Plan drawing help

Discussion in 'Boat Design' started by oddboatout, Aug 23, 2013.

  1. oddboatout
    Joined: Oct 2007
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    Location: Nor Cal

    oddboatout Junior Member

    So I have my plan drawn. I have taken it from paper to Draft sight. I have the top view, side view and front/back view. I am really pleased with how it looks in 2D. What I need to do is take these drawings and put them down flat so that I can make a model. I like to print on heave card stock first. It is a hard chine design. How do I draw the sides flat so that when I put them together they have the correct curved shape. I read an article about conic projection but am more lost than before.:(

    Thank you.
  2. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    It is quite possible that you do not need to resort to the "conical projections", on the other hand, I do not know what they are. Everything depends on how is your boat. Would be helpful if you drew some transverse sections and, if possible, that these cross sections could be drawn only with the help of straight lines.
  3. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    I'm assuming that you have drawn curves representing the sheer, chine, keel, stem and transom outlines first on paper, and then as 2D drawings in DraftSight. Now you want to build a paper model. It looks like you are asking how to determine the shapes to cut the paper into for the sides and bottom of the model so that the pieces of paper will bend into the correct shape when joined together.

    There is not an easy way to determine the shapes using paper and pencil or 2D software such as DraftSight. It's much easier using 3D software such as Rhino or DelftShip/FreeShip. Sam Rabl described a 2D method which is less and which generally gets close to the exact shape. Rabl's description can be downloaded in post 94 of another thread But it is still a lot of work in 2D. Obtaining the shapes is much, much easier using suitable 3D software such as Rhino or DelftShip/FreeShip.

    Another method for creating a paper model is to mimic how a full size boat is typically built. First draw a set of transverse sections if you haven't done so already. Mark a baseline above the sections. Then find some cardboard and cut the sections in cardboard with the cardboard extending to the baseline. Also cut a piece to cardboard to the shape of the keel and stem, again extending to the baseline.

    Next you need a piece of wood or stiff cardboard which will be used as a base for the sections and center profile. Mark the centerline and the station locations on the base, and then glue the transverse sections and center profile to the base. If you cut full width sections rather than half width you'll need to cut your cardboard sections down the center and glue them to either side of the center profile. You now have a mold to build the model over.

    The mold is "planked" using thick paper, cardboard or thin wood. Cut an oversize piece of paper/cardboard/wood and wrap it around the side of the mold. (If it won't lie against the mold then the shape you've drawn isn't "developable". The shapes of the lines will to be adjusted.) While holding it in place on the mold mark the locations of the sheer and chine at each station. Take the side off the mold and bend a thin batten so that it goes through the marks for the sheer. Trace the shape of the batten onto the side. Do the same for the chine. Now you can cut the side using those lines and it should fit the model. Repeat the process for the bottom.
  4. oddboatout
    Joined: Oct 2007
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    oddboatout Junior Member


    I am not afraid to learn new things, I have downloaded DelftShipFree. I will try it.

    Thank you

  5. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    The easiest way to get your lines into DelftShip is to create a small file of the measurements based on your manual drawings.

    This is the content of a plain text file called Kayak.txt


    .08 0 .07
    1.5 0 .01
    2.5 0 0
    4.5 0 .055

    .04 .0 .09
    1.5 .2 .02
    2.5 .22 .022
    4.75 0 .1

    .02 .0 .18
    1.5 .27 .07
    2.5 .29 .08
    4.9 0 .19

    0 .0 .32
    1.5 .29 .24
    2.5 .36 .23
    5.03 0 .34


    It will generate a 16 ft kayak lines drawing. The explanation can be found in the delftship help file, under the topic Import Chine File.

    A screen shot of the result is attached for your info.

    Its relatively painless for software

    Attached Files:

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