Is it possible to build a sail boat from spray foam?

Discussion in 'Boat Design' started by HCB66, Jun 5, 2018.

  1. HCB66
    Joined: Oct 2017
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    HCB66 Junior Member

    A long time ago in the 70's an archtect built houses by spraying foam over a balloon and deflating it when the foam set. Apparently it is still done today. I'm wondering if some sort of foam technique like this could build a sail boat? Other types of water craft like small barges or house boats might be possible as well. A good mold with a good solid frame set into the foam for parts like the engine , mast etc. Maybe something constructed like a dune buggies tube frame could be embedded in the foam?
     
  2. rwatson
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    rwatson Senior Member

    Yes. This has been promoted before.
    Years a go there was a guy in Victoria, Australia that would build a boat interior, sit in a steel frame and spray foam in between. Then he would cover it in fibreglass. He ended up with a well insulated, positive buoyancy yacht according to his blurb.

    The problem is, low density foam absorbs moisture over time. You also cant spray high density foam. It has to be autoclaved.
    It also adds a lot of weight to the boat.

    Its a lot more effective to do strips or panels of high density over a frame, and glass over that.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    Wasn't it concrete that was sprayed over the inflated bladder to make those domed buildings ? Foam has little structural value at the lower densities, and not a lot at the greater densities, unless reinforced, as in some engineered panels now used as an alternative to plywood in transoms, etc.
     
  4. rwatson
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    rwatson Senior Member

    Yes, it was concrete. They were called Bini Domes, and there are still several standing. The method was abandoned after they sprung leaks after a few years.

    Mind you, a number of Geodesic Domes were made by laying foam insulation blocks on a frame, and laying re-inforcing steel and concrete on top.
     
  5. Blueknarr
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    Blueknarr Senior Member

    I thought it was foam first to support workers who top coated with reinforced concrete
     
  6. rwatson
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    rwatson Senior Member

    Nah.

    The minimal reinforcing for Bini domes was laid on top of two layers of plastic, and the dome was inflated to the Dome shape. Then the extra reinforcing was laid, and the concrete sprayed on.
     
  7. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Thanks for the corection.
    Ill alter my memory bank
     
  8. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    It is possible...
    but it's also possible to wash your feet with your socks on.
     
  9. engineer137
    Joined: Jun 2018
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    engineer137 Junior Member

    There are many different versions of spray concrete/spray foam houses. I knew a guy in Italy Texas who built Monolithic domes. Here is a quote I found after quick google search:


    Source: Green Home Building: Shotcrete Systems http://www.greenhomebuilding.com/shotcrete.htm
     
  10. gonzo
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    gonzo Senior Member

    How well do they float?
     
  11. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    that works pretty good, actually. I remember doing some backpacking and it was always an issue that your feet would feel in need of good wash and no running water around, then one time we were more or less forced to get our boots soaked crossing a stream and when we made camp 1/2 day later it was like our feet had been washed. :)

    Anyways, back to foam-boats. I'm something similar to stitch and glue "instant boat" but instead of plywood some more flexible semi-stiff plastic mesh.Plastic Canvas 7 Count 10 Inch X 13 Inch-purple 082676203145 | eBay https://www.ebay.com/p/Plastic-Canvas-7-Count-10-Inch-X-13-Inch-purple-082676203145/1000356708?iid=331830916101&var=540915967709&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D44039%26meid%3Ddc4527d2d48b4a7bba5e2bb1814cee3d%26pid%3D100005%26rk%3D5%26rkt%3D12%26sd%3D263541211409%26itm%3D540915967709&_trksid=p2047675.c100005.m1851

    I bet this would thermo-form nicely with heat-gun. Maybe heat then stretch over pool noodles, which themselves are formed by pvc, or thin bendable aluminum tubing.

    Spray foam then screed for smooth surface.

    I used Polycell expanding and NON-expanding foam on an industrial scale insulating houses. Came in about 3 gallon steel cans with hose and wand. I had an old van that had been rolled and side doors were all jacked, so I just used the foam to seal and it worked great. The doors were jacked slightly outward so with the foam bulging out it looked like the whole van was full of foam and about to pop!

    The foam seemed completely durable. I heard it released cyanide gas when burned.
     

  12. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Ya, that's what I said, it's possible.
     
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