Transom repair

Discussion in 'Fiberglass and Composite Boat Building' started by rovi, Nov 17, 2012.

  1. rovi
    Joined: Jul 2011
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    rovi Junior Member

    Hi all,i'm repairing the transom of a 21ft.wellcraft but there is a slight curve that has me puzzled.After removing the laminates i realize how difficult it's going to be to get that curve especially since i have to put in two 3/4 ply instead of one,does anyone have any ideas or experience about these repairs?Thanks much
     
  2. Frosty

    Frosty Previous Member

    Well if it were me I might not replace the curve, as you say that will be a bit of a problem.

    A wellcraft with flat transom !!!!.
     
  3. michael pierzga
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    michael pierzga Senior Member

    Dont know what a Wellcraft transom looks like or whether you are simply replacing the old core or building a complete transom with camber.

    The classic way to bend plywood is to KERF it.

    Use a circular saw and cut 50 to 75 percent thru the ply and the panel will become more flexible. three quarter inch ply will become flexible like one quarter inch . The camber on a transom is small so not so many cuts like in the picture.

    Google "kerf bending plywood "
     

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  4. FMS
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    FMS Senior Member

    Laminate the curved transom using more layers of thinner plywood. A curve provides a classy appearance and gives the transom additional strength.
     
  5. PAR
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    PAR Yacht Designer/Builder

    If you kerf the plywood as Michael is suggesting you'll ruin the benefit of using plywood in the first place. Plywood is used fora few basic reasons, it's cheap/easy to work and it's very stiff for it's weight/price point. If you cut the veneers, you've ruined the construction of the panel, even if it's filled with epoxy. This technique is fine for a cabinet, but not a transom.

    Plywood can be force or convinced into easy curves without much trouble. Just wet one side of it good and leave it in the sun. Conversely, you could probably force 3 layers of 1/2" (13 mm) plywood into the shape you need fairly easily as well. Glue and screw each layer as you good. Place two saw horses 7'6" apart and place the plywood on them, then wet out the top of the panel. It'll take a slight curve in a day or so. If you want more curve, wet it out again, after it dries possably with a weight or two in the middle of the unsupported panel.
     
  6. garrybull
    Joined: Nov 2010
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    garrybull Senior Member

    have you thought about using bendy ply?

    over here you can get it up to 12mm thick maybe thicker.

    works very well in area's that have a curve in it.
     
  7. tunnels

    tunnels Previous Member

    Make a former on a bench and bend and epoxy the two layers of plywood together with just a fraction more bend than is required !!
    in actuall fact you are better to use 3 layers of 12 mm and glue then together it will have less tension and holds its shape better .
    just make sure the ply you use has the least number of ply veneers as possible !!! Doing a thousand cuts is going to uses a ton of glue and can you say 100% 0f those cuts will be completely filled with glue to keep the water out????? dont think so !!not a good idea!! :confused::mad::eek:
     
  8. michael pierzga
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    michael pierzga Senior Member

    Gee...the guy says he has access to three quarter inch ply in Antigua. Why propose solutions using thinner ply that he doesn't have ?

    No need for a thousand kerf cuts to deflect 3 quarters ply for camber .

    The Missing fibers of ply can easily be replaced with glass fibre laminate .

    There is no structural issue.

    The repair challenge is to remove the inside skin and work inside the boat. Removing the outside skin and working from the outside is very much work with long laminate overlaps on the topsides, bottom deck and refairing
     
  9. Frosty

    Frosty Previous Member

     
  10. PAR
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    PAR Yacht Designer/Builder

    Frosty and I are in complete agreement, you don't kerf a transom. As I mentioned, 3 layers of 1/2" (13 mm) will bend easily. The curve on this transom is modest and easily done in both 3/4" or 1/2". 3/4" will test your abilities, if this sort of thing is new to you, but 1/2" will easily take a "set".
     
  11. gonzo
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    gonzo Senior Member

    Are you sure there is supposed to be a curve on the transom or is it bend because the old core was rotted?
     
  12. PAR
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    PAR Yacht Designer/Builder

    It would be helpful to have the model and year WellCraft, so we know what transom.
     
  13. rovi
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    rovi Junior Member

    yes there is definitely a curve,will supply a photo in the morning.I'm not hip to these things but i want to do it on my own,with some advice of course,so that i can at the least,accomplish something for myself
     
  14. rovi
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    rovi Junior Member

    One other thing,the curve is across
     

  15. Frosty

    Frosty Previous Member

    I am suspicious of this curve. An engine saddle is flat and needs a flat surface.

    A curved transom would hinder the seat, unless the was a flat bit in the middle making this repair tricky.

    I think I would be going for a modified flat version.
     
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