Transverse frame calculation

Discussion in 'Class Societies' started by DUCRUY Jacques, May 1, 2010.

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  1. apex1

    apex1 Guest

    Oh god.............

    What a utter nonsense.....



    Brent,

    when will you stop bothering us with the advertisement of your quite questionable building method? (and your book of course)

    Regards
    Richard
     
  2. conceptia
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    conceptia Naval Architect

    brent wrote a book?? Must be a fiction on boat building.. :)
     
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  3. dskira

    dskira Previous Member

    Yes $20 plus shipping and he send you a spiral bound photocopie.
    Daniel
     
  4. LyndonJ
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    LyndonJ Senior Member

    I haven't read it. Perhaps Brent could scan it and post here his structural arguments .
    Others that did read it say there are major errors in the "Engineering" logic.

    What he doesn't seems to acknowledge is that there is a real limit to his minimalist framing technique and he talks people into bigger (50 60 foot) boats which are not strong enough.
     
  5. Brent Swain
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    Brent Swain Member

    Anyone who tells you that an arc has little or no structural advantage over a flat surface, is full of ****, regardless of who he is. Ask architects why they use arcs for bridges, and quantset huts , instead of a flat span, given that there is no difference between them ,structurally. Try building a quantset hut with all flat surfaces and no shape advantage , out of the same thickness of metal ,and see how it works out. So much for Lloyds theories.
    The topsides of a sailing hull are arcs, closely suported by chines and the hull deck joints, the equivalent of fully welded steel bulkheads, structurally. Chines are the equivalent , structurally, of fully welded longitudinal bulkheads. Longitudinals maintaining the shape are for more effective in maintaining structural rigidity, over a much wider area. Transverse frames only stiffen it a few inches either side of the frame.
    It is the infantile inability of some to comprehend this basic geometry, which has held back the development of small steel sailing craft for far too long. Dont let the kindergarten club run the show.
    Anyone who says that boats which have survived a single season passage thru the NW passage, a winter return from Xmas Island to BC, and year round cruising in Hecate Strait area ( in a 55 foot framless origami aluminium boat), weeks of pounding on a lee shore on the west coast of Baja, pounding across 300 yeards of Fijian Coral in an open ocean swell, circumnavigations, collision with a freighter in Gibralter, etc etc, are not strong enough , is a liar, or self delusional.

    When we work with a heavy material like steel , it is vital that we take advantage of every option we have in gaining stiffness, such as the huge advantage we get in sailing hulls all being portions of arcs and cones. Have you ever handled the thickness of steel used in autobodies, then compared it to the finished autobody, with all it's curves? Or done the same with the metal in an aluminium runabout? Try it, you'll learn something.
    Fools, like the bureaucrats at Lloyds, treat the structural issues of a flat sided power boat the same as a well rounded sailing hull, which is abysmally naive.
    I have been told that Lloyds no longer publishes scantling rules for small steel sailing craft. By what they have done in the past , they had no business being in that game in the first place.
    Again , bring me your Lloyds approved 31 ft wood or fibreglass sailboat, and we'll have a demilition derby. If you are unwilling to do that ,then you don't believe your own ********.
     
  6. Brent Swain
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    Brent Swain Member

    I don't do spiral bound . The pages fall out too soon. I use staples and book binding tape. People building my boats from a set of plans and a book, said every question they came up with, they found in the book. By the end of the project the book was frayed and dog eared , but they never lost a page.
    Those who lend the book, never get it back.
     
  7. Brent Swain
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    Brent Swain Member

    Before you put enough pressure to deform a curved skin with a logitudinal under it, both the skin and the longitudinal are under compression , if it is in an arc. Thiis not the case in a flat surface , which sailing hulls don't have. That is a totally differtent scenario.
    Two 55 footers were built by Ken Splett in Port Hardy using origami aliminium methods, no transeverse frames . Harvey cruises the south coast of BC in one and Jean Marc cruises the north coast, and owns old Bella Bella , the former cannery there. The last time I saw the boat was at Xmas island in october 2002 . He was just leaving, so I tried to radio him, but couldn't make connection. I was later told he headed back to BC in October- November, and had done enough full time cruising on the northern BC coast to have done several circumnavigations in the same distance. He is the kind of guy who prefers sailing in a full gale , or better yet , storm conditions. Both boats are surveyed and approved by transport Canada for charter work . When Transport Canada surveyors were told they were frameless origami boats ,they said " We are familiar with the method, no problem."
    Whenever I see someone who is about to be subjected to an enormous amount of uneccessary work and expense, due to someones ******** ideas, I will always speak up.
     
  8. dskira

    dskira Previous Member

    You realy have a problem.
    Daniel
     
  9. LyndonJ
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    LyndonJ Senior Member

    Mr Swain

    The level of your misinformation is astounding , You really appear have no concept of structures or their failure modes. The emotive arguments that work in your book on dreamers don't hold water with anyone who understands structural mechanics.

    Do you have one engineer that ever supported your theories?


    Buckling is always the principal failure for smaller vessel hulls .

    Theres a very big difference between local plate stiffness ( as indiced by curvature ) and global hull stiffness in say the hypothetical 60 footer you declared needed no transverses.

    A 31 or a 36 foot boat has a completely different design requirement to a 60 foot boat and you don't seem to fathom that.

    As for curvature and panel collapse try the following, hit an edge supported flat sheet of 1mm mild steel with a hammer .......................you get a dent

    Curve the sheet away from you and hit it the back .....................smaller dent

    Curve it bow towards you and hit it .............................largest dent of all

    Now beef up the plate to hull thickness hit that with the equivalent force of a boat being washed onto a very fixed rock . The extent of the local collapse could be massive unless there are restraints which fix the plate and let it stretch to absorb the impact and limit the buckling.

    You refer to a 55 foot alloy boat, what are the details of that? I think you'll find transverse framing of some description since alloy is no where near as stiff as steel and a 55 footer would be flexing all over the place.

    Collisions and groundings are so common for your anecdotes to be useless . Look at the photo of the steel yacht "Gringo" that was hit by a ship bulbous bow midships. Consider haw bad that would have been without framing and how daft your argumets re curvature are.
     
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  10. Brent Swain
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    Brent Swain Member

    The aluminium hulls were 3/8th inch 5086 .
    The Gringo wouldn't look much different had she been built the same weight in origami construction. The impact was parallel to the frames, not acoss them . You dont strengthen a plate longitudinally by putting something transversely across it.
    Hit a plate in the middle and it probaly won't dent. Hit any of my hulls well away from any hard points, with a pick axe, and it will spring right back . Hit a framed hull right next to a frame and it will defintiely dent, far easier , and probably go right thru.
    If you want a better understanding of the overall structural principles , take out a square tupperware container from your fridge, take the lid off and twist it. It twists easily. Put the lid on and try twist it again. It is structuraly far more rigid. The hull-deck joint and other longitudinal seams are where overall stiffness comes from , not transverse framing.
    Origami huls are extemely floppy , untl you put the decks on. Then they get as stiff as a brick, and a diagonal 3 ton come along can't twist them.
    Yes I have a problem; tolerating ********. I'd be worried if I didn''t have a problem with that.
     
  11. Steve W
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    Steve W Senior Member

    Brent,while your hulls may not use transverse framing in the building process if they have the usual transverse bulkheads,vee berth fronts,cabinet sides etc which are attatched to the hull then they have transverse framing.unless of course the entire interiors are suspended from the deck without being attatched to the hull.
    Steve.
     
  12. dskira

    dskira Previous Member

    You should worry, you tolerate your own ********.
    Daniel
     
  13. conceptia
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    conceptia Naval Architect

    seems like it more of obsession towards the Lloyds. Please do keep in mind that this a forum to share knowledge but not obsessions. So, please calm up your anger, and talk wise.
     
  14. LyndonJ
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    LyndonJ Senior Member

    Here's Gringo a conventionally transverse framed European build vessel. To German Lloyds scantlings.

    They were never meant to cope with such an impact. Note that the stretched and buckled area is limited in size because the frames made the plate much stonger and absorbed energy in deforming. The undamaged frames limit the damage and keep the hull shape overall.

    A frameless origami BS hull could have collapsed cartastrophically and globally.

    And Brent note that the plate did not tear adjacent to the frames as you keep preaching on other threads.

    Transverse framing is good
    Transverse framing makes the boat stronger

    Lloyds Reg , Germal Lloyds and every commercial class requires them but they are all wrong of course.
     

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  15. sorenfdk
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    sorenfdk Yacht Designer

    No, they don't.

    Yes, they do.
     
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