NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Navigation Survey
From: John Kabel
Date: 2001 May 27, 11:32 AM
From: John Kabel
Date: 2001 May 27, 11:32 AM
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@verimail.com > 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@home.com