The good, the bad and the ugly - Steel building methods that is....

Discussion in 'Metal Boat Building' started by Wynand N, Aug 18, 2010.

  1. magwas
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    magwas Senior Member

    When I first heard about this method, I imagined that alu plate is laid horizontally to the top of the hole. I was wondering how it is not torn apart by the blast.
    Well, it is not the case, Instead a hull is roughly built to shape, and the blast does the "finishing touch".
    So the question is how much deformation can be safely achievable with this method?

    I guess this method is in the "don't try it at home" category:)
     
  2. Milan
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    Milan Senior Member

    Attached Files:

  3. Wynand N
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    Wynand N Retired Steelboatbuilder

    Magwas, no need to be rude - that is the very reason some of us are here now, to be polite and informative...:(

    I believe you missing the point - you are bend on origami and if that is the case, rather pursue that in the origami thread.
    But, if you had cared to read the link Apex had given, you will notice that Micheal Kastens - well respected steel boat designer and builder of long standing, is very specific about the limitations of shape in this method and explained why.

    Back to your quote. Big claims you are making and perhaps you should stand up and deliver.

    Origami means folding paper and the purpose is to shape a single piece of paper / steel into a shape without CUTTING. These hulls are pulled into a sort of conical bow and stern section and midships has a piece of steel cut out to help the steel forming. The whole point is to shape the hull with the minimum of cutting and welding.
    Developable shapes are not necessary origami friendly and most of the time need heavy plate forming equipment to shape these developable surfaces. I can tell firsthand as a qualified boilermaker.
    As soon as one has a few longitudinal cuts (chines) in an origami hull to get a reasonable shape, you would find that it is then actually faster to have a CAD developed chine plate boat build like the vd Stadt 34 with "free" shape for instance.

    If you want to pursue the origami method, perhaps it is best to post that in the origami thread as we have been there, done that and have badges.
    However, if you care to count the posts on origami already posted here compared to other boats, and all but BS (in drag) from you, perhaps you would understand the tone of members remarks towards you, including myself.

    But as I said before, should an origami post spring up from time to time by "new" member, yes, it is our duty to inform.

    Milan, I respect Gerd and his Yago project was linked to my steel boat building webpage. Him and I swopped many mail in the past. His method and application of origami technique is truly fantastic and a joy to look at, compared to some creations from BC. Gerd is very meticulous about detail and strength and I will guarantee that he has done the "numbers" for his boat.
     
  4. Milan
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    Milan Senior Member

    Me too. He is a very nice person, intelligent, knowledgeable, sense for humor…

    Yes, he did the numbers. He used Dave Gerr’s book for scantlings.

    What happened to your webpage? It was very interesting, pity that it’s gone.

    I like his work, but I think that some of his comments on this particular subject of shape limitations of folded plate method are wrong.
     
  5. magwas
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    magwas Senior Member

    I am sorry for the wording, but I was overwhelmed by the amount of personal attack from him. And to be honest I am glad that I could drive him to silence. I will not repeat it in this thread.
    I appreciate your moderating effort, but I would like to ask you to use the same measure towards everyone.

    As I have already pointed out, Kastens was not aware of certain facts about origami design. He may be well respected, but this lack of information have driven him to false conclusion.

    I am ready for the challenge. Just give me a developable hull shape. (I cannot stop pointing out that not me who have failed to deliver so far.)

    I think our definition of origami are compatible ones.

    To summarize:
    1. Some of the developable forms need heavy equipment when built as origami.
    Well, definition of "heavy" is a matter of personal circumstances and taste. However I am yet to encounter a real-world boat shape which needs much more effort than the amount needed for the usual origami builds. Feel free to provide one.
    2. Some hullforms are faster to build chined than origami
    One can say it also depends on the builder. However let's try to stick to measureable quantities: the length of cuts and welds are necessarily less with an origami build than with the same boat built chined.

    Sorry for being overwhelming, but for a long time I am just answering issues brought up by others. I do think that discussing building methods don't have to be done in the tone which is in the origami thread. This is why I do not post there, and I try hard not to be carried away from factual statements.
    I understand your attitude towards Brent (I do not elaborate here on why both sides fail to understand each other), but I don't think it should be a reason to dismiss the method he happens to use.
     
  6. Tad
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    Tad Boat Designer

    I don't want to get bogged down in a "frameless"/ "origami" / " plate first" discussion......there are lot's of "best" ways to build a boat. The best way in your particular circumstance depends on a number of factors.....Your budget, the boat's design, material available, construction skill available, and your finish level expectations are all important in choosing which construction method might be "best" for you.

    Some folks insist their method (the one they are selling) is the only one worth bothering with. This is not the case. I have designed so-called frameless steel boats, as well as fully framed (transverse webs plus longitudinals). Both worked well and the clients are still happy. A fully framed workboat designed and built 25 years ago is still worked every day by the original owner.....framing is not a bad thing.

    The origami/folded plate/frameless/platefirst method is a quick way to get a boat shaped object....but it's just a bare shell...everything else takes exactly the same amount of hours to build. Argument could be made that scribing and fitting the framing will take longer as you are working down in the hull, rather than on the shop floor. Framing in a "frameless" boat must be hand scribed because the shape is not precisely known before hand, and is not repeatable. At least not to normal yacht design standards of 1/16" or so. Again there are arguments that this precision is not necessary, well it is if you are going to NC cut a lot of expensive material.

    This is to my mind the biggest downside of the plate first method, in areas of compound curvature the shape depends on the material stiffness and the amount of heat/welding distortion.

    To my mind it is possible to create a variety of shapes using the plate first method. Lundstrom's 1981 patent shows 7 different dart/fold systems that all create hulls of different forms. Below are three hull forms I folded up from three different patterns....and then I created my own pattern for the schooner below, which is a different shape again. But I'm a nitpicky NA and what are to me large variations may seem small to others.

    In the photo below the upper hull is a pattern from the Origami Magic site, the one on the left is a Brent Swain model, and the lower one is from the Yago site......

    P1010002.jpg

    DSCN1146.jpg
     
  7. rugludallur
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    rugludallur Rugludallur

    Another angle

    Here is something that I have been thinking about that I think has a bearing on this subject.

    How much of the time spent building a boat is spent on framing and/or welding hull sides together?

    From my own experience I would say about 5-10% depending on the process and shape of the hull, to be clear I'm not counting the time spent on rolling plates for round bilge.

    Based on my observation I would therefor deduce that which ever method is used any time saved or spent is not going to have a major impact on the total build time or budget.

    Anyone else have an opinion or observation relevant to this?

    Jarl
    http://dallur.com
     
  8. apex1

    apex1 Guest

    Again completely besides topic.

    Nobody here and in the "other" threads has ever "dismissed" or miscredited the way BS hammers his boats together.
    There are several good examples of boats built to that method. (not by BS)
    But one has to understand the limitations and drawbacks, which all the pro´s here do understand easily, but you don´t.
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    This just shows the ignorance of many who are not professional NA and have no idea of the implications of their throw away statements.

    To make such a comment simply highlights how little you actually know what is required to design a boat, safely and with confidence. Yet you continue as if you have the “right” as if this statement is an absolute and must be listened too and debated further.

    No professional NA would engage is such nonsense, suggesting mechanical strength is not relevant when designing ANY type of vessel.

    Exactly, it is just supposition.

    To establish whether your pure suppositions are supported by any evidence you need to either provide proof, or just ask those professionals that do this for a living so you can gauge if what you are saying is nonsense or has merit. This is called learning and being educated. Maybe you think, you know everything hence your stance?

    A stance of “I think my views must be right and carry weight”, based upon personal suppositions and no real evidence or otherwise, shall elicit replies that you have already received.

    This thread is about exploring and understanding, for those that do not and have no experience in such real issues on a daily basis.
     
  10. welder/fitter
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    welder/fitter Senior Member

    Jarl,
    I've always felt the same way about this issue. When I put my fishboats together, it was the mechanical, electrical, interior fittings - which were very basic - that took so much time to complete.
    Mike
     
  11. welder/fitter
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    welder/fitter Senior Member

    Tad's Ragsdale36.jpg


    That's what keeps me looking at origami. I still have great concern over the first-time, no welding/fab experience builder pulling the chines/darts and hull sides together, but this design of Tad's has always "revved my engine". I know, I'm mixing the issues of aesthetics & construction methods, but gee whiz...lol.

    For multiple builds:
    With the understanding that plating-then-frames would be quicker than frames-then-plating, couldn't one design a female mould in such a manner that one could pull plates into shape, using comealongs, hydraulic rams & saddles (supported by the mould verticals, etc., to shape the hull bottom plates, then hull side plates? I've done this with plates before to get a specific radiused shape. My main objective, here, is to reduce the forces on the centreline weld while it is welded and to arrive at more of a radiused hull, than hard chine. That is what caught me about Terho's models. It looked to me as though each side of the hull could be formed in a female mould and that there would be no problem with the centreline seam. Yes? No? Really, it's just like a single chine, but plate before frames, isn't it?
    Mike
     
  12. Robbo
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    Robbo Junior Member

    sorry but Ive got to say that this seems a pretty old fashioned viewpoint.
    Aircraft design was once the same-when they were covered with fabric and dope, and native canoes covered in animal skins. Good in their day but maybe time to move on:) Id guess it was an "older" designer?

    I think engineering design in general has long progressed past that viewpoint.
    Note monocoque car design, modern aircraft design etc where the outer skin is a structural part.

    This isnt a comment on Bretts designs, I dont know anything about them-but how many have been built and how have any of them sunk (out of curiousity?)
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    Mike.
    As with anything in engineering, anything is possible (just about). So the simple answer is yes, this can be done.

    Aluminium, for example, can be formed into almost any shape, if done correctly. BUT, in shipbuilding no. Shipbuilding requires curves which are easy to bend...bend in one-plane and bent using cheap machines and hand. Forming, for complex curvature, can only be achieved, by plastically forming (or deforming) the metal over a die (as you mentioned) or similar. Like this:
    http://www.superform-aluminium.com/aboutsuperform/historyworcester.html

    BUT, as soon as you preload plating, by 'forcing' or 'pushing' or 'restraining' it into position, prior to welding, you introduce residual stresses, if still in the elastic range of the properties. These residual stresses are the killer, for the structure and also the weld.

    One needs to understand the implications of the methods being used.

    Does this mean one shouldn't force/push plating etc in place.??..yes. That is why in strictly controlled environments, this practice is not allowed. Hence being to Class and with proper QA procedures, this method of ‘plating’ is not allowed.

    Does it mean it can't be done...no. Since clearly others do do this. All they are doing is ignoring the caveats which come as major baggage when constructing in such a way. Perhaps in the ‘hope’ that ‘they’ wont be affected by such events, because they are not aware or think it is all “made up nonsense”.

    It is ostensibly the difference between amateur fabrication and professional fabrication. Since when something goes wrong, beit a small minor insignificant crack, to a major structural failure, the professional must pay for the repair…the amateur doesn’t. Any loss of life has serious implications for the professional…non for the amateur. The consequences of ones work are either recognised, or ignored.

    Thus, ones preferred method boils down to the attitude and hence professionalism of the person regardless of whether one is an amateur or a professional. Since I’ve been in several yards where the fabricator is more than happy to produce rubbish as shown on another thread, similarly, I’ve seen amateurs produce some seriously good quality work.

    This “attitude” is totally independent of methods or style of building/designing.
     
  14. welder/fitter
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    welder/fitter Senior Member

    Adhoc,
    Thanks!
    (I wrote further on this, but decided that my queries were getting off topic. I'll save them for another topic at another time.)
    Mike
     

  15. welder/fitter
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    welder/fitter Senior Member

    How many Hunters lost their keels when that was an issue with a certain vintage and how many sank? How many of BR's designs lost their skegs and/or sank before they came out with a beefier alternative? What I am saying is that a designer shouldn't wait until one of their designs sink before they make improvements. I think that that is a benefit of this site. If there is a glaring issue with a design, other experienced designers/NAs/engineers are going to point it out. They're not doing it to poke fun at a design/designer, but to draw the designer's - and prospective builders - attention to an apparent inadequacy. But, wouldn't the discussion of a specific designer's work be better discussed on another thread?

    Mike
     
    Last edited: Aug 20, 2010
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