Repair on a fiberglass hull

Discussion in 'Multihulls' started by Troyboi08, Oct 17, 2017.

  1. Troyboi08
    Joined: Oct 2017
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    Location: Texas

    Troyboi08 Junior Member

    Im currently building a 16' powercat trimaran for running the river. The pontoons I salvaged are pretty old, maybe 30 years or so. I'm a already gonna have to patch some fiber glass, but I was wondering what I could do to re-enforce the entire pontoons. The sun has definitely done some damage to them and I'd prefer not to crack them when I'm hours from civilization. I've looked into truck bed liners, and so far I've read negative input on that. Any advice?
     
  2. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    Strengthen them in what way?

    They could sit out in the sun for decades and it would have no effect on the strength, the gel coat on the surface will be faded and chalky, but UV rays will have never touched the laminate. Gel coat is a cosmetic coating that also protects the laminate from UV rays.

    If they were built correctly when new they should only need patching where needed, poorly built pontoons may need some help though.
     
  3. Troyboi08
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    Troyboi08 Junior Member

    They just seem real soft, I could just apply a gel coat all over after I patch it, but I'm that smoking a rock or tree limb wold do some damage. They are from a Hobie cat 16, well built, just old and not made for taking a slight impact at that speed. I'm not planning on hitting anything, but our river is somewhat murky and shallow in places.
     
  4. Troyboi08
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    Troyboi08 Junior Member

    Any other advice would be great, just so everyone has an idea of what I'm thinking, I have one hobie 16 pontoon, and two hobie 14's, I'm gonna fix them up good, attach a aluminum frame at about 5' wide, and deck it. Im hoping it'll be shallow drafted enough with the pontoons that close together and still carry a couple of pals with me.
     
  5. ondarvr
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    ondarvr Senior Member

    Since they weren't designed for that type of use they may need some added strength. Can you access the inside, or does it all need to be done from the outside?
     
  6. Troyboi08
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    Troyboi08 Junior Member

    I can't get to the inside, it would all have to be done on the outside. I was looking up some lightweight truck bed liner, if I'm not too worried about drag or a little extra weight. Or is there some other product that I could apply to add some abrasion absorbtion?
     
  7. ondarvr
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    ondarvr Senior Member

    Bedliner can add some abrasion resistance, but can be very heavy and costly. By the way, the cheap stuff you can get at the auto parts store won't work, you need the professionally applied products, and even those aren't all going to work.

    Adding glass and supports to the inside would be the best, doing it from the outside requires a lot of extra work to make it look acceptable again. It may be worth cutting the tops off and doing it from the inside.
     
  8. Troyboi08
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    Troyboi08 Junior Member

    Ok, I was gonna use my deck design, basically a frame on top that would lock into some strats or bands that wrap around the pontoons, so that'll beef em up enough I think. Is there special fiber glass epoxy or gel coat that is extra strong that I could add?
     
  9. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Truck bed liner is extremely flexible and will add zero stiffness to the hulls, though it will add a lot of weight and improve water proofness. What you need is a good idea on the weight of the new structure, the newly installed equipment (engines, batteries, etc.) and a full up, well fed crew. This will give us an idea if your party barge will float rightside up. Those hulls really can't take a lot of weight, before they're overwhelmed. As for reinforcement, well, (as mentioned) this should be done from inside the hull shells, not externally. It can be done on the outside, but you'll be adding a fair bit of drag, weight from fairing it all in and you don't know pain, until you have to fair huge areas of hull shell, if you haven't done this before. You can cut open the hulls, lay in some athwart bracing, reinforcements and beam landings, close and bond it back together and it'll look like no one was even in there, plus make fairing something less than a new career choice.

    Maybe some images of what you want to do. Rough MS Paint sketches will do, so we can see how much this puppy will weigh, which will be the major limiting factor.
     
  10. Troyboi08
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    Troyboi08 Junior Member

    I don't think that the hulls are in bad enough shape to consider cutting then open, I'm just gonna patch the glass, and use gluvit over the whole thing.

    As far as weight, I wanted to keep my deck narrow, like 5'-6' and use aluminum tubing as the frame and TREX pvc decking as the deck. I'm talking light. I'm gonna get a surface drive twister short long tail from mud-skipper motors, have a small fuel tank in the back, maybe 15 gallons, and then the cooler and live well on the other side for balance. Other than that just a few buddies and their fishing gear. I read that a Hobie 16' with the sail and deck (which is heavy, I found out, at a junkyard, in 110° Texas weather, with my pregnant wife watching, haha). That it'll hold 4 people, does that sound right?
     
  11. ondarvr
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    ondarvr Senior Member

    There's no simple coating that can be applied to the outside that will increase the strength, glass is required to make it stronger.
     
  12. Troyboi08
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    Troyboi08 Junior Member

    Like these, but without the weight of a console, and a much shorter rail that the Camo one
     

    Attached Files:

  13. ondarvr
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    ondarvr Senior Member

    I'm not sure what you're expecting the Gluvit to do, but it's not going to make them any stronger.
     
  14. Troyboi08
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    Troyboi08 Junior Member

    Ok, so just fiber glass the entire thing hulls?
     

  15. Troyboi08
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    Location: Texas

    Troyboi08 Junior Member

    Im not sure what I'm expecting it to do either, I just researched it 5 minutes ago. It said that it adds abrasion resistance on the website and reveiws.
     
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