Calculating capacity of a boat designed in Cad?

Discussion in 'Boat Design' started by Jmooredesigns, Dec 20, 2017.

  1. Jmooredesigns
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    Jmooredesigns Junior Member

    does anyone have the ability to calculate the capacity rating of a small boat designed in Inventor? Looking to find out what that maximum capacity is from the design. I know the weight of the boat but not sure what software or how to do the calculations. Thank you in advance for any help or guidance.
     
  2. TANSL
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    TANSL Senior Member

    Could you get the 3D model of your boat in iges, dxf or dwg format?
     
  3. Jmooredesigns
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    Jmooredesigns Junior Member

    I believe so. I have it in Step format now.
     
  4. TANSL
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    TANSL Senior Member

    If you wish to maintain the confidentiality of your project, send me the information by email.
    I'm going to send you a PM in which I indicate my email.
     
  5. Richard Woods
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    Richard Woods Woods Designs

    Don't forget its more complicated than just knowing the displacement. For sure you need to know the CofB and CofG, otherwise it won't float level. And then if you want the boat to move efficiently you will also need to know a lot of other hydrostatic data

    Richard Woods
     
  6. Jmooredesigns
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    Jmooredesigns Junior Member

    All I need is displacement of the hull with weight placed in the cockpit area. The rest I can handle.
     
  7. JosephT
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    JosephT Senior Member

    This might be worth a look for a quick estimate if you know your loading requirements. I'm not aware of a lot of Inventor use for boat design. I would export the geometry to a boat design package and get a better idea. See software section for list of apps. Good luck!

     
  8. messabout
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    messabout Senior Member

    You are not familiar with the methods and practices for extracting displacement, but you believe that; "the rest I can handle".

    The "rest" amounts to quite a lot more than drawing a fashionable boat. Richard Woods , above, was polite about your need to know how to calculate and evaluate some of the other critical factors.

    It will serve you well to be aware of the widespread human characteristic of; failure to know what you do not know. That is not a criticism it is merely a reality.
     
  9. gonzo
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    gonzo Senior Member

    JosephT likes this.
  10. Ike
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    Ike Senior Member

    There is a way to do this. In your CAD program define a waterline that is as high as possible on the hull, without water entering. That will give you the maximum displacement. Divide the maximum displacement by five if it is an outboard powered boat, by seven if it is an inboard (or I/O). That will give you the maximum safe load. This is exactly how it is done in the test tank. Weights are loaded until the boat reaches a point where water would enter. (sometimes the boats attitude has to be adjusted for cutouts at the transom or openings in the hull) If it's an outboard the weight is divided by five. If an inboard by seven.
     
  11. Squidly-Diddly
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    Squidly-Diddly Senior Member

    In Solidworks I'll just Cut-Extrude the hull above the waterline, and calculate the volume of what is left, then X the density of H2o.

    But I'm switching to Inventor because they give you free Student Edition without any fuss, and they are a bigger company than SW.
     
  12. gonzo
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    gonzo Senior Member

    You also need to subtract the weight of the superstructure. The extrusion will make the waterline go up; that is the hull will float lower. Boat don't float where you draw them unless all the rest of the calculations are done. The CG of the boat will align itself vertically to the center of flotation. That calculation is tedious but not difficult. Basically it is the sum of moments.
     
  13. Angélique
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    Angélique aka Angel (only by name)

    Is your confidentiality status known by the OP . . ?
     
    Last edited: Dec 23, 2017

  14. TANSL
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    TANSL Senior Member

    Gonzo, with those words you are going to scare the OP and anyone. Once the appropriate 3D model has been obtained in Inventor, the procedure to calculate the total volume can last no longer than 3 seconds: press the command "calculate properties" (or the equivalent), point to the solid on the screen and wait 1 second.
     
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