Reinforcing dinghy gunwale

Discussion in 'Stability' started by Gabe Long, Jun 12, 2025.

  1. Gabe Long
    Joined: Jun 2025
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    Location: Rhode island

    Gabe Long New Member

    Hello! I’ve got a small dinghy that I use as a tender to my sailboat. The dinghy is lightly built, which is fine for its purpose, but when I’m rowing the gunwales flex so much I’m worried I’ll crack them over time.

    I’m guessing the proper fix would be to fully replace the gunwales with more solid wood, but I’m daunted by the idea of getting the old wood separated from the fiberglass (and since it’s just a putter around boat I don’t need it to look perfect). I’m thinking I could glue 3” strips of plywood just under the gunwale to stiffen it. Good idea? Bad idea? Other ideas? Apologies for the bad photo, I’m not currently with the boat. Thanks!
     

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  2. montero
    Joined: Nov 2024
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    montero Senior Member

    Hello!
    You can use wide strip of glass fiber fabric and just reinforce gunwale by more layers of laminate. Or use strip of foam beneath gunwale and as above . Second way maybe need only one layer of glass.
     
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  3. Gabe Long
    Joined: Jun 2025
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    Location: Rhode island

    Gabe Long New Member

    That makes sense, thanks!
     
  4. fallguy
    Joined: Dec 2016
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    fallguy Boat Builder

    You ought to be able to remove the wood from the glass. Then add blocking to the areas and double the thickness of the inwhale, or change the inwhale wood to something better. Or jist screw new inwhale wood to the poorer wood. Some white oak, though heavy it quite stiff.

    IMG_3328.png
     
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  5. Tops
    Joined: Aug 2021
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    Location: Minnesota

    Tops Senior Member

    The nice thing about a laminated solution versus bending on a new solid wood strip/wale is less tendency for the new pieces to 'spring' the hull out of its current shape.
    One could use 6 c-clamps to a 3x36" piece of plywood under the gunnel centered about the oarlocks and see if the sheer behaves better. If that helps, gluing it will help even more. A little flex might be better than overall too stiff.
     
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  6. Tops
    Joined: Aug 2021
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    Tops Senior Member

    I do like scuppered/slotted gunwales too. I have yet to do one myself, it might happen on the current project...
     
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  7. Gabe Long
    Joined: Jun 2025
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    Location: Rhode island

    Gabe Long New Member

    Thanks! Would I need to steam solid wood? One of the things I was attracted to about plywood is that I’m thinking it’s bendy enough to just glue and clamp.
     
  8. Tops
    Joined: Aug 2021
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    Tops Senior Member

    My guess is that most likely one would need to steam solid wood.
     
  9. fallguy
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    fallguy Boat Builder

    I think you could try about 1/2” oak and see what it does….bend looks pretty slow to me
     
  10. kapnD
    Joined: Jan 2003
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    kapnD Senior Member

    Laminating thin strips can form the desired curvature without putting excessive pressures on the hullsides.
    Brace the inside with stick braces across the boat where needed.
     
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  11. fallguy
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    fallguy Boat Builder

    You could glue two rips of 1/4” white oak with titebond..
     
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  12. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    A 1x2 of pine will stiffen it enough. The stiffness increases with the cube of the dimension. Twice the thickness is 8 times stiffer.
     
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