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    Re: The Darn Old Cocked Hat - the sequel 1
    From: Gary LaPook
    Date: 2013 Mar 12, 22:10 -0700
    I said the same thing back in 2010 when we were discussing this same topic. You pick the point inside the cocked hat that is closest to danger and use that as the fix to plan the next leg. If you are very close to the danger then allow for several SDs outside the cocked hat that may contain the true position.

    You must pick some point to use as the fix and, even though the true position may be outside the cocked hat, there is no way to choose a spot to use for the fix outside the hat. The symmedian  point is the least bad point to choose for the fix but other points inside the hat are almost as good but any point outside the hat is much worse than any point inside to choose as the fix.

    gl

    --- On Tue, 3/12/13, William Hawes <williamhawes{at}rogers.com> wrote:

    From: William Hawes <williamhawes{at}rogers.com>
    Subject: [NavList] Re: The Darn Old Cocked Hat - the sequel 1
    To: garylapook---.net
    Date: Tuesday, March 12, 2013, 9:03 AM


    Gary, Tom and all,

    Although perhaps not mathematically robust, when I was in the navy I was taught, that when in coastal or pilotage waters, to pick the worst scenario/most dangerous position in the cocked hat. Otherwise when well offshore I generally picked the position closest to the centre or if I had a good DR/EP, I would place the fix closest to the DR/EP position. Of course as Tom pointed out below, when transitioning from ocean to coastal to pilotage you typically were transitioning from heavily weighting celestial observations to other fiixing methods better suited to more confined restrictive waters.

    Which navy? I served as navigator of submarines (Oberon Class diesel boats) in both the Royal Navy and Royal Canadian Navy back in the 70's. I was a member of the RCN but served a 3 year exchange tour with the RN. We did hand sextant observations from the bridge when surfaced and, very occasionally, used the artificial horizon sextant that was built into the Barr and Stround Attack Peicope.

    wmh
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