Kevlar Canoe Repair Question

Discussion in 'Fiberglass and Composite Boat Building' started by RTinkess, Aug 30, 2017.

  1. RTinkess
    Joined: Aug 2017
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    Location: Ontario

    RTinkess New Member

    IMG_0383.JPG I've got a 14 foot Scott Elite Kevlar canoe. It's got a few hairline cracks on the stern.

    My question is if these cracks need to be repaired and if so how would you recommend repairing them
     
  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    What does the inside look like?
     
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Agreed, what does the inside of the laminate look like. Those appear to be flexural in nature and likely is just the resin yielding. It's unlikely the fabric is compromised, though if left unchecked, eventually the fabric will "hinge" at these locations and become damaged.
     
  4. RTinkess
    Joined: Aug 2017
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    RTinkess New Member

    I dont have a picture but the inside looks fine, I don't see any cracks or lines.
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    What's on the inside; ribs, seat(s), etc. around this area that could explain the flexing?
     
  6. RTinkess
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    Location: Ontario

    RTinkess New Member

    IMG_0385.JPG
    The cracking is in between the back seat and the stern.
     
  7. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    It looks like the stress cracks mitigate through the laminate stack, though not on common paths, clearly not enough "structure" to prevent flexing comprising the resin. The fix is to grind down through the surface resin, but not enough to cut fabric fibers, install some reinforcement (which can be one of several things), then apply a resin repair over the cracks, before flood coating the surface again. These types of cracks are common to see in larger unsupported areas on a single skin GRP hull shell. You'll note just under the thwart braces and seat, the cracks get progressively smaller and all but disappear. This is because the seat and it's braces help support the hull shell, preventing excessive flexing. In the areas away from this localized support the cracks appear. Can you provide an overall shot of the whole one end of the inside of the boat, so we can see the structure?
     
  8. RTinkess
    Joined: Aug 2017
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    Location: Ontario

    RTinkess New Member

    IMG_0369.JPG IMG_0370.JPG
     

  9. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    If you grind into Kevlar it turns into a fuzzy mess, so try to keep from doing it.
     
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