Flat bottom Jon with modified V bow

Discussion in 'Wooden Boat Building and Restoration' started by Tungsten, Aug 20, 2019.

  1. Tungsten
    Joined: Nov 2011
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    Location: Canada

    Tungsten Senior Member

    I’ve had the aluminum version 1648 and it’s worked well for what I do. I’ve since sold the boat and need to build myself a new one this time stitch and glue with plywood
    To create the V I assume I should start with a strong back with forums every 2 feet or so. 3/8 ,9 mm ply is my choice for the hull but that’s going to be too thick to torture into shape. I plan on OAL of about 14’ floor width at 48”
    Thoughts on maybe doing the V in 4mm ply ,2 layers. Then some how scarfing them to 3/8 about 3-4 feet back from the tip or stem where the floor goes flat no dead rise.
    I have plans for similar type boats and have built 2 small boats before.
    Any advice or tips? Thx
     
  2. Deering
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    Deering Senior Member

    How about kerfing the plywood at the insides of the tight bends, still using the 3/8. You could fill the kerfs with thickened resin and glass over after it’s assembled.
     
  3. Tungsten
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    Tungsten Senior Member

    Yes that will help.Thx. I’ve only played with Mylar so far as to where and how to cut the floor to shape the V.
    I’ll find a pic of what I’m trying to do.
     
  4. Tungsten
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    Tungsten Senior Member

    Hope this works. So the kerfs would have to be right we’re the transition starts. That seems to be where the most twist is. Would I need kerfs in both the X and Y direction?
     

    Attached Files:

  5. Deering
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    Deering Senior Member

    Are you certain that you can’t bend the 3/8 as is? Those curves aren’t that tight.
     
  6. Tungsten
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    Tungsten Senior Member

    Keeping the floor flat where the bend starts is the goal.Id assume I would get a little V or deadrise at that point.I haven't tried 3/8 yet.
    That pic is probably from a bigger boat then I plan on,so the bend can be less.
    This boat will probably be powered by a 9.9hp.
     
  7. Deering
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    Deering Senior Member

    You could always try to form the unmodified 3/8 and then kerf it if you find that it won’t work. 9.9 hp might be a bit small for that size boat. A 20 would probably be a better choice if you think you’ll carry more than one person occasionally.
     
  8. Tungsten
    Joined: Nov 2011
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    Tungsten Senior Member

    Deering thx for the help, car topper so 9.9 is why.
    Any thoughts on how to cut the ply. Is it as simple as one cut down the 0 axis maybe 30” or so,perhaps a small radius to form a slight curve in the stem V.
    I’ve only played with Mylar so far. Plan is to take some scrap 3/8 ply from the local dumpster and try.this weekend I hope.
    Edit. Truck with boat racks. Not car topper. Lol.
     
    Last edited: Aug 21, 2019
  9. DCockey
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    DCockey Senior Member

    The kerfs would need to be perpendicular to the direction of the curvature - not transverse.

    How deep at the sides? How wide at the top? I may be able to work up a simple design.
     
  10. Tungsten
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    Tungsten Senior Member

    Hi thank you,sides approx 21"533mm beam approx 65"~70" 1650mm + In the pic you can see the beam narrows as you get to the bow,was going to add on some ply there so when tortured into position I dont lose so much beam if that makes sence.Small boat need to make it as roomy as possible.
     

  11. Tungsten
    Joined: Nov 2011
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    Tungsten Senior Member

    Here is a non modified and modified bow
     

    Attached Files:

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