Excell VPP Polar Diagram

Discussion in 'Sailboats' started by quequen, Jun 6, 2013.

  1. quequen
    Joined: Jul 2009
    Posts: 369
    Likes: 15, Points: 28, Legacy Rep: 199
    Location: argentina

    quequen Senior Member

    In addition to this old thread:
    http://www.boatdesign.net/forums/sailboats/vpp-polar-diagrams-20641.html

    Attached a simple excell file with the Gramp34 solution (post #6).
    The spline's ends are a bit distorted, so more points are needed there.
    Simple, fast, and it works.

    I must to add that my usual method for AutoCAD/Draftsight is even easier: copy the polar coordinates to the clipboard, call the Spline command, then paste the polar coordinates directly into the "Command:" line (Ctrl V). Then do a "zoom-all". No scripts, no lisp, no nothing. To try it, copy and paste the following (including the empty rows):
    3.29<44.35
    3.21<79.43
    3.35<121.23
    3.04<136.83
    2.24<180.01




    4.65<42.31
    4.75<77.04
    4.97<117.77
    4.71<135.40
    3.47<180.01




    4.96<40.00
    5.27<73.80
    5.58<113.33
    5.45<132.44
    4.30<180.01




    4.90<37.68
    5.58<70.86
    5.93<109.12
    5.88<128.84
    4.98<180.01



    exclude this line
     

    Attached Files:

  2. tspeer
    Joined: Feb 2002
    Posts: 2,283
    Likes: 251, Points: 83, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    FWIW, here's a spreadsheet that has a polar with circles of constant apparent wind speed/boat speed ratio and constant apparent wind angle. These circles form an orthogonal grid with the advantage that they are directly observable from on the water. So there are really three orthogonal coordinate systems shown - Vmg vs Vmc, boat speed vs true wind angle, and apparent wind speed/boat speed vs apparent wind angle - all superimposed on the same chart.

    The circles are universal, so only the sheet with the boat's polar data needs to be changed. There is one field on the CircleData chart that is used to scale the circles for the strength of the true wind.
     

    Attached Files:

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