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    Re: What do offshore recreational navigators really do?
    From: Lu Abel
    Date: 2005 Jun 6, 10:03 -0700

    Joel:
    
    What you relate is what a "good" offshore navigator might do -- pre-plan
    sights, try for a true fix rather than LOPs, etc, etc.
    
    But there's "good" and there's "good enough" and there's "common
    practice."
    
    I was interested in the "common practice" end of things.
    
    Lu Abel
    
    Yourname Here wrote:
    > Some further comments.
    >
    > What I meant to say when I referred to yachties was that a person's
    > training would dictate how he spaced his sights throughout the day, what
    > he chose to shoot, and how frequently he took them.
    >
    > Also, I failed to respond to the questions about shooting from small
    > craft. These are not in order of importance, but should improve the
    > accuracy of your sights from that platform.
    >
    > Plan you sights beforehand, and use precalcualted altitudes and azimuths
    > when appropriate.
    >
    > 1. Select a compfortable and secure spot where you are well braced so
    > you don't have fear of your own safety and be standing.
    > 2. If possible have a time keeper record the sights
    > 3. Only shoot from the crest of a wave, never the trough
    > 4. Take 3 sights in sequence of each body and average the results.
    > 5. When doing stars, shoot away from a setting sun first in the evening,
    > and towards a rising sun first in the morning.
    > 6. Check your index error at the end of daytime sights and before taking
    > twilight sights.
    >
    > In case you were wondering, we did not have a SatNav, Magnavox 4102 or
    > otherwise on board.
    >
    > Joel Jacobs
    >
    >
    > --
    > Visit our website
    > http://www.landandseacollection.com
    >
    >
    >     -------------- Original message from Lu Abel :
    >     --------------
    >
    >
    >      > Henry Halboth noted the tradition of 0800, 1200 and 2000 position
    >      > reports to the captain of commercial and military ships, along
    >     with a
    >      > tradition of a noon sun shot. I'm 100 years ago one could also have
    >      > seen several sextants on the bridge wings of any such ship at
    >     dawn and
    >      > dusk, trying to bring down as many bodies as possible to get a
    >     perfect
    >      > "pinwheel" fix.
    >      >
    >      > These navigators had an awesome responsibility of keeping safe a
    >     very
    >      > expensive ship with hundreds of people aboard, so I can certainly
    >      > understand their meticulous behavior. They were also navigating
    >     large
    >      > ships with long turning times and deep draft, so "whoops, there's a
    >      > hazard, hard alee" wasn't an option as it might be on a small! er
    >      > recreational craft
    >      >
    >      > A year ago or so someone told me (and, unfortunately, I don't
    >     recall who
    >      > it was, so I can't go back for more details) that a recreational
    >     sailing
    >      > magazine had polled recreational sailors who had made long offshore
    >      > passages (including quite a few circumnavigators). Of those who
    >      > regularly used celestial, the vast majority reported that they
    >     simply
    >      > took morning, noon-ish, and afternoon sun shots and advanced the
    >      > resultant LOPs. No star shots, no fussing at dawn and dusk, just the
    >      > sun. While I didn't question my friend, I'd assume these folks might
    >      > also take daytime moon shots.
    >      >
    >      > I suspect their theory was that in the middle of the ocean, knowing
    >      > position to a few dozen miles was more than enough. I also note
    >     that in
    >      > a bouncing small craft, taking a sight with any degree of
    >     accuracy is
    >      > extremely difficult.
    >      > *> Comments? Especially from anyone on this list who has made long
    >      > offshore passages on a small craft? *
    >
    
    
    

       
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