motoryacht design

Discussion in 'Boat Design' started by lopese2, Feb 23, 2009.

  1. lopese2
    Joined: Dec 2008
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    Location: design

    lopese2 Junior Member

    Hy
    I’m student
    I design a motoryacht using maxsurf but I need to know if my hydrostatic at DWL results are correct and if they are accepted by the safety regulations.
    please can u help me

    Displacement 57.9 tonne
    Volume 56520312122.2 mm^3
    Draft to Baseline 1100 mm
    Immersed depth 1097.4 mm
    Lwl 25265.4 mm
    Beam wl 6434.9 mm
    WSA 124116116 mm^2
    Max cross sect area 4323844.7 mm^2
    Waterplane area 98014767 mm^2
    Cp 0.517
    Cb 0.317
    Cm 0.614
    Cwp 0.603
    LCB from zero pt 9388.4 mm
    LCF from zero pt 9996.2 mm
    KB 723.2 mm
    KG 0 mm
    BMt 4347.2 mm
    BMl 54306.7 mm
    GMt 5070.4 mm
    GMl 55029.9 mm
    KMt 5070.4 mm
    KMl 55029.9 mm
    Immersion (TPc) 1.005 tonne/cm
     
  2. Kreso
    Joined: Aug 2004
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    Location: Trogir, Croatia, Europe

    Kreso Junior Member

    Hi !

    Safety regulations require GMt, but you didn't give KG (KG 0 mm) so Maxsurf GM isn't real. !
    GMt=KMt-KG !!! :!:

    You must predict or calculate KG of your motoryacht design.
    Good luck ;)
     
  3. lopese2
    Joined: Dec 2008
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    lopese2 Junior Member

    hi thanks for your help
    but i would like to know how can i calculate KG for the motoryacht
    please can u help me.
    thanks
     
  4. Kreso
    Joined: Aug 2004
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    Location: Trogir, Croatia, Europe

    Kreso Junior Member

    You are student of naval architecture ? If you are I'm sure you talked about calculation of center point...
    If you don't have much time you can predict KG with percent of height. Attach sketch of your design with given height and I'll give you KG.
     
  5. lopese2
    Joined: Dec 2008
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    lopese2 Junior Member

    Sorry but I’m not a Naval Architecture student
    I’m CAE student and I have to design and analysis a yacht using FEM tools for my final year project
    I’m using Maxsurf to design and Hydromax to help me with the analysis

    Thanks for your help
    yacht data
    LOA 27700 mm
    beam 6996.6 mm
    Depth 3777.9 mm
    Draft 1100 mm
    Displacement 57.9 tonne at DWL
    thanks for your help
     

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  6. lopese2
    Joined: Dec 2008
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    lopese2 Junior Member

    sorry mr Kreso
    But I manage to fixe my maxsurf setting and I go KG result
    But I still need to know if the results are ok for safety regulations
    can u help me
    Displacement 58.3 tonne
    Volume 56878966682.8 mm^3
    Draft to Baseline 1100 mm
    Immersed depth 1099.8 mm
    Lwl 25269.1 mm
    Beam wl 6441.2 mm
    WSA 124965042.2 mm^2
    Max cross sect area 4399645.6 mm^2
    Waterplane area 98184198.7 mm^2
    Cp 0.512
    Cb 0.318
    Cm 0.621
    Cwp 0.603
    LCB from zero pt -4774.1 mm
    LCF from zero pt -4151.3 mm
    KB 721.9 mm
    KG 1100 mm
    BMt 4344.5 mm
    BMl 53993.7 mm
    GMt 3966.5 mm
    GMl 53615.6 mm
    KMt 5066.5 mm
    KMl 54715.6 mm
    Immersion (TPc) 1.006 tonne/cm
    MTc 1.237 tonne.m
    RM at 1deg = GMt.Disp.sin(1) 4035.8 tonne.mm
    Precision Highest 200 stations
     
  7. Kreso
    Joined: Aug 2004
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    Location: Trogir, Croatia, Europe

    Kreso Junior Member

    Hi !
    Your KG is to low, my suggestion is to take assumption of cca.0.75 of Depth, that gives for your design KG=2.55m.
    For stability check you need to go in Analysis menu , than in Criteria and in Criteria you set on IMO A.749(18) Ch.3 Code on Intact Stability.
    Read manual of Hydromax for details.
    Ciao ;)
     
  8. lopese2
    Joined: Dec 2008
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    lopese2 Junior Member

    thanks for the help
    but 0.75 of depth is not to low for motor yacht
    thanks
     

  9. lopese2
    Joined: Dec 2008
    Posts: 6
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    Location: design

    lopese2 Junior Member

    coefficient values

    Help please
    how can I find the safe values accepted for coefficient for a racing motor yacht?
     
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