Those things were strong enough to handle any wave imaginable. Big waves just cover them and then move on.They don't flood when they get swept, after all. Then there is the other sub. the fabric one. Gunny sack, cat, and brick. Just kidding, we love our four cats. We got them from a shelter that doesn't kill animals, they will keep them forever. Casady |
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"Richard Casady" wrote: Steel is a good material for a homemade fifty footer. Steel is a bloody joke. My epoxy/knitted glass/Airex cored hull has stopped a copper jacketed ..357 mag dead, and it doesn't rust. How much steel is required to stop that .357? Lew |
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On Tue, 21 Aug 2007 18:30:09 -0500, "KLC Lewis"
wrote: "Richard Casady" wrote in message .. . On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long" wrote: Strong as wood, heavy as steel, about sums it up. My inland lake fishing boat is 22 feet of riveted aluminum. It has a bow locker with two tiny bunks. Too thin to weld. It is both strong and light and I love it. It cost two grand, and if the available steal had been glass, I would have that. Steel is either too thin for good welding, or too heavy, in anything smaller than maybe seventy five feet. You can perhaps rivet that stuff too. Aluminum killed the wood boats before there even was glass. Where I do my boating there are a bunch of aluminum boats mostly fifty years old, no maintainence ever, and lighter than the wood they replaced. Aluminum is good, but it is a bit noisy in the sheet metal type thicknesses. Of course, destroyer hulls were famous for noisy oil canning. Why they called them tin cans. Quarter inch plates. What is this repeated comment about "steel...too thin for good welding"? Unless we're talking about foil, thinner gauge steel (16 or even 18 ga) is entirely weldable. I should think 1/4" steel would be excellent for below-the-waterline on a 35 footer, perhaps going to 1/8th or 3/16ths above the waterline and for decks. Frames could be trussed to achieve strength without excessive weight. I believe that the biggest reason for having extreme thickness in steel hulls is to provide more material that can be lost to corrosion before compromising the hull. But with modern epoxy coatings, perhaps overlaid with glass or some other material for abrasion protection (to protect the epoxy barrier), this could be made unnecessary. Just thinking aloud. What he is talking about is that the wrinkled steel hulls that you see are generally pretty thin. But the wrinkles are generally a factor of economics. If you want to pay for the experience and the time there is no reason that a welded metal boat can't be pretty damned fair. But it is going to cost you so much money that it won't seem worth it. Much cheaper to slap on the filler and sandpaper it. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
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On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote: They are heavy for their length though and you'll probably find that you can carry a lot more sail then the fiberglass boats. But a LOT less than a cored glass boat of the same shape and equal displacement with the weight saved in the hull carried as ballast. The glass boat will also be much stronger if some of the weight savings is used to add material. Give the ferro a break and compare it to cheaper solid glass, and it still comes off second best. How is cored for home building? I like riveted aluminum myself, and it is easy to work with. They use it for airplanes. Some are home built. Nice thing about it is, you can drill out rivets, replace mangled metal, and have it exactly like it was. How do you repair ferro after say, a collision. Can you say shipping container. Those weigh almost forty tons when awash. Casady |
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On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote: They are heavy for their length though and you'll probably find that you can carry a lot more sail then the fiberglass boats. But a LOT less than a cored glass boat of the same shape and equal displacement with the weight saved in the hull carried as ballast. The glass boat will also be much stronger if some of the weight savings is used to add material. Give the ferro a break and compare it to cheaper solid glass, and it still comes off second best. How is cored for home building? I like riveted aluminum myself, and it is easy to work with. They use it for airplanes. Some are home built. Nice thing about it is, you can drill out rivets, replace mangled metal, and have it exactly like it was. How do you repair ferro after say, a collision. Can you say shipping container. Those weigh almost forty tons when awash. Casady |
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On Aug 24, 10:33 am, (Richard Casady)
wrote: ... How is cored for home building? ... Very good. For one offs it is about as cheap to build cored hulls as solid glass on male tooling and cheaper than solid glass on female tooling. There are many strip-plank methods that involve laying strips of core over bulkheads (typically produced with a flat panel cutter) and then glassing. These methods eliminate lofting and greatly reduce tooling. Done well they do require a lot (really huge amounts of back breaking horrible work) of fairing after the planking stage otherwise they will need to be heavily bogged to get them as fair as traditional female tooled boats. There are other methods like (http://www.kelsall.com/methods.html which I've seen used with impressive results) that can cut down on fairing. Of course, the job really starts once you've turned the hull over. Fit-out costs are pretty much unrelated to the hull construction method and for a typical cruising boat the great majority of the work and cost is fit out. The hull may only represent 20% of the completed cost of a nicely fitted yacht. -- Tom. |
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On Sat, 25 Aug 2007 16:00:32 GMT, (Richard
Casady) wrote: On Sat, 25 Aug 2007 09:34:34 +0700, wrote: How do you repair ferro after say, a collision. Can you say shipping container. Those weigh almost forty tons when awash. Actually they make some sort of almost instant curing "cement" originally designed to fix leaks in water tanks. The "Fero" boys all carry that and according to a mate who sailed into a rock at about 7 K it works real well in fixing holes in fero boats. The whole point to fero boats was that they are cheap to build. Good point. I will check out that quick curing cement, my curiosity is aroused. Home Pro here sells several brands. But do read the instructions and where it says, "you have 60 seconds working tim," believe! It is fast. As others have pointed out, the hull is a relatively small part of the cost of the finished boat. On a slightly related note, as people like to say about building a warship with room for growth in equipment fit: " Steel is cheap. and air is free " Casady That is true but not what people who are building a dream want to hear or believe and most of the ferro boats were built by that kind of people. Bruce in Bangkok (brucepaigeATgmailDOTcom) |
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