Freeship, design a backbone

Discussion in 'Software' started by Aneblanc, Mar 10, 2016.

  1. Aneblanc
    Joined: Nov 2011
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    Location: Brittany

    Aneblanc Junior Member

    I am using freeship to design a wharram style catamaran.
    What would be the fastest way to insert a backbone (stem, keel, stern) parallel to the longitudinal center plane between the 2 halves of the V hull?
     
  2. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    FreeShip is not very good at assembling a hull out of pieces. You just have to model the exterior surface of the assembled boat as one surface, otherwise the hydrodynamics don't work properly. It does allow stitching bits together, but it is awkward and requires the control points to have been selected with that in mind if you want a fair surface. For developable surfaces, this is basically a nogo. I begin by enclosing the entire hull. Once I have the below water profile, I set the sheer, then extrude the toe rail up, in, and down and then extrude a ribbon across the deck midship. I can then get the deck sorted out with cockpits and deck houses. Then I close the transom, establish a reference waterline, and shift the hull to line up with station numbers. Then I make a few copies and save under different names. I don't physically attach centerboards to the model, they are just fully enclosed and sitting under the hull. You can do the same with a skeg.

    For what it's worth, I design on paper, and only use Freeship for hydro calcs, and material estimates.

    There is another thread on developable surfaces and freeship.
    http://www.boatdesign.net/forums/bo...-intersection-two-cones-two-planes-51910.html
     
  3. Aneblanc
    Joined: Nov 2011
    Posts: 44
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Brittany

    Aneblanc Junior Member

    Thanks for the reply.
    I am very new to Freeship and still exploring its possibilities. I haven't yet used the extrusion function. I need to use it a bit more to understand your message fully re. "shift the hull to line up with station numbers" or "sitting under the hull". Do you mean that you design a detached centerboard and move it under the hull afterwards?

    My plan is to be able to develop the 2 sides of the hulls to build a 1/12 model (23' hull) to check the panels. I had used Carene5 15 years ago to design and build a dinghy and had been pleased with the result. I just don't want to spent more time than necessary at the computer. The catamaran hull I am designing is very simple, it is basically a double ended canoe whose 2 sides are stitched and glued to a thicker backbone formed on a number of irregularly spaced bulkheads.
     
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