Simpson's formula

Discussion in 'Boat Design' started by Coen, Mar 3, 2005.

  1. Coen
    Joined: Aug 2004
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    Location: The Netherlands

    Coen Junior Member

    Hi y'all

    As I wrote before, we are designing an offshore support vessel. We thought we finished drawing the lines plan, but according to rhino there is quite a big difference between our calculated immersed volume and the immersed volume calculated by rhino. The frame surfaces are equal, which makes me think that we are doing something wrong in our calculation. I will give you the facts:

    Lpp = 59,4 m

    We have 12 ordinates, spaced 9 frames between. As the frame distance is 600 mm this leads to 5400 mm between the ordinates. The ordinate surfaces are as like this:

    Ordinate Surface
  2. DaveB
    Joined: Dec 2003
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    DaveB Senior Member

    might be a good idea to post the 3dm file and spreadsheet.... have you checked the direction of your surface normals? Is it a closed surface?

    I'd be happy to use rhinomarine (phaser) to get a displacement if you send me the file...


  3. yipster
    Joined: Oct 2002
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    yipster designer

  4. Palmer
    Joined: Nov 2002
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    Palmer Junior Member

    Simpson's requires an odd number of ordinates. IF you don't want to redefine them you could use the Trapezoidal rule instead. It's not quite as accurate as Simpsons but should be within a couple percent.
  5. icetreader
    Joined: Jan 2003
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    icetreader Senior Member

    The metric system is really easy!
    -I still use my fingers :D
  6. Coen
    Joined: Aug 2004
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    Location: The Netherlands

    Coen Junior Member

    Hey guys,

    I'm am sorry to say, my thread was a mistake. While I was writing it I decided to go to the teacher and ask him :p

    Accidently I probably pushed 'submit'. Thank you very much for your replies anyway.

    When I have an answer I will let you know!

    Tnx again,

    Coen Meerbach

  7. terhohalme
    Joined: Jun 2003
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    Location: Kotka, Finland

    terhohalme BEng Boat Technology

    In Rhino, Phaser, check: Help-> Plug-ins-> Protheus Hydrostatics and Stability Plug-ins-> Checklist. It's all there. In the beginning I made many mistakes, which solved by these notes.

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