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    Re: New compact backup CELNAV system
    From: Hewitt Schlereth
    Date: 2009 Mar 19, 15:00 -0400

    At the risk of shameless self-promotion, you might want to take a look
    at my Sight Reduction Tables for Small Boat Navigation. It's 229 cut
    down to one 7"X9"X1" volume. The reduction of 229 was done by 1)
    limiting declinations to 29N-29S in the usual one degree increments;
    2) limiting latitudes to those between Cape Farewell Greenland and
    Cape Horn (58N-58S) but in 2-degree increments; 3) likewise tabulating
    LHA in two-degree steps; 4) using the 249 interpolation table for
    declination increments.
    What this means is your AP must lie on an even degree of latitude and
    your assumed Longitude must give you an even degree of LHA. (By even,
    I mean divisible by two.)
    So, at the price of sometimes having long intercepts, you have an an
    inspection table, which is what most navigator's learn with. With
    SRTSBN there's nothing new to learn.
    PS I don't have books to sell. They've been out of print for quite a
    while. The copy I have was bought through Amazon Marketplace. -H
    On 3/19/09, Anabasis  wrote:
    >  > Though in this day and age emergency navigation seems to mean drifting
    >  > in life raft without any control and praying that coast guard got your
    >  > mayday or EPIRB signal and will pick you up before water runs out.
    >  > Navigation without mobility is quite useless.
    >  >
    >  > Martin
    > For a merchant ship I would agree with this Martin as liferafts are
    >  completely uncontrolable, and most lifeboats have only 24 hours of
    >  fuel and oars (sails are extremely rare on L/B's these days) and
    >  therefore you don't "go anywhere" but rather flip on the EPRIB and
    >  SART and await the proverbial cavalry.  However, another "emergency"
    >  navigation system that would require actual navigation is in a
    >  sailboat where a wave or other failure wiped out all of the
    >  electronics (except a watch which should survive) mid voyage and you
    >  are "stuck" with celestial navigation.  Instead of packing all sorts
    >  of volumes of sight reduction tables in your limited space, you might
    >  want to have the various tools described in this thread.
    >  My 2 cents,
    >  Jeremy
    > >
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