Calculation

Discussion in 'Stability' started by naupigos_gr, May 7, 2010.

  1. naupigos_gr
    Joined: Feb 2009
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    naupigos_gr Junior Member

    Hello, I have a pre-design project for my university.
    I have to calculate main dimensions and coefficients of an LNG tanker with capacity of 145.000 cu.m., and speed 20 knots.
    I found a list of similar vessels but i got lack of parameters in many vessels, such as Displacement.
    Without the parameter of Displacement i can not design a curve through Regression analysis.
    I tried many different web sites, like vesseltracker..
    Is there any practical way, to calculate Displacement?

    thanks john b.
     
  2. jehardiman
    Joined: Aug 2004
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    jehardiman Senior Member

    Why not do it the old fashioned way....Lay out the cargo holds, add an engine room, and then draw a hull around it. If this is for a school design project, you should have been taught all the tools and concepts you need.

    Come on, this is not a time to copy, this is a time to have fun with design and self expression because there is no "correct" answer. You only need to show that you understand the concepts of design trade-off.
     
  3. naupigos_gr
    Joined: Feb 2009
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    naupigos_gr Junior Member

    yea, okay...
    but working with 19 vessels or more it is hard to draw 19 different plans
    thanks anyway...
     
  4. JRMacGregor
    Joined: Oct 2005
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    JRMacGregor Junior Member

    Typical block coefficient for that size of LNGC is 0.67 to 0.72. That works for speeds in range 18.5 to 20.5 knots.

    With the CB and the main dimensions you can work out the displacements of your hulls.
     
  5. hoytedow
    Joined: Sep 2009
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    hoytedow Carbon Based Life Form

    Why don't you start with the size and number of holding tanks needed, then design the ship around that?
     

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  6. conceptia
    Joined: Nov 2009
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    conceptia Naval Architect

    naupigos,

    Please refer to Practical ship design by Watson.. It gives you empirical formulas to fix your main dimensions. Remember one thing, your final displacement will have a reasonable change with the priliminary, so be conservative on primary fixing of displacement. You can also refer PNA, and Ship design for efficiency and economy by Schneekluth.

    All the best for your project.
     
  7. ejim
    Joined: Apr 2010
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    ejim Not Really Junior Member

    Your question is how to calculate displacement, right?
    here the formula : L x B x T x Cb x (density of water)
     
  8. Grant Nelson
    Joined: Feb 2005
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    Grant Nelson Senior Member

  9. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    $1130 is the minimum registration fee on that site? Geeee! :eek:
     

  10. conceptia
    Joined: Nov 2009
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    conceptia Naval Architect

    nelson, ship register dont provide free trial as of now. I did try for that 2 months back, but they told cannot give a free trial.
     
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