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    Re: Navigating Around Hills and Dips in the Ocean
    From: Rino
    Date: 2003 Aug 16, 10:08 -0400

    I can't claim to speak for all mariners out there today, but in my
    experience and studies gravitational fields were never considered directly
    as a factor in planning passages. I'm sure the Admiralty would have devoted
    a chapter to it in their 'Ocean Passages' publication had it been a factor
    of importance.
    While I won't pretend to be in the same scientific class as some of the
    members here, I would say that Mr. Huxtable's input on this seem to make the
    most sense.  But even if he's wrong, and you could go 'downhill' at sea,
    ultimately this discussion is futile as to the question (paraphrased):
    "Would ships benefit from planning a 'downhill' voyage based on the
    gravitational data?"
    If we assume a voyage of 7000km, with a difference in height of about 200m
    between the gravitational lows and highs, the downhill angle will be in the
    order of thousandths of a degree, and the 'extra downhill force' is
    negligible relative to the total effort needed to keep the ship moving.
    That's about as scientific as I can get on this, so if I made a error in
    calculation or logic, I'm sure I will hear about it.
    Still enjoying the list as a great way to stimulate the brain,
    P.S.  Of course I have no problem with sailing on Friday the thirteenth, but
    I would definitely be extra careful...

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