Delamination between Hull and Cabin Sole

Discussion in 'Fiberglass and Composite Boat Building' started by Evelyn 32, Mar 21, 2021.

  1. Evelyn 32
    Joined: Mar 2021
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    Evelyn 32 New Member

    Greetings,

    looking for some advice on repairing a small delaminated section between the hull and cabin sole. The additional glass was installed as part of a keel sump reinforcement a few years ago.

    I plan on beveling the edges around where I removed the delaminated glass and Laying progressively smaller glass sheets until flush.

    looking for any advice!
     

    Attached Files:

  2. fallguy
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    fallguy Senior Member

    That looks like something bad happened. e.g. grounding event bad enough to break that floor?

    Before anyone helps you; it is going to be important to better understand the cause of damage. Pictures of the boat. Story about the cause, etc.
     
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  3. fallguy
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    fallguy Senior Member

    And important to realize there is more wrong than the delam on the small timber.

    D49A5504-3A50-4D58-9E74-AD9C62F1EC28.jpeg
     
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  4. bajansailor
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    bajansailor Marine Surveyor

    Evelyn, this is potentially a fairly major repair job that you are undertaking - you will certainly need to do a LOT more than simply
    "beveling the edges around where I removed the delaminated glass and Laying progressively smaller glass sheets until flush."

    Take note of what Fallguy says above - that fracture in the transverse frame (highlighted by Fallguy) looks rather ominous.
    And please do provide as much background information as possible re the boat and the circumstances that caused this damage to occur, even if you think that it might be irrelevant - size and type of boat (and a photo or two of her), and some more photos of the area where the damage has occurred will all be very useful.
     
  5. kapnD
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    kapnD Senior Member

    Can’t really tell what’s really going on there, photos from further back would help.
    Looks like the added reinforcement piece did not adhere to the old glasss, so it’s going to take some serious grinding to make new glass stick.
     
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  6. wet feet
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    wet feet Senior Member

    Whatever the cause,the application of progressively smaller pieces of glass is not the way to go.You start small and go bigger with each successive laminate.
     
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  7. fallguy
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    fallguy Senior Member

    yes and no both

    to fix a hole; you are correct (don't call me one!)

    to fix this right; this is incorrect

    to fix this well, the problem must be addressed in full; the glass must be ground back further from the failures and large pieces must be laid and smaller pieces on top of that to avoid air and an amateurish repair, but the concern here is the laminate UNDER the smaller frame is broken and that requires removal of that frame!!! If you put a fiberglass cast over a human broken arm; it fuses back together; here, not so, the frame and fracture do not heal. And so, you would have a frame with a crack under it.

    it is not a matter of a few small pieces of glass fixing a hole
     
  8. fallguy
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    fallguy Senior Member

    I would add the larger floor further back that I marked also need to be closely inspected. If it looks that way on the other side; then the event that caused this probably also broke that bond. And it may be necessary to rebed that floor as well or more.

    At any rate, the smaller floor must be removed. (Floor is the smaller transverse frame)

    Also, if the keel is leaking is an obvious question. If so, then much more serious.

    If this if the forward side of the boat, then the keel strike pulled down here and cracked things up. The aft side might have been a push. If it is not fixed correctly; heavy seas or another strike could be catastrophic. A lot depends on what boat and where used, etc. as well. If this is a bw boat; don't mess around treating that like a hole repair. It ain't.
     
  9. wet feet
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    wet feet Senior Member

    To be clear,bonding bulkheads,bonding floors,repairs are all treated the same way-start with small pieces of glass and work up to wider/larger pieces.
     
  10. fallguy
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    fallguy Senior Member

    here we go...this, again

    not according to any professional builder I know; this results in air entrainment on the subsequent bonds at the interface; there is no advantage to a shingling effect in fiberglass work-it is fallacy..this debate goes on and on because someone believes shingling adds something structurally when it actually creates a poorer bond at higher risk for air entrainment and sand through of the wider layer if fairing is needed

    The time when smaller to larger works and only works is for hole repair. The hole is typically smaller in the bottom, etc.

    If you lay a small piece of 1708 down; it creates a ridge of about 0.050" and the subsequent pieces do not make good contact with the substrate. We even see this problem in a joint specified as say two staggered 4" tapes. So even a spec'd joint has this 'flaw'. There is no reason to build this flaw into unspecified work. Certainly a consolidation roller helps, but a close look always reveals technical errors when laminating anything bigger over smaller.
     
  11. wet feet
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    wet feet Senior Member

    I have no idea what 1708 might be.Here in Europe we describe laminates by weight,usually in gsm.We also stagger glass laminates from smaller to larger always.The surveyors from Lloyds or other bodies like it that way.You might like to try using torn edge CSM to get better contact between laminates.
     
  12. fallguy
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    fallguy Senior Member

    The surveyors are wrong.

    1708 is 600/225.

    if you read through the rationale; you'd understand, but mainly, please don't throw off the OP; if they do a smaller to larger hole repair; it will be done WRONG as it is not a hole repair as they originally suggested

    They need to remove the small frame; grind paint/gc off and bond it and fillet and tab it to the hull. The tabbing particulars as to wide first or wide last are honestly less relevant, unless they misunderstsnd and do a hole repair!!!
     
  13. wet feet
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    wet feet Senior Member

    Wow! Somebody who knows more than representatives of one of the oldest classification societies in the world. I think I will stick with established practice and/or do what the designers specify. It's worked for me for the last 45 years.
     
  14. fallguy
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    fallguy Senior Member

    The debate is ages old and my experience is valid. I don't really care how many surveyors are wrong.
     

  15. missinginaction
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    missinginaction Senior Member

    Maybe you can do it either way. I learned from Paul Ricelli. Relatively small to large and overlap. I built my engine stringers and the bulkhead that hold up the aft cabin wall that way. Haven't moved in a decade. Tabbed inside cabin sole this way. No issues in about 15 years. I had a couple of holes to fix where I took out thru hull transducers in favor of the in hull type. Started small and went progressively larger. No problems. I made a mistake and built a hard spot into my side deck years back and the paint cracked at a forward bulkhead. That was the scary one. PAR told me to grind the hell out of it (about half way through the ply deck I think), start filling it with chopped up glass and resin until it was just a small dip. I started to then fill the dip, smaller pieces to larger. Just 4 oz. cloth. Worked out fine.

    Just my two cents. I miss that guy.

    MIA
     
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