drawing midship section of catamaran

Discussion in 'Boat Design' started by shrijeet mishra, Apr 1, 2020.

  1. Suhas
    Joined: Apr 2020
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    Suhas Junior Member

    So from your scantling calculations, you will get a min required thickness based on the section modulus of the stiffener you are trying to design. Thickness in FRP depends on the layer sequence you provide it. And thickness of each layer depends on the glass content and method of fabrication. You get these values from Chapter 7, Page 14 equation for thickness.
    So if you are using a CSM of 300 GSM from that equation youll likely get a thickness around 0.6mm.
    For example:
    If I have a sifffener of Size: 60(H)x40(B)- Layering:2xCSM300. Then its thickness will be 2x0.6=1.2mm.
    You need to stack up these layers to meet your section modulus.
     
  2. Suhas
    Joined: Apr 2020
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    Suhas Junior Member

    I work at Navgathi Sreejith. Its near CUSAT .
    Since this is your final year project, Id suggest you to make your own model from scratch. It'd be a good opportunity to learn hull modeling and fairing. Will prove to be helpful in future.
     
  3. rxcomposite
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    rxcomposite Senior Member

    It is the poles that makes the ship stand.o_O
     

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    Last edited: Apr 5, 2020
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  4. TANSL
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    TANSL Senior Member

    Thanks Rx, I'm sure Ad Hoc knew about it but couldn't remember right now. Now he can rest, uffff .... thank goodness!
    In these deep, intellectual and scientific discussions, a little humor is always welcome.:)
     
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  5. shrijeet mishra
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    shrijeet mishra Junior Member

    thank u so much sir fo rmaking me understand
    ill try learning and getting it done in soft copy.
     
  6. Ad Hoc
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    Ad Hoc Naval Architect

    Well, those are the only 'stands' that I know of, that you cite.

    But Tanls appears to know, or think he knows, of another:

    So if it is NOT those poles/stick/stands to support the hull of a model or during construction....what is the "calculation" being referred too?
    I simply have no idea...which is why I asked the question. But of course... no clarification.

    Sadly just utter nonsense in reply...as usual...and still the question remains unanswered.

    Why do posters use terms they do not understand merely to appear/sound knowledgeable eludes me...

    At least you replied...many thanks RX :)
     
  7. TANSL
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    TANSL Senior Member

  8. Ad Hoc
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    Ad Hoc Naval Architect

    I could not agree more.

    You cannot answer a simple question based upon clarifying a terminology that you used, no one else, yet you cannot supply the definition of the term.
    Just endless misdirection obfuscation and trolling...

    Pathetic!!
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    Ive found these online too:

    [​IMG]

    Tailor made for the job. No need to calculate.
     
  10. shrijeet mishra
    Joined: Feb 2020
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    shrijeet mishra Junior Member

    suhas sir
    shall i proceed with these dimensions in excel to draw like the reference drawing i got

    if have some time and if possible can you guide me with your rough drawing if any changes are required.?!
    thank you
     

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  11. gonzo
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    gonzo Senior Member

    I think you still have a fundamental error on this design. If it is a fast catamaran, the displacement should be reduced dramatically. Another major problem is the very wide and flat stern that is submerged. That will generate a huge amount of drag that will make it impossible for it to be a fast boat. Also, the beam is too wide for a fast displacement hull. If you need it to have a large beam, it should be a Vee bottom so it can plane.
     
  12. shrijeet mishra
    Joined: Feb 2020
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    shrijeet mishra Junior Member

    sir ill cross check it over once again.
     
  13. Niclas Vestman
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    Niclas Vestman Senior Member

    Dear Shrijeet
    If I understand correctly, your main subject of study is structural engineering. And that you have not yet focused on hull shapes, hydrodynamics or seakeeping. Correct me if I am wrong.
    I am just an amateur myself, but I would like to agree with the experts who have mentioned that your general design should be abandoned and totally redone.
    Take a look at the designs of a recognized skilled naval architect with expertese in multihulls. His 85' power cat has very similar traits to your requirements. Scaled down 10% and then make the bridgedeck 3m narrower. That will yield a 24m x 8m, 1m draft, 20 tonne lightship with 20 tonne payload, 30 knots capable semi-displacement cat.
    Well, I for one love his designs... Good luck with your project!
    Kurt Hughes Multihull Design - Catamarans and Trimarans for Cruising and Charter - 85' Term Charter Catamaran https://www.multihulldesigns.com/designs_stock/85powercat.html
     
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  14. Niclas Vestman
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    Niclas Vestman Senior Member

    Kurt Hughes Multihull Design - Catamarans and Trimarans for Cruising and Charter - 61' Catamaran Ferry https://www.multihulldesigns.com/designs_other/61ferry.htm

    This narrower 65' design might be even closer yet, to your SOR. Same designer. (Yes I am a fan of mr Kurt Hughes' designs ). Just keep in mind that he often makes quite light designs with thourough structural engeneering that requires the builder to be careful to not ad extra weight. My guess is that those designs could very well be heavier and require more displacement, if drawn/enginered by someone else. But that is just my amateur guess.
     
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