Origami steel yacht construction

Discussion in 'Metal Boat Building' started by origamiboats, Nov 30, 2001.

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  1. Brent Swain
    Joined: Mar 2002
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    Brent Swain Member

    Right. It is where you put the material ,and for puncture resistance, it's best put in plate thickness.
    My current boat, a 31 footer , was launched 30 days after the plate arrived. Until you can do that with a framed boat, the time saving is huge.
    On a steel boat, where you build in your details and weld them down, which would have cost exponentially more in a non metal boat, the finished steel work is thus a far greater portion of the finished boat, than it is for non metal boats.
    As I point out in my book, people often fail to differentiate between resale value and resale price. Resale price is what you can get for a boat. Resale value is the difference between what you can get for a boat and what she cost you in the first place. It is common for people to spend an extra $40K on a boat to increase the resale price by $20K a net loss of $20K
    My last boat sold for more that 4 times what she cost me. Many of my boats sell for many times what their owners have in them.
    The fact that McNaughton is too dense to comprehend basic geometric principles has nothing to do with structural reality.
    The picture above is of wooden planking ,which has no strength across the planks , which is exactly what frames were developed for. It has little relevance in steel which has equal strength in all directions. Moitessier's boat, Joshua, which survived the worst the southern ocean could throw at her, in two circumnavigations, with no problems, had 2 inch by 1/4 flat bar frames on roughly 2 ft centres. So make up such a frame for a 40 footer, and I can bend it by hand, by simply putting one end against the wall and pushing on it.
    There is nothing floppy about a finished origami hull.Such comments reveal an absolute naivety about the subject.
     
  2. LyndonJ
    Joined: May 2008
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    LyndonJ Senior Member

    mmmm.... On the one hand you are desperate to infer non existant properties to the longitudinals so they can replace conventional framing, then in the next framing is not required at all :(

    As for the cost beatup, you were asked before just how much it would really cost on another thread (in time and dollars) to add 5 or 6 transverse bar frames to a 36 foot steel boat.

    The transverse frames you give an example of the 2" by 1/4" may appear weak to you, but restrain them ( by welding to the plate) and two things occur
    1: the section modulus increases. If we used 5mm plate then the minimum section modulus will more than double. (It gets twice as strong)

    2: They are now restrained and that is everything in strength in elastic structures. So it is stiffer. The attached framing limits damage and provides safe stress paths which is not only a strength and stiffness issue but also a fatigue issue. Every stress has to go on some path through a structure.


    Nobody said that origami hulls are floppier, they are just weaker becasue the framing is floppier than a conventional frame. There's an important distinction here. Since your method of framing is floppier for being pre-stressed then the hull structure will buckle more easily.
    The load at which it collapses is the important issue. Most folks seem to be in agreement that thats ok for your 36 footer.

    But you need to accept that some of your reasoning doesn't scale well to larger boats with much higher loads.
     
  3. Brent Swain
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    Brent Swain Member

    Points 1 and 2 apply equally to longitudinals, as they are equally supported by their being welded to the hull plate, with the added structural advantage of going around a curve, yet you insist on calculating them as stand alone, with no attachment to, or support from, the hull plate.
    Another good example of the effect of shape on stiffness is the cabin top. By itself, it is as floppy as hell, but once it is tacked down, with a 7 inch camber, with no structural members under it, six guys can stand and jump on it, without it buckling or deforming in any visible way. It does develop soft spots once the longitudinal welds are done , which is why I force flat bar beams up under it, on 18 centres , along the direction of the curve, like longitudinals , not fore and aft, across the curve , like transverse frames. This is far quicker and easier than putting them in before the plate is on..
    It doesn't cost much to put 6 transverse frames in a hull, once it has been pulled together using origami methods, altho I know one guy who turned a couple of frames into a several week project, to increase his total income for the job.The point I am making is, if you put the frames up first, then try put the plate on to fit the frames, the cost and time goes up exponentially. Frames still remain structurally irrelevant on boats under a certain size.
    Post 191 says they are floppier. ********!
     
  4. peter radclyffe
    Joined: Mar 2009
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    peter radclyffe Senior Member

    QUOTE by B S
    .wooden planking ,which has no strength across the planks , which is exactly what frames were developed for. It has little relevance in steel which has equal strength in all directions.
     
  5. dskira

    dskira Previous Member

    When I designed and latter on built (sorry, I built too, but that is not relevant since you want to be the only one here) if we don't put frames the vessel will have been not able to do its work properly due to wickness, let alone having the cargo capacity strength needed to pay for itself and being safe. They have to make long crossing, light and full, buy all weather. The deck is weakest point, the design need more attention since some renforcement can be detrimental localizing the stress inset of difusing it. The corner of cargo hacth is always the start of the failure. As always it is a balance.
    I forget, I am the culprit to put stupid frames on a submarine.
    The relevance of frames is quite necessary to make the whole ship an almost corrugate systeme, with all the strength in all the direction. You have to think in term not flat, but corrugated. The rouding of the steel will not get it stronger, it still a flat plate. And the control of the shape is nill, and that is not acceptable for an proffessional customer.
    Now when the round plate is transformed in chine on your design, you have an intense stress point there, and that is no good practice. In steel you have to avoid brutal change in a short length. The welding can't save it.
    Of course since you don't design you can't control any form any shape.
    Steel winn, you are just the welder without power. It's sad to waste intelligence for the sake of welding.
    I know you cut some paper to see how it looks. Cute.
    By the way hows your weight distribution is done? I mean before you start building.
    By the way in your Paul 60' the fore step mast is a accident to happens. It will first twist the plating, second will wooble the deck, and third the mast will go thru the hull. No saine insurer will touch this thing.
    If I was you I will put a disclamer: Paul is wrong, I never designed this boat.
    As for your other boat, they all are ceiled in wood inside and seams to cost much more that a Swan. Even cast bronze, nice $5000 electronics, rigging galore, engine, shafts and so on.
    Nice saving theorie, the reality on you pictures tell an other story. Could show us your book? Of a finish boat of course.
    The hull always cost little, in every vessel. 101 shipbuilder.
    Fisherman and commercial are tough with the money, every cent is acconted, but you don't know that.
    Now giving us number of stress to prove you right is wrong.
    Number are just that, it is how you use them which make the difference.
    Since you don't make plans, why you bother with number. You are worst than an engineer, or even a naval architect.
    By the way I would like to mention, a vessel of a certain size is never ever designed by one person, same for building. I thought you knew that, but evidently you don't, since your very mean attack on my resume prove it.
    A newspaper folded in eight, the corner of the folding as more strength than steel. Is a paper boat right? The number say yes.
    Brent you are just lucky, you devised a system, you don't know why it works.
    And you think: it works, I am a genius. Until the **** happens. It always happens, don't kidd yourself. Fortunatly you built always the same boat, the risk is less.
    Must be boring to built the same boat for 30 years.

    Daniel
     
  6. apex1

    apex1 Guest

    Daniel,

    this was thought to be posted on another thread, but....

    as often as I used to contradict Brents cheap advertisement and sometimes mad claims, removing him is not what I would recommend or feel to be right. He quite obvious is a victim of his "el cheapo" philosophy and as obvious has not the sufficient education to proof his wild assumptions and broad, anecdotal statements.
    But he seems to be at least a honest one when it comes to his own designs or homebuilt boats, and in the end he always stayed in the backgroung when his rant or "argument" was proven wrong.

    We may argue about his biased opinions, about his terribly obvious lack of understanding some basic engineering, but we cannot argue that he does it to harm or insult other members.
    Well, he fought back sometimes with insults, but we did not treat him really nice either!

    No, he should NOT be removed, just ignored a bit more...........
    I know there are visitors here which cannot really get it together, where is the knowledge and where the anecdote.
    But thats their problem, they are on a internet forum. There, a dumb welder with insufficient and outlasted licenses can blame a well established boatbuilder of being a novice.

    You know?

    And do´nt bother about Gonzo, he does not like you, you do´nt like him, and his statement about the strength of steam bent frames has told us much about his knowledge...................

    Regards
    Richard
     
  7. dskira

    dskira Previous Member


    I am on the way to redemption :D , I asked Jeff to remouve my thread about Brent.
    Well we have to find a way to be polite to each other with Gonzo. No big deal.
    Daniel
     
  8. Milan
    Joined: Apr 2005
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    Milan Senior Member

    Brent concentrated on single chine V-hull forms.

    Reverse clipper bows and wine glass cross sections would be difficult but practically any other single and multi chine hull form can be done in origami.

    This is also origami: (http://www.origamimagic.com/)
     

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  9. LyndonJ
    Joined: May 2008
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    LyndonJ Senior Member

    Brent

    You are wrong.

    The Analysis of the longitudinal did consider the hull plate (see the transverse framing thread again)

    And they are not as strong, denying that and crying ******** doesn't help you.

    It's clear that the longitudinals go into tension, suffer stress reversals and consequently deflect more that a pre bent frame. You got that completely and utterly wrong too.

    If you don't agree that's your prerogative but it has just becomes a myth I'm afraid.
     
  10. Milan
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    Milan Senior Member

    Yes. Actually, whole designing process, all calculations, is for “normal” chine / multi-chine hull. When boat is designed, plates patterns are produced and laid flat. Highest strake stays in one piece, lower strakes are cut in the middle and ends of the plates are connected.

    That can be done by the software, or you can build chine model and take the strakes patterns from it..

    Gerd explained it very well in his free-download book.

    http://www.yago-project.com/component/option,com_weblinks/catid,95/Itemid,104/lang,en/

    Try this simple paper model of Yagoo:
     

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  11. Brent Swain
    Joined: Mar 2002
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    Brent Swain Member

    As I only build one hull a year, a couple of weeks work, and on every on I work with the owner, who's lifelong dreams are coming true , quickly before his eyes, it never gets boring. Their excitement , and enthusiasm in seeing a hull take shape in a few hours from flat plate, is contagious. It's like it's my own project, every time.
    The end of the chine where the cone begins is solid plate once the chine ends, not weld, so one is not dependent on the weld for strength. The pressure there is inward.
    Where Paul's mast goes thru the deck, a large doubler of heavier plate, plus some flat bars on edge eliminates the chances of anything wobbling . That has happened on junk rigs which have only deck plate thickness to support it.
    The only compression on the mast is only the weight of the mast, rigging and sails on a junk rig , unlike the tremendous compression on a marconi rig. It's a fraction the pressure of a marconi rig. No chance of it going thru any steel hull.
    Colvin estimates 1,000 hours for a hull and deck, something origami lets you do put together in under 100 hours. Given shop rates, that is a huge saving.
    As I pointed out in the cabin top example, a curve drastically increases the stiffness of a piece of plate .
    None of my boats have ever had problems getting insurance at the best rates, or passing survey. One had the surveyor over all thru the building process , and he gave her top rating.
     
  12. Brent Swain
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    Brent Swain Member

    Does this hull look boxy? It's considerably different from my designs. So much for the one shape theory!
     
  13. dskira

    dskira Previous Member

    Hope it will stay that way. It is after all the main goal of all of us, to have the customer sailing on a safe boat.
    Daniel
     
  14. Brent Swain
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    Brent Swain Member

    I have made wineglass sterns by welding the last few inches of centreline first, before cranking the deadrise out with the hydraulic jack. Its easy, but not that big a wineglass.
    As Herreschoff pointed out , in smaller boats, clipper bows tend to stop a boat dead in her tracks when they hit a steep head sea. On a hot summer day, you can see this when riding a BC ferry thru the fleet. The spoon bows go thru a head sea easily while the clipper bows stop dead in their tracks. My last boat was a bit too hollow up foreward and had this problem. My current boat, with about three inches of outside curve , goes thru a head sea far more smoothly, with far less resistance.The buildup of buoyancy is far less sudden.
    Many of my hulls have saved their owners from the disasters which would have resulted in most other cruising boats out there.
    Thanks for posting the picture Milan. A picture is worth a thousand words.
     

  15. MikeJohns
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    MikeJohns Senior Member

    The hull looks very swish from that angle but where's the proof of the pudding ? And did they get it through any class survey?

    The website looks a bit amatuerish and seems a bit abandoned too.

    The hull will need a lot of framing following on from that picture and I'm skeptical that in the long run with a vessel that size it might just re-allocate the build time. Instead of building frame then plating it's an outside-in job; plate then frame.
    Roberts has a method which is said to be fast, its bottom plate then framing then the rest built bottom up.
     
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