Origami steel yacht construction

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

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  1. Brent Swain
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    Brent Swain Member

     
  2. Bubblehead
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    Bubblehead Junior Member

    I'm no NA, but steel is steel, right?

    First, AISC will have an allowable shear of about 20% of Fu if I recall. So you need to derate your material for that, unless you're OK with the yielding/deflections. This already puts you well below the loads you describe, even before 20-30 years of corrosion reduces the plate thickness further.

    Second, this is clearly a cyclic/fatigue loading condition and I suspect there should be further strength derating for that. It appears that the connection has this shear being applied entirely in the HAZ of the weld (and your calculations indicate likewise) and I believe this would cause unfavorable performance under fatigue loading.

    Rolling a plate into a conical section does not magically transform Steel into Unobtanium.
     
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  3. Brent Swain
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    Brent Swain Member

    Man that guy with the glasses is some slick . Takes a slick and quick boxer to be able to box without getting his glasses out of place, the kinda guy who wouldn't even have to put his drink down to win a street fight.

    I got rid of my glasses a couple of years ago. Wunnerful! I can highly recommend laser surgery to any cruisers. It feels like having a set of 7X50 binocs on my head.
     
  4. MikeJohns
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    MikeJohns Senior Member

    My comments are within your quote in red, I wish you'd try and be sensible Brent, nobody appreciates this sort of childishness.

    Just look up distributed load verses point load and then go and calculate the shear stress in that plate. Post back here what that stress is and I'll tell you how many cycles you'll have to failure ....................another free offer.

    What I suspect, strongly is that not only have you never actually calculated that shear load on the plate, but you don't even know where to begin. You were even completely ignorant of shear as a failure mechanism a few threads back. You still don't appear to have looked that up.
     
    Last edited: Jul 22, 2010
  5. pdwiley
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    pdwiley Senior Member

    This is a waste of everyone's time, Brent doesn't have the data so he can't produce it. It was details like that mast support and looking at the as-built bits by Brent in Alex's video that turned me off. I wasn't so worried about the static load of the mast as I was the dynamic load and the number of cycles before fatigue failure occurred. Brent's comment about shroud strength is totally off the point; the mast is going to have DOWNWARDS momentum taking load OFF the shrouds and applying it to the hull plate where those supports attach every time the boat comes off a wave. I'm no engineer so I can't calculate what the load will be, but for sure it's higher than the static load in compression by the shrouds. I seem to recall that there's a bit in David Lewis' autobiography 'Shapes on the Wind' where he's sailing a (new?) ferro boat out of NZ, it falls off a wave and the mast punches straight through the hull, sinking the boat. Sure, it was ferro, but hey, reinforced concrete has huge strength in compression, right? Pity about the tensile & shear strength and how momentum adds load..... The ferro boat mast was fine alongside under its static load applied by the shrouds, which is EXACTLY Brent's argument as to why his design is OK.

    As for masts being supported ultimately by the hull plate as Brent claims, ******** in the general case. The design I'm building has the mast supported by a 200x25 keel shoe welded to floors approx every 900mm and those to ring frames, tied together by longitudinals on 300mm spacing from the bearding line. The hull plate basically keeps the water out.

    I'm done with this. There's only so much incoherent ranting and red herring dragging I'm prepared to read, and Brent has gone over quota.

    PDW
     
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  6. MikeJohns
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    MikeJohns Senior Member

    Yes PDW thank's for your posts and plesae keep us informed of your progress with the Colvin design.
    I very much doubt you will ever regret dropping Brents design for Toms. I've had good hard data from Tom before readily supplied, the sort of data Brent has never been able to furnish, and probably never will.

    As for the mast load on the plate here's Brent's 'mangling' of a simple calculation in which he manages to get quite wrong:


    This is complete and total garbage dressed up as engineering.

    The real concern is that he has been told before, long ago, that it's garbage and that shear is the failure mode of the plate not tensile. However he just believes away inconvenient facts. Not only is shear the failure mode here, but the shear loads must be below a relatively low stress limit to ensure that they don't fail through fatigue.

    All this is very basic and simple engineering. Without doing these calculations there is a risk of the safe load being exceeded and the plate being holed either through direct applied load or eventually through fatigue on the 1000 hard 'whomp' off a wave.

    I wouldn't take one of these boats to sea as Brent designs and builds them.
     
    Last edited: Jul 25, 2010
  7. LyndonJ
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    LyndonJ Senior Member

    Looks like he's about to go down from a left jab followed by a hard right.

    A bit like his arguments swinging wildly and with no focus playing to the crowd and not noticing he's making a fool of himself.

    BS
    You really have no idea about engineering. You just make it up until it sounds good and put it in print. Then you just try and bash anyone who says it's wrong. All this to run a scam and make tens of thousands of dollars from people you suck into your weak boats.

    I just got your book from Mike ( Welder Fitter) thanks Mike!

    There's so much rubbish in there dressed up as engineering it's killing me:

    I'll post some of it later.
     
  8. terhohalme
    Joined: Jun 2003
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    terhohalme BEng Boat Technology

    Oh, my Brent,

    You have a black room called "Naval architecture & Engineering". You are afraid of what is inside, you shout load outside banging the door and trying to desperately repeat occasional terms and guessing their meanings. Unfortunately, you are not able to open that door yourself, and it has become your bugbear and enemy.

    I hope someday you'll let a NA or Eng to open that door for you and turn the lights on.

    Terho
     
    Last edited: Jul 22, 2010
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  9. Wynand N
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    Wynand N Retired Steelboatbuilder

    None.
    In fact, all my clients bought their plans from reputable designers that are listed with SNAME (Society of Naval Architects and Marine Engineers) or other similar institution for the very reason you would not understand. They want peace of mind that the designer who designed their boat does indeed has the qualification and abilities to design such a safe vessel and are bound by professional ethics, such as records kept of all hydrostatic data, scantlings and other calculations.

    I never said that. Do not put words to my name to defend your stupid arguments and defenses. Funny, why would all the professionals be wrong and you, the savior of origamai, the only one being correct. Makes one think:confused:
    As for you and your clients to disagree; birds of a feather flocks together....:rolleyes:

    Sorry to piss on your parade. That privilege would be a matter client and builder confidentiality. Some of us still abide by a or some code of ethics.

    But this question actually shown your lack of knowledge and understanding regarding proper designed boats. My question to you would be to define a 36ft boat. It is all about displacement - heavier, the more expensive the boat. BTW, I would not bill you for this top secret and classified bit of information.;) Just do not tell others..
     
  10. LyndonJ
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    LyndonJ Senior Member

    They have been trying, and Brent has been very trying in return :)

    But if he did find a Pro to sit down with how would it go? BS'd be screaming 'Liar' and 'I know I'm right and the rest of the world is wrong' and bumble bees cant fly on the titanic which proves numbers all wrong, and other crap ad infinitum.

    Then he'd say the Pro was a dinosaur and fails to see the BS revolutionary technology of weak unsafe designs that cost more than conventional sensible designs with redundancy (redundancy that saves lives and assets).

    In reality world he's been told he's got it all wrong, it's been proved to him in gentle polite steps in the past. And his response to this is there for the world to google.

    He's working really hard at not knowing, and preventing his victims from knowing. He's doing that cause it's in his book and all his marketing and the Origami website and he wants to appeal to a certain type of client to get there hard earned $$$

    Here's a line from his book under Fundamentals at the start

    Quote
    " Resistance to holing goes up by the cube root of the plate thickness "

    Yep you read it right :D And this is the latest edition too of BS engineering for beginners.

    He just makes everything sound like it's engineering and most of it he's just made up out of thin air. Proclamations of distorted BS 'facts' like frames make a boat weaker ( more prone to holing) only longitudinal frames are worthwhile etc etc etc and it's all just dribble.
     
  11. SheetWise
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    SheetWise All Beach -- No Water.

    It's not really that complicated. And the Winner is ... (click)
     
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  12. LyndonJ
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    LyndonJ Senior Member

    Hey Wise
    That's a great video sums it up really well. ******** baloney and posturing verses cold hard sensibility.

    I love it Thanks.
     
  13. MikeJohns
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    MikeJohns Senior Member

    I just watched the Origami boats video by Alex Christie and Brent Swain. I've reproduced some stills for educational purposes. (Very educational purposes).

    They are not the only mistakes either. The welders here should probably look away this may be distressing to some viewers ;)

    Well it's no wonder that Brent can get a 36' hull together in a few hundred hours or so. He's fast, but his fit-up is very rough and ready, so is his welding.

    You could knock several designers fully framed hulls together with great speed with that level of workmanship.

    And this was the show hull for Alex and the video !

    Of particular interest this is the very poor keel support transverse end termination I was trying to point out to Brent. The final article is pretty bad.
     

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  14. TeddyDiver
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    TeddyDiver Gollywobbler

    Now we know how "extremely strong flatbar" looks like :D
     

  15. waikikin
    Joined: Jan 2006
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    Location: Australia

    waikikin Senior Member

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