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    Re: Sextant/3 Arm Or Gyro Bearing Pmp Plot
    From: Jeremy C
    Date: 2010 Nov 25, 03:42 EST
    I think that you misunderstood what I was saying Byron.  I was saying that for me to plot the three bearing lines at anchor is much quicker with a 3 armed protractor than my normal parallel rulers/triangles that I would otherwise have to use.  I don't know about a plotting machine as I've never been on a ship so equipped. 
     
    I am also doing this alone and am not using a sextant at all.  I take 3 bearings with a bearing circle, find the angular differences of bearing between them, set the arms, and overlay it on the chart.
     
    My other option would be to take the three gyro bearings, apply the GE & Repeater error, then plot them individually.  This process takes me much longer for the scale chart I am using as I need a long straight edge as well as my triangles.
     
    I am not sure why you would need to "evaluate" the 3 armed protractor bearings.  The only errors that come into play are a scale error in either the repeater circle or protractor, or an error in observation.  Compass error should play no part as the basis of the observation is relative angles.  If fact, to make the math the simplest, taking relative bearings with heading as zero is actually the way to go.
     
    I am sure a plotter and bearing team (consisting of more people than are on my bridge during maneuvering) can certainly lay a position quickly, but that is not an option with us.  Then again, we aren't using a 3-armed protractor except at anchor either.
     
    Jeremy
     
    In a message dated 11/24/2010 7:00:10 A.M. Central Asia Standard Tim, byronink---.com writes:

    Someone said that the sextant 3 arm is faster
    than bearing plot. My experience is that is incorrect. Also I say that the 3 arm can not be evaluated as to how accurate the fix is as easy as the bearing plot.. The 3 arm can be very accurate and quick, but will take the back seat to a gyro bearing team and a plotter.Give me your augment?
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