NavList:

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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