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post #101 of 330 Old 07-01-2006
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Well...I'm all for anyone who wants to learn Celestial and it is just one more from of backup...but with the price of GPS units today you can safely store several units cheaper than you can buy a sextant and it would be extremely unlikely that you would have such a massive loss of equipment without losing the boat! With 3 GPS's...batteries and an EPIRB I feel SAFER than if I had 1 GPS and a sextant...I can put myself right into that tropical reef pass and not depend onn something with a 1-2 mile error.
Again...I think Celestial is wonderful to learn and it certainly makes for good navigation skills outside of celestial ...BUT...I'd rather have 3 GPS's than 1 Celestial navigator!
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post #102 of 330 Old 07-02-2006
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Not necessarily true...

Quote:
Originally Posted by camaraderie
Well...I'm all for anyone who wants to learn Celestial and it is just one more from of backup...but with the price of GPS units today you can safely store several units cheaper than you can buy a sextant and it would be extremely unlikely that you would have such a massive loss of equipment without losing the boat!
A single lightning strike could take out all the electronics on a boat, and yet leave the boat and the people relatively unscathed. The EMP pulse generated by a Lightning strike is more than enough to fry all the IC-based electronics, which can not tolerate much in the way of overvoltage. Even a near miss might generate enough of a transient voltage spike to fry the electronics, with little or no other effect.

There are other causes that could leave you without your electronic nav aids. Two that I can think of off the top of my head are:

First, all electronics are pretty battery dependent, and saltwater and batteries are not a great combination. A lightning strike wouldn't even be necessary, if the saltwater ruins the batteries or just corrodes the electrical contacts/circuits enough.

Second, electronics are generally far more valuable as merchandise for thieves to resell than are sextants. You could also be deprived of your electronics due to a thief in the last harbor you were in. It isn't all that likely that he would take your sextant though...

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her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

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post #103 of 330 Old 07-02-2006
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Well...I'm not gonna convince you sailingdog...and vice versa too I'm sure. Been out cruising 5 years and through lightning storms and hurricanes and have yet to have even one of my GPS's fail. Indeed...the battery operation is a plus when everything else is blown out. I keep my battery stash (and spare GPS's) in a pelican waterproof case and one GPS in the microwave when at sea which acts as a Farraday cage. As for theft...I think I'd notice and replace it before I left harbor.
I've also been out in a 3 day gale where we didn't see anything but gray...would hate to approach a harbor via sextant in those conditions.
Again...each to his own...see ya out there and I'll give ya a position fix if ya need one! :-)
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post #104 of 330 Old 07-02-2006
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I know little of offshore boating, and almost nothing about sailing. What I do know a lot about is GPS. With a Dad that works for NASA in Florida, and an Aunt who literaly wrote the manual for the first GPS reciver in the 80's for ground infantry in the army, I come from a family in the know. I wrote a college thesis on GPS technology as well.

The most imporatant thing to remmember is that GPS is made up of two seperate components, the reciever, and the Transmitter. You have complete control of the reciever. You can buy recievers that are almost indestructable, water proof, and I would say much more reliable than a sextant (which before today i thought was spelled sexant)

But the reciever is only half of what is required to use GPS. Almost everyone in the United States relys on the Department of Defenses NAVSAT Array, a series of 24 satalites that your recevier uses to triangulate a position. The Russians have an incomplete array, and the EU is planning to put up an array, GLOBAL something or other.

First and formost thouse sattlites are for the deffense of this nation, and will, and have been used as such! The military did not release the full potentional of the GPS system untill Clinton told them to unscramble the signal in 2000 (then called selective avalablity) And they withold the ability to rescramble and even stop the signal for use by the military if they need it.

For example, in the Iraq war they would move as many of the NAVSAT sattlites as possible over Iraq (up to 7 of the 24), then program them to compensate for weather affecting the signal, and this is just what has been declassified! Do you think a civilian GPS recevier worked anywhere near Iraq during the first months of the war?

And this is just what the Department of Defense can do to the signal, what about solar interference that can make gapping holes in satilite coverage, or space trash destorying satilites? God forbid you the only one relying on GPS for navigation when the military moves a sattlite from over the south pacific to fill a hole in thier covarage elsewhere.

Dont take GPS for granted, its not yours. Only the reciver in your pocket is yours. On the other hand, a sextant is yours, you have control over it. You can drop it, but at least you will know why it doesnt work.
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post #105 of 330 Old 07-03-2006
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For what it's worth, my philosophy is for every high-tech "must-have" keep a low-tech equivalent
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post #106 of 330 Old 07-04-2006
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Quote:
Originally Posted by sneuman
For what it's worth, my philosophy is for every high-tech "must-have" keep a low-tech equivalent
Sounds like my philosophy too. Occasionally, the caveman technology saves your butt...

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You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
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her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

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post #107 of 330 Old 07-04-2006
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Excuse me...I have to go print out my hard drive on paper now. Then I'm gonna run down to the mega phone store as I don't have a no-tech backup for my VHF.
The US Navy is doing away with paper charts and no longer teaches celestial at the academy. (They teach sextant use but not the computation except through PC's). I still carry paper charts but the sextant thing is overkill.
I've got more chance of being struck by lightning personally than all of my GPS's being knocked out at once. And the odds of the GPS satellites being shut down or shot down while I'm at sea are ones I can live with too.
Again...nothing against those who enjoy learning and using Celestial....but don't try to convince me I am in any way less safe at sea than you are with my multiple back-ups. I am SAFER than if you have no GPS backup other than your sextant.
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post #108 of 330 Old 07-04-2006
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To Headingsouth, I still have an address book,dictionary,phonebook, and I make my living trying to keep computer systems running.Dont you just love it when you try to run some backed up data and you get the message "windows cannot find the program which created this document" . If that magic grey smoke didn't find a way to escape those electronic components,I'd have to find another way to pay my bills, but then I still have some non self tailing winches on my boat and pencil& paper in the drawer under my nav.desk,I also have an old Danforth compass besides the fluxgate.Do you still splice ropes, or do you use superglue? My tires on my car have a 70,000 warranty I've got roadside assistance, but I've still got a jack in the trunk,next to the spare, callme an old fuddy duddy. Art.
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post #109 of 330 Old 07-05-2006
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And despite the fact that internal combustion engines have come a long way, and have proven to be very reliable.......my boat still has sails. :-)
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post #110 of 330 Old 07-05-2006
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Camaradie: It's funny, I just made a very similar point on another thread. Here Here! Here is the celestial navigation from my perspective. (I learned it at 16 and am now 47).
1. It is not super accurate and Frankly obsolete. It's nice to know that you are within 100 miles give or take of something I guess.
2. Ideally, you want to use a computer to make your calculations! But those pesky battries. Or you could use a pencil--no calculater and the grid.
3. It is important to chart you exact location, speed, time direction at regular intervals when sailing offshore. As so many much experienced sailors than I have noted battery failures are not only possible but likely.

The advantage of studying celestial navigation in my opinion is that it teaches you to grasp the concept of where you are in the world based upon a fixed time, (Mean Time), your speed, wind direction and current.
In my opinion, this is the problem with GPS. It makes non-sailors think they know everything they need to know about navigation because a computer screen gives them information. Yet so many lack the most basic understanding of the principles of navigation.
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