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2564Re: [Weta-Trimarans] Re: DB lift discussion

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  • Bruce Fleming
    Aug 3, 2011
      This issue is now one of a confusion nomenclature. It is hydrodynamic lift that the DB is using to provide lateral resistance in opposition to the side force generated by the sails, and the same for the rotational force from a pointer fin on a windsurfer. Therefore, one strategy for surviving when you're extremely overpowered--on a Weta, Laser, and other small craft--is to raise the DB a bit. It reduces the boat's tendency to heal.

      The point is, neither foils contribute forces for lifting their respective vessals vertically. Did we ever see a flying Moth before the put "Ts" on their foils?

      Sent via BlackBerry...please forgive the typos.

      -----Original Message-----
      From: "David" <mariner1460@...>
      Sender: Weta-Trimarans@yahoogroups.com
      Date: Wed, 03 Aug 2011 17:56:36
      To: <Weta-Trimarans@yahoogroups.com>
      Reply-To: Weta-Trimarans@yahoogroups.com
      Subject: [Weta-Trimarans] Re: DB lift discussion

      If you've ever tried a sailboard on a windy day with a "pointer" fin, you'll know how much lift a "hydrodynamic" foil can generate--the thing will try to torque the board right out from under you.

      --- In Weta-Trimarans@yahoogroups.com, "Richard Stephens" <richard@...> wrote:
      >
      > Davo was talking about the "feeling" of lift, and I know what just he means.
      > The boat is a joy to sail upwind.. It lifts your heart!
      >
      > The effect of the bow lifting out of the water when sail fast is caused by
      > the rocker, or upward curve, in the main hull. The flow of water under the
      > aft part of the hull sucks the stern down. This feature adds wave drag, but
      > it is very helpful when sailing downwind, when you want to keep the bows
      > from digging in. Also, the floats are narrower at the back than at the
      > front, so when the boat is pressed hard, the stern goes down more than the
      > bow. Both of these are design features that make the boat easy and
      > forgiving to sail, but they do limit the top speed.
      >
      > Richard.
      >
      >
      >
      > <http://geo.yahoo.com/serv?s=97359714/grpId=21833906/grpspId=1705065792/msgI
      > d=2560/stime=1312390432/nc1=1/nc2=2/nc3=3>
      >
      >
      >
      >
      > [Non-text portions of this message have been removed]
      >





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