Transom Angle?

Discussion in 'Boat Design' started by ddrdan, Sep 2, 2010.

  1. PAR
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    PAR Yacht Designer/Builder

    Use double planked 3/8" or 1/2". Better yet would be a 1/2" plywood core with a 1/4" planked veneer on each side. The plywood core will stabilize the solid wood planking, so it can't leak. Also you can do this without fasteners, so no bungs or fastener head filler to fool with, which is a good thing.
     
  2. jimbo2010
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    jimbo2010 Junior Member

    Thanks,

    How about adding a lite 4oz fiberglass cloth (or mat) between the the ply and planked veneer, clamp until cured.

    I don't think a 5 hp will flex that.
     
  3. alan white
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    alan white Senior Member

    The strip method will work best if the middle layer is 1/4" plywood in which case the strips can be wider than typical bead and cove (which you don't need at all if you use a 1/4" ply core).
    1/4" x 2 1/2"-3 1/2" would be better looking and less work and yet won't be wide enough to create an expansion differential with the more stable plywood layer.
    A curved transom is inherently more stiff than a flat one and doubly attractive, so consider that possability with a 3-layer transom. As described, with a light glass layer inside and out, you'll get your 7/8".
    Just noticed PAR's comment (after initial posting) to use 1/2" ply, which would be fine for a flat transom, which is likely what you'll be building anyway.
     
  4. jimbo2010
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    jimbo2010 Junior Member

    Alan, tks

    Since I'm exploring all possible scenarios how do you build a curve into it?

    Just build a say a 2" curved form and bend each layer over it?



    .
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I usually employ a curved transom, even on straight transom boats. In this case I'd use two internal 1/4" plywood layers, glued to the curve, then veneer over it on both sides with 1/4" solid stock.

    If you do use a curved transom, you'll want knees in the upper corners to transfer loads to the inwale. Bend in the plywood rough to get an idea of the curve you want. The best looking transom curve will actually be a conical, not a cylindrical shape. The last one I did on a boat that size had about 3" at the top and 2" at the bottom. It could have been more, but I was going for subtle look.
     
  6. jimbo2010
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    jimbo2010 Junior Member

    I understand, something like this

    [​IMG]

    I think that was 2 1/2 to zero, but that's the idea, correct?
     
  7. PAR
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    PAR Yacht Designer/Builder

    No, 4 ounce 'glass between the layers will not control much. Epoxy two layers of 1/4" ply together at the curve you want, then veneer it. I'd do it right on the boat.
     
  8. jimbo2010
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    jimbo2010 Junior Member

    Hi, spoke to tech support at West they agree no cloth just bond with resin.

    By the way not sure I mentioned the transom is 30"W X 18" H
     
  9. PAR
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    PAR Yacht Designer/Builder

    Next time, mention me to tech support over at West and see how they react . . . (my luck you'll get the new kid)

    Thicken the resin with silica and milled fibers or wood flour (not saw dust). This will improve the bond and compensate for surface irregularities.
     

  10. jimbo2010
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    jimbo2010 Junior Member

    Thanks for all your time on this issue, pics will follow.
     
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