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    Re: What do offshore recreational navigators really do?
    From: Joel Jacobs
    Date: 2005 Jun 6, 16:45 +0000
    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
     
     
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    -------------- Original message from Lu Abel <lunav{at}ABELHOME.NET>: --------------


    > 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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