catamaran design

Discussion in 'Boat Design' started by Zaigham Ul Islam, Oct 26, 2022.

  1. Zaigham Ul Islam
    Joined: Feb 2022
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    Zaigham Ul Islam New Member

    Hello there,
    actually, I am working on a catamaran ferry design, and I am not having much of information of the concept design of catamaran so I'll be thankful if anyone could help me in finding the complete method or any book for catamaran design.
     
  2. gonzo
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    gonzo Senior Member

    The first thing you need to do is write a Statement of Requirements (SOR). That includes goals like fast, low draft, economic to operate, etc. It also has constraints, like maximum length and beam, number of passenger, regulations, etc. You then look at any conflicts between them and decide what compromises can be made. We call this the "design spiral" because as you change one thing it goes around and may create new conflict that require compromises/ changes. You go around and around until you reach a satisfactory result. At that point, you can start designing and specifying materials, sizes, etc. For example, this process will question why are you designing a catamaran and not a barge. At each step you need to prove what works best.
     
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  3. oldmulti
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    oldmulti Senior Member

    Gonzo SOR is a very good starting point. I do not know what level you are at but here is a few idea sources.

    First is a cat ferry design with some structure information: “White Dolphin II” – 26m Catamaran | Welcome to Global Marine Design- Marine Kits https://www.marinekits.com/catalogue-kit/white-dolphin-ii-26m-catamaran/

    Next is some of the secondary issues to think about relating to meeting SOLAS rules etc. High Speed Aluminum Catamaran Passenger Ferry -Newbuilding Principal Requirements https://www.academia.edu/40948770/High_Speed_Aluminum_Catamaran_Passenger_Ferry_-Newbuilding_Principal_Requirements

    Finally a numerical study of hull resistance versus actual performance: https://www.researchgate.net/figure/Proposed-design-of-a-130-m-medium-speed-catamaran_fig2_301720016 When you use this link you will find in the bottom left corner an automatic download of the pdf and you do not have to “join” research gate.

    Sorry if this is to detailed for your requirements.
     
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  4. bajansailor
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    bajansailor Marine Surveyor

    @Zaigham Ul Islam please take heed of the excellent suggestions above.

    How far have you got so far with the design of your catamaran?
    If you have a Statement of Requirements, please list them here, even if there are only very basic so far.
    Have you done any drawings or sketches yet?
    Is this for a college project, or are you intending to build this ferry once you have designed it?
     
  5. Zaigham Ul Islam
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    Location: Karachi Pakistan.

    Zaigham Ul Islam New Member

    i have been through all this analysis i am designing a ferry for a pasig river in phillipines and there are so many bridges in the route with a low height so to compensate the payload and passenger we need to lower the air draft that's why i am going for catamaran so that i will have more space .
     
  6. Zaigham Ul Islam
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    Location: Karachi Pakistan.

    Zaigham Ul Islam New Member

    I am in the initial concept design for catamaran. there is no requirement of a catamaran but on the research basis from previously operating ferries on pasig river and due to less air draft and more passengers i prefer to design catamaran
     
  7. TANSL
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    TANSL Senior Member

    If we assume that you want a catamaran then the discussion about whether it is mono or multi hull should no longer arise. Let's not insist on that and take steps forward.
    As stated previously, an SOR, as detailed as possible, is the first thing you need. The second step would be to draw a General Layout plan, forgetting, for the time being, the shapes of the submerged hull. The third and following steps should wait until the first ones are finished.
     
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  8. rxcomposite
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    rxcomposite Senior Member

    There is an air height restriction. That is from the waterline to the uppermost part of the boat. The air height part is the distance of the river water (at its highest) to the lowest part of the bridge.

    There is a 150 PAX composite catamaran ferry plying the Pasig river.
     

    Attached Files:

    Last edited: Oct 27, 2022
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  9. gonzo
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    gonzo Senior Member

    Are there beam and draft restrictions as well?
     
  10. DCockey
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    DCockey Senior Member


    A catamaran will frequently have more air draft than a monohull of similar size and capacity due the need to have sufficient clearance under the structure between the hulls. It may be possible to make the catamaran wide enough that fewer decks are needed than on a monohull which can reduce air draft.
     
  11. Ad Hoc
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    Ad Hoc Naval Architect

    As already noted above by several..without an SOR...it is not so easy to provide data/info.

    Indeed, and why the SOR is important.
    Here is a typical one we have around the rivers in Osaka:

    upload_2022-10-28_10-39-44.png

    All monohulls...as there are many any bridges and almost all of them are low :eek:
     
  12. Ad Hoc
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    Ad Hoc Naval Architect

  13. Zaigham Ul Islam
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    Zaigham Ul Islam New Member

    no but as per the references available length ranges from 20-25m and beam ranges from 7-10m
     

  14. rxcomposite
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    rxcomposite Senior Member

    Yes, some parts of the river are not deep. Also the beam is dictated by the spacing of bridge columns. There are areas where you can enter but not turn around. Ahead or sink.
     
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