Post Number: 225
|Posted on Wednesday, March 01, 2017 - 07:26 am: ||
A recent post from Ocean Navigator:
The thrill of the fix
Dec 29, 2016
BY JERRY RICHTER
To the editor: Technologies are invented and adopted because they make some aspect of human life easier or more efficient. However, ever since Socrates argued almost 2400 years ago that writing was the enemy of memory and wisdom, the benefits of new technologies have been weighed against the loss of the human physical, intellectual and intuitive skills that they supplant. In recent years, technology has evolved so quickly that it is sometimes difficult to recognize the changes that it imposes on our innate and learned abilities, talents and our very concept of the world around us.
The rapid growth of GPS technology is probably the best and most recent example of this displacement. In his recent book, Pinpoint: How GPS is Changing Technology, Culture and our Minds, Greg Milner notes that U.S. park rangers have coined the phrase “death by GPS” to describe incidents when travelers blindly follow GPS directions onto abandoned roads and become stranded in dangerous and hostile wilderness. I would contend that GPS has had an even greater impact on those who travel the waters of the world rather than its roads.
For several thousand years, humans have been refining ways of finding their way across open water to a desired landfall. These methods ranged from the arcane observational skills and conceptual models of the Polynesian navigators, to the mathematical methods of celestial navigators in the west. All of these methods require varying degrees of skill, judgment, science and art, as well as being subject to variables that are beyond the navigator’s control. For a celestial navigator, a high tolerance for ambiguity is a useful personality trait. Marking a latitude and longitude on a chart and saying “we are here” is frequently more an act of faith than of certainty. GPS has changed all of that, for better and for worse.
The role of a celestial navigator on an ocean crossing is an emotionally rich experience. One becomes attuned to the precession of the celestial sphere as navigational stars are tracked day after day and the sun is held to account daily. The fact that you are plotting your position relative to a point on the earth’s surface to which you are tied by your relationship to a heavenly body, based on the time in Greenwich, U.K., is, in its way, awe inspiring. You are truly a part of the giant clockwork of the universe. The ultimate pride and satisfaction, of course, is making your landfall as planned and predicted.
GPS, even in the form of a simple hand-held model operated on AA batteries, completely changes the navigation picture. There is no longer any uncertainty or anxiety in overcast weather, no need to schedule our activities, including sleep, around star times, no need to suffer the ambiguity of an imperfect fix. A perfect latitude and longitude can be obtained at any time, day or night, by pressing a button and waiting a few seconds for the requisite satellites to be acquired by the device and produce coordinates accurate to within feet. On the other hand, there is no longer a reason for a navigator to feel satisfaction or pride for a perfect fix, or to study and learn the stars and constellations and their movement through the heavens, or even to appreciate the steadfastness of the sun in its daily travel, or essentially, to feel a part of a cosmic scheme. Finally, when the navigator becomes a screen reader, the saddest loss may be of his image as a shaman in the eyes of the crew.
It is interesting to ponder how these technologies — developed to increase the ease with which we can undertake maritime adventures — also negate the very elements of the experience that formerly formed a large part of that adventure. Today, voyagers embarking on an ocean passage as a navigator most likely would not leave the dock without a GPS. However, knowing the limitations of AA batteries and electricity in general in a wet and salty environment, I would also bring along my sextant and almanac. I’d take to heart Kipling’s warning to the master of Nakoda: “The new ship here is fitted according to the reported increase of knowledge among mankind. Namely, she is cumbered end to end, with bells and trumpets and clock and wires, it has been told to me, can call voices out of the air of the waters to con the ship while her crew sleep. But sleep thou lightly. It has not yet been told to me that the Sea has ceased to be the Sea.”
—Jerry Richter is a former U.S. Navy navigator, has worked as a marine surveyor and is based in Pennsylvania.
Post Number: 42
|Posted on Tuesday, February 06, 2007 - 06:47 am: ||
One man's take on the value/practicality of a sextant:
Jan, you said "I am wondering what kind of sextant an ocean
crossing/circumnavigating sailor needs these days?"
My answer = 0
Sextants -- as you know -- are only adequate for ocean passages
because the relative accuracy is only about 4 to 6 nm (3nm is damn
good). So you really should figure in your use verses expense. I
did over 10,000nm of deliveries last year and I may have used my
sextant just a couple of times for fun/practice.
Unless the satellites fall from the sky you'll always be dependant on
GPS for your basic navigation (daily fix). Using a sextant requires
that it really become your primary instrument/method. Why? Because
you'll need to do a variety of shots throughout the day (perhaps
twilight to twilight) and that takes a lot of time, brain power and
also takes away from very valuable bunk time. You'll find that you
would rather sleep than rattle around with that clumsy thing.
That said, we at Club Nautique still teach CELNAV and actually use it
on OPM (Offshore Passage Making) classes where we go out for a 600nm
+ sail around the Eastern Pacific. During my last OPM we never once
got the chance to shoot the sun or anything else due to thick cloud
cover for 6-days straight. Instead we DR'd for 24-hour periods. The
best DR got us to within 12nm of our actual position...compared to
32nm for our worst after 24-hours. That's quite a lot of error just
in your DR position let alone your sextant sight reductions/fixes.
However, a fine sextant (and knowing how to use it) has always been a
source of pride for many sailors. The Astra IIIb looks the part and
works great (full horizon mirror is top shelf). That's the top end
I'm willing to pay for. The cheap Davis sextants will get you past
the OPM class level practical test and will work in a pinch as part
of your "emergency navigation" strategy (just keep them out of the
sun). The case, tables, almanac and perhaps a sight reduction
computer (CelComp) add to your cost. I probably have over $1200 tied
up in sextant stuff that I barely ever use.
If you're a cruiser I suspect you'd find many more ways to spend that
kind of cash. You could just as easily navigate to Hawaii with a
hand bearing compass, ocean chart, 50-foot length of string and a
hair brush...so where's the "emergency?"
PS There are some plotting sheets available that are far superior to
the West Marine variety...but I can't remember what they are called
(from the UK and not sold on the west coast). I'll try to remember
and let you know. A good plotting sheet could probably make a "mile"
of positive difference in your fix.
Post Number: 23
|Posted on Wednesday, January 24, 2007 - 03:38 pm: ||
Greetings folks, for those who are interested in historical info, I just finished a book called Line of Position Navigation by Vanvaerenbergh and Ifland, which chronicles the early celestial navigators up through Sumner and Hilaire, the two fathers of modern celestial navigation techniques. Very interesting and a good read.
Post Number: 140
|Posted on Sunday, February 05, 2006 - 06:25 pm: ||
SEAMANSHIP AND NAVIGATION DEPARTMENT
Title: NAVIGATION AND PILOTING
Description: Builds on concepts learned in NS100 and Third Class Summer Cruise. Specifically COVERS CELESTICAL and electronic navigation; basic meteorology; tides and currents; and voyage planning.
Offered: Spring 2005-2006, Summer 2006-2007, Fall 2006-2007
Requisites: Prereq: NS100.
IT'S A LIE.
MarkHowe (Unregistered Guest)
|Posted on Sunday, February 05, 2006 - 06:11 pm: ||
I heard somewhere that Annapolis had stopped teaching celestial nav cause everything was now electronic; gps and gis/ chartplotter etc. Any truth or another lie?
Post Number: 341
|Posted on Sunday, February 05, 2006 - 10:19 am: ||
Back in 1992 a Brazilian gentleman named Omar Reis created a celestial navigation program to run on an HP 95LX, a handheld computer running MS-DOS.
In 1996 he started his own web site dedicated to celestial navigation: http://www.tecepe.com.br/nav/
Its a wonderful portal for celestial navigators of all levels of experience. You can find the following resources there:
Celstial Navigation fundamentals
Directions on how to create your own sextant from a CD and a few odds and ends
An online Nautical Almanac
An online star finder
Links to other resources for those interested in the art of celestial navigation.
You can also purchase his amazing celestial navigation software (now running on Windows) for $50. It include
A perpetual almanac
A star finder
A meridian passage calculator
A Line of Position calculator
An astronomical position calculator
A running fix calculator
A printable star finder
A printable nautical almanac
Fundamental celestial navigation training
While not quite as polished as Starpath's StarPilot PC, it is also 1/3 of the price...
I highly recommend a visit...
Post Number: 137
|Posted on Saturday, March 06, 2004 - 12:46 pm: ||
Excellent portal for all things Celestial Navigation. For those who appreciate the art of Cel Nav.
Post Number: 135
|Posted on Saturday, March 06, 2004 - 12:43 pm: ||
Greetings All, an online version of the Nautical Almanac, giving you a 3 page "Daily Page" once you input th date.
Post Number: 170
|Posted on Tuesday, May 04, 2004 - 09:16 am: ||
Greetings All, a greate portal from the Astronomical Applications department of the US Naval Observatory. These are the folks that publish the Nautical Almanac...