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    Easy Navigation Books
    From: Gordon Talge
    Date: 2005 Apr 24, 10:51 -0700

    I wouldn't be too critical of Mary Blewitt's Book. A lot of
    things are "wrong" but in a sense still work.
    My uncle read Blewitt's book and sailed from Bay Saint Louis, MS
    to Cozumel, Mexico and back. This was before GPS and stuff. He had been
    coast sailing for years to FL and so on, but this was his first big open
    ocean trip. He made it just fine.
    This reminds me when I had a small part-time job helping out in
    a hospital. I had a friend did urine tests. She put a little
    bit in a test tube and then put in a test strip. If it turned
    blue it meant this, and if it turned red it meant something else
    and so on. Neither she nor I knew how it worked, or what we
    were doing, but it got the job done.
    Spherical Trig is not really taught in regular college math
    classes. The university where I got my Master's in Math had
    no such classes. If you wanted to learn spherical trig you were
    on your own. Spherical triangles are hard ( for me ) to visualize
    and the formulas are long, unfamiliar and complicated. They are
    made more complicated because in the era before calculators,
    they did everything to make hand calculations with logs and
    tables "easy". Take for example the Law of Cosines for plane
    trig: cos^2 = a^2 + b^2 - 2ab cos B, I quote from "Trigonometry
    for Navigation Officers" by W. Percy Winter (1928) concerning the
    law of cosines,
    "The student will see that the process is both
    lengthy and cumbrous; for that reason the cosine law is said to
    be not adapted to logarithmic computation."
    Today, the law of cosines is no problem with a calculator, so there
    would be no need for an alternate.
    There is a place for simple hand waving books. Bluewitt's audience
    is not the professional navigator, mathematician, or even the
    advanced amateur, but it gets the job done.
    The first book I read on Navigation was when I was 14. It was
    called "How to Navigate Today". I forgot the author, but I
    think it is still in print. It is along the same lines a Blewitt's.
    PS: The best "simple" books I have found are books written for the
    war effort in WWII, both in Britain and the US. They needed mass
    amounts of people competent in navigation and fast. They couldn't
    spend 4 years in college learning the stuff, they needed navigators
    in 6 mo. or less. They trimmed the fat and cut to the essence of
    what was really needed.
                                 (. .)
    | Gordon Talge WB6YKK         mail: gtalge AT silcon DOT com |
    | (o-    Debian / GNU / Linux                                |
    | //\    The Choice of the GNU Generation                    |
    | v_/_                  .oooO                                |
    |    - E Aho Laula -     (  )   Oooo. - Wider is Better -    |
    +-------------------------\ (---(  )-------------------------+
                               \_)  ) /

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