The New and Improved Celestial Navigation Poll

[IslandHopper]

Originally Posted by deckofficer

That brings me to a question for captains with a specified tonnage license, was celestial nav required for those licenses?

From 2nd mates through to Master Unlimited, it is still a requirement here in Aus....and even though i have at my disposal some of the most high tech, big dollar Nav equipment available on the bridge, there is still a Sextant and all the tables....

[s/v Jedi]

Originally Posted by hummingway

I wonder about that. The reason I asked about dead reckoning from the middle of the Pacific is that it strikes me that trusting your compass to get you somewhere means a long sail without a clue what's below in terms of reefs and currents and above in terms of weather patterns. 2000 nm east or 2000 nm west to a major land mass. I guess you do what you can to survive but if the GPS goes out and the clocks don't you might wish you had some means to use the sky to guide you.

When there's reefs, you normally have arrived. The weather doesn't care anything about you having a sextant or not. It is actually the weather (wind direction mostly) that would decide where I go which, in your scenario, would probably be west even when that is 3000 nm. The sky is a guide for that too: follow the Sun, the Moon, Venus etc.

Of course I would try to keep DR but without a log that becomes difficult with those distances so it would be like "we should be about half way" etc. But I am not going to find and instal a Walker log anymore either

The 2000 nm wouldn't be a problem because you intended to sail that distance anyway. The only question will be "which is the land we just sighted and where is the anchorage and the bar/restaurant?"

ciao!
Nick.

[Capt.Don]

Bought a used German Freiberger Sextant in the early days of the Internet from an eBay listing in Russia. Was an interesting exchange, wire transfer, etc., but sextant arrived in mint condition. Practiced a few times and have been amazed at the accuracy!
Don

[kaimusailing]

I just got a Freiberger sextant from Craig's List and it is very nice. I have to relearn almost everything, but such things as noon sights are not too difficult.

There are a couple of books out there on Polynesian star navigation techniques and the techniques for approaching land apply to using celestial navigation. You may be off by a mile or so, but such things as birds, wave patterns, seaweed, and clouds can get you closer.

The problem is that sometimes reefs can be out of sight off the coast or the island, and sometimes they are steep to, so you will get a sounding and then hit it at the same time.

If GPS is down, you could have lost your batteries, so you need a mechanical clock. Or, if it's them, you will have no time ticks on the radio, and you need a mechanical clock. Some of the bird and wave pattern island techniques can get you to an island, then you have to negotiate the coast.

[s/v Jedi]

Originally Posted by kaimusailing

If GPS is down, you could have lost your batteries, so you need a mechanical clock. Or, if it's them, you will have no time ticks on the radio, and you need a mechanical clock. Some of the bird and wave pattern island techniques can get you to an island, then you have to negotiate the coast.

Exactly, all those with sextants must also carry an accurate mechanical clock and keep it adjusted and accurate. That said, I haven't seen a boat with both sextant and clock for a long long time! So to add to the collection, a nice hardwood box with mechanical clock for your wish lists

cheers,
Nick.

[deckofficer]

Originally Posted by IslandHopper

From 2nd mates through to Master Unlimited, it is still a requirement here in Aus....and even though i have at my disposal some of the most high tech, big dollar Nav equipment available on the bridge, there is still a Sextant and all the tables....

For the USCG it is 3rd mates through Master Unlimited, but I was curious for the specified tonnage licenses.

[msponer]

Originally Posted by s/v Jedi

Exactly, all those with sextants must also carry an accurate mechanical clock and keep it adjusted and accurate.

Well, it's pretty easy to measure latitude with a sextant and no clock. And that may be good enough for many landfalls.

Take a look at the emergency navigation books. You can also do a lot with a clock that keeps good time, but is not set to any known time. So one could theoretically keep a wind up watch packed away, and after the electropocalypse, dust it off and wind it up. You can use it to measure changes in longitude, which, if you know where you started, may be as good as the actual longitude.

It's not necessary to adjust the watch if you know how many seconds/day it gains or loses. Which is easy with a GPS, when it's working, anyways. Though I felt like using the radio time signals on WWV, the British robot lady talking with the bong-bong-bong and tick-tock in the background, was pretty cool.

[IslandHopper]

Originally Posted by deckofficer

For the USCG it is 3rd mates through Master Unlimited, but I was curious for the specified tonnage licenses.

Not sure what you mean there, possibly because we have different a system here....

Anyhow, i had better go and finish my handover notes for my relief, going on leave for a month tomorrow....

[deckofficer]

Originally Posted by IslandHopper

Not sure what you mean there, possibly because we have different a system here....

Anyhow, i had better go and finish my handover notes for my relief, going on leave for a month tomorrow....

Month on, month off, that was my sked also. Documenting any problems with equipment for the hand over, and then your off for a month, enjoy.

[nigel1]

Originally Posted by IslandHopper

Not sure what you mean there, possibly because we have different a system here....

Anyhow, i had better go and finish my handover notes for my relief, going on leave for a month tomorrow....

Me too, just punched through the ice into Norrkoping, Sweden, alongside at 0630, should be this afternoon, 5 weeks off, davits and solar panels next

[Geoduck]

GPS quit? Can't get a sun sight? DR chart went up in smoke while roasting wienies?
Fire up your EPIRB - someone will be along in a minute!
My sextant says, "U.S. Bureau of Ships" 1942 on it.
Lost? Look up in the sky and follow the jet streams!.

[Celestialsailor]

Originally Posted by Geoduck

GPS quit? Can't get a sun sight? DR chart went up in smoke while roasting wienies?
Fire up your EPIRB - someone will be along in a minute!
My sextant says, "U.S. Bureau of Ships" 1942 on it.
Lost? Look up in the sky and follow the jet streams!.

It always amazed me, the amount of people who did just that in the 70s-80s...followed the jet streams from California to Hawaii!...

[rebel heart]

Originally Posted by s/v Jedi

Come on people. I'll give it another try: in the age of exploration, a sextant was like a secret weapon and it or more primitive devices was all that was available to determine ones position. Not that there was much important about it because they did not know what was lying ahead of them... they were drawing the first charts as they went.

Ever since that day, navigators have embraced newer technologies and devices and now today the secret weapons of navigation are receivers that can work with Russian, Chinese and soon European satellite constellations in addition to the US military GPS system.

So let us assume a disaster in which a lightning strike takes out all of our electronics. Would you still have an accurate clock? Did you ever think about that? Any clock that takes a battery will be taken out by the lightning strike. I for one, must admit that I would loose all clocks aboard. Which would make my sextant only usable for the noon shot if I recall my lessons correctly (I lied.. I did get my celestial navigation paper but it's so long ago that I couldn't do it without instructions today).

So here we are and we have had this lightning strike. This does NOT put us back into the age of exploration because we are now in an emergency mode... we only need to be saved, to find safe haven and civilization; we don't need to find a West passage to India!

All we really need is a compass. On any trip I make, I only need a compass to save myself.

ciao!
Nick.

Successful navigators embrace new technology, but they don't ignore the older technology that still works. I can guess the beaufort scale pretty well by eyeball without the need for the wind indicator, and am somewhat good at judging speed down to a 1/2 knot based on the wake (if I know the boat well enough).

A couple hundred bucks and some study time. That's all this comes down to, and anyone who's buying gizmos and doo-dads for ten times the price but passing up celestial nav is really out there to me. Endless threads on here with people arguing about **** that really has zero bearing on safety at sea, and celestial navigation gets lumped in with shitting off a plank with a whole in it between the head and the bowsprit.

[deckofficer]

Hey Eric,

You can answer this from a previous post of mine........

Like I said Nick, I'm glad they dropped the code requirement for the General HAM radio license, sure don't need CW anymore. I just wonder if celestial navigation will be dropped sometime in the future for Unlimited licenses? That brings me to a question for captains with a specified tonnage license, was celestial nav required for those licenses?

[msponer]

Originally Posted by deckofficer

I just wonder if celestial navigation will be dropped sometime in the future for Unlimited licenses?

You know, when my wife was in graduate school, someone from the military came to talk about how interested they were in her groups research because it could be applied to mechanical nanocomputers. The only reason I can think a mechanical nanocomputer makes any sense is because it's immune to an EMP.

And in my software work, availability of a system is counted by the number of 9's in 99.999....%. And 5 nines, like that, is about 5 minutes a year of downtime. This is not really the number most people are interested in because it's an average over an infinite time period. What people are really interested in is "how likely is it to go down?" and "what's the longest it could reasonably be down?".

And I am not tinfoil hat, at all, and have a lot of faith in smart people with a lot of money trying hard to do things right -- as is the case with the GPS system.

But... It is possible that an electropocalypse or some kind of distributed software bug could take it out for ... days? Who knows. Think of the big Amazon web services outage last year, where a relatively minor and momentary mistake in their network topology caused tens of thousands of individual pieces to try to do the right thing on their scale, but all of them doing that on a macroscopic level added up to a kind of enormous storm (or plague of locusts eating bandwidth) that cascaded across their data centers to a scale of failure that most people did not see as possible (most folks had planned for maybe 1 data center to go down, not a whole geographic region). Even though we humans realized what happened pretty quickly and fixed the bug, backing out of it, to get all the insect-brains of individual machines and pieces of intelligence to line back up and resume the coordinated dance that they had before, took over a day.

So... for an "Unlimited Tonnage" license, I do think maybe there is value in a backup to a "1 in a 100 year" "3 day" outage (if that's the way the "how likely" and "how long" questions would be answered for the GPS system). Otherwise, what would you have? Container ships stopping dead in the water offshore and waiting for GPS to come back?