Maxsurf was not correct to calculate the beam water line of catamaran

Discussion in 'Stability' started by thinhuk, Oct 7, 2019.

  1. thinhuk
    Joined: Jul 2018
    Posts: 7
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    Location: Vietnam

    thinhuk Junior Member

    Hi every one,
    Does any meet the problem as picture shown in below during calculate the hydrostatics for catamaran by using Maxsurf Stability or Maxsurf Modeler? From the image, it looks like at admidship draft t=1.623 the value of beam max on WL was incorrect lead to the Cb value was incorrect at the same draft?
    Thanks in advance
     

    Attached Files:

  2. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    Hi thinhuk

    Welcome to the forum.
    Reason is that the programme is not intuitive. It does not understand there are 2 hulls when calculating the Cb.
    Since the Cb is a block, by definition. But when there are 2 hulls, the programme uses the extreme limits of the 'block', that is outside of hull on port side to outside of hull on stbd side. The beam it uses is this value, not the beam of each individual hull. If you want to know the Cb...make a copy and delete one hull...then you will get the beam for the block.
     
  3. thinhuk
    Joined: Jul 2018
    Posts: 7
    Likes: 0, Points: 1
    Location: Vietnam

    thinhuk Junior Member

    Thanks Ad Hoc,

    Accordingly your answer, but how about at the draft t <= 1.595m and the programmes was correct calculate for beam max on water line as well as Coefficient Block? Although, this model has been created directly by Maxsurf Modeler and it was just only created for one hull the other just to press button haft net as picture attached shown
     

    Attached Files:


  4. Richard Woods
    Joined: Jun 2006
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    Location: UK, USA and Canada

    Richard Woods Woods Designs

    There are a number of CAD programs that don't calculate catamaran hydrostatics properly so be careful when buying/using and check with supplier first

    RW
     
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