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Old 17-02-2010, 17:32   #46
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Suspect there is a divide between people sailing where DR can get you 'there or back', and people seeking small dots in the great Pacific.

Then again, some just like mastering traditional skills or tricky things, or need to satisfy the demands of our professions or governments.

Have lots of sympathy for those relying on multiple GPS units, but remain convinced that Murphy wants to play with me. Power supply, lightening strike and inconvenient breakages are IMHO more of a threat than global war and the assumed conspiracies of super-powers.

Much of this discussion assumes the sole use of a sextant is astro nav. Pilotage applications also exist, particularly simple distance calculations.
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Old 17-02-2010, 20:24   #47
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Originally Posted by Hank&Karen View Post
I had the same question...any thoughts or recommendations?
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Originally Posted by hellosailor View Post
3-Requires some skills and either a sight reduction program/calculator, or tables
Search this forum for “sextant”, there is all ready plenty good information in this forum.

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Originally Posted by hellosailor View Post
Reasons not to have a sextant:
1-If you drop it, it is toast.
2-Will tie up $400-800 or more, depending on your choices.
3-Requires some skills ..
May be also a reason not to have a boat if you intend to fall over board.
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Old 17-02-2010, 20:43   #48
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Hank-
If you do a web search, there are a number of free sight reduction apps out there for computers and for PDAs. John Manson's "Navigation" package for the Palm PDA is a good one, and you can buy an inexpensive used Palm PDA to dedicate for the task. (Palms are much more well-behaved than laptops and run for weeks on 2xAAA cells.)

Buying a sextant on eBay is like anything else on eBay, you have to look at the seller's feedback rating and their description and picture and then go by your gut feel for whether they are reliable. Buying a sextant--or anything else--from Russia can be problematic if the payment is something like Western Union where you have no options and expensive air freight if it isn't what you expected.

Each sextant is somewhat unique. A catalog description of a C&P Ultra may not seem very different from an Ares or Astra...but C&P seems to neglect mentioning that their mirrors are tinted, one red the other green, so that when you align a star it "pops" into white compared to the two tinted images. I haven't seen that on Plath, Tamaya, etc. and it certainly isn't necessary--but it makes a nice refinement, as does their split horizon prism and the quick zero feature. In practical navigation from a small craft at sea, none of that will probably matter conmpared to larger ways of making errors.<G>
And then again, oddly the C&P telescopes (eyepieces) that I've seen adjust from the rear, so they go out of focus if rotated against your eye or glasses. Where a much cheaper Freiberger adjusts focus from the front and doesn't suffer that problem.

Good reasons to try finding some sextant users (at a planetarium perhaps) and getting your hands on a few to see which one really makes friends with you.
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Old 17-02-2010, 21:26   #49
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The US government trusted the brits charts more than their own in the pacific during WW2

You may have heard of a brit called captain cook,he ended up as dinner for the natives but he could navigate and he produced charts that are still being used today

Wonder what he would have thought of a sailor who could not use a sextant?
Bastonjock,

I certainly did not mean to imply that the British government should not be trusted. I simply meant to point out that for the last 500 years or so, governments (British, then U.S. and others) have been playing a key role in providing navigation services. GPS, LORAN, OMEGA, time service (first the ball and cannon signals at Greenwich to allow you to set your chronometer, then WWV shortwave time signals, and now GPS), HO/NOAA 229/249 Sight Reduction Tables, Nautical Almanac, and just about all charts are produced by governments--U.S., U.K., or others. If you don't feel you can trust the government(s), you've got to revert to latitude sailings and ded reconing, for even with your trusty $35 Casio watch, without help from the government you wouldn't have an accurate time reference to set it.

I also didn't mean to imply that having a sextant and knowing how to use it is a bad idea. It can be satisfying, and anyway, the government cautions mariners not to rely on any single mode of navigation. However, in practice, a complete collapse of the GPS system is extremely unlikely. And even if half the constellation failed, you would still be able to get accurate fixes more frequently from GPS than by using sextant.

And by the way, Capt. Cook made his voyage in the service of His Majesty's Government, in order to explore and chart the unknown waters for use by future generations of sailors. Some of his contemporaries probably looked down at masters who didn't sail down latitudes using the astrolabe for navigation.
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Old 17-02-2010, 21:52   #50
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I guess I am just plain paranoid...

I have 3 GPS units, a handheld, one for my PC, and one built into my AIS unit.

I also have 4 Sextants.....
A Tamaya that I inherited from my father
A Friedberger that I found in a local trader shop for under $200
A Tama Sokki that I bought on this forum for under $150
And finally a Davis Master that was a gift from a friend.

The old Tamaya is too far gone to have repaired cost-effectively, but I hang on to it for sentimental reasons. I learned to use a sextant with that unit. All of the others are servicable and in adjustment.

As for dropping a sextant, that is easily remedied with a light lanyard attached to the grip that goes around your neck while handling the instrument. If you drop it, the lanyard prevents it from either going overboard or hitting the deck.
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Old 18-02-2010, 11:36   #51
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Gee Rusty,
I am just starting my collection.
Do you want to part with one of those sextants and maybe an old GPS ????
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Old 18-02-2010, 12:06   #52
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As for dropping a sextant, that is easily remedied with a light lanyard attached to the grip that goes around your neck while handling the instrument. If you drop it, the lanyard prevents it from either going overboard or hitting the deck.
I have learned much since begining my sailing career and the fisrt lesson was that "Neptune is Greedy" and wants anything and everything you own aboard a boat.

Having lost a few tools, a cellphone and my wife's Kitchen Aid blender overboard (I dove and recovered than one.....) I now have lanyards on anything I want to keep.

The blender, BTW, is forbidden from ever going back on the boat and you can be assured that my sextant has a lanyard.
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Old 18-02-2010, 12:12   #53
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Actually, if Captain Cook had caught an ordinary sailor *touching* a sextant much less using it, he probably would have had the man thrown in irons and interrogated in a most painful manner.

Sextants, like all navigation equipment, were often the subject of confidences and competitive intelligence among nations and navigators. Touch the navigator's chest without his invitation, and the odds were he'd kill you as a spy.

Navigation was a state secret, right down to the charts, for hundreds of years. Indeed the British charts are still Royal Crown Property, unlike US charts.
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Old 18-02-2010, 12:37   #54
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Sure, but it's MY sextant. I have a large measure of control whether it gets dropped. Not so regarding the risks to GPS.

Comes back to self-sufficiency.

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Originally Posted by hellosailor View Post
Reasons not to have a sextant:

1-If you drop it, it is toast.
2-Will tie up $400-800 or more, depending on your choices.
3-Requires some skills and either a sight reduction program/calculator, or tables

If you get a sextant, it is for intellectual exercise, like playing chess. Sure, the government could turn off GPS, the Chinese could shoot 'em all down, or the kids next door could jam it but let's come back to "If you drop the sextant" that's the same problem, isn't it? So now you need a backup sextant as well...Which will cost you as much as 2-4 GPSes, that usually still work well after being dropped.

I'm not against sextants (or chess) but as a practical matter, if the entire GPS system GOES DOWN, I suspect I'll have bigger issues, like trying to avoid warships and find a safe harbor. If all else fails, I can still figure out the compass directions and find land that way.
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Old 18-02-2010, 12:44   #55
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Hiracer, control is an aillusion at sea. Ever get your ribs slammed into a countertop or table as the boat decides to sidestep out from under you?

Same thing with whatever you are holding, or slung around your neck. Stuff gets bumped, and optical instruments are reknowned for not appreciating that.

Personally...If the entire system goes down...did you read "On The Beach"?
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Old 18-02-2010, 12:59   #56
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Hiracer, control is an aillusion at sea. Ever get your ribs slammed into a countertop or table as the boat decides to sidestep out from under you?

Same thing with whatever you are holding, or slung around your neck. Stuff gets bumped, and optical instruments are reknowned for not appreciating that.

Personally...If the entire system goes down...did you read "On The Beach"?
Control may be imperfect and incomplete, but it ain't no illusion.

And I never claimed absolute control. Just a large measure of control. Even that it matters.

I agree with the basic premise of the Pardeys: Make your boat unstoppable. That means, in part, that the boat is operable without electricity. I require the ability to navigate without electronics. In the overall scheme of things, it's not that expensive or that difficult, and the redundency makes a lot of sense to me.

And yes, I do carry a lead line too.

OTOH, I come to sailing from a different angle than most people. I learned keel boat sailing and cruising in Alaska. My first boat was up there. Many times we were truly on our own, outside radio contact and nobody else around, totally isolated. Self-sufficiency took on a very concrete meaning for me. In fact, I've sailed bays that were not even charted.

I've been in jams on the boat and gotten myself (and family) out of harms way. Lesson learned first hand. I will never change in this respect. Self sufficiency is huge for me.

Dual navigational systems seem very appropriate from my perspective. I've learned to expect the unexpected.
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Old 18-02-2010, 13:02   #57
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So to back up your sextants do you guys all carry astrolabes?

The Mariner's Astrolabe
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Old 18-02-2010, 13:14   #58
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I guess I come at the issue from a very simple, child like perspective. Two independent navigational systems are better than one.

If the back up system is not overly expensive, does not consume a lot space, and is not too esoteric, I can't find a compelling reason to leave it at home.

For me the issue is whether I bring the plastic sextant too. Got to draw the line somewhere or the whole boat fills up with spares. Haven't decided yet. Prolly not bring it.
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Old 18-02-2010, 13:18   #59
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So to back up your sextants do you guys all carry astrolabes?

The Mariner's Astrolabe
Kewl! You can download the image file and save it onboard. If you need it, bring up the file, print it out, cut it out and assemble it. A backup for your astrolabe!
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Old 18-02-2010, 13:27   #60
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However, in practice, a complete collapse of the GPS system is extremely unlikely.
All it takes is for MY electronics to go out, something that is NOT far from remote. The tropics have been doing that to boats ever since electronics were first introduced.

Sextants more lightning proof, so long as the time piece on your wrist survives (and the sextant doesn't take a direct hit and get welded). Not so with GPS units.

I've even gone as far as thought about a mechanical wrist watch stored in an aluminum box with breather holes drilled in, along with a couple of extra calculators.

And an extra handheld GPS unit in there too! LOL
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