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    Re: Small Craft CN Using Hp Graph
    From: Gary LaPook
    Date: 2011 Jun 30, 11:25 -0700
    Did you try graphing precomputations?

    --- On Thu, 6/30/11, Patrick Goold <goold@vwc.edu> wrote:

    From: Patrick Goold <goold@vwc.edu>
    Subject: [NavList] Re: Small Craft CN Using Hp Graph
    To: NavList@fer3.com
    Date: Thursday, June 30, 2011, 7:20 AM

    This is very interesting, Greg!  I am still not getting near as good results but then I am really a novice at this, my boat is smaller, my sextant poorer and the weather has been at least as problematic.  Pre-calculating does help.   Perhaps eventually I will get results I won't be embarrassed to share.
    Thanks again!


    On Wed, Jun 29, 2011 at 10:38 PM, Greg Rudzinski <gregrudzinski@yahoo.com> wrote:

    Finally I have had a chance to test small craft CN using a graph of pre-calculated Hp altitudes. The weather was overcast and windy with a 3 ft chop. The vessel was a 42 ft. sloop on a close reach using a jib and main to average 5.5 kts in 10 to 12 kts of true wind. From the starboard quarter of the cockpit 5 successive observations were made of the Sun through a thin layer of clouds. A Cassens & Plath equipped with a whole horizon mirror and 4x40mm scope was used. See links of index card working notes, graph, plot, and additional observations while at anchor.

    The average intercept for this sea trial was 2.7NM from the GPS position which is not that good but acceptable considering the motion of the sailboat and the intermittent appearance of the Sun through the thin clouds. The five observations made while at anchor were much easier under ideal conditions and so it is no surprise that the average intercept there was a respectable 1.3NM from GPS.

    Notice the neatness contrast between the index card underway working notes and the at anchor working notes . Writing legibly while underway is tricky.

    Greg Rudzinski
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    Dr. Patrick Goold
    Department of Philosophy
    Virginia Wesleyan College
    Norfolk, VA 23502
    757 455 3357

    Charles Olson: "Love the World -- and stay inside it."

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