New America's Cup Boat with Box Keel

Discussion in 'Boat Design' started by srimes, Oct 26, 2020.

  1. srimes
    Joined: Sep 2008
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    srimes Senior Member

    Bolger would be proud:
     
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  2. fallguy
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    fallguy Senior Member

    Its a boat, no its a plane, no its a boat plane!
     
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  3. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    Wow.
    Thanks SR
     
  4. wet feet
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    wet feet Senior Member

    Interesting video and its good to see the boats so clearly.No surprise that a lot of attention has been paid to reducing drag,but I wonder what difference it will make to deck work-if there is any amount of deck work.I wasn't entirely convinced by the explanation regarding the skeg and it's length;surely having it so far forward means that it can act as a kind of water ski and assist with lifting the boat onto the foils.I know of at least one motor boat that had a flattish keel with not much of a corner radius that had "interesting" handling characteristics when the keel hit a large ripple and the lift changed abruptly-it didn't always come down deal level and the lurch to one side could be fairly shocking.A similar design with a larger keel radius and very similar hull form had no problems in this regard.Given the area exposed to the water flow the lift force on an AC hull from the bottom of the skeg could be significant.The account in the video of using the skeg to seal the airflow over the rig seemed a bit fanciful given the flow direction of any air at the mainsail foot.Even the air leaving the headsail foot would be a boat length astern before getting anywhere near water level.Have I misunderstood?
     

  5. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    yes, misunderstood

    consider the skeg a sail under the boat independent of the sail above

    the idea is the underneath skeg behaves same as a sail and pressure from the wind going under the skeg woulld create drag

    interestingly, and unlike the sail above, if the skeg contacts the water, then more drag and cursing the foiling

    given the wide variety of differences; outcomes will really be telling

    if none of them break their foils to bits; that will also be uplifting (hehe)

    despite my fun wordplay; I'm fairly serious...I'd like to see the foils be treated more like an outboard engine, i.e. replaceable...of course, given their enormity, perhaps I ask too much
     
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