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Old 13-02-2011, 13:05   #31
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When I first crossed the Pacific SATNAV was way too expensive and GPS had not been invented. Necessity required I learn celestial navigation and the sextant was one of those tools. I will always carry one aboard but may not use it. For the price of a new Nautical Almanac each year for 4 years you can buy a new simple GPS. Hopefully our satellites will be in the sky and giving us good information for many years to come but if something does happen then it'd be good to have a backup. Otherwise, a lot of folks who are unwilling to learn will be selling their cruising vessels.
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Old 13-02-2011, 13:58   #32
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My belief is that a sextant & tables is another tool in a sailor's arsenal which allows him/her to navigate the world independently & confidently. I do, as well, believe in carrying paper charts/equipment & publications for all planned cruising areas and do update my charts/etc., as needed.

Is it essential? No. I believe in redundant systems and value the sextant in this regard. Also, relying on electronic nav. & comm. equipment, alone, doesn't seem wise to me. How much more challenging is it to learn to use a sextant, than today's avg. SSB/Ham?

Then again, I suppose that one could buy a quadrant, manual, tables, and spend those long days in the life raft learning how to use it... you do have a liferaft on your list, don't you?(lol)
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Old 13-02-2011, 14:52   #33
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One of the greatest experiences of my life was when I did my first crossing of the Coral Sea using DR and Celestial (self taught). Satnavs and GPS were still a dream then. It gives you great faith in your ability as a mariner and I would recommend that you do a genuine trip one day using only DR and Celestial. You WILL be proud of your achievement.
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Old 13-02-2011, 15:46   #34
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Originally Posted by Eleebana View Post
it's hard to get excited about learning to use this ancient contraption.
I got quite excited about learning

I have a fairly cheap davis mk25 which could get me home from offshore probably if it really came to it. But that possibilty really isn't something which is even close to featuring on the list of things to worry about. Running out of extra virgin olive oil comes much higher
But it's fun to play with on a passage. And learning a bit about astro I found gives a better mental picture of what goes on on our little spinning bit of rock as it orbits the sun.
AIS now means it's even harder to turn off the gps, making an entire offshore passage sans gps must be a wonderful feeling. I started sailing after gps, any nav without it has been through choice.
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Old 13-02-2011, 16:01   #35
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have 2 davis sextants on board,primarily for teaching,use the gps position so the crew can work the calculation backwards and find the correct altitude on a noon site.

i stopped getting grey hairs when gps arrived...................
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Old 13-02-2011, 18:43   #36
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The final straw, for me, came in 1997 when the US Navy stopped requiring officers to learn celestial.
The US navy has less need for celestial than small boats IMO. The Pentagon controls GPS - if they put in a huge dither, or shut off the open signal altogether, they still have the equipment to use the encrypted signal. They don't have to worry too much is GPS fails outright, as modern warships have sophisticated gyro's and inertial navigation systems - so their DRs are, in reality, extremely accurate EPs. And when you have enormous radars 100 feet above the water, it's fairly easy to make radar landfall at 100 miles or so. That said, it is far less likely that the GPS system would go before the systems on your boat will, and for the small boater there are other options, so celestial is only viable if you learn and practice it.
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Old 13-02-2011, 19:10   #37
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The thing I don't like is the way Lights and Marks are slowly and quietly disappearing all over the place... where once there were many there's now handfuls... and since this crisis many more have gone.. my last delivery was a real eys opener... so many times I was looking for something no longer there or working.. if the GPS system ever did go down for a while it'd be interesting...

There was an article in one of the mags awhile ago talking hypothetically how much money could be saved by not having or maintaining navaids. The reason for this was to talk about virtual navigation software that is being developed. You look through your HUD and you can see all the navaids.

I don't think that they were talking about this one, but here's an example:

Sea Technology Magazine - Worldwide Information Leader for Marine Business, Science and Engineering
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Old 13-02-2011, 19:54   #38
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I learned navigation in the 70's. The Navy ROTC program at my college allowed civilian students to enroll in their navigation course. I loved it and got to be pretty good at it. I had a sextant, kept a copy of Bowditch, knew how to do much of the rather obscure stuff in there, sometimes amazed my fellow crew members with my ability to find what we were aiming for.

But, as I look back, the reality was that most of the time I was bloody well lost and well aware of it. At least I conducted myself as if I were lost, and thereby avoided many disasters.

Over the decades since, I've come and gone from boating. I remember when the first Loran units came out that recorded a little monochrome track line. Once we had gone out of a harbor, we could always follow the little line back in. One morning, though, we were going out of a new harbor when a pea soup fog dropped in. Without the little track line to follow, the captain was lost. "Where are your parallel rules?" I asked him, grabbing for the chart. "What are those?" he replied. I used a couple of cassette tape boxes to walk compass courses across the chart and DR'ed us through the fog. The other crew members thought I was a magician.

Years later, I remember sailing the Caribbean with a big, built-in GPS that displayed only lat/lon, which we then plotted on paper charts. That was the first time I ever got in trouble. I sailed right up onto a reef, just knowing I knew exactly where I was. I did. I just didn't know a reef was there.

Then later came the monochrome GPS chartplotter, and the track line that ran a good 200 yards off to the north of the ICW through the salt marsh, even though we were running down the center of the channel. And now the computer that is always completely accurate with the complete catalog of full color charts loaded in.

And sure enough, I plowed right on to a sandbar in the middle of the night last summer knowing exactly where I was, staring right at the computer and all the flashing lights around me, on a crystal clear night.

I no longer have a sextant. But maybe I ought to get one. I'd be lost all the time, but I might be a better navigator.
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Old 13-02-2011, 20:05   #39
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You're forgetting the Chronometer...

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Originally Posted by Eleebana View Post
All right, I've read all the arguments for why I need a sextant and agree it could be handy one day if all else fails. But as the day draws closer to throwing off the docklines and I tick off the next thing I need to learn, it's hard to get excited about learning to use this ancient contraption.

What I want to know is what percentage of cruisers out there don't even have one on board or if they do, could not reasonably navigate home with it anyway?

Come on, it's me your talking to so tell me the truth.

Greg
I have one-an Ebco.But it's nearly useless without a CLOCK-a mechanical device that freed sailors from the guess-and-by-God of Latitude sailing-(notably a risk waiting for a clear sky north/south of the tropics)...Harrison's Chronometer was BIG news at the time...the GPS of the day!

Which is to say,how many have Chronometers?How many hoary,hairy cruisers don't or didn't rely on WWV to check their watches?Is gps any different than that?
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Old 13-02-2011, 20:30   #40
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Originally Posted by Eleebana View Post
All right, I've read all the arguments for why I need a sextant and agree it could be handy one day if all else fails. But as the day draws closer to throwing off the docklines and I tick off the next thing I need to learn, it's hard to get excited about learning to use this ancient contraption.

What I want to know is what percentage of cruisers out there don't even have one on board or if they do, could not reasonably navigate home with it anyway?

Come on, it's me your talking to so tell me the truth.

Greg
It's prudent to carry a sextant and more importantly know how to use one. Celestial navigation will be here long after satellites fall out of the sky, and GPS can be suspended at any time (which was the cast back in the 90's during on of the Gulf wars).

There are other forms of navigating that do not rely on GPS as well such as being able to identify a lighthouse on your chart, and draw some bearing lines to it.

If you're offshore, I'd carry a sextant. If you're near coastal (~100 miles), I think you can pass it up but make sure you bone up on other-than-gps methods.
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Old 14-02-2011, 05:07   #41
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I used a sextant at times back in the seventies, but even then, I would have a more accurate fix if I could pick up three RDF signals. Now my emergency back-up is a spare GPS still in the box. At this time I'll not be worrying about the rate that satellites are falling from the sky.
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Old 14-02-2011, 06:29   #42
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Own a very nice Tamaya sextant that I use once or twice a year to stay in practice and just for the pure enjoyment of doing it. If you want to get started in celestial pick up a copy of Stafford Campbell's "The Yachting Book Of Celestial Navigation" it's quick and easy, no theory, just the steps necessary to get a fix. It's a small book and you only need to read the first 39 pages to get a line of position. I can be learned in and afternoon. Vamoose is Quietly anchored in English Harbor Antigua I think I will take the sextant out today for a little practice
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Old 14-02-2011, 07:30   #43
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Jeepers more myths about GPS
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"and GPS can be suspended at any time ,which was the case back in the 90's during on of the Gulf wars"
GPS has never been suspended at any time since its activation, satellittes were repositioned to get greater coverage, but the system wasnt "suspended".

Quote:
Years later, I remember sailing the Caribbean with a big, built-in GPS that displayed only lat/lon, which we then plotted on paper charts. That was the first time I ever got in trouble. I sailed right up onto a reef, just knowing I knew exactly where I was. I did. I just didn't know a reef was there.
Chart Issue, not GPS.


Quote:
Then later came the monochrome GPS chartplotter, and the track line that ran a good 200 yards off to the north of the ICW through the salt marsh, even though we were running down the center of the channel.
Again Chart datum issues, not GpS,exact same problem would exist with a sextant, except that the sextant error hides the chart error.

Quote:
The Pentagon controls GPS - if they put in a huge dither, or shut off the open signal altogether, they still have the equipment to use the encrypted signal.
The coarse acquisiton signal ( C/A) is needed to use the precision one (P/Y) one cant be turned off on its own.

GPS is a worldwide asset, a fact ackowledged , most of teh worlds militaries can selectively deny GPS in a area if they desire. Hence turning off the system will never happen, short of global conflict. Equally the other GNSS are coming online with Russia, the EU, China and japan, commited to establishing GNSS systems. in reality its here to stay like electricity or the telephone.

That said I like traditionall navigation, I can use a sextant, ( and its gets one great kudos, going through airport security, they look at you in a new light!).

Dave
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Old 14-02-2011, 09:04   #44
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This sounds a lot like the knife/gun, ssb/satphone, paper/electronic chart, and radar debates that seem to go on all the time. All of these tools have their place, but whatever you pick, and for whatever reason, you still need to know how to use it. As for me, I

am a very good shot, but only carry a knife (and only for rigging).

have a cell phone, but only use radios (vhf and ssb) on my boat.

have OpenCPN loaded on my laptop, but carry a full set of paper charts I use when underway.

have a tri-lense radar reflector, but got rid of the old active radar that came with the boat.

have several handheld gps units, but prefer to use a compass, watch, and sextant for navigation -- not yet proficient with the sextant.

So, all I'd say is to make sure you know how to use whatever equipment you decide to carry, and get rid the stuff you don't know how to use -- takes up valuable space.
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Old 14-02-2011, 09:10   #45
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I used a sextant at times back in the seventies, but even then, I would have a more accurate fix if I could pick up three RDF signals. Now my emergency back-up is a spare GPS still in the box. At this time I'll not be worrying about the rate that satellites are falling from the sky.
They don't have to fall from the sky. Some of them are quite old and merely have to be taken out by a decent-sized solar flare or cosmic-ray burst.

Nonetheless, it's governments who press the buttons. There is currently a proposal that Homeland Security in the U.S. can have a sort of "kill switch" for the Internet (at least in the U.S.) in case of "external/internal threats to national security".

Just like Egypt did last week.

I think that if that is up for discussion, it would be naive to assume that unencrypted access to accurate GPS data wouldn't be turned off, either.

People forget that ALL U.S. civilian air travel was stopped (and plenty of non-U.S. air travel as a consequence) for several days after 9/11 (Security Control of Air Traffic and Air Navigation Aids - Wikipedia, the free encyclopedia).

If I am four days from landfall in a 14-day Pacific passage near known reefs and whatnot the next time this sort of thing happens, at least I'll carry a Plan B.

Again, I don't care if anyone else does, with the exception of idiots who slave their AP to the GPS and don't keep a watch...a positive danger as far as I'm concerned, but then I had to give way in October, 2006 four miles offshore in Lake Ontario because some bozo in a 27 footer was below for 20 minutes making coffee or anyway NOT KEEPING A WATCH probably because he thought "It's October: Nobody's out, never mind this far out!"

Wrong. He got the appropriately brisk sound signal as I skimmed his stern at six knots (it was a breezy day).

When it comes to navigation, vigilance is part of competence and practice is the golden key.
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