another non-boat design challenge: Solar Oven Umbrella/Light Reflecting Umbrella.

Discussion in 'Boat Design' started by Squidly-Diddly, Apr 1, 2016.

  1. Squidly-Diddly
    Joined: Sep 2007
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    Location: SF bay

    Squidly-Diddly Senior Member

    Seems like a match made in heaven. Strong, cheap, ultralightweight 90% reflective Mylar and an Umbrella frame.

    This guy just tried tape and worked OK for a bit and good for proof of concept.

    I guess I'll try some spray contact cement on an old umbrella and old space blanket.

    It would be sweet if it could still collapse.

    About "Light Reflecting": I seriously think that a fully reflective underside of an umbrella would be a great help when using after dark. Just the ambient dim light from the ground reflected back down on to your path SHOULD make a noticeable difference. Add even a small additional light source placed just about anywhere and the big umbrella should catch and reflect it onto your path in a nice very user friendly well defused manner. Much better than little spot from flashlight.

    I'm nuts for anything that serves two completely separate purposes.

    Now I'm wondering if a titanium umbrella frame couldn't also be a usable coracle without excessive weight.:idea:

    PS-what would be the Terminal Velocity of 200lb man holding a 68" umbrella if the umbrella didn't collapse or shred? Like if it had paracord lines from the handle to end of each frame finger.

    Oven/Boat combo that folds down to stored umbrella size! If it starts raining too hard you'd still be OK. ;)

    Boat, Oven, Umbrella, Survival Tent, "Night Vision", Parachute: I guess thats enough features for now for a package that small.
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    To use it as an oven or concentrated heat source the curve needs to be parabolic so that it can have a focal length. That is do-able.

    Whatever the curve it can serve as a sail or a drogue. :)
  3. Squidly-Diddly
    Joined: Sep 2007
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    Location: SF bay

    Squidly-Diddly Senior Member

    Seems like this photographer's parabolic umbrella's focus would be about 6 ft in front of the dish ring.

    The #1 "Frog" looks about right, since as a practical matter there would be a clear wind proof sheet stretched over the disc rim to keep the heat in, so the cooking vessel would be well inside the umbrella.

  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Instead of using eye bolts and eye screws, consider using lashing or strops instead, to attach things like the halyard blocks to the mast. It's lighter, much less likely to bind, will make a "fair lead" when pulled taut, and will not weaken the mast, like a hole and bolt does, etc.

    Lashing is pretty simple, just wind a few turns around the mast or spar, use a chain link or a stainless ring and a couple of brads to hold the two ends to the mast, so it doesn't unwind. Most will apply varnish under where this lashing goes, wrapping the line in the wet varnish as they go, which helps to lock it down. Lastly, more varnish over top of the line will protect it from UV.

    Of course banding is the traditional way, though you need metal fabrication skills. This is bullet proof, but heavy.

    Looped is pretty common, simply a seized loop. The disadvantage with this is the loops have to be placed over the mast (in the right order), which is a pain in the butt.

    The gasket and loop is what I did last on a little gaffer. I seized a ring onto a line, then made a gasket at the other end. I looped it over the mast so the ring end came through the loop, which self locks it down. The thumb cleat just ensures it stays at the height its supposed to.

    Look closely at the block attachments on this boom and you'll see how the gasket and loop setup works. The block is seized to the line and a gasket (loop) is on the other end. Light, strong, self aligning, no binding, no clanking noises, doesn't crush the spar, etc.

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