PKBoats Plans (no diagonals?)

Discussion in 'Boat Design' started by Jammer Six, Aug 1, 2014.

  1. Jammer Six

    Jammer Six Previous Member

    Looking over the plans from PKBoats, I notice there are no diagonals.

    Can anyone shed light on this? What reason is there for not including diagonals?
     
  2. gonzo
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    gonzo Senior Member

    If you have the other lines, the diagonals are derived from them. They are not usually necessary on construction plans. The only areas that they may be useful for fairing are extreme flair in the bow or tucks in the stern.
     
  3. Tad
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    Tad Boat Designer

    If you want diagonals draw them, you are lofting the boat, right? I have no idea what program Paul used for lines fairing or drafting but many do not include diagonals as the software was not created by boatbuilders.
     
  4. Jammer Six

    Jammer Six Previous Member

    Thanks, I didn't realize they were a lofting artifact rather than a design creation.

    I don't believe the K5 has much flair.
     
  5. TANSL
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    TANSL Senior Member

    I'm a little confused, Gonzo says that the diagonals are not "necessary on construction plans" while Tad says no diagonals because "the software was not created by boatbuilders".
    So if the software had been created by a boatbuilder, logically to create construction plans, does the software would draw diagonal or not?
    Of course, if Jammer Six needs the diagonal (what for?), I agree with Tad, has no choice but to draw them.
     
  6. gonzo
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    gonzo Senior Member

    Diagonals can be used to visualize the water flow when the boat is heeled too. However, once the design has been completed, a builder doesn't really need them to loft the frames or molds.
     
  7. JSL
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    JSL Senior Member

    I have lofted several boats and diagonals provide a quick check for fairness of hull ( double redundancy so to speak). The extra time of adding these in is often worth it
     
  8. Jammer Six

    Jammer Six Previous Member

    So, I take it that one just selects a point on the center line and strikes the diagonal?

    For some reason, I thought there was magic in the location of the diagonals, and that the designer put them in that location for a specific, mystical naval architect reason.
     
  9. gonzo
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    gonzo Senior Member

    The placement of diagonals matters in the sense that they help fair lines that don't show well on waterlines or stations. For example, at the sharp turn of a bilge. I sometimes add them while lofting. As you get more experience, it becomes easier to find where and if they are needed.
     
  10. TANSL
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    TANSL Senior Member

    The diagonals are another element to check the smoothing of shapes and as Gonzo says, in some areas of the ship they are the best way to detect certain irregularities. However, because the fairing is the first, and most importantly, construction plan of the hul (is the plane that says how are each and every one of the frames and construction serves to develop the hull plating or determine the shape of the transverse bulkheads)l, I have to say that for the construction plans are necessary, indispensable, diagonals. They are always needed, if you will do a proper job.
     

  11. Tad
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    Tad Boat Designer

    Here's a body plan I hand drew many years ago. There are eight diagonals on this lines drawing. Lines that cross each other at a shallow angle are inaccurate in hand drawing (not so in the computer when fairing a surface) at small scale. These shallow crossings are called "rank" intersections. Diagonals are used as a fairness check in areas where the waterlines or buttocks are too "rank" to be accurate. Note that the upper diagonal "L" crosses the transom at it's widest point and runs forward through the tumblehome, it's a fairness check in that area. M, N, and O are double-checks through the bilge area. P picks up the forefoot and fairs into the aft hollow next to the keel. Q is a check on the bottom fairing into the aft reverse. R, and S are checks of fairness through the keel fillet. No magic, every line is there for a reason and if it's not needed don't bother with it.

    10002sections.jpg
     
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