About a floating island which the bottom is similar to barge.

Discussion in 'Boat Design' started by kilbysg, Feb 12, 2008.

  1. kilbysg
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    kilbysg Junior Member

    Thanks for your quick response senior jehardiman.
    So where am I able to get the standard for the grove?
    What I have here is a diameter of 20 mm.
     
  2. jehardiman
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    jehardiman Senior Member

    Thats the point, an O-ring that big won't seal as the press area is too uneven. Go back to a woven seal with tar or sealent. It's only low pressure.
     
  3. rwatson
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    rwatson Senior Member

    JH is correct - its not an O ring because it has an O section, but only when the whole thing looks like a ring. Like a toilet pipe gasket.
    It might be the drawing, but these designs look decidely two dimensional to me.
    You will actually need a U shape gasket ( maybe with an O section).
    The bottom of the U will run nearly the width of the hull, the two sides of the U will need to be at least as high as the waterline. (See attached childlike drawing.)
    To be safe, you may want to have two of these (one smaller than the other) which seems to be what you are planning in those drawings.
    My preference wold be to have the internal walls as high as the waterline, so you wouldnt need any kind of gasket. It would be just one more thing to build and go wrong.
     

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  4. kilbysg
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    kilbysg Junior Member

    Oh, I see what you mean Sir Jehar. But, what about if I make the grove deeper enough which, the volume space of the grove and the part of the o-ring exposed above the grove is equal (approximately), then I can have an even press area. Do you think it's a good idea?
     
  5. kilbysg
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    kilbysg Junior Member

    I already had a section drawing that shows the linear of the gasket. Just like the drawing you had.
    But sir RW, how would i design the grove for the gasket? How deep it should be?
     

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  6. jehardiman
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    jehardiman Senior Member

    Not really. O-rings work because they have very small gaps that do not allow the soft o-ring to be extruded. If you had an O-ring that large with comperable gap space, it would have to have a duro too high to allow proper sealing pressure to be generated within normal tolerances. To lower the sealing pressure would require machining over the face that I know you cannot afford (think millions of US$). Woven gaskets will take up tolerances in the range that you are looking at with your construction methods.
     
  7. brian eiland
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    brian eiland Senior Member

  8. kilbysg
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    kilbysg Junior Member

    Sir RW, may you explain to me why should I have two gaskets with different sizes just to be safe? And also the main reason I am using those gaskets is to prevent the water penetrate on the holes for the bolt, because the level of those bolts is below the waterline.
     
  9. TeddyDiver
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    TeddyDiver Gollywobbler

    Instead of using "throw the hull" bolts I'd use either
    1. Bolts under the hull. It's idiot safe and nowadays there's a lot of divers around..
    2. If that's still a problem so making a kind of latch btw the hulls wich could be operated from the deck. Again no holes...
     
  10. kilbysg
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    kilbysg Junior Member

    Somehow I am looking and analyzing the links that Sir Brian posted earlier.
     
  11. rwatson
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    rwatson Senior Member

    Thank you Brian E.
    Hull sections that are the same size as a container is what I postulated back on 20th Feb - so nice to see that I can have a viable idea every now and then.
    Kilbysg - thanks for the further explanation of what it is that your O rings are for - that concept didnt come across in your drawings. I understand what you saying.
    I think you should look carefully at the links in Brian E's last post as well - there are some good concepts there.
    By way of explanation on the concept of "two gaskets, one smaller than the other " I attach another rough sketch with the concept I was alluding to.
    As regards smaller O rings ( they would truly be O rings ) for individual bolts, I see in my mind two large metal hulls slowly squashing and compressing and grinding 5 or 10 small 3 inch rubber doughnuts, as water and wind move the hulls around - and it appears to me that might create a number of small problem areas that would cause leaks.
    Two big big U shaped gaskets could be very thick and robust and actually prevent moving and "chaffing" of the two hull sections while maintaining watertightness.
    Something to consider.
    Do you think you will end up actually building something - it would be fun to see. Also, is this really for a "client", or is it your project ?
     

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  12. kilbysg
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    kilbysg Junior Member

    Sir RW - regarding on your question "Do you think you will end up actually building something?", I will say "YES" we will end up building something. Its one of our projects, and our first client would be my Boss's Partner in our Research & Development and Outsource Engineering... BANDACORP PI INC.
    and it would be really fun to build this one. And it is really interesting too (cool!)
    As for the gasket, i think i will end up using a square sectioned gasket instead of O sectioned.
    and as for the leak, we may put some cork like thing to suck on the holes and then when on the other side, the bolts are being pushed on, the cork like thing will loose on the holes while the bolts are being screwed on, so it will prevent a small water leakage. actually, we are prepared on that kind of problem, just getting the best idea and stay on track.

    By the way, thanks for your previous explanation.
    I hope you might have time to visit our website.
     
  13. kilbysg
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    kilbysg Junior Member

    What rule book should I apply for ny scantling calculation?

    My section spacing for the island has a span of 2230 mm (this span is what I've divided the whole island to fit on the container), so what i'm planning to do is locate 3 ordinary frames in that section (which is the both ends are my watertight bulkheads).
    Then I have a bulkhead spacing of 2230 mm; a transverse frame spacing of 557.5 mm (to be exactly) and longitudinal spacing of 500 mm...:rolleyes:
    Here is an attachment drawing in 2d to for your review base on what I am talking about...:idea: :idea: :idea:
    And please tell me if I am on the right track.:confused:

    Hope for your response and good guidance...:) :) :)
    Best regards,
    Kilby:cool:
     

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  14. kilbysg
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    kilbysg Junior Member

    any ideas please???
     

  15. kach22i
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    kach22i Architect

    Just something which came up earlier in the thread.

    http://www.globalsecurity.org
    Amphibious Cargo Beaching Lighter
    http://www.globalsecurity.org/military/systems/ship/acbl.htm
     
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