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Subject: Re: Navigation Survey
From: John Kabel (jjkabel@XXX.XXX)
Date: Sun May 27 2001 - 13:31:46 EDT
John Kabel replies:
Dan Hogan wrote:
>
> Please enter the Navigation-l survey. This will aid in future Silicon Sea
> Legs and maybe help increase list discussions. Feel free to expand any
> category.
>
> Post replies to the list primarily. I will summarize and post the results.
>
> Be aware that most of the better celestial navigation books were written
> before 1980. So still list yours.
>
> Navigation-L Survey
>
> a) Dead Reckoning
>
> What is the method used most?
> Mid-Latitude-----:
> Mercator Sailing-:
> Rhumb Line-------:
I use the rhumb line method with parallel rulers, and the Cockpit
Plotter #61 (my version is from RPT Sales in Toronto, Canada),
essentially a course protractor. Adjustments for variation from chart
compass rose as usual, and appropriate deviation table.
> Other(Name?)-----:
>
> b) Sight Reduction
>
> Which is your primary Sight reduction method?
> Computer Program(Name?)--------:
> Calculator(Name?)--------------:
I use two methods depending on circumstances. For routine work I use a
HP-48GX with the Celestian Navigation Pack on a ROM card. This is the
Sparcom Celestial Navigation Pac written by Tom Metcalf. There are a
few auxilliary programs available off the Web, to allow setting of
positions as variables in memory, a small starfinder program, and a
"traditional sight reduction" module which gives you intercept and
azimuth in the usual format. The Pac incorporates intercepts into a
least-squares fix calculator, and doesn't show the individual intercepts
n a separate fashion. All almanac data is calculated from scratch
within the pac and has never varied from manual methods more than 0.1
arcmin.
The second method I use is that taught by the Canadian Power and Sail
Squadrons, using their sight reduction form and the calculator method at
the bottom (solving the navigational triangle with the basc trignometry
cosine equations). The Nautical Almanac is used for the celestial
data. I use the same HP48-GX, but without entering the CelNav Pac at
all. I use this manual method periodically to keep my skils up,
otherwise I get too dependent on the CelNav pac.
I have used Ageton tables and the Nautical Almanac methods, but find
them cumbersome!!
> Short Navigation Tables,
> H.O. 211 etc.(Name?)-------:
> Standard Navigation Tables,
> 229, 214 etc.(Name?)-------:
> Other(Name?)-------------------:
>
> c) Plotting
>
> How do you do your plotting?
> Computer Program(Name?)---:
> Universal Plotting Sheets-:
I typically use Universal Plotting Sheets or the plotting sheets that
are partially pre-drawn in the CPS Navigator course, adjusted for
latitude as usual.
> Maneuvering Board----------:
> Radar Plotting Sheets-----:
> Home Made(Describe)-------:
>
> d) Navigation Manuals
>
> Name your main reference manual-:
Bowditch (single volume 1995) and Chapman's 61st edition are my primary
references.
>
> Name a manual/book that helped you the most-:
Two books got me over the celestial navigation hump. One is Mary
Blewitt's classic, "Celestial Navigation For Yachtsmen". This gem
treats the subject in terms that make sense. The other is Bruce Bauer's
"The Sextant Handbook".
For mental exercise, I also read David Burch's "Emergency Navigation";
this gets you involved in the annual cycle of celestial phenomena in a
way that helps you remember. Finally, I have tried to absorb what I
could from the books about the Pacific Island navigators. They treat
the celestial (sidereal) compass in some detail.
For "browsing" celestial phenomena and trying out things, I use Bisque
Software's "The Sky."
>
> e) Do you use the Nautical Almanac?
> Commercial-:
> USNO-------:
I always buy the Commercial edition from my Squadron every fall, to keep
my hand in.
>
> Dan Hogan WA6PBY
> Catalina 27 "GACHA"
> dhhogan@XXX.XXX
> Navigation-L List Owner
> http://www.wa6pby.com
Of course, none of this applies on my present vessel, which is navigated
by a Lowrance GlobalMap 100, augmented with charts drawn in OziExplorer
and Ozi MapCreate, and which always carries a waterproof compass and
laminated charts of the area of current navigational interest. The deck
is not stable enough for celestial work, and one would never take it far
enough from shore or out after sunset, to use celnav.
P/Cdr John Kabel, _N_
Past Commander and Electronic Communications Officer
London Power and Sail Squadron
Sea-Doo GTX "As My Whimsy . . . "
jjkabel@XXX.XXX
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