35th Americas Cup: Foiling Multihulls!

Discussion in 'Multihulls' started by Doug Lord, Sep 26, 2013.

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  1. Doug Lord
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    Doug Lord, Feb 25, 2015
    #196
  2. Doug Lord
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    Doug Lord, Feb 26, 2015
    #197
  3. Doug Lord
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    Doug Lord, Feb 26, 2015
    #198
  4. Doug Lord
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    Doug Lord, Feb 26, 2015
    #199
  5. Richard Woods
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    Richard Woods Woods Designs

    Yes that was us

    RW
     
    Richard Woods, Feb 26, 2015
    #200
  6. Doug Lord
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    35th America's Cup on Foils--Upwind Foiling/Wallying

    Wallying: http://www.virtac.com.au/

    "The benefits of Wallying on foils in an AC62 will be substantial, but the penalties for getting it wrong will also be great. For example, if forced to sail a header for any period of time due to the proximity of a boundary or a competitor, the VMG obtained from sailing on foils will be dramatically worse than would be available from sailing in high mode."
     
    Doug Lord, Mar 1, 2015
    #201
  7. Doug Lord
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    Doug Lord, Mar 3, 2015
    #202
  8. Doug Lord
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    35th America's Cup on Foils---Oracle

    Fun on the water, or should I say just above the water:
     

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    Doug Lord, Mar 3, 2015
    #203
  9. catsketcher
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    catsketcher Senior Member

    Oracle tacking

    Does anyone have any info on how Oracle seems to be able to tack so quickly and smoothly. Do they play with the boards as they tack?

    Will the new AC boats have the same restrictions on foil movement? It seems a little strange they haven't gone for wands yet.

    cheers

    Phil
     
    catsketcher, Mar 5, 2015
    #204
  10. tspeer
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    tspeer Senior Member

    The foils can move in cant and rake. A big change from AC34 is hydraulic accumulators (of limited size) are now allowed. This was done for safety reasons, to ensure the rake of the daggerboard and rudder could be controlled (for short periods) even if the crew weren't pumping enough. Another big change is a limited amount of movement of the rudder elevator incidence is allowed while racing. Previously, the rudder elevators had to be fixed before the start. For details, see the AC62 Class Rule.

    Wands are not allowed. A wand would constitute an additional appendage. A mechanical linkage between the wand and board would not be appropriate for these boats like it is for the Moth, because the loads are much higher. Putting an electronic sensor on the wand to feed back to the hydraulic control system would go against the restrictions on feedback control systems.

    The teams wanted to keep the boats manually sailed and not open up an arms race to develop computerized closed loop control systems. Hence the restrictions on feedback and sensors. The hydraulic valves are allowed to be activated electrically, but the level of electrical functionality is equivalent to a mechanical linkage, and could (in principle) be done entirely mechanically. The electronics they're using in the control system are actually cheaper and simpler than an equivalent mechanical linkage, which is why the limited use of electronics is allowed under the rule.
     
    tspeer, Mar 5, 2015
    #205
  11. Richard Woods
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    They are certainly smoother both tacking and gybing than Artemis, but I don't know if that is due to crew work or design. They also seem to be more stable in flight and fly closer to the water, which I assume is good as more foil in the water means less leeway

    So Tom, what makes the whining noise we heard?

    RW
     
    Richard Woods, Mar 5, 2015
    #206
  12. cavalier mk2
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    cavalier mk2 Senior Member

    I just got back from the Bay area but didn't have time to take in the cats...The whining I heard comes from sailors wanting to sail on these machines.
     
    cavalier mk2, Mar 5, 2015
    #207
  13. Doug Lord
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    35th America's Cup on Foils----wands

    Tom, thanks for your thinking on wands. The largest boat I know of using wands on foils with flaps was Dr. Bradfields 40' SKAT:
     

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    Doug Lord, Mar 5, 2015
    #208
  14. Doug Lord
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    Doug Lord, Mar 6, 2015
    #209

  16. Doug Lord
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    Doug Lord, Mar 10, 2015
    #210
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