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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    Location: British Columbia

    Brent Swain Member

     
  2. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    But they haven't. When you scaled your 21 footer up to 36 feet the keels were inadequately supported, tore welds and damaged the hulls from groundings. Anyone knowledgeable could have told you the design was inadequate...................and your response would have been the same!

    The one and only torn weld was a hull hityting the rocks at over 14 knots which had keels which were not built to my design. No other has ever torn a weld. You lie !
    The 31 and 36 were designed form scratch and were definitely not a scaled up version of anything. Again , you lie!


    Using statistics of all your 21 to 35.5 foot boats and excluding the failures doesn't prove anything.
    The torure tests they have endured and hundreds of thousands of ocean miles they have crossed, without a single failure at sea, proves their reliability beyond all reasonable doubt, as Dudly Dix pointed out.. Again, you ;lie!

    While at the same time Your engineering knowledge is abysmal and demonstrably proven so by your own design failures.

    What failures?

    On the other thread where we were trying to get you to discuss structures, it was clearly stated that your 36 design has inherant unecessary weakness, and severe stress raisers which are likely to cause fatigue failure at some stage in the vessels life if it's used at sea.

    Hasn't happened in 30 years of ocean cruising. Structural weaknesses don't wait that long to show themselves. Again you lie!

    You can't determine when that failure occurs or what the extent of the damage will be. Since there is no redundancy in your structure it could be seriously catastrophic, for example, if it's in the middle of a severe storm.
    They have had no structural problems in 30 years of every storm they have encountered. Again you lie!

    I have said repeatedly that you can add a day or two and a hundred or two dollars worth of material and do the job properly. But your response is this:

    'More like the difference between $17,000 and $80,000, or more



    While you disregard all concern about safety, couldn't give a toss about the people and their safety. And won't even look at the very serious structural issues raised.

    They have been delt with by 30 years cruising experience, far more valuable and accurate than number on a paper.
     
  3. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    Thanks for the contact info. I'll send it toCclive who is keenly interested in a demolition derby.
     
  4. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    The 36 brentboat in this photo is busy , heading for Chile, Cape Horn and South Georgia this fall.
     
  5. MikeJohns
    Joined: Aug 2004
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    Location: Australia

    MikeJohns Senior Member

    I can leave much of my prior comments intact.

    You said yourself that they were your own design, the design you had before you beefed it up after it became apparent that they were not strong enough.

    That's my point, you revise your design after failures such as "keels being driven up into the hull" in your own words.


    They are scaled on the same principal of a pull together largely frameless shell. What works for a 21 footer isn't necessarily valid for a 36 or a 40 and invalid for a 57 or a 60 footer.

    Using statistics of all your 21 to 35.5 foot boats and excluding the failures doesn't prove anything.

    Dudly dix pointed out what exactly and when ? Also Dudly is a good yacht designer not an engineer, so he follows ABS design rules. You don't. All you have left now your engineering misunderstanding has evaporated is tall tales from yourself about what happened to other people.

    Your engineering knowledge is abysmal and demonstrably proven so by your own design failures.

    Rotating keels into hulls is not a feature, its a failure. You had to revise your design, after it became apparent. Had you understood some basic principles you could have avoided that initially. I was commenting onthe process you adopt which is Trial and error design.


    On the other thread where we were trying to get you to discuss structures, it was clearly stated that your 36 design has inherant unecessary weakness, and severe stress raisers which are likely to cause fatigue failure at some stage in the vessels life if it's used at sea.

    Says who? can you draw me a SN curve ? do you understand fatigue? if you do you are being very evasive, otherwise you are just ignorant of the actual process.


    You can't determine when that failure occurs or what the extent of the damage will be. Since there is no redundancy in your structure it could be seriously catastrophic, for example, if it's in the middle of a severe storm.


    I have said repeatedly that you can add a day or two and a hundred or two dollars worth of material and do the job properly. But your response is this:

    Be sensible, you could add a proper set of floors from plate offcuts. A few flat bar transverse frames would add a few hundred at the most.

    While you disregard all concern about safety, couldn't give a toss about the people and their safety. And won't even look at the very serious structural issues raised.

    Until the tail falls of the aircraft, or the bridge collapses its safe, that's not an argument for poor design.
     
  6. welder/fitter
    Joined: Jun 2008
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    welder/fitter Senior Member

    So... In this thread and/or others,
    We've discussed the no frames vs. transverse frames aspect of this method of construction. We've discussed the forces acting on the centerline tacks/welds when these boats are pulled together, without delving deeply into the consideration of how these forces would increase with thicker plate used on larger boats. We've discussed lack of keel support, though there seems to be some confusion as to whether, or not, the boat that suffered the keel damage was of Brent's design. Hull to deck joints, chines/darts/whatever, the manner in which internal support stanchions are attached to hull, etc., have been addressed, to some degree.

    In the end, to all but the cheerleaders, the design(s) is/are a big question mark. Suppose Brent did have an engineer/NA/designer take a look at his design & address any inadequacies. I see 5 possible outcomes(for brevity I will use "engineer" only):

    1) The engineer addresses the perceived inadequacies, Brent incorporates them, and, aesthetics aside, there is nothing more to question.

    2) The engineer addresses the perceived inadequacies, Brent & the engineer agree to disagree, the question mark remains.

    3) The engineer, after careful analysis, decides that Brent is correct and that there are no inadequacies, and informs the rest of us of his or her(not pinpointing a specific engineer, though a significant offer has been made) findings.

    4) Brent launches a pre-emptive strike by showing us that he has the capability to work out the numbers, does so, and they are indisputable.

    5) The drawings Brent gives the engineer do not allow for analysis due to being lacking in some manner.

    Anecdotal evidence, alone, does not adequately address opinions based on sound mathematical & scientific principles. It has some value in supporting claims, yet, is insufficient when standing on it's own. Not one for believing in messiahs, I fail to see the miracles.

    Regardless, "they" say that doing/saying something over and over again, in the same manner, and expecting different results, defines insanity(anecdote). It is, seemingly, uncanny how my mind anticipates Brent's responses to the questions, before he posts them. The anecdote or abrasive statement comes to mind long before it is (re)printed, at times, verbatim. Eventually, some regulatory body will come into effect, or an existing regulatory body will enjoin, those who question the method of design & construction of these boats & their designer. How the designer will defend himself in a hearing, tribunal or court of law is beyond me. Until that time, to remove the personality conflicts - which only serve to distract - this will be my last post on the subject of these boats & their "designer".
    Mike
     
  7. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    Brent, with all due respect, here is your chance to show everyone wrong...

    1. If your design is passes this analysis, you can scream it from the roof tops and post it on every site in cyberspace, and we will have the insult on us by doing the right thing to apologize to you.
    2. That said, if your design fails the analysis, you be man enough to acknowledge the fact and inform your current and past clients with the professional engineering assessment thereof.

    For once, set aside your derby demolition standard and get to the real world with some numbers. Numbers are used every day scientifically to design safe goods like for instance your car, everything you touch and feel, even right down to the ***** bowl for comfort and flushing capacity with minimum water wasted:cool: NASA even used numbers to put a man on the moon.
    Why cant numbers be used on your or any other boat?

    Use MikeJohn's offer that is worth $$thousands and have your design analyzed and certified by a professional. Only a fool would decline such an offer unless one has something to hide or fear of truth. OTOH, If one is sure of one's design, what a way to have it marketed with a professional structural analysis and certification.

    Your call....
     
  8. junk2lee
    Joined: Jul 2010
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    Location: Canada

    junk2lee Junior Member

    Hello all.I've been lurking here awhile but finally,I have to join in....I have a fibreglass hull and am too lazy for the build-yer-own thing when there are so many good ol' glass units to wear out.
    However,I have sailed a BrentBoat up the west coast of USA to windward for 20 days-the same boat that was wrecked and dragged off the Baja by close friends of mine.(I have the pictures of this.)The fir mast was horizontallyfractured by the pounding on the beach and had to be fished and lashed for the leg I did from San Diego to Victoria but the boat was a good sailer.Didn't smack or bang or stop-dead as I thought she might and were it not for the hassling with the corroded electrics I figured I needed,and the SS forestay snapping,the trip would have been a pleasure.I didn't use the engine (a handcrank aircooled Hatz diesel) until I went into Neah Bay to get out of the fog+ships in JuanDFuca.

    I'm interested in boatdesign of course and i have a lot of opinions. My experience with the boat,rig,(or cellphone or OS!) I've been stuck with is more about the analysis after-the-fact ...of the mistakes designed into a !...that could have been avoided if the designer had ever actually spent time with their creations.
     
  9. junk2lee
    Joined: Jul 2010
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    Location: Canada

    junk2lee Junior Member

    I guess my previous post may not seem so pertinent to the chunky bile in this thread.My take on BrentBoats is that they are a recipe for the home builder to get-going.Brent has always been generously free with tons of advice but once the backyard builder gets goin' on it,it's really a one-off every time.It should be plain that Brent can't defend every one of these in detail.I've seen some crazy ideas in with the good basic Brentboat.I personally know of 3 people who having built one straightforward BrentBoat,went on to build for other people incorporating their own theories as improvements.They are still plainly based on BrentBoats though.That's not to criticize these.Just to make the point.For a bad instance,that boat I sailed home to BC had a wooden cabin against Brent's advice but the builder was adamant..No amount of math or argument would shift this homebuilder.It was strong and it leaked like a sieve when sea aboard but It made him happy to have wood.

    With origami,you get a shape of a hull sitting in your yard right away.Block her up so she looks good to you and then stiffen it.Similar to a fg hull popped off a mold,if you ask me...the arguments arise here in the details but the original skin if built with heavy scantlings sucks up a lot of error even if it don't have the elegance of a bird.My professionally designed and semi-professionally built glass boat with bulkheads wrings in a chop.To be fair many could blame the unstayed mast but I would disagree.Want to argue?...Like I said,boat design on this thread seems too often to be a lot of analysis after-the-fact.BrentBoats work well.The Truth is out there.
     
  10. RHP
    Joined: Nov 2005
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    RHP Senior Member

    What about a Brent Boat made in Thailand?? :D


    I´ll get my coat..........
     
  11. terhohalme
    Joined: Jun 2003
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    Location: Kotka, Finland

    terhohalme BEng Boat Technology

    This "one-off" phenomenon is a direct result of not having decent drawings and documentation. When there is no detailed drawings, the builders start to create their own ideas. This can be hazardous. I can show one extremely dangerous structure; the strut (pillar) which should lead the mast compression to the hull structure is in some boats welded direct to bottom shell and not to stiffener or floor! (a floor is not the same in boat and home)

    As I understand, none of engineers here have demanded heavy scantlings, just good practice in boat engineering and decent documentation for backyard builders. The European authors will insist changes in structure of BS boats, if they appear to European market.

    And Brent should stop talking nonsense of the mystic strength of origami shapes. It is just a V-bottomed boat hull with conical ends of sheets. In the middle part (most of the boat) the origami is a simple V-bottom structure and should be engineered as one.

    I agree the suitability to backyard builders after above is corrected.

    Terho
     

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  12. SheetWise
    Joined: Jul 2004
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    Location: Phoenix

    SheetWise All Beach -- No Water.

    Brent?
     
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  13. LyndonJ
    Joined: May 2008
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    Location: Australia

    LyndonJ Senior Member

    Yeah but what boat :(

    What size was that one on the beach? How much did it pound? What was the build like? Did Brent build it or was it built with better structure that he indicates in his plans?

    We were looking at specific details on his 36 footer. There are some horrible built in delayed destruct mechanisms in his plans for the 36. Anyone with a small amount of sense would correct those design deficiencies, and they do. The only ones that don't are the non-savy types that brent builds for.

    With the crappy sketches sold as plans no two boats are the exactly the same. There's not even dimensions on many of the spacings and shapes.

    The amount of framing is often increased over Brent’s ‘framing’ design, floors and entire ring frames are added as well. Brent himself says this is common and to quote Brent “people can add whatever framing makes them feel comfortable”

    If Brent didn’t build it then maybe its only the concept he can claim credit for not the design if it's not built to his actual design.
    Brent mixes everything up, even climbs on other designers success 'origami' 57 footers for example which bear no resemblance to his design at all.

    Real statistics like:
    How many Brent built as-designed 36 boats with the poor keel supporting frames have done passages and been washed over reefs and pounded on hard beaches………….

    The anecdotes need fixing to real data of the vessels for a start. Then they need the tale from the skipper direct unblemished and untainted. Eve then there’s always a terror factor in the height of the waves, the width of the reef………..

    What's the tale that you heard about the beaching? I'm curious was it was purchased as salvage on the beach or salvaged by the original owner?
     
  14. LyndonJ
    Joined: May 2008
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    LyndonJ Senior Member

    Absolutley, you said some of what I did sooner. Those mast steps are bad, the plate is in shear right next to the stiffeners chine and transverse floor. There should be a connection to the transverse.

    Thats Evan Shalers version of the 36 , Brent told me along with -ve feedback that it's his old design (and that his new one is better) :rolleyes:
     

  15. junk2lee
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    junk2lee Junior Member

    Sheetwise,I get your joke.

    Lyndon J,Brent built this hull excepting the wood cabin that the owner wanted.It ended up at a slight heel tilted oh,about 15 degrees upright into the sand.that was up to the gunnels.Baja is wide open to the Pacific there.It pounded as they dragged it seaward with anchors and comealongs.It's not a "tale".The mast was fractured across grain because of it.
    The owner is a great guy although his navigation/caution skills were weak.In fact,he drove that boat back onto a Baja beach AGAIN several years later.
    Terhohalme,the plans are specific enough.BrentBoats are recognizable..
     
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