Modular Pontoons design

Discussion in 'Boat Design' started by eng.naval, Nov 28, 2012.

  1. eng.naval
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    eng.naval Junior Member

    Dear all,
    I'm working on a project of designing 10 modular pontoon which can be coupled together in the water not on dock. I've come up with an idea for the coupling system. Please look at the attached files and tell me if this idea will work or not and what if it's missing something. If there are any clarifications required, please don't hesitate to ask.
    Thanks
    3d model.jpg

    3d model - coupling.jpg

    Couling Assembly.jpg

    View attachment GA.pdf
     
  2. TANSL
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    TANSL Senior Member

    Hi Ayman, I'm glad to hear from you again. Have you thought about the possibility of this relative motion?. Note that there are waves in the sea.
    Regards
    Ignacio
     

    Attached Files:

  3. taniwha
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    taniwha Senior Member

  4. eng.naval
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    eng.naval Junior Member

    hello Ignacio, glad to meet you too. Actually that what I'm concern about. I've thought at first with the idea in your attached picture, with this type as I imagine the assembly is not possible on-board. Plus there will be relatively big space between the pontoons. As you said the wave motion is my concern. The coupling bar locks the motion in the horizontal direction. The vertical direction is my concern, for instance if a weight added to one of the pontoons or as you said the wave motion, all I can see is the locking plates will collide. The question is can it take this type of stress. Sorry if my words aren't clear but i don't have the drawings with me right now to explain. Maybe tomorrow I'll upload some pictures explaining my idea.
     
  5. TANSL
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    TANSL Senior Member

    I enclose a plane for a modular tubular pontoon and studies to test the effect of waves on the joints. The joints between pontoons are rigid, not as shown in figure my previous post, but are calculated to withstand the stresses induced by the waves, in addition to the loads on the deck.
    The idea of tubular modules greatly simplifies the construction and maintenance of the pontoon
    Hope this helps.
    I am at your disposal for anything you need.
     

    Attached Files:

  6. PAR
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    PAR Yacht Designer/Builder

    Pin alignment will prove interesting in all but a dead calm waterway.
     
  7. eng.naval
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    eng.naval Junior Member

    Thank you very much Ignacio for sharing that.
    May I mention to all that the pontoons are already being built. We've finished two and we will launch them for trials.
    In the attached files there are two arrangements. The first one are 10 pontoons loaded with gantry and other items as shown in the figure. The second arrangement are 5 pontoon and loaded only with the gantry. The gantry is used to hoist a cofferdam to be used in maintenance operations for quay sheet piles. We haven't decided yet to use the 10 pontoons arrangement or the 5 pontoons to load only the gantry. The maintenance operations will occur at harbors. I don't know if I'm correct but I think it's a sea state 1 (not deadly calm).
    The gantry will be welded to the pontoons, so as I think these pontoons will have a rigid connection in addition to the pin alignment. I'm waiting for any comments.
    Thanks to all.
     

    Attached Files:

  8. philSweet
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    philSweet Senior Member

    I think the gantry needs to be designed so that it distributes all of it's load directly to individual pontoons, and doesn't rely on pontoon/pontoon connection for global loads.

    Have you thought about a 9-toon where five slide up the middle of the gantry supported by a box beam that's part of the gantry, and then two more toons are added width-wise outboard? this lets all but two pontoons attach directly to the load bearing frame. I think all nine pontoons could be identically framed this way, which is a big deal in modular gadgets. Post tension with big cables and self aligning bosses, then bolt her up.

    Alternately, 2 of the pontoons could be the gantry frame itself. These would be specials, and six other would be modular flotation with no load transmitted between their faying surfaces, and the seventh would be the ballast unit.
     
  9. eng.naval
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    eng.naval Junior Member

    Thank you Phil for your comment, but it didn't fully understand your ideas.

    Yes I think it's the best case to be done.

    I'm sorry but i didn't fully understand the arrangement here. It will be great if you can explain a little bit more or draw a sketch for me.

    How are two pontoon can be the gantry frame itself?
     
  10. kerosene
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    kerosene Senior Member

    wouldn't it be better if every attachment point was identical and the extra components would serve the locking and "lego" like function. That way you could have much more flexibility for different combinations from fewer different kind of modules.
     
  11. MaV
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    MaV New Member

    In your drawing the gantry is orientated 90° from your pontoons, in this way your couplings wil have to bear all of the forses.
     
  12. eng.naval
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    eng.naval Junior Member

    What do you mean by the extra components?
     
  13. eng.naval
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    eng.naval Junior Member

    Is there any other way? How will the orientation of the gantry affect this matter. I think in all cases the couplings will have to bear all the forces.
     
  14. SamSam
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    SamSam Senior Member

    I have trouble understanding this thread. You are looking for advice on your design that is already being built. What good is advice going to help now?
     

  15. eng.naval
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    eng.naval Junior Member

    I'm asking if there's any modification i can do and what are the flaws in the coupling system.
     
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