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    Re: Wind & Current Navigation
    From: Rodney Myrvaagnes
    Date: 2003 Apr 22, 23:44 -0500

    I don't think theory, except at the crudest level, will help practice
    in this case. Your boat has a certain exposure to current, which may or
    may not be the same at the surface as at the bottom of your keel. It
    also has a windage exposure. The wind makes no difference in a calm,
    but if it gusts hard enough it can become comparable to the current for
    a moment.
    So, current (if any) always matters, wind sometimes matters, and how
    much depends on the boat. The current can be predicted from tide tables
    after you have been there through a couple of cycles.
    On Tue, 22 Apr 2003 08:56:00 -0700, Dan Allen wrote:
    >On Monday, April 21, 2003, at 02:36 PM, Charles Tait wrote:
    >> I severely doubt that any equation will fix this better than judgement.
    >I know that the equations that govern marina navigation are very
    >complex with currents and winds added, and that there may be no current
    >good real-time calculation mechanism to make use of them.
    >But I am looking for us to develop a more rigorous theory of what is
    >happening so that we can learn from it and make some progress on
    >understanding the physics of winds and currents so we can have some
    >first principles to work from while at the helm.  I am therefore
    >looking for the theory that will help practice.
    Rodney Myrvaagnes                                               J36 Gjo/a
    "That idiot Leibniz, who wants to teach me about the infinitesimally small! 
    Has he therefore forgotten that I am the wife of Frederick I? How can he 
    imagine that I am unacquainted with my own husband?"

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