Foil Optimist

Discussion in 'Boat Design' started by Manfred.pech, May 16, 2016.

  1. Manfred.pech
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    Manfred.pech Senior Member

  2. Doug Lord
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    Doug Lord Flight Ready

    Foiling Optimist

    Thanks, Manfred! One of your links showed the (almost) foiling Opti put together a few years ago by Adam May, a well known Moth sailor. They used a wand for altitude control but apparently this new boat relies on crew movement? Works on kitefoilers and foiling windsurfers-may work here....
    No foiling pix that I could find.....
     
  3. Manfred.pech
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    Manfred.pech Senior Member

    Do you think it is possible to balance it ?
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Foiling Optimist

    Yes! The people who foil kiteboards control altitude with balance. I think a wand system might be easier but I imagine if you learn to balance the thing it will become second nature.
     
  5. Skyak
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    Skyak Senior Member

    No.

    They would need much more freedom to move. Kites and windsurfers have the full length of their legs to move in 3D and the sail can move in 3D independently of the hull which they brace with. This opti sailor has a hard time even moving in 2D and the sail has only rotation which will not do much downwind. The kicker is that the rudder is too short -the main foil will still be lifting when the rudder comes out of the water. The loss of lift aft will increase the angle of attack to stall or more likely pop out of the water and come crashing back down.
     
  6. Doug Lord
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    Doug Lord Flight Ready

    Opti Foiler

    On almost all foilers with fully submerged foils the rudder foil is closer to the surface static, but as the boat pitches up the rudder foil moves down relative to the main foil. It's important to have the rudder higher than the main foil or the wake of the main foil will screw up the rudder foil.
    I like the way they increased the distance between the main foil and rudder foil-effectively increasing the "footprint" of the foil system w/o using a gantry like on a Moth. The F&A separation of the foils(far larger than on a kiteboard foil system) will be a big asset and would tend to help make it possible to balance with just weight movement.
    These guys seem to be pretty experienced boat builders and probably know what they're doing. I'd imagine a kid could stand up in the thing if needed to improve balance....
    I still think a wand system would be better but if they can balance it w/o too much hassle then you can't get much simpler.
     
  7. Skyak
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    Skyak Senior Member


    I would predict this 1.0 version will be way too difficult to sustain foiling. That rudder is way too short. A wand and flap is what they need but it's pretty much a do-over. The foils are so big they might have been able to do something like a V to control height -no moving parts, simple build.

    It might be possible to use the surface proximity to help control height but that is more like planing than real foiling.
     
  8. SukiSolo
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    SukiSolo Senior Member

    It's amazing how fast the 7 year olds will pick up foiling....;)
     
  9. Manfred.pech
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    Manfred.pech Senior Member

  10. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Looks pretty good.
    I might tweak a few sail ties a mm or two. ;-)
     
  11. portacruise
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    portacruise Senior Member

    Thanks for pics of a nice set up.

    Anyone seen a setup where the foil can be retracted, so the boat can be used efficiently when conditions are hampered by the foil? Examples like low draft, launch/retrival, debris, insufficient wind/power, etc.

    PC
     
  12. Tiny Turnip
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    Tiny Turnip Senior Member

  13. Tiny Turnip
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    Tiny Turnip Senior Member



    Top two comments made me giggle.
     
  14. Manfred.pech
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    Manfred.pech Senior Member

    Here is the wing for the thing:

    [​IMG]
     

  15. CT249
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    CT249 Senior Member

    From my very limited experience, it does depend on what "reality" you're talking about. In steady medium winds it's surprisingly easy (although it depends on one's sailing background, of course) but gusty winds or heavy conditions make it something else entirely.

    I tend to think that foiling dinghies (and perhaps cats) will end up following the windsurfer model; that is, a very high proportion of them will move away from the mainstream sailing areas and clubs, and just sail in windier times and places. That may already be happening in places like Sydney, where only a very small proportion of the foiling Moth fleet does regular club racing.
     
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