Inflatable sailing catamaran with tubeclamps

Discussion in 'Multihulls' started by DimitriW, Jun 13, 2013.

  1. Wavewacker
    Joined: Aug 2010
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    Location: Springfield, Mo.

    Wavewacker Senior Member

    Check out the inflatables that can be custom made at "Jack's Plastic Welding" mostly catarafts but they add rocker or have straight tubes, the big ones do get pricey but not too bad.
  2. Skyak
    Joined: Jul 2012
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    Location: United States

    Skyak Senior Member

    I don't know for sure based on your description, but my suspicion is that your old hypalon outer tube failed due to UV sunlight degradation just because it is the most common cause of outdoor fabric failure. For a replacement I would suggest PVC impregnated polyester. There is a substantial industry manufacturing this material for trucking tarps and commercial awnings so the price is very reasonable. The material is also used in lower priced inflatable boats though there is much debate over it's value relative to hypalon. The base polyester weave fabric is the same as hypalon (or can be, there is a wide variety of denier values available) but PVC is used instead of hypalon rubber. Hypalon stretches farther before failing so it can be applied thicker and still folded without developing pin holes. PVC is also more susceptible to chemical attack by things like brake or hydrolic fluid (this also makes pvc easy to 'chemical weld). PVC does soften and melt so be careful of chafe. PVC is generally better at stain rejection and UV life but as I said Hypalon can be thicker. PVC welds and sews much better than hypalon. Since you don't need defense against pin holes PVC should work fine and cost about a third of what hypalon does.

    One other option is to use polyester weave fabric and then seal it with urethane. The advantage is that you can sew a more optimal shape without darts. Pre-impregnated fabric is limited to 'conic' shapes because the weave is not free to move. I don't know the UV life of urethane but SOF kayakers use it.

    Kevlar (and other aramids) is super strong and stiff but about the same UV life as polyester. I don't know of any commercially coated aramids and I don't think the stiffness is beneficial. I would use a higher denier poyester fabric for strength before I would pay for kevlar which is much more expensive.

    Polypro is the opposite - much weaker and stretchier than polyester -cheaper too. I don't know of any coated polypro materials and I suspect that it doesn't work well because the adhesion needs to be greater than the stiffness of the coating relative to the base fabric.
  3. Wavewacker
    Joined: Aug 2010
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    Location: Springfield, Mo.

    Wavewacker Senior Member

    For cheap materials you might check at a sign shop for the used banners and billboards that are taken down, a PVC material, turn the vinyl printing on the inside, unless you want to look like you're sponsored by a beer company.

    Another source are swimming pool companies for old liners and pool covers, might find useful vinyl and PVC there.

    Trucking companies should have old tarps you could get cheap.

    I have an almost new pool cover, my dad changed to an automatic cover, that I'm trying to figure out what project to donate it to, probably a SOF boat.

  4. wasafari
    Joined: Apr 2012
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    Location: Bulgaria

    wasafari New Member

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