Origami steel yacht construction

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

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  1. pdwiley
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    pdwiley Senior Member

    Let us NOT get started on legal opinions having any correlation with engineering ones based on repeatable and analyzable data, please.

    PDW
     
  2. Ad Hoc
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    Ad Hoc Naval Architect

    Wikipedia is for those without any real books. It can be biased and incorrect.

    A boat is designed and built upon facts, not legal arguements.

    If you wish to comment on serious issues like stablity by quoting 'legal arguements' as a form of defence, then i suggest you start your own thread. You will not get any professional here supporting such nonsense. You are only exposing how naive you are by either assuming Brents reasoning is correct (without any foundation for doing so) or treating stability as "..it isn't such a big deal.."!

    You can split legal "hairs" if you wish. But the rest of us prefer to put the safety of our clients first, as any professional should. There is no debate on this issue.
     
  3. MikeJohns
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    MikeJohns Senior Member

    Anecdote is not a substitute for engineering, just the same way the fishermans tale of the one that got away doesn't constitute a fish survey.
    The anecdotes and tales Brent dishes up all need normalising and are often more than a little inflated second hand accounts. I'm sure your mother told you that tales always grow in the telling.

    Disappointing to whom exactly ? The facts are certainly going to be disappointing to many people I should think.

    And what progress exactly? Deflecting the heat away from the fact that Brent Swain knowingly lies about the the derivation and the stability of his designs?
    He's been taking a lot of liberty with the truth but this isn't just a tall tale this is serious falsehood for financial gain. Do you understand the seriousness of that charge ?

    There's nothing anyone can say to put any positive light on this. It's not criminally negligent, it's criminally misleading conduct. Hubris and egotism have absolutely no place in safety issues.

    Brent Swain needs to speak for himself . No one else can do that now.
     
  4. Wynand N
    Joined: Oct 2004
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    Wynand N Retired Steelboatbuilder

    I do not believe this.....

    Read the posts again, and other threads, and you will see that Brent has been asked numerous times for a set of line for this very reason. People like MikeJohns and others offered to this free of charge and still BS must stand up and deliver.

    BTW, in my personal opinion origami boats are the ugliest of all steel boats - limited in shape, and ugly chine - looking homemade smack in the centre of the hull, narrow boats with little initial form stability etc, no need for me to say the obvious any further.
    Why not go and build a proper boat from many well proven and safe designs out there. Actually, you will find it is in fact easier to build the "conventional" way and going that way, you will probably get your moneys worth in a few years.
    The thing with origami - yes, it is easy to make a few cuts in a plate, pull the monstrosity together with chainblocks and wallah, you have a "boat" with a few welds. Again, expect your moneys worth with the limitations of this methods. But then the crap starts and this BS will not tell people - to get the hull properly supported, one has to start adding the interior framing that will take you quite a long time.
    Much like painting the walls before you build them is the best way to describe this building method and the result would be the same.

    Lastly, on one of his many visits to my shop Dudley Dix once told me and I quote;

    "The hull plating is there just to keep the water out of the boat"

    Maybe this will put things in perspective as MikeJohns and others try to tell BS and others all along - a boat does need some framing. In BS case, if the plates keep the water out of the boat, the question then is what boat:?:
     
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  5. LyndonJ
    Joined: May 2008
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    LyndonJ Senior Member

    Whats totally ridiculous to a rank amateur can be very sensible to an experienced hand.

    There are people commenting here that design metal boats professionally. They are well educated knowledgeable people. Such people tend to have insight that you can't imagine. That goes for structure as well as operational factors like stability. It's also a first principal of DESIGN that you determine stability properly. That doesn't work with a model unless you know the CG.
    You can't know the CG without doing weights and moments calculations.

    It's also impossible for those boats to have stab to 175 deg. :( Any designer except Brent will tell you that.

    If you want to comment sensibly on stability it would be a good idea to read up on it like maybe some basic NA boat design books .

    Its also a bit precious dude to imply people are being unreasonable in their treatment of BS. I reckon he's had fairness he never deserved considering he's the author of the most vehement rants. He's been given every opportunity and a lot of leeway to insult lie and distort on the way. He's alone out there with his views ..... cept for the occasional friend or follower trying hard to pretend his swamp is prime real estate :)

    Get real BS is not a good designer, just the stability issue alone says he's a backyard amateur, then the structural side and his stupid engineering logic is laughable.
     
  6. larry larisky

    larry larisky Previous Member

    junky, junky, wikipedia now.
    next will be martha steward
    as i said, try the forum in general, you wil learn something, you need it.
     
  7. pdwiley
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    pdwiley Senior Member

    It's actually not ridiculous, it's sound scientific method.

    In science you rarely can actually PROVE anything conclusively, what you do is set up a hypothesis, define a method of testing it and if you can't DISPROVE it, then you TENTATIVELY accept it pending further/better data.

    Engineering is applied science.

    Religions assert that so and so is such and such, then challenge you to disprove it. That's Brent. Facts don't matter to him as he's in possession of a higher truth. Scientists &engineers provide data, analyse it and then argue over the interpretations of it. This stability discussion is easily resolved if the data were made available. Brent can do that (he says). He won't.

    What do you want to be, a religious acolyte or a supporter of scientific method? Which strand of philosophy created the equipment you're currently using?

    PDW - ex scientist.
     
  8. hoytedow
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    hoytedow Wood Butcher

  9. junk2lee
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    junk2lee Junior Member

    of course not.I was just looking for an analogy.Sorry to touch a nerve here and there but it seemed appropriate.Maybe I could have said,since there isn't any other DATA available now except pictures,Brents experiment and my observations,that the only AVAILABLE conclusion is some stability-not NO stability. To refine this would be interesting and, I see,through the clutter,a popular notion.As to ALL the other postings,I've been reading a lot of them but not all.There's years of them.
    One idea I'll toss into the ring that has always been available is an approximate model,ie: similar vessels."Similar vessels" would form a grouping in which the Brent boat is sure to lie....

    To me.Apparently a model CAN be made by a careful person with a calculator as I was describing it back in post#627?or as in:the hull pulled down from the masthead...I think I could write some simple programs for my SHARP and then just get the inclinometer readings and force applied by knowing the springscale reading and my distance as the "opposite side" where the hauling line's angle-to-masthead were known...a sextant might even help with this angle.This would help in narrowing down the "group"too.Boats with similar results at that heel angle would be candidates.

    Hopefully,I won't start an argument about "data",because observations are data too.say,a report of "broaching weather helm"or "wanton acceleration"( a Toyota? but better-a sailboat!)
     
  10. Ad Hoc
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    Ad Hoc Naval Architect

    So, what size scale model will you use?
    Is it an accurate representation of the final boat?
    Is your “spring balance” used to derive the force, is this calibrated, and to what error readings?
    What is the percentage error in your force measurements at the scale, and how does this relate to percentage errors full size?
    What is the area under the GZ curve?
    What is the angle at which downflooding occurs?
    What is the dynamic stability in varying sea states, with which sail plan?
    Does the stability satisfy any of the known and current minimum stability criteria requirements?

    And of course the first data you need before you can even begin, what is the KG and LCG of the model and is this the same as the “as-built” boat?

    Anything is possible, but only if you know what you’re doing. Just simply saying it is so, doesn’t make it so.

    There are no “nerves” being hit here at all. That is your interpretation based upon the replies you read, which may not align with your expectations. Your interpretation of these replies is based upon your lack of knowledge of what naval architecture and design entails. You are approaching this from a very simplistic and amateur way, rather than a professional and responsible manner. The two are chalk and cheese.

    To be a qualified professional naval architect isn’t simply a matter of building a small model and/or writing a book about a “gee whizz way of building to save money”. Sure anyone can design…..but can the design be demonstrated to comply with current minimum standards for structure, stability, build quality etc to ensure the safety of those onboard. This separates the men from the boys….and those boys act like petulant teenagers when exposed as lacking and react accordingly.
     
  11. MikeJohns
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    MikeJohns Senior Member


    If there's no data available then how are you intending to determine the centre of mass ?

    Brent has apparently recently been supplied the lines to his hull by a third party and is distributing them along with the design sketches he sells as plans.
    Whether you derive the stability from a model or from the lines or from a PC 3D model you do need the centre of mass aka CG.

    Brent won't be able to give you that since he doesn't have weights and moments claculations for his design.

    I wouldn't hold my breath waiting for Brent to produce a W&M sheet. The best thing you could do is to let us talk you or someone else through an inclining test on one of the boats already in use and derive a CG from that.

    If you did derive a proper CG then all you need is a virtual 3D model and I for one would post a GZ curve, using numerical methods (math) on a PC. Which will be a lot more accurate than you will ever manage (providing the lines are accurate).

    Then given the GZ curve there are recommended operational areas for vessels based on its length and stability. As a vessel gets smaller it's stability becomes much more important.

    Other factors which are usually incorporated in a target design by a properly trained designer would be metacentric height a and even gyradius and related roll period.

    The fact that Brent Swain has knowingly misrepresented stability and lied on public record about it is going to cause him some considerable mischief.
     
  12. junk2lee
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    junk2lee Junior Member

    Thanks,AdHoc.That's a good list...hopefully my answers are readable here

    Finally the shifting of buoyancy,metacentre,etc-I have a modelling problem with these.... but the sides of a bathtub would be slippery.and fore-and aft motion can be controlled with booms so the model has free motion...there'd have to be an inclinometer in the model.

    but there is.Plate thickness,engine,mast,rig,ballast it's all "out" there I think.Brent is very specific in construction and has a ton of specific recommendations that in sum,build the boat.But it'd take a time to get it all together.I'm suprised someone in this forum hasn't already done it.I wonder if it doesn't suprise Brent too.
    The best thing you could do is to let us talk you or someone else through an inclining test on one of the boats already in use and derive a COG from that.
    yes,that'd be fun where all the pieces can be brought together...But walking through it in the event is not as good as being set up beforehand.Describe (or draw) a picture of the "event"you have in mind,realworld.It has to be primitive.IE:what's aboard or easily found in situ (poles,pulleys(with a friction table),line,weights(a tested anchor and chain or ballast?)assuming also a good calculator and/or computer app.(suggestions?)

    If you did derive a proper COG then all you need is a virtual 3D model
    I have freeship but haven't had much practise with it.This is a November project!and Brent'd have to want to do this with me,too.There are already some online,I saw.But yes,computers would be so tidy! where the inputs are included with conclusions garbage in,garbage out,eh?...again,I'm suprised it hasn't already been done roughly,anyways, somewhere here with extant info .
     
  13. Tad
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    Tad Boat Designer

    How? If you don't know what the VCG is or the displacement....measured from an existing vessel...how will you duplicate them at scale?

    Every regulatory body in the world (and every professional Naval Architect I know of) accept only one method of establishing stability. The inclining experiment, the flotation measurements, and then GZ calculation using computer or calculator or hand. No one accepts model experiments.....they are meaningless because there is far to much room for error which is magnified by scale. Working at full scale for flotation and VCG minimizes error. Computer precision helps in this case.

    No one is saying these boats are unstable, but they are saying the actual stability characteristics are unknown. And we are saying that these boats do not "have positive stability to 175 degrees".

    This is why I am posting to this thread, I bear no one any ill will and I have no interest in personal attacks....but I do want to try and correct mistaken assumptions or assertions concerning structure and stability. I too have a set of Brent Swain 36' plans dated 1988, they contain no hull lines drawing. But, assuming the drawings included are reasonably accurate, I can construct a 3D model that will be fairly close to the actual boat. I just need a real boat to incline and measure for flotation, then a real stability curve can be posted here.
     
  14. Tad
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    Tad Boat Designer

    An Inclining Experiment requires several hours, a flat calm day, tanks either pressed up full or completely empty, empty bilge, a barrel or some tubs to hold water (our known heeling weights), a hydrometer to measure specific gravity of the water, a plumb bob on a string, and a measuring tape. Using the known weights in a series of movements we'll heel the boat to a max of about 3 degrees either way and measure the distance heeled with our plumb bob and tape. That's it.....
     

  15. junk2lee
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    junk2lee Junior Member

    Well,I like the simplicity in THAT!Thanks for replying.The hydrometer I would have missed but it's obviously important now you mention it.
    ("3" a typo you mean 30 degrees?)

    yes it's an approximation certainly and in lieu of the real thing .That's a given.But to me it's interesting and it narrows down the possibilities.If I dug up a rotted native canoe,a viking ship or the MARY ROSE, I couldn't use the real thing.
     
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