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Subject: Re: [Nml] Spherical earth model vs. ellipsoid
From: Dan Hogan (dhhogan@XXX.XXX)
Date: Fri Mar 12 1999 - 13:47:23 EST
The errors one will get from using celestial navigation at sea. will be
not from any mathematical equations. But from a navigator that is
"green-around-the gills" after 3-4 days of storm on a small boat
bouncing on a rolling ocean. Toss in a hazy sky and uncertain DR and
you have it.
As the textbooks say. The mid-shipman makes a precise mark on the chart
and says, "We are here.". the Fistmate draws a small circle and says,
"About here.". The Captain comes in, slaps a spread out hand down and
says. "We are someplace around here."
On a small boat, making 5-8 knots, a daily Noon sight becomes just
about right. Also, living on a boat for days on end that is doing much
over 5.5 Knots gets to be downright miserable.
So good seamanship dictates that a good lookout, a consistent DR and
periodic position fixes be mixed with common sense.
So if you get a cocked hat of about six miles, you are someplace around
there.
Dan Hogan WA6PBY
dhhogan@XXX.XXX
Catalina 27 "GACHA"
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