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steel hulls?
Anyone owned a steel hulled sailboat in the 40 foot range and have
some advice on what to look for when buying one? Thanks as always. |
steel hulls?
ray lunder wrote:
Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. Ray, Are you looking new or used?? Howard |
steel hulls?
"ray lunder" wrote in message ... Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. The word I'd be worried about :: Rust... There is a metal [ not sure if it is steel ] sail, yacht, near me in the boatyard. There are holes large enough to put your hand through on the bottom of the hull. |
steel hulls?
On Mar 6, 4:11*pm, wrote:
On Thu, 06 Mar 2008 00:01:18 -0800, ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. Make sure the steering quadrant can't fail and sink the boat by poking holes in the hull. For that size and weight of boat; lots of money! Health and fitness and a certain amount of strength. Also probably some crew, unless it is fitted with fairly elaborate gear. Good luck. |
steel hulls?
ray lunder wrote:
Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I've seen some power boats less than 50' which are steel, but not, IIRC, sailboats. Anyway, I helped in a survey of a steel hulled boat mostly to learn what there is to learn about them. The surveyor had a great deal of experience with these. Mostly I learned that if I ever bought one, I'd insist that the survey be done by a surveyor with specific steel hull experience. -paul |
steel hulls?
Ray,
First I have a real problem with anyone responding to queries when they have no experience or specific knowledge of the subject and yet it happens all the time in these use groups. Out of all the responders to your query only Ken Marino should have responded. For the benefit of all, steel boats offer the most for the least. The very best yachts are made from steel. There are many good reasons why that is so. However, they do have a poor reputation with the uninformed for a few reasons. The first is that steel boats are virtual stones and cannot get out of their own way and that can be true IF the boat was built from a design not specific for steel. The second is that rust is a killer and the risk cannot be economically mitigated. This is patently untrue. It is a risk, but very easily prevented and most importantly, very inexpensive to deal with if it should occur. The last is ugly, yes, they can be, but they don't have to be. Did you ever see an ugly Super yacht? Steel boats go away from the inside. Condensation is the killer. Stop condensation and they will last forever. I had a freind that built a 28' steel sloop and lived on it as a university student. He had no money and couldn't afford paint. When he graduated he sold the badly rusted boat, but the bottom of the boat was still shiney steel. No bottom rust in 4 years in salt water. The inside of the hull must be sprayed with insulation material. There are a few materials that work, but not many. The first is polyurethane foam, another is special cork based materials. All others are suspect and due dilligence and scrutany is required. Another problem area is teak decks. I could write a book on that subject alone. The last area to be mindful of is dissimilar materials, potential electrolysis and the electrical wiring system. The hull must never be electrically connected to the wiring system in any capacity, even earth. If any of these situations are discovered during an initial inspection, a very serious survey should be undertaken. Hulls that have not violated these very basic rules will outlive you. Steve "ray lunder" wrote in message ... Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. |
steel hulls?
"ray lunder" wrote in message ... Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. Why buy one? Just get a good side scan sonar and do a search of the Gulf of Mexico from zero to 20 miles downwind from where "Red Cloud" was prematurely abandoned and left to her own devices and was, consequently, lost because of a frightened, unskilled and unseamanlike captain and crew. If you can't afford side scan sonar then look for the coffee colored water. Bwahahahhahahahahhahahahahhahahahahhahhah! Greg Hall |
steel hulls?
Steve Lusardi wrote:
Ray, First I have a real problem with anyone responding to queries when they have no experience or specific knowledge of the subject and yet it happens all the time in these use groups. Ignore this fool's post. He clearly has no idea what he's talking about. |
steel hulls?
"Paul Cassel" skrev i en meddelelse . .. Steve Lusardi wrote: Ray, First I have a real problem with anyone responding to queries when they have no experience or specific knowledge of the subject and yet it happens all the time in these use groups. Ignore this fool's post. He clearly has no idea what he's talking about. Such arrogance- had it occured to you that he might actually know what he`s talking about? Clue.... what he says is correct, so what does that make you? Bob Larder |
steel hulls?
Gentlemen,
It isn't arrogance, it's knowledge. I have done this steel boat thing for 30 years. I have spent my money and done my time. I do know what I'm talking about. How many steel boats have you built? Steve wrote in message ... On Thu, 6 Mar 2008 22:57:30 +0100, "Robert Larder" wrote: "Paul Cassel" skrev i en meddelelse m... Steve Lusardi wrote: Ray, First I have a real problem with anyone responding to queries when they have no experience or specific knowledge of the subject and yet it happens all the time in these use groups. Ignore this fool's post. He clearly has no idea what he's talking about. Such arrogance- had it occured to you that he might actually know what he`s talking about? Clue.... what he says is correct, so what does that make you? Bob Larder Paul Cassel's post couldn't hold a candle to Lusardi's for arrogance. |
steel hulls?
hpeer wrote:
ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. Ray, Are you looking new or used?? Howard Ray, I have a 33 foot steel boat, a bit small for steel but that's OK with me. The best advise is to go to the Metal Boat Society and get on their forum. That site has a number of professional designers and builders and they are generous with their advice. The advice about boats rusting from the inside out is true. You can get to the outside, but not as readily to the inside and that is where the moisture traps and causes rot. Warmer climes with humidity are worse. See if you can find out how the inside was treated and if it was done by someone competent. Interior metal preparation is probably the single biggest deal in the boat for you will play hell redoing it. Insulation is a big deal for a couple of reasons. I like the sprayed on insulation as it seems to protect the underlying steel best. Proper weep holes that let the water run down into the bilge are also important. Keep the moisture off the hull. I have seen some boats where the welding was pretty shabby, especially if it was done by a home builder who was not up to par. My boat, lucky me, if very fair by comparison. I have had my boat three years. It is about 1,200 miles from where I am so I only go out for 6 weeks in the summer then close her up. Last year I had someone put a heater in her and when I got to her she was filled with water almost to the sole. It cause some of the interior coal tar epoxy to separate from the metal. I spent too much time them sanding and recoating with two part zinc primer. My knees still hurt. However, the metal was shiny underneath. Steel expands something like 16 times its original thickness when it rusts so you should be able to see rust when it starts. You will need to get on it right away to control it. There is disagreement over monel or mild steel. From what I can tell either will do just fine. The builder needs to be careful of using dissimilar metals and you need to pay attention to bottom paints. On the other hand lighting is not much of an issue for you as opposed to glass boat. You do have to go outside to use the cell phone and the GPS won't work for beans down below. Another issue is hard chine or fully developed sections. From what I can see it makes no difference. Some even say they prefer the hard chine. I think it is mostly a European vs American preference. The thing about steel, or even aluminum, boats is that they are Gaud awful strong. Very hard to hole the boat. A couple of years ago an older fellow was single handing down from Nova Scotia, got beat up beating, and called to be taken off. His boat washed up on the beach back in Nova Scotia. By all reports she was a total wreck, because the scavengers stripped her, but the hull was still good to go. I saw a boat in Annapolis that had the port side all dented up and canned in. Seems that it was an older couple who lived on their boat for many years. They were motoring out of the harbour to lay on a mooring happy as clams. Then again, I saw a boat in NC that was for sale. Inside was fine but the fore lines were all messed up. At first I thought that the boat had hit the rocks but by all accounts she hardly ever left the berth. Seems as though it was just nasty welding. Strong but ugly. What a shame. Then again, I was helping a guy dock a 40 something glass cat and he wacked the dock, not hard but firmly. I could see the hull deform and the gel coat fracture and leave a spider web where he hit. Ouch. I love my steel boat. Bernard Montisiour went with steel. When his boat got caught on the hook in a storm it dragged up on the beach. Then they dragged it off again. Other boats were a total loss. Supposedly his losses were because of down flooding through an open or damaged hatch. If its good enough for Montisiour that's pretty good. |
steel hulls?
Steve Lusardi wrote:
Gentlemen, It isn't arrogance, it's knowledge. I have done this steel boat thing for 30 years. I have spent my money and done my time. I do know what I'm talking about. How many steel boats have you built? Steve Any top posting fool can claim that. I have been building steel hulled boats, as small ast 12 feet, for 86 years. |
steel hulls?
Paul Cassel wrote:
Steve Lusardi wrote: Gentlemen, It isn't arrogance, it's knowledge. I have done this steel boat thing for 30 years. I have spent my money and done my time. I do know what I'm talking about. How many steel boats have you built? Steve Any top posting fool can claim that... By invoking "top posting" silliness, Paul gives away the fact that he is really a 15 year old nerd who has never been within 100 miles of the ocean. |
steel hulls?
Being correct and arrogant is much better than being wrong and groveling.
But if one is 100% correct then how could they be arrogant? If you find the message hitting a psychological raw nerve --- shoot the messenger! Jakob |
steel hulls?
Thanks everyone. Timely, concise, accurate as always.
On Thu, 6 Mar 2008 19:23:17 +0100, "Steve Lusardi" wrote: Ray, First I have a real problem with anyone responding to queries when they have no experience or specific knowledge of the subject and yet it happens all the time in these use groups. Out of all the responders to your query only Ken Marino should have responded. For the benefit of all, steel boats offer the most for the least. The very best yachts are made from steel. There are many good reasons why that is so. However, they do have a poor reputation with the uninformed for a few reasons. The first is that steel boats are virtual stones and cannot get out of their own way and that can be true IF the boat was built from a design not specific for steel. The second is that rust is a killer and the risk cannot be economically mitigated. This is patently untrue. It is a risk, but very easily prevented and most importantly, very inexpensive to deal with if it should occur. The last is ugly, yes, they can be, but they don't have to be. Did you ever see an ugly Super yacht? Steel boats go away from the inside. Condensation is the killer. Stop condensation and they will last forever. I had a freind that built a 28' steel sloop and lived on it as a university student. He had no money and couldn't afford paint. When he graduated he sold the badly rusted boat, but the bottom of the boat was still shiney steel. No bottom rust in 4 years in salt water. The inside of the hull must be sprayed with insulation material. There are a few materials that work, but not many. The first is polyurethane foam, another is special cork based materials. All others are suspect and due dilligence and scrutany is required. Another problem area is teak decks. I could write a book on that subject alone. The last area to be mindful of is dissimilar materials, potential electrolysis and the electrical wiring system. The hull must never be electrically connected to the wiring system in any capacity, even earth. If any of these situations are discovered during an initial inspection, a very serious survey should be undertaken. Hulls that have not violated these very basic rules will outlive you. Steve "ray lunder" wrote in message .. . Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. |
steel hulls?
Paul Cassel wrote:
Steve Lusardi wrote: Gentlemen, It isn't arrogance, it's knowledge. I have done this steel boat thing for 30 years. I have spent my money and done my time. I do know what I'm talking about. How many steel boats have you built? Steve Any top posting fool can claim that. I have been building steel hulled boats, as small ast 12 feet, for 86 years. I never understood the top versus bottom posting controversy. Even though I post at the bottom, I like top posting better because I don't need to sift through all the messages to find the latest like you do if the reply is at the bottom. My guess is that you just need to call people names. |
steel hulls?
Jim wrote:
I never understood the top versus bottom posting controversy. Even though I post at the bottom, I like top posting better because I don't need to sift through all the messages to find the latest like you do if the reply is at the bottom. Jim, you're not supposed to "sift through all the messages", the poster is supposed to cut the irrelevant bits and leave only the parts relevant to his reply. It's like many guidelines/rules; a single rule out of context may make no sense. Posting rules stem from day's of limited bandwidth, but also lead to succinctness and clarity. Cheers Marty |
steel hulls?
"ray lunder" wrote in message
Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Yes, of course. Get hull sonogram when the boat is surveyed. A surveyor who is knowledgable about steel hulls (and you might consider a commercial/ industrial surveyor, not a yacht surveyor) will know this without being prompted. "Steve Lusardi" wrote: First I have a real problem with anyone responding to queries when they have no experience or specific knowledge of the subject and yet it happens all the time in these use groups. Out of all the responders to your query only Ken Marino should have responded. So, you know everybody that might be on the internet today or in the near future? You know all their qualifications and their sailing/ cruising history? For the benefit of all, steel boats offer the most for the least. No they don't. That's absurd. .... The last is ugly, yes, they can be, but they don't have to be. Did you ever see an ugly Super yacht? Yes, many. Rich people can have just as poor judgement & taste in yacht aesthetics as anybody else, and they are in position to indulge their whims more. However, you're correct that steel yachts don't have to be ugly. Ranger (along with most of the J-class) was built of steel, and she was beautiful. Steel boats go away from the inside. Condensation is the killer. Yep .... The inside of the hull must be sprayed with insulation material. There are a few materials that work, but not many. The first is polyurethane foam, another is special cork based materials. All others are suspect and due dilligence and scrutany is required. *all* is suspect, even the proper materials can be installed with (or age can create) a slight air gap that will quickly form a rust pocket. .... Another problem area is teak decks. Agreed again, but then I have always had heretical opinions of teak decks since having some real experience sailing on them. I could write a book on that subject alone. No doubt. You've already written at least a chapter. .... The last area to be mindful of is dissimilar materials, potential electrolysis and the electrical wiring system. Yep. Hulls that have not violated these very basic rules will outlive you. Wrong. Maybe you're thinking of a shorter life span than most of us would be considering reasonable? Or maybe you're one of those folks that think the U.S. Navy doesn't know anything about steel hull construction or maintenance, but I suggest you ask them about what the useful hull life is. They have more experience than anybody... just about more than everybody else combined. Steel hulls, given the right sort of great care, can be as long-lived as wooden boats. We don't know exactly how long, because there are examples of wooden boats in the 200+ age range and steel ones in the 100+ age range. However you might consider the amount of expert work they require to achieve that. Fresh Breezes- Doug King |
steel hulls?
On 2008-03-07 20:30:57 -0500, said:
"ray lunder" wrote in message Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Yes, of course. Get hull sonogram when the boat is surveyed. A surveyor who is knowledgable about steel hulls (and you might consider a commercial/ industrial surveyor, not a yacht surveyor) will know this without being prompted. Unluckily, I had experience in an industrial setting with this.... He reported a section of pipe as being full thickness (1/2") about a day before it blew out. It had to be paper-thin. Make sure the guy can *find* thin metal! Another PITA was that all paint had to be removed before the reading could be made. I'm not sure a better method wouldn't be to "sound" the hull with a big hammer, or maybe a small pickaxe. -- Jere Lull Tanzer 28 #4 out of Tolchester, MD Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/ Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/ |
steel hulls?
|
steel hulls?
Get hull sonogram when the boat is surveyed. A surveyor who is
knowledgable about steel hulls (and you might consider a commercial/ industrial surveyor, not a yacht surveyor) will know this without being prompted. Jere Lull wrote: Unluckily, I had experience in an industrial setting with this.... He reported a section of pipe as being full thickness (1/2") about a day before it blew out. It had to be paper-thin. Hmmm... now that you mention it, I've known that to happen too. But that doesn't invalidate the method.... it's technology, not magic! Make sure the guy can *find* thin metal! Another PITA was that all paint had to be removed before the reading could be made. The instruments I'm familiar with will read thru paint, but the paint has to be bonded and uniform thickness. You have to have a test section that is known to be sound & up to spec. I'm not sure a better method wouldn't be to "sound" the hull with a big hammer, or maybe a small pickaxe. Sure. Any place it leaves a dent, you know the hull isn't thick enough ;) DSK |
steel hulls?
ray lunder wrote:
Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I have owned one steel sailboat, and will never, ever own a steel boat again. The rusting just never stops. Any injury to or failure of the corrosion protection system must be repaired immediately and perfectly, or the rusting area will expand rapidly and sooner or later threaten the structural integrity of the vessel. Despite your vigilance, some (or more often many) parts of your steel boat, generally the most difficult areas to inspect and repair, will be in the process of turning to rust. My advice is to look instead for a good quality fiberglass sailboat, and save yourself a great deal of trouble. |
steel hulls?
Unfortunately your experience provides fuel to these other responders who
actually have no experience with steel boats. I will not dispute your experience, it happens far too often, but I must ask what effort you expended to find expertice with steel hull corrosion? There really are people out there that know how do deal with rust economically and effectively. If the other casual readers of this thread think that rust is such an insurmountable issue for steel boats, they should consider the plagues of other lower density hull construction methods like fiberglass and wood with fiber osmosis, rot, the lack of ability to host high load fasteners and the cost or effectiveness of their repair. Steve "Moonshadow" wrote in message ... ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I have owned one steel sailboat, and will never, ever own a steel boat again. The rusting just never stops. Any injury to or failure of the corrosion protection system must be repaired immediately and perfectly, or the rusting area will expand rapidly and sooner or later threaten the structural integrity of the vessel. Despite your vigilance, some (or more often many) parts of your steel boat, generally the most difficult areas to inspect and repair, will be in the process of turning to rust. My advice is to look instead for a good quality fiberglass sailboat, and save yourself a great deal of trouble. |
steel hulls?
On Mar 6, 4:01 am, ray lunder wrote:
Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I own a steel trawler and there is much to be learned in dealing with metal boats. The boats of today should have been white blasted immediately followed by multiple coats of epoxy primer before any finish coatings and all interior areas have at least 2-3 inches of high density foam sprayed in before building interiors. Exterior rust is actually less important than interior rust. Many steel vessels rot from the inside out. Then there's electrical isolation techniques.....a whole new topic. Overall, maintenance is somewhat higher (your labor), but not a bad trade off in terms of vessel strength. If crossing the pond and you happen to bang into a semi-submerged cargo container, you may get a dent in the steel. With fiberglass, you're boat is likely to take the Davey Jones express to the bottom. Capt. John http://www.blueseas.com |
steel hulls?
wrote in message ... On Mar 6, 4:01 am, ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I own a steel trawler and there is much to be learned in dealing with metal boats. The boats of today should have been white blasted immediately followed by multiple coats of epoxy primer before any finish coatings and all interior areas have at least 2-3 inches of high density foam sprayed in before building interiors. Exterior rust is actually less important than interior rust. Many steel vessels rot from the inside out. Then there's electrical isolation techniques.....a whole new topic. Overall, maintenance is somewhat higher (your labor), but not a bad trade off in terms of vessel strength. If crossing the pond and you happen to bang into a semi-submerged cargo container, you may get a dent in the steel. With fiberglass, you're boat is likely to take the Davey Jones express to the bottom. Capt. John http://www.blueseas.com Why not go all the way and zinc spray before the epoxy is put on? |
steel hulls?
wrote in message ... On Mar 6, 4:01 am, ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I own a steel trawler and there is much to be learned in dealing with metal boats. The boats of today should have been white blasted immediately followed by multiple coats of epoxy primer before any finish coatings and all interior areas have at least 2-3 inches of high density foam sprayed in before building interiors. Exterior rust is actually less important than interior rust. Many steel vessels rot from the inside out. Then there's electrical isolation techniques.....a whole new topic. Overall, maintenance is somewhat higher (your labor), but not a bad trade off in terms of vessel strength. If crossing the pond and you happen to bang into a semi-submerged cargo container, you may get a dent in the steel. With fiberglass, you're boat is likely to take the Davey Jones express to the bottom. Capt. John http://www.blueseas.com |
steel hulls?
Steve Lusardi wrote:
wrote in message ... On Mar 6, 4:01 am, ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I own a steel trawler and there is much to be learned in dealing with metal boats. The boats of today should have been white blasted immediately followed by multiple coats of epoxy primer before any finish coatings and all interior areas have at least 2-3 inches of high density foam sprayed in before building interiors. Exterior rust is actually less important than interior rust. Many steel vessels rot from the inside out. Then there's electrical isolation techniques.....a whole new topic. Overall, maintenance is somewhat higher (your labor), but not a bad trade off in terms of vessel strength. If crossing the pond and you happen to bang into a semi-submerged cargo container, you may get a dent in the steel. With fiberglass, you're boat is likely to take the Davey Jones express to the bottom. Capt. John http://www.blueseas.com Oh no!!! Not a top poster, not a bottom poster! It's the dreaded NO poster! Gordon |
steel hulls?
John,
You are correct about hull strength. The standing rig on my sloop came from a 70ft aluminum sloop whose owner decided to convert from a masthead rig to a fractional rig. The name of the boat was the "Dance II" out of Southampton in the UK. When the new rig was fitted, the owner set out for Gibraltar for some chartering. At 0200 in the morning running at 8 knots 200 miles off the coast of Portugal, the vessel struck a partially submerged shipping container that holed the aluminum hull. The Dance II was lost, but fortunately without loss of life. Had the hull been made from steel, there would have been a very good chance the boat would have survived that collision. Roger, Aluminum is good, but corrosion is actually a much bigger problem than with steel. Even marine grade 5000 series aluminum is very reactive in salt water, both electrically and chemically. Addionally, it is very difficult to get a good paint scheme to adhere properly with aluminum. This is especially true now that Zinc Chromate primer has been banned almost everywhere. However, the construction techniques available for both steel and aluminum support watertight bulkheads, where the existence of those are almost impossible with low density materials and had they been present in Dance II, the loss of the vessel would have most likely been prevented. Steve wrote in message ... On Mar 6, 4:01 am, ray lunder wrote: Anyone owned a steel hulled sailboat in the 40 foot range and have some advice on what to look for when buying one? Thanks as always. I own a steel trawler and there is much to be learned in dealing with metal boats. The boats of today should have been white blasted immediately followed by multiple coats of epoxy primer before any finish coatings and all interior areas have at least 2-3 inches of high density foam sprayed in before building interiors. Exterior rust is actually less important than interior rust. Many steel vessels rot from the inside out. Then there's electrical isolation techniques.....a whole new topic. Overall, maintenance is somewhat higher (your labor), but not a bad trade off in terms of vessel strength. If crossing the pond and you happen to bang into a semi-submerged cargo container, you may get a dent in the steel. With fiberglass, you're boat is likely to take the Davey Jones express to the bottom. Capt. John http://www.blueseas.com |
steel hulls?
On 2008-03-09 11:21:29 -0400, "Edgar" said:
Why not go all the way and zinc spray before the epoxy is put on? The experience on the Tanzer list's iron keels has been that POR-15 is far superior when properly applied. Zinc spray sounds like a great idea, but it's about the least of the solutions that work -- many coatings don't. -- Jere Lull Tanzer 28 #4 out of Tolchester, MD Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/ Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/ |
steel hulls?
Capt. John
Overall, maintenance is somewhat higher (your labor), but not a bad trade off in terms of vessel strength. If crossing the pond and you happen to bang into a semi-submerged cargo container, you may get a dent in the steel. With fiberglass, you're boat is likely to take the Davey Jones express to the bottom. I wonder if there isn't a practical way to make the underwater section of the bow/keel stronger on an existing fiberglass boat stronger/more impact resistant. Surely someone has figured this out, no? Red |
steel hulls?
|
steel hulls?
I wonder if there isn't a practical way to make the underwater section
of the bow/keel stronger on an existing fiberglass boat stronger/more impact resistant. Surely someone has figured this out, no? Red Salty: Yes. It's often accomplished by the addition of a layer or two of kevlar cloth during layup. As I understad it, Kevlar is not only difficult to get a good bond with, its not all that great for collision protection as it is for puncture protection. Besides, your answer doesn't address what I was asking - something that can be applied on an older existing hull. I believe Kevlar would not bond well enough on old polyester to make this practical anyway. Is this correct? red |
steel hulls?
On 2008-03-09 15:54:59 -0400, Red said:
I wonder if there isn't a practical way to make the underwater section of the bow/keel stronger on an existing fiberglass boat stronger/more impact resistant. Surely someone has figured this out, no? Our designer made the first 5-7' of our 28' boat an isolated chamber. We, or an errant hole in the bow, could fill that section up without much compromising our sailing ability as it's disconnected from the rest of the boat, buoyancy-wise. As I review the boat's layup, we could take holes a bit further back with little problem, though absolute safety would require our being pretty much upright. I should review my numbers in view of what I've learned since, but at one time I calculated that if we got a BIG hole in the middle of the boat, we'd likely not sink due to the massive isolated chambers in our bow and stern. We might not float high, but we'd float. In other words, I believe this problem has been figured out, but not by assuming that we could make the holes impossible, which I feel highly improbable, but by ensuring that the boat was properly buoyed when holed. -- Jere Lull Tanzer 28 #4 out of Tolchester, MD Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/ Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/ |
steel hulls?
Jere Lull wrote:
In other words, I believe this problem has been figured out, but not by assuming that we could make the holes impossible, which I feel highly improbable, but by ensuring that the boat was properly buoyed when holed. That's because your boat was designed for Canadian sailing, so some ice-breaking ability was a requisite. Cheers Marty |
steel hulls? adding armor to FG hulls
Red wrote:
As I understad it, Kevlar is not only difficult to get a good bond with, its not all that great for collision protection as it is for puncture protection. "Kevlar" as applied in structural composites (ie boat building) is cloth made of fibers, same as fibgerglass is cloth made of glass fibers. No magic here. BTW it may be interesting to note the structural properties of fiberglass, some other composites, and steel. It is relatively easy to build a composite that is as strong as steel. It's also easier to scale the structural properties to the size of the vessel. This latter property is why steel doesn't make good small boats. Besides, your answer doesn't address what I was asking - something that can be applied on an older existing hull. I believe Kevlar would not bond well enough on old polyester to make this practical anyway. Is this correct? No. Kevlar bonds just fine to existing hulls. I know of several boats that have had this done. It would be better to apply it to the inside of the the hull, where impacts put the laminate in tension, rather than the outside (compression) face. However this is not always practical, and it certainly helps the impact resistance of "conventional fiberglass" to have a layer of Kevlar cloth on the outside. A big problem to beware of is that Kevlar can't be faired... sanding into the cloth leaves frizzies that will NOT lay down no matter how much resin or paint you try to cover it with. So any attempt to armor an older hull should have a thin layer of matt or finishing cloth sandwiched over the Kevlar. It would also be a very good idea to add positive flotation. Fresh Breezes- Doug King |
steel hulls? adding armor to FG hulls
Doug King replied:
No. Kevlar bonds just fine to existing hulls. I know of several boats that have had this done. It would be better to apply it to the inside of the the hull, where impacts put the laminate in tension, rather than the outside (compression) face. However this is not always practical, and it certainly helps the impact resistance of "conventional fiberglass" to have a layer of Kevlar cloth on the outside. A big problem to beware of is that Kevlar can't be faired... sanding into the cloth leaves frizzies that will NOT lay down no matter how much resin or paint you try to cover it with. So any attempt to armor an older hull should have a thin layer of matt or finishing cloth sandwiched over the Kevlar. It would also be a very good idea to add positive flotation. Fresh Breezes- Doug King I hear ya on the flotation! :) The reason I asked is that I read an article somewhere way back on some boatbuilding site that kevlar wouldn't bond adequately to old poly resin. I'm curious though, why would it be better for the kevlar to be on the inside? Wouldn't that make it less effective in a collision due to the layer being in tension so it wants to seperate? I would have thought that being on the outside would be better to provide a barrier to the forced entry. Could you explain further? Thanks Red |
steel hulls? adding armor to FG hulls
Red wrote:
I hear ya on the flotation! :) A lot of people seem to think it isn't practical. It would indeed mean giving up some interior space, but IMHO many production boats could have positive flotation installed and give up maybe 15~20% of useable stowage. A lot of space could be used for flotation that is up in tight angles & inaccessible spots. The reason I asked is that I read an article somewhere way back on some boatbuilding site that kevlar wouldn't bond adequately to old poly resin. Can't think why that would be. It's just fancy cloth. More would depend on the surface prep & type of resin. .... I'm curious though, why would it be better for the kevlar to be on the inside? Wouldn't that make it less effective in a collision due to the layer being in tension so it wants to seperate? I would have thought that being on the outside would be better to provide a barrier to the forced entry. Could you explain further? Thanks I can try. A laminated structure almost always fails in compression... same as a mast BTW. As force applied increases and the structure bends, at some point the strength of the bond between layers starts to fail and the inner face of the bend, the skin that is under compression, starts to buckle. This is where local tears in the skin form. After this point failure occurs, the whole thing comes apart like a zipper until the strain is relieved. Kevlar is very very strong in tension, and along the tension face or skin will distribute load over a much wider area than conventional fiberglass cloth, thus avoiding critical point loading in the opposite compression face. OTOH if you're thinking of an object piercing the hull like an ice pick, having the Kevlar layer on the outside might not make much difference. In any event, having it on the outside is better than nothing. Fresh Breezes- Doug King |
steel hulls? adding armor to FG hulls
OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much difference. In any event, having it on the outside is better than nothing. Fresh Breezes- Doug King ------ Actually I was just pondering this as there are frequent stories about the various partially submerged objects such as shipping containers sinking boats. Since I am getting closer to buying a boat, I wondered if there wasn't something that could be done to at least reasonably increase protection from said objects. I realize you aren't going to make it bullet proof, but any amount of improvement without too much tradeoff in weight, etc, may be worth it. Peace of mind sort of thing. Thanks. Red |
steel hulls? adding armor to FG hulls
On Mar 10, 3:30 am, wrote:
... Kevlar bonds just fine to existing hulls. I know of several boats that have had this done. It would be better to apply it to the inside of the the hull, where impacts put the laminate in tension, rather than the outside (compression) face. ... Amen. But, having been tangentially involved in a completely disastrous attempt to bond Kevlar (tm) fabric to PVC foam with epoxy I strongly advise getting advise from the fabric provider before bonding. A Method that worked very well with both epoxy and polyester with stitched glass didn't fly with Kevlar (literally as the structure was a wing for an ultra-lite). And, yeah, you're right, the stuff goes all fuzzy if you look at it funny and it kills scissors. Carbon is less of a pain to work with but you can't use it to armor existing hulls. -- Tom. |
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