Looking for measurement numbers..

Discussion in 'J/24 Talk' started by ampostell@gmail.com, Nov 30, 2013.

  1. ampostell@gmail.com

    ampostell@gmail.com New Member

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    Happy Thanksgiving everyone!

    Working on fairing my keel and making the trailing edge min length. I would like to hear about measurements for section 2 and the tip of the trailing edge of keel from the transom. I know the measurement number for section 4 (3095-3125mm) and the top of the keel (2996-3020) per the manual, but looking to learn from your experience and expertise for the correct numbers! Can anyone provide me with these measurements for all sections?

    Thanks for your help.
     
  2. Dogfish4255

    Dogfish4255 Member

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    There are no specified numbers in the measurement guide or manual for the datum points that you're referring to, but some strong trigonometry and a bit of drafting paper could probably get you those numbers by breaking a few bigger triangles into right triangles. Ultimately the important part is to ensure that the length of the trailing edge is less than or equal to the max trailing edge length, and within +/-5mm from a straight edge without any intentionally manipulative shaping.

    Edit . . . And with the "at the hull" and "section 4" reference points from the transom, I'd suggest going 2-3mm short of the maximum measurement points, because those reference points are measured from a curved transom with a radius edge. Ease of measurement is worth a lot once you start worrying about getting a measurement certificate.
     
  3. twinger

    twinger Member

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    If you have numbers for back of the sump and section 4, you are pretty set. Those numbers should be close to maximum. after that you keel's trailing edge must be no more than 5mm from a straight line defined by those two points. Not much more that you can do than that.
     

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