Origami steel yacht construction

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

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  1. Landlubber
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    Landlubber Senior Member

    Of course it can, i do not think anyone here has suggested otherwise anyhow, like all things built by man, some do it well some simply have no idea at all.

    They do seem to be limited by practical sizes, somewhere less than 40 feet, but I saw a beautiful frameless boat (50 footer) in Sydney 30 years ago that was origami built.

    Quality craftsmanship and standard practices apply and the boat will be very sound (even concrete boats follow this, just that most are crap)
     
  2. Brent Swain
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    Brent Swain Member

     
  3. Brent Swain
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    Brent Swain Member

    how are the "school bus windows" secured?

    I don't do schoolbus windows. I bolt half inch plexi windows overlaping the steel by a couple of inches.
    I had little to do with the building of MOM. I certainly didn't design that wheelhouse ,nor the schoolbus windows.

    ps. and as I have stated before I'm a fan of high cabins, wheelhouses and narrow hulls among other things I agree with Brent. And in my own buildings sometimes go with the feeling rather than calcs (despite the fact that I can do the math)
    Good boats are a blend of feeling, based on past experience and logic, and calcs.
     
  4. Brent Swain
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    Brent Swain Member

    Brent has no lines plan,

    ********. All my plans come with lines drawings.

    Brent refuses to to understand basic structural mechanics and cannot even answer a simple question.
    I've answered all relevant structural questions. You just haven't bothered reading them.


    unfortunately in this ‘strength’ they fail to point out that this only addresses tensile uniaxial loading. It does not address displacement, instability and fatigue, nor multiaxial loading, which all boats must account for in structural design. But, they are trying…

    Your picture shows the max loading on the keels where they are backed up by a fully welded cap on the lead ballast, and poured in ballast up to that height.
    Your picture , on which your calculations are mad, have only the vaguest resemblance to the actual shape, makig conclusions drawn from them, extremely doubtful.
    I see similar screwups in tidal current predictions, based on a computer drawings of the coast line, which is made up of squares. The conclusions they draw about currents have little resemblance to reality.


    Brent constantly states how quick and easy it is to build, yet only he has built them that fast.

    Most builders take a couple of weeks to get a shell together, as well as many amateurs. I sent Gerd Meuller in Hungary a book, and he pulled his own origami 30 footer together in a week, with no previous experience in origami. How many first timers can do that with a framed boat. It's quite a stretch to claim that one can build and set up frames, bend longitudinals around them, then fit plating to an existing framework, and do four times the amount of cutting, grinding , matching up plate edges and welding , in the same amount of time as pulling together a fraction the amount of seam in an origami boat.
    Tom estimates a frame a day. Pulling the hull together takes as much time as three or four frames, not counting setting them up, straightening them up, bending longs around them , the fitting the plate to an already existing framework, then up to four times the welding.

    Another huge advantage in origami boat building, is reducing the amount of chine in a 36 footer to 14 feet per side, a chine which is below the water line , and invisible in the water , giving a boat that is often indistinguishable from a round bilged design.

    These guys reckon around 14 months to build.

    Pretty quick, working part time, while holding down a job,from scratch to sailing, compared to back yard builders building framed boats.
    Many amateurs take that long to get the hull alone done, in framed boats.

    Whenever anyone asks Brent for simple clarification to simple questions, rather than getting replies or answers, as noted in the “origamimagic” website, how does Brent reply?

    I give simple, affordable answers to metal boat questions, on this and other sites, saving people tens of thousands if dollars, and hundreds of man hours, at no personal gain to myself.



    So, you have to ask yourself this question if you are sold on the origami approach. Would you buy your plans and dream from people that try and address your questions, are open with the data they have.

    Get your advice from those I have built boats for , people who have experience building and cruising in my boats, not from those who have a personal stake in keeping the price of boats high, or workaholics who have never themselves managed to get off the treadmill, and are motivated by envy of those who have.

    First, talk to those who have built and cruised in my boats, not those who never have.
     
  5. Brent Swain
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    Brent Swain Member

    Correct me if wrong, but the Van de Stadt 34 is 4mm steel and the Brent36 is 3/8" which is 9mm.

    My 26 is ten gauge hull plate, my 31, 36 and 40 are all 3/16th. I only suggested 3/8th for a 60 footer.


    "What's the problem?",

    The problem is, mistakes in stating the thickness of my hulls, however honest , and unintentional, have to be corrected.
    I wouldn't let anyone believe that I use 3/8th plate on 26, 31 , 36 and 40 ft hulls, as I have a right to correct such mistatements.

    I do wish we had the option in Canada of 4mm for the 31.
     
  6. Brent Swain
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    Brent Swain Member

    It was suggested that the midship shape only was all that was required to do stability calculations. That would exclude the buoyancy of the wheelhouse.
     
  7. hoytedow
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    hoytedow Wood Butcher

    Would not wheelhouse buoyancy apply only if the wheelhouse were in the water?
     
  8. Brent Swain
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    Brent Swain Member

    Yes, which is definitely the case in ultimate stability calculations.
     
  9. Brent Swain
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    Brent Swain Member

    A chain is as strong as its weakest link and when steel is joined by whatever method, that would be the weak link.

    Most welds done by amateurs on boats are very suspect with only partial or no penetration at all, slag filled etc and with very high caps that makes welds in fact weaker and in NDT procedures would be rejected, even when done faultlessly by a professional welder. More worrisome is the fact that most of the welds are grind smooth leaving very little left.

    Its the inside welds, which are not ground smooth which maintain the strength, unless your boat was built by Foulkes or Amazon ,which have no inside welds, and the outside ones are ground smooth.
    When I worked as a detail fabricator for Great west steel, many of my welds were X-rayed. None failed.
    As long as an amateur grinds out the outside of chine welds, to solid metal , with no slag or cracks remaining, after fully welding the inside, and uses 6011 for overhead, there is no reason for lack of penetration or slag inclusion. All the seams on my boats are either two square edged plates joined at an angle, which leaves them wide open on the outside, or the edges are ground to a 45 degree angle , which makes penetration a non issue.
     
  10. LyndonJ
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    LyndonJ Senior Member

    Yep the load form the bottom of the compression post shouldn't just land on the 3/16 plate. The load is taken in shear, it's important that Brent thought the surrounding plate had to stretch in tension for it to fail.
    Shear is much weaker than tensile, and then you want half that failure load as a maximum to stay within the fatigue limit. Plus you have to add another load which is the operational load from the bottom pressure flexing the plate too.

    There's a very reliable way of calculation whether the design is up to the job but Brent couldn't have calculated it as he misunderstands the failure mechanism. It's the same with the inner ends of his twin keel support bars. They terminate abruptly and they can be under very high stress levels in some situations. It's a shocking design.

    Steels an incredibly tough material, but like all materials its really dumb not to use it properly to full effect. Brent actually designs potential failure points. You could say they were designed to break under certain load combinations and cycles. If you suggest he add a bit of plate offcut as a floor (cost nothing time a few hours) he says it will cost thousands and take months. :rolleyes: :rolleyes:

    His structural replies are the old "It aint happened yet therefore it wont" He counts that rhetoric as a full and detailed anlysis with which he's replied to every engineering concern. Then he can lie shamefacedly about having addressed every concern :mad: :mad:

    Brent showed no interest in how you'd actually assess a structure, he's just wedded to whatever idea he sketched at the time and refuses to allow improvement.

    The load should be distributed into the whole hull and tying it into the lower transverse is a much better way of doing it.
     
  11. LyndonJ
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    LyndonJ Senior Member

    Like positive stability calculated form the lines to 180 degrees? Which was your BS claim where you were shown to be deceitful again.

    One person who was not a naval architect made one mistake once and you sieze upon it and use that as spin to distort the stability issue to wriggle out of dumb statemets like "the ends of the hull or the deckhouse isn't counted"...........:rolleyes:
     
  12. TomThumb28
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    TomThumb28 Junior Member

    Exactly, all the seams in your hull design are outside corner joints (except the last couple feet of the aft centerline and that could be pre-beveled) so there would be no need to grind anything on the outside (besides a few tacks) IF the plate edges were properly dressed before pulling the hull together. They could simply be cleaned with a twisted wire wheel prior to welding. By the same token, since we're talking about 3/16" plate here, gouging the seam with a 1/8" disc (your recommendation) isn't going to clean out all the slag, especially on the more acute angle joints like the bow.

    [​IMG]

    Nevermind the poor fitup because of high and low spots on the unground edges and slag holding the joint apart like here.

    [​IMG]

    Besides that, you can't possibly maintain that it's easier to to grind seams overhead fighting gravity than grinding on the flat. Grinding the centerline lying on your back between the keels would be a terrible job. No wonder you don't wan't to do it, no wonder your customers don't want to do it (and I know you don't impress upon them that it's important; if you did they'd question why you're making it hard for them); and so it doesn't get done. Another example of bad practice that isn't saving anyone any time, except you, and that's what it's about isn't it; because you're lazy. Give it up Brent, why don't you just admit that the seams end up not being ground properly on boats you tacked together?

    And please, for the love of god, learn to use quote tags! http://en.wikipedia.org/wiki/Bbcode
     
  13. pdwiley
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    pdwiley Senior Member

    Assuming you're referring to Tom Colvin above, please provide a reference for that statement or admit that you imagined it.

    I have every one of Tom's publications plus 10 years of correspondence with him and nowhere have I seen any such figure written. It's on a par with your assertion of 1000 hours to do a hull. The only reference to 1000 hours is Tom's statement that it took 1000 hours to put the interior into his GAZELLE. Sure, you'd take 10 hours but so what? A tenement without running water, power & heat takes a lot less time to build too. Someone with an equally sloppy work standard and scavenged materials could do a rough interior on any boat quickly.

    Personal experience shows I can build 3 frames a day easily and without working very hard or for a full day. There are 17 frames in the Witch. Do the math....

    With respect to the chine welds I agree with you, there are a lot more weld runs in the Witch or any other conventionally plated design than an origami design. This is one of the things that attracted me to the origami technique in the first place. What turned me off was your total lack of knowledge of basic design and use of materials coupled with a lack of respect for everyone else in the entire industry and hostility/contempt for people whose work is far more successful and enduring than your own. There are 120+ BS designs sailing out there? BFD. There are over 700 Gazelles alone.

    Many, many people are telling you that your design could be substantially improved with minimal extra work and materials during the building process and you point blank refuse to listen to any of them. That shows an arrogance running to hubris. It's also costing you sales and really, anyone who reads these threads would need to be insane to contemplate building or buying one of your vessels.

    PDW
     
  14. junk2lee
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    junk2lee Junior Member

    But there IS a pad plate under the post in turn welded to the hull...I see it in earlier pictures.It doesn't just go to hull or is that what you mean?
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    The load goes from the strut to the pad. Then from the pad to the plate. All the pad has done, is increase the total circumfernce and thus the amount of "area" that is transfering the shear load.

    A 100x100mm pad has a circumference of 4 x 100 = 400mm

    If the strut is say 75mm diamter, the circumference is 237mm.

    The failure mode remains, as Lyndon says, shear. But this is a static shear laod. The strut, as Lyndon again noted, is subjected to fatigue and dynmaic loads, this changes the "static shear" laod case considerably.
     
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