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accuracy of second hand on analog watches


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#1 peterchech

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Posted 25 January 2014 - 02:40 AM

For celestial navigation. Is the second hand on a standard quartz watch actually accurate enough to rely on when syncronized with utc? Is it actually synced with the movement? Because it never actually seems to line up exactly with the dial, seems to land in between the marks as often as not. Seems random...

#2 Gouvernail

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Posted 25 January 2014 - 03:24 AM

Consider it this way ...
If the watch gains or loses twenty four minutes a day it is only off by a second per minute.

Lousy old wind up watches ($5 Timex ) were good to about three or four minutes a day.

Really good mechanical watches were generally more like a minute a day

The Bullova Accutron came out in 1960 and the guarantee was two minutes a month

Quartz watches followed soon and some did better


My guess is the second hand on your watch with you extrapolating what it says between clicks is the least of your accuracy challenges

#3 USA190520

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Posted 25 January 2014 - 04:02 AM

The watch movement plays a huge part here, a cheap Chinese Quartz will be as accurate as the wall clock in your kitchen- so you could, in theory, navigate your way to a late night snack if needed.

Better quartz movements usually Japanese have finer movements, some are quite good. Bulova is a good example, so in theory you could venture out for sushi and get back safely

Mechanical watches or automatics vary in accuracy depending on the movement used and the maintenance they receive- just like all machines they require tune ups and care-so in theory you may be able to cross an ocean or maybe not...

Look at the Bulova precisionist line for a good accurate quartz at a decent price point.

#4 peterchech

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Posted 25 January 2014 - 04:19 AM

Thats not really the question.

I mean the second hand itself.

My digital quartz watch loses exactly 6 seconds per month at room temperature. So im just wondering if sucj a measurement Is possible on an analog watch

#5 USA190520

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Posted 25 January 2014 - 04:31 AM

Why wouldn't it be?

The precisionist movement sweeps the second hand at 16beats a second, not the one big tick your average $50 Fossil has.

Your question depends on the quality of the analog quartz you're using at the time.

#6 SloopJonB

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Posted 25 January 2014 - 04:31 AM

What's a watch? :P



#7 Rex II

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Posted 25 January 2014 - 04:53 AM

What's a watch? :P

This

 

51Y3GXQZLKL._SL500_AA300_.jpg



#8 silent bob

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Posted 25 January 2014 - 05:51 AM

Even a broken Timex is right twice a day!

#9 DA-WOODY

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Posted 25 January 2014 - 05:56 AM

Rather than trust the reliability of a second hand

Why don't you just buy a new one ????

#10 chewey

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Posted 25 January 2014 - 06:35 AM

Before you go Celestial Navigating, MEASURE YOUR ERROR!!!!     That is not Rocket Science!!!



#11 Shaggy

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Posted 25 January 2014 - 07:21 AM

My watch with 10 diamonds on it says it is 5:00 somewhere...  so what's your problem??  



#12 Par Avion

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Posted 25 January 2014 - 07:57 AM

what sunglasses are best with this watch with celestial navigating in mind?



#13 soak_ed

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Posted 25 January 2014 - 08:56 AM

WTF, this is more inane then the endless parsing the rules questions.



#14 Presuming Ed

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Posted 25 January 2014 - 10:28 AM

Before you go Celestial Navigating, MEASURE YOUR ERROR!!!!     That is not Rocket Science!!!

 

Must do Stokey Woodall's celestial course. http://international...-at-the-skypad/

 

For celestial navigation. Is the second hand on a standard quartz watch actually accurate enough to rely on when syncronized with utc? Is it actually synced with the movement? Because it never actually seems to line up exactly with the dial, seems to land in between the marks as often as not. Seems random...

 

As someone who's never done celestial, I always understood that the point of a chronometer wasn't that it didn't gain or lose time, but that it gained or lost time at a constant rate, which you measure before you leave. 

 

And then there's the thing about having one watch or three. But not two. 



#15 Autograph

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Posted 25 January 2014 - 02:00 PM

No.

I will qualify that.

It depends.

#16 ancientseawolf

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Posted 25 January 2014 - 03:05 PM

It's all "good enough for government work" .  My everyday Timex is better at keeping accurate time than the navigator's watch I navigated with 60 years ago.  Just maintain a correction log.  The second hand is more accurate than you can read at sea anyhow.



#17 Moclips

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Posted 25 January 2014 - 03:45 PM

Use the clock on your GPS. Is very accurate.



#18 WarBird

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Posted 25 January 2014 - 04:29 PM

Use the clock on your GPS. Is very accurate.

:lol:



#19 sledracr

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Posted 25 January 2014 - 04:40 PM

In answer to the OP's question.... yes, it is accurate enough.  Keep a log so that you know how much time it gains/loses, but... if you get the time right to the nearest second, you're doing fine.

 

I had a piece-of-crap Casio digital watch in my sextant case for years, with a log keeping track of adjustments.  It gained (on average) about 4 seconds a month, and so (in general) all I had to do was add a second in my reduction calcs for each week since I'd sync'd it, and my LOPs came out just fine.



#20 peterchech

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Posted 26 January 2014 - 02:36 AM

WTF, this is more inane then the endless parsing the rules questions.


So inane you posted a useless comment?

#21 jerryj2me

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Posted 26 January 2014 - 05:05 AM

If you want to go old school, sync yourself to the WWV or WWVH SW time broadcast.

 

http://tf.nist.gov/stations/wwvh.htm

 

Re-sync your watch every day and see what your gain-loss is per day and you can interpolate from there.

If you watch is gaining 5 seconds a day, and your last time sync was 8 hours back then subtract 5(8/24) seconds from your time mark.

 

Last time I did this sort of thing we would get the WWV sync adjust before going on deck to do elevation sightings.

 

Once you did the math the time accuracy was not the problem in location reduction it was the getting a consistent elevation number.

 

Celestial navigation and Morse code, two of my more useful skills! (LOL!)



#22 peterchech

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Posted 26 January 2014 - 03:43 PM

If you want to go old school, sync yourself to the WWV or WWVH SW time broadcast.
 
http://tf.nist.gov/stations/wwvh.htm
 
Re-sync your watch every day and see what your gain-loss is per day and you can interpolate from there.
If you watch is gaining 5 seconds a day, and your last time sync was 8 hours back then subtract 5(8/24) seconds from your time mark.
 
Last time I did this sort of thing we would get the WWV sync adjust before going on deck to do elevation sightings.
 
Once you did the math the time accuracy was not the problem in location reduction it was the getting a consistent elevation number.
 
Celestial navigation and Morse code, two of my more useful skills! (LOL!)


Haha unfortunately not skills that will get u laid! But im trying to learn anyway...

I have synced my digital watch with nist. My question was whether anyone knows if the second hand (60 seconds in a minute, that hand) on a regular quartz analog watch is accurate (ie coordinated with the movement itself), or if it is really just for show.

#23 DRDNA

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Posted 26 January 2014 - 04:06 PM

well, my seconds hand on my Seiko kinetic dive watch lines up right on the marks every time, so I'd say "yes" for this watch.



#24 Moonduster

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Posted 26 January 2014 - 06:48 PM

Peter,

 

The second hand goes around the face exactly once per minute of time on the watch. In most watches, the second hand cannot be adjusted. No one doing navigation cares about the time shown on the face of the watch - it's only used for relative time keeping. To do reliable navigation, you need a quality below-deck time piece or access to a reference time like WWV.

 

One uses it to note the time of the sight. Once you get below deck, you use the reference time and the watch time since your sight to compute the actual time of your site. The watch won't gain or loose enough time to screw up your site in those 10 to 20 minutes - remember, 4 seconds is a mile and good celestial navigation is more like plus/minus 10 miles.

 

The whole wristwatch thing is really a pain in the ass because you have to make note of the time. Instead, use a watch with a chronometer or buy a cheap stop watch. Start the timer at the time of the site and stop the timer when you get the time fix from WWV. It's much, much easier. You'll get better time accuracy if you have a rhythm from mark-to-click, counting out three or four seconds from when the sight is taken until you stop the watch so that it's always a known delay rather than racing to do it as soon as possible and never knowing if that was 2 seconds or 5.

 

But the real question is ... why bother? You can buy 10 hand held GPS for less than the price of a reasonable sextant.



#25 SemiSalt

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Posted 26 January 2014 - 07:27 PM

I agree with others that the if you do the time corrections correctly, the accuracy of the second should not be a problem. My experience is that failure of the timepiece as a whole is a bigger risk, not perhaps I'm just bitter because my $350 Tissot has a habit of stopping for no particular reason and two trs back to Tissot didn't get it fixed.

I also agree about redundent GPS units, but if I was going celestial, I would have redundant, decent quality quartz watches and multiple programmable calculators.

#26 Somebody Else

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Posted 26 January 2014 - 07:52 PM

remember, 4 seconds is a mile and good celestial navigation is more like plus/minus 10 miles.

 

+/- 10 miles?!?! eek.gif

 

Moonie, you're doing it wrong! I get better than that in 4 meter storm swells. In smooth water it's more like +/- a mile... or less.

 

There are two difficult aspects to celestial navigation:

  1. The physical aspect -- learning to recognize when a site is "good." In a big sea, this takes lots of sites with check-marks next to the ones which "felt right." The more you do it, the more adept you become at catching good accurate horizons.
  2. Adding and subtracting base-60. Ugh! If all time was was measured in hours.decimal_hours, celestial would be a doddle.

The rest can be done with decently crafted fill-in-the-blanks forms.

 

In open ocean, I would frequently take a single site if I knew it was a good one. If I was off by two miles, 700 mile from the nearest land, I didn't lose much sleep over it.

 

 

 

The whole wristwatch thing is really a pain in the ass because you have to make note of the time. Instead, use a watch with a chronometer or buy a cheap stop watch. Start the timer at the time of the site and stop the timer when you get the time fix from WWV. It's much, much easier. You'll get better time accuracy if you have a rhythm from mark-to-click, counting out three or four seconds from when the sight is taken until you stop the watch so that it's always a known delay rather than racing to do it as soon as possible and never knowing if that was 2 seconds or 5.

 

Yep. A stopwatch with lap-timing feature is great. Sync it with the chron before going up, then punch the "lap" button, make a note of it, then punch "resume" and take your next site. If you're not solo, have another person do the site logging as you call "Mark!" I taught a newbie during a crossing and after a few days I was doing the timing for her. Getting her involved early in the process was key in keeping her interested.

 

 

 

why bother? You can buy 10 hand held GPS for less than the price of a reasonable sextant.

 

Why bother? You need a reason? How about, the Chinese are proceeding full speed ahead with anti-satellite weapons. Is that a good enough reason?

 

Even with 10 GPS receivers, you're still putting all your eggs in 1.5 baskets; you've got hardware redundancy covered, but once the system gets taken down or jammed, you're back to pre-Columbus techniques.

 

Plot your positions on a chart (or plotting pad... can you still buy those?) and keep a log of speed, course, wind & sea state, etc. Cover all your bases. If those poor blokes on Aegean had been plotting on a chart they would have never laid in a course directly for Salsipuedes Point which, as it just so happened, had the north tip of North Coronado Island directly on the rhumb line.



#27 jerryj2me

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Posted 26 January 2014 - 08:19 PM

Even with 10 GPS receivers, you're still putting all your eggs in 1.5 baskets; you've got hardware redundancy covered, but once the system gets taken down or jammed, you're back to pre-Columbus techniques.

 

Plot your positions on a chart (or plotting pad... can you still buy those?) and keep a log of speed, course, wind & sea state, etc. Cover all your bases. If those poor blokes on Aegean had been plotting on a chart they would have never laid in a course directly for Salsipuedes Point which, as it just so happened, had the north tip of North Coronado Island directly on the rhumb line.

 

Amen on the above. I was at the local boat show yesterday to look at a friends new Clorox bottle. State of the art everything and brand new. Electronic or electric everything navigation, winches, furling systems, you name it.

 

With a 48 foot boat they had included a micro chart table. (11x17 inches or less no joke) and it was evident that the strategy of the design was set up to be 100% dependent on electronic navigation. 

 

I looked the boat over and had to ask one question: What are you going to do when the electronics goes dead?

 

Blank look.



#28 Somebody Else

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Posted 26 January 2014 - 10:03 PM


I looked the boat over and had to ask one question: What are you going to do when the electronics goes dead?

 

Blank look.

 

You are a salesman's nightmare!  lol.gif



#29 jerryj2me

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Posted 26 January 2014 - 10:18 PM


I looked the boat over and had to ask one question: What are you going to do when the electronics goes dead?

 

Blank look.

 

You are a salesman's nightmare!  lol.gif

You bet, but then I've been on a boat with 6 inches of water down below

and the electronics out due to that sloshing around and causing havoc.

 

It doesn't take much to kill the electronics.



#30 peterchech

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Posted 28 January 2014 - 05:06 AM



I looked the boat over and had to ask one question: What are you going to do when the electronics goes dead?
 
Blank look.

 
You are a salesman's nightmare!  lol.gif
You bet, but then I've been on a boat with 6 inches of water down below
and the electronics out due to that sloshing around and causing havoc.
 
It doesn't take much to kill the electronics.

A leaky stanchion took out my autopilot and chart plotter 30 miles south of east Hampton Long Island. Handheld backup saved the day.

But being way out of sight of land, in the dark, I realized how clueless we would be if that didn't work, or ran out of batteries.

I think we all rely way too much on gps and not just for offshore also coastally. How many sailors know the magnetic deviation where they sail, or could ded reckon using celestial/swell patterns/etc if the compass failed or it's light went out?

I'll never have time in my real life to master celestial navigation, but I find tremendous value in at least learning to take noon sites and Polaris, and get an understanding of the basics of how our earth spins and of the celestial bodies.

#31 Somebody Else

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Posted 28 January 2014 - 05:26 AM

I'll never have time in my real life to master celestial navigation, but I find tremendous value in at least learning to take noon sites and Polaris, and get an understanding of the basics of how our earth spins and of the celestial bodies.

 

It's not that hard. The physical aspect of getting a good shot needs to be understood and practiced.

 

Other than that, it's just a set of procedures -- filling out a well laid-out form and adding Base-60 (hours/minutes/seconds) is all there is. I didn't like the forms you could buy so I ended up making my own.

 

I took two courses at my local community college (Orange Coast College) either for free or damn near next to free -- I can't remember; it's been 30 years...! The instructors knew their material well and could answer all of my questions. The first course was the basics -- mostly sun sights and running fixes. The second class worked with moon, star, and planet sights and refined techniques.

 

Reducing the sights hunched over a chart table in 50-knot winds and large swells is not a very comfortable activity. I pretty-much do not get sea sick, but the closest I came was double-checking my addition in storms.



#32 SloopJonB

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Posted 28 January 2014 - 06:30 AM

 


I looked the boat over and had to ask one question: What are you going to do when the electronics goes dead?

 

Blank look.

 

You are a salesman's nightmare!  lol.gif

You bet, but then I've been on a boat with 6 inches of water down below

and the electronics out due to that sloshing around and causing havoc.

 

It doesn't take much to kill the electronics.

 

That's what I used to think - you'd be a fool to go offshore without a sextant. Then I spoke to a friend who crewed a 42' from Vancouver to S.F. before GPS. They didn't get a single shot the whole way - heavy overcast for 12 days. They had to DR the entire trip. The Pardey's described their trip across the north Pacific in Seraffyn from Japan to Victoria - 45 days with only 2 very iffy sights through overcast.

 

Multiple GPS units - a plotter, a couple of handhelds and phones with GPS apps would seem to be better - I'd have paper as well of course and do old style logging on the paper so one could DR if GPS went out.

 

Seems like it would usually be better and, at worst, be no worse than the old ways.



#33 Swanno (Ohf Shore)

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Posted 28 January 2014 - 06:59 AM

Use the clock on your GPS. Is very accurate.


Took me second but then I very much LOL'd

#34 Moonduster

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Posted 28 January 2014 - 06:30 PM

Electronics failures are inevitable - that's why a few hand held GPS receivers and a pile of batteries and a few paper charts make good sense.

 

I'd suggest it's far more likely that the only person who knows how to do sight reductions might fall over board than that the GPS system fails. In fact, it's probably more likely that you'll get holed by a whale, run down by a commercial ship, get hit by debris falling from outer space or fall into a gas bubble from an erupting submarine volcano than experience a widespread outage of the GPS system during any given passage.

 

Like it or not, celestial navigation has about as much place on a modern cruising boat as an RDF. Is it fun to use, a nice curiosity to show your friends, a way to keep in touch with tradition - sure, no question about it. But it's no longer a reasonable approach to backup navigation.

 

For those who do carry sextants, almanacs, plotting sheets and sight reduction tables - tell me this. Is your almanac up to date? Do you carry all these things in addition to a couple of hand held GPS? Do you also know morse code?

 

And to the guy who says his offshore sights are more accurate than several miles, let's remember that Cook had Tahiti off by five miles - and that's after three visits, thousands of observations from dry land and a transit of Venus.



#35 NoStrings

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Posted 28 January 2014 - 07:06 PM

In 2010 we dumped the electronics about 30 miles out of SFO. 9 days later we arrived safely in Kaneohe with my Garmin 76CS and a box of AA batteries. The only difficulty we had was missing our gybe point by 6 hours because we had no working wind instruments.

As for "jamming" can you please explain in your own words how this works? Because in all of my time I've always understood that jamming is targeted at the receiver, not the transmitter. IOW, for your GPS to be "jammed", you need to be operating in an area where someone has a jammer degrading GPS. In that case, I might suggest that you have bigger problems than your GPS.

#36 durundal

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Posted 29 January 2014 - 05:21 AM

why bother? You can buy 10 hand held GPS for less than the price of a reasonable sextant.

 
Why bother? You need a reason? How about, the Chinese are proceeding full speed ahead with anti-satellite weapons. Is that a good enough reason?
 
Even with 10 GPS receivers, you're still putting all your eggs in 1.5 baskets; you've got hardware redundancy covered, but once the system gets taken down or jammed, you're back to pre-Columbus techniques.
 
Plot your positions on a chart (or plotting pad... can you still buy those?) and keep a log of speed, course, wind & sea state, etc. Cover all your bases. If those poor blokes on Aegean had been plotting on a chart they would have never laid in a course directly for Salsipuedes Point which, as it just so happened, had the north tip of North Coronado Island directly on the rhumb line.

If the Chinese manage to take out the entire GPS constellation it'd be a real shooting war with a lot of other things to be worried about even if you had a celestial fix. And as was said, a sextant isn't much use when it's overcast or you're in a fog near some islands, where a GPS will work just fine. There was a boat that went on the rocks outside the Richmond breakwater this summer at night because the owner was trying to tell lights apart and wasn't looking at his electronic chart. It really isn't often you get to buy a gadget and use a $15 billion dollar system for free.

GPS jamming refers to local receiver spoofing with a fake signal that overwhelms the broadcast ones, not realistic to do on orbit jamming as your jamming satellite has the same issues as the real ones with regard to SWaP to have a stronger signal, and you'd need to cover a majority of the constellation's satellites.

#37 Somebody Else

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Posted 29 January 2014 - 06:21 AM

Re: jamming:

 

You can get a fix with as little as 0.032 watts at the receiver. So a jamming signal at, say, 1 watt would be 30x more powerful than the weaker received signal. It has been mentioned that the jammer would need to be pretty close to the receiver to allow line-of-site without using a satellite system. Sure. Like on shore as you are approaching landfall. A powerful jammer can be made by modifying off-the-shelf hand-held xceivers. The most effective jammers are just barely more powerful than the legitimate signals, emitting data just slightly different than the legit data.

______

 

I really like GPS. I was an early adopter and have several hand-held units. But if I am in unfamiliar waters, I plot my positions on paper regardless of how I arrive at those positions. And I always corroborate lights and other physical features with my perceived position so I have multiple things to fall back on should things go wrong.



#38 durundal

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Posted 29 January 2014 - 06:44 AM

Do you check your almanacs before each voyage to make sure they haven't been tampered with by these unnamed adversaries, too? That would be a lot more sneaky than broadcasting a signal showing where you are.

#39 P_Wop

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Posted 29 January 2014 - 12:19 PM

Back OT...

 

As much as I loved celestial, it really is a bit gone now.  As others have said, if GPS goes out (atmospheric nuclear explosion, EMP, Chinese, meteor impact, whatever...) then there are other problems to be looked at.

 

However celestial did save our bacon in the 79 Fastnet when all the electronics (and batteries) when to ratshit.

 

But for the OP:

 

Yes, use the watch as a "repeater" for the master chron below, with a known difference between your watch sweep second hand and the chron second.  Just one more correction to add, but a simple one.

 

And sun sights are so much easier in a seaway if you take several, i.e. a dozen or more, and graph them on a bit of square grid paper, time along the bottom, and altitude up the side.  You can immediately see (and exclude) the outlying error sights, and when you draw a line through the remaining ones you can just choose a convenient whole-minute point on the graph to start your reduction.  You immediately gain an order of magnitude improvement on the sight accuracy.  



#40 Steam Flyer

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Posted 29 January 2014 - 01:22 PM

... ..

I really like GPS. I was an early adopter and have several hand-held units. But if I am in unfamiliar waters, I plot my positions on paper regardless of how I arrive at those positions. And I always corroborate lights and other physical features with my perceived position so I have multiple things to fall back on should things go wrong.

 

In other words, n-n-navigating?

 

The thing about all this "GPS does the navigating for you" attitude is that it is based on a lack of comprehension what it takes to safely and efficiently get a vessel from one point on the globe to another. Yes you can look at a little screen and usually see where you are; I can see where people think that's "navigating" because that's what we envision navigators doing, making little marks on a chart where he thinks the boat is.

 

Navigation is the art of correctly answering 3 fundamental questions: "Where am I"  and "What direction should I steer?" and "What hazards are in my path?"

 

GPS is a magnificent tool. However owning a GPS does not make you a navigator any more than owning a fine saw makes you a carpenter. GPS can only answer 1 of those questions, when it's working. And there are a LOT of things that make a GPS not work without going into the issue of jamming or a-sat missiles.

 

One of the best tools included in a GPS is a watch so incredibly accurate it would have been a science fiction dope-dream to previous generations. With regard to the OP's question, an analog watch can also be a very good navigator's tool, but like a saw it needs sharpening rating. Take care of your tools and they take care of you.

 

FB- Doug



#41 Life Buoy 15

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Posted 29 January 2014 - 07:06 PM

Use the clock on your GPS. Is very accurate.


Took me second but then I very much LOL'd

One of my celestial nav students came up with a great business plan. He was going to develop a sight reduction app for an IPhone.
I told him not to quit his day job just yet.

#42 Life Buoy 15

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Posted 29 January 2014 - 07:13 PM

Back OT...
 
 
And sun sights are so much easier in a seaway if you take several, i.e. a dozen or more, and graph them on a bit of square grid paper, time along the bottom, and altitude up the side.  You can immediately see (and exclude) the outlying error sights, and when you draw a line through the remaining ones you can just choose a convenient whole-minute point on the graph to start your reduction.  You immediately gain an order of magnitude improvement on the sight accuracy.  


^ Bingo. This is what I teach and slightly more accurate than Somebody else's ' felt good' technique!

#43 jerryj2me

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Posted 29 January 2014 - 07:22 PM

Some comments about the extra GPS units as backups -

 

Fresh batteries stored outside the GPS (avoid leaking old batteries in the units)

GPS units in sealed watertight cases.

 

Not fully old school here but If there's 3 different ways of determining where I am at and what is around me and they all agree, thats a good thing.



#44 Ishmael

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Posted 29 January 2014 - 07:38 PM

Just as an FYI...the second hand on most analog watches is friction-fit onto the center post. You can adjust it to hit the marks if it matters to you.



#45 Presuming Ed

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Posted 29 January 2014 - 08:00 PM

Fresh batteries stored outside the GPS (avoid leaking old batteries in the units)

GPS units in sealed watertight cases.

 

Always though best practice was to have a spare unit in a metal box - a Faraday cage - to guarantee that it would work after a lightning strike. 



#46 Steam Flyer

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Posted 29 January 2014 - 08:02 PM

Some comments about the extra GPS units as backups -

 

Fresh batteries stored outside the GPS (avoid leaking old batteries in the units)

GPS units in sealed watertight cases.


... ...

 

Might be best to keep batteries in them, but check the unit once every month or so & let it lock on. Update constellation plus keeping the caps on the chip charged.

 

Also storing them in a metal box or wrapping in foil, then putting into watertight container. I've known lightning to fry everything electrical on a boat, much less all the electronics.

 

 

... ...

 

Not fully old school here but If there's 3 different ways of determining where I am at and what is around me and they all agree, thats a good thing.

 

That also is part of "navigating" ... the prudent mariner will not rely on a single source of data in making decisions on course/speed. Sort of like the way it's smart to treat all guns as loaded until proven otherwise

 

FB- Doug

.



#47 bgytr

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Posted 29 January 2014 - 08:12 PM

Let's start another thread on the accuracy of second hand analog watches...

#48 Life Buoy 15

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Posted 29 January 2014 - 09:32 PM

Some comments about the extra GPS units as backups -
 
Fresh batteries stored outside the GPS (avoid leaking old batteries in the units)
GPS units in sealed watertight cases.

... ...

 
Might be best to keep batteries in them, but check the unit once every month or so & let it lock on. Update constellation plus keeping the caps on the chip charged.
 
Also storing them in a metal box or wrapping in foil, then putting into watertight container. I've known lightning to fry everything electrical on a boat, much less all the electronics.
 
 

... ... 
Not fully old school here but If there's 3 different ways of determining where I am at and what is around me and they all agree, thats a good thing.

 
That also is part of "navigating" ... the prudent mariner will not rely on a single source of data in making decisions on course/speed. Sort of like the way it's smart to treat all guns as loaded until proven otherwise
 
FB- Doug
.

So for hundreds of years those navigating solely buy celestial nav were not being prudent?

#49 DA-WOODY

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Posted 29 January 2014 - 09:43 PM

 

Some comments about the extra GPS units as backups -
 
Fresh batteries stored outside the GPS (avoid leaking old batteries in the units)
GPS units in sealed watertight cases.

... ...

 
Might be best to keep batteries in them, but check the unit once every month or so & let it lock on. Update constellation plus keeping the caps on the chip charged.
 
Also storing them in a metal box or wrapping in foil, then putting into watertight container. I've known lightning to fry everything electrical on a boat, much less all the electronics.
 
 

... ... 
Not fully old school here but If there's 3 different ways of determining where I am at and what is around me and they all agree, thats a good thing.

ockquote>  
That also is part of "navigating" ... the prudent mariner will not rely on a single source of data in making decisions on course/speed. Sort of like the way it's smart to treat all guns as loaded until proven otherwise
 
FB- Doug
.

So for hundreds of years those navigating solely buy celestial nav were not being prudent?

 

 

 

GPS was waaaay too expensive

 

and not all that accurate

 

till they invented the orbateing thingies 



#50 Somebody Else

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Posted 29 January 2014 - 09:53 PM

And sun sights are so much easier in a seaway if you take several, i.e. a dozen or more, and graph them on a bit of square grid paper, time along the bottom, and altitude up the side.  You can immediately see (and exclude) the outlying error sights, and when you draw a line through the remaining ones you can just choose a convenient whole-minute point on the graph to start your reduction.  You immediately gain an order of magnitude improvement on the sight accuracy.  


^ Bingo. This is what I teach and slightly more accurate than Somebody else's ' felt good' technique!

 

You missed the part about taking multiple sights and marking the ones which 'felt good'.

 

Once one gets a feel for it, it becomes pretty common to have those 'good' sights to line up in a row with the not-so-good sights being the outliers.



#51 Somebody Else

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Posted 29 January 2014 - 10:02 PM

So for hundreds of years those navigating solely buy celestial nav were not being prudent?

 

Nobody ever navigated solely by celestial.

 

They were doing DR, observing physical features of the sea and wind and land and bottom (when close enough).

 

Celestial has always been one more tool in the kit.



#52 Steam Flyer

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Posted 29 January 2014 - 10:13 PM

 

Some comments about the extra GPS units as backups -
 
Fresh batteries stored outside the GPS (avoid leaking old batteries in the units)
GPS units in sealed watertight cases.

... ...

 
Might be best to keep batteries in them, but check the unit once every month or so & let it lock on. Update constellation plus keeping the caps on the chip charged.
 
Also storing them in a metal box or wrapping in foil, then putting into watertight container. I've known lightning to fry everything electrical on a boat, much less all the electronics.
 
 

... ... 
Not fully old school here but If there's 3 different ways of determining where I am at and what is around me and they all agree, thats a good thing.

ockquote>  
That also is part of "navigating" ... the prudent mariner will not rely on a single source of data in making decisions on course/speed. Sort of like the way it's smart to treat all guns as loaded until proven otherwise
 
FB- Doug
.

So for hundreds of years those navigating solely buy celestial nav were not being prudent?

 

 

Hey, they were using more than one star... waddaya want?

 

on a side note, I was teaching some of our advanced students (teenagers) to use a sextant, taking altitudes of some handy fixed objects (radio tower & water tower) as well as the sun. They all caught on to the physical technique of it just fine, but one boy was confused by the vernier readout and asked "so, this side tells you the latitude and the other side tells you the longitude?"  I need to work on explaining stuff more clearly.

;)

 

FB- Doug



#53 mustang__1

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Posted 29 January 2014 - 10:19 PM

ok, so all electronics are fried, but you have your sextant and up to date tables and charts. How do you do your DR without the boatspeed log? guestimate? Make an actual log out of a cocnut and Ginger's underwear? I actually know the fundamentals, thanks to flying, for DR (using a mechanical computer, E6B, doing it all by hand is not something i've done), but thei seem to recall that speed is rather important part of the calculation... 



#54 DA-WOODY

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Posted 30 January 2014 - 01:34 AM

I have an Aircraft Sextant in a green cube :o  



#55 Life Buoy 15

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Posted 30 January 2014 - 03:19 AM

So for hundreds of years those navigating solely buy celestial nav were not being prudent?

 

Nobody ever navigated solely by celestial.

 

They were doing DR, observing physical features of the sea and wind and land and bottom (when close enough).

 

Celestial has always been one more tool in the kit.

 

 

Really? Nobody ever navigated solely by celestial? Well I certainly crossed several oceans back in the day doing just that. Yes and the least accurate of all navigational techniques, the DR, was part of that. Not having a 4000 meter lead line and eye sight that could make out coastal features from 1000 miles out that was all we had. But the world has moved on. As I said before, why start using this newfangled compass when the good old lodestone has served us so well.

I have taught navigation for the last 20 years, and the 20 years prior to that I, like most people of my age used celestial navigation for fixing our position in the absence of anything else. Personally it I found it to be a pain in the arse, standing there holding a 1.5 kilo weight up to your eye on a rolling yacht, then having to fuck around at the chart table to pot a dot on the chart. Some of you beardy types might have (and still do) enjoy that kind of thing but the convenience of fixing the position instantly with a degree of accuracy never before known, well, only a dickhead would chose to rely on a more tedious and less accurate method. Yes we are talking only about fixing position - all that celestial navigation does - not shaping a safe course to steer. (Of course you can do this quickly and safely on a chart plotter if you have the computer skills of a retarded 7 year old)

 

GPS is safe and reliable, in the right hands. I firmly believe in and teach a thorough understanding of chart knowledge, tides, tidal streams, shaping a course to steer and pilotage techniques. I don't bother dwelling too much on 'doubling the bow angle' or 'distance of by vertical sextant angle' anymore. And the last thing I want my students doing is fixing there position by DR (or EP for that matter) alone when a glance at their phone will be much more accurate for fucks sake.

And once they get that I show how to use their chart plotter. The redundancy example is a no brainer. Even most shorthanded offshore yachts these days have a hard wired unit, a battery operated hand held, a laptop, an IPad and 2 IPhone.

That's 6 chart plotters- all independently fed amps. (You can cross an ocean on two double A batteries after all. you only need to turn it on once a day!) Put one in a Faraday cage if you must, wrap one in the Koran or sheep’s entrails, whatever turns you on. Since you didn't take 6 sextants, 6 almanacs, 6 chronometers and 6 copies of the chart to sea with you, the GPS users are much better off than you Beardy types with your pipes and your walker log's. So we can discard the "What if we lose power" argument against GPS.

Now for some fun.

 

'What if the Chinese blow up all the GPS satellites?" What are you smoking? Let me tell you a little story. In China there is a Mr Chow. He is the manager of 'The Peoples power station No 126' Mr Chow needs lots of cheap coal to run his power station so he can keep his boss Mr Chew (Controller of the Peoples power stations in onebungthong province) happy. If Mr Chew is happy he gets to keep his job and flash apartment with the inside toilet. He also needs to keep Mr Lee happy. Mr Lee is a local 'Businessman' and party member and Mr Chow keeps him happy by giving him free power. If Mr Chow keeps Mr Lee happy Mr Lee supplies Mr Chow with girls and doesn't have him pushed into the coal furnace.

Now in the Australian outback there is a chap named Kevin. Kevin used to drive a digger at the blue sky coal mine but since he was replaced by a robotic GPS digger, he just sits in the pub all day. With Wayne who used to drive the trucks and Frank who used to drive the trains. But thanks to GPS the cost of digging up the coal and sending it to China is cheaper. So Mr Chow can make enough power to keep both Mr Chew and Mr Lee happy and keep playing the beast with two backs with Ling May in his office each Tuesday night. In other words WHY THE FUCK WOULD CHINA WANT TO DIS ABLE THE GPS SYSTEM?

Do you also lose sleep at night worrying about a Zombie Apocalypse? It's much more likely.

And as for jamming the system, mate you really got to stop reading so much Clive Cussler. All that pot is making you paranoid dude.

 

GPS is the new Harrisons Clock mate. It’s better than what came before and you should embrace it. If it makes you beardy types happy, then wave your sextants in good health.

But drop the crap about GPS not being as reliable as Celestial Navigation.

End rant.

 

 



#56 DA-WOODY

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Posted 30 January 2014 - 03:40 AM

^^^^^  I hear there are Monster Snakes heading to SoCal

 

but they have allot of attorneys to pass in LA on the way to DAGO

 

why would they leave LA ???



#57 Somebody Else

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Posted 30 January 2014 - 03:44 AM

GPS is the new Harrisons Clock mate. It’s better than what came before and you should embrace it. If it makes you beardy types happy, then wave your sextants in good health.

 

But drop the crap about GPS not being as reliable as Celestial Navigation.

 

End rant.

 

How can you read those things into my posts?

 

As I've stated multiple times in this thread, I LOVE GPS. I use it a LOT. I program the displays on my hand-held to to enable me to feed my skipper EXACTY what he needs to WIN RACES without all the interpretive BS and distractions. I use it to pick shifts, when to tack and jibe, how to stay in favorable current, etc.. My skipper is confident in my ability to use the tools at my disposal and we have the rooms-full of trophies to back it up.

 

People accuse me of relying too much on GPS and think that if they have the same unit or same verified waypoints, they can beat me. But when it matters, I back up my fixes with other sources. That's just prudence.

 

I haven't used my sextant in 20 years.



#58 Life Buoy 15

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Posted 30 January 2014 - 04:06 AM

No worries then. Now about those Chinese.....

#59 Somebody Else

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Posted 30 January 2014 - 04:24 AM

No worries then. Now about those Chinese.....

 

I don't like 'em.



#60 Leka

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Posted 30 January 2014 - 04:46 AM

 

So for hundreds of years those navigating solely buy celestial nav were not being prudent?

 

Nobody ever navigated solely by celestial.

 

They were doing DR, observing physical features of the sea and wind and land and bottom (when close enough).

 

Celestial has always been one more tool in the kit.

 

 

Really? Nobody ever navigated solely by celestial? Well I certainly crossed several oceans back in the day doing just that. Yes and the least accurate of all navigational techniques, the DR, was part of that. Not having a 4000 meter lead line and eye sight that could make out coastal features from 1000 miles out that was all we had. But the world has moved on. As I said before, why start using this newfangled compass when the good old lodestone has served us so well.

 

 

 

I have taught navigation for the last 20 years, and the 20 years prior to that I, like most people of my age used celestial navigation for fixing our position in the absence of anything else. Personally it I found it to be a pain in the arse, standing there holding a 1.5 kilo weight up to your eye on a rolling yacht, then having to fuck around at the chart table to pot a dot on the chart. Some of you beardy types might have (and still do) enjoy that kind of thing but the convenience of fixing the position instantly with a degree of accuracy never before known, well, only a dickhead would chose to rely on a more tedious and less accurate method. Yes we are talking only about fixing position - all that celestial navigation does - not shaping a safe course to steer. (Of course you can do this quickly and safely on a chart plotter if you have the computer skills of a retarded 7 year old)

 

 

 

 

 

GPS is safe and reliable, in the right hands. I firmly believe in and teach a thorough understanding of chart knowledge, tides, tidal streams, shaping a course to steer and pilotage techniques. I don't bother dwelling too much on 'doubling the bow angle' or 'distance of by vertical sextant angle' anymore. And the last thing I want my students doing is fixing there position by DR (or EP for that matter) alone when a glance at their phone will be much more accurate for fucks sake.

 

And once they get that I show how to use their chart plotter. The redundancy example is a no brainer. Even most shorthanded offshore yachts these days have a hard wired unit, a battery operated hand held, a laptop, an IPad and 2 IPhone.

 

That's 6 chart plotters- all independently fed amps. (You can cross an ocean on two double A batteries after all. you only need to turn it on once a day!) Put one in a Faraday cage if you must, wrap one in the Koran or sheep’s entrails, whatever turns you on. Since you didn't take 6 sextants, 6 almanacs, 6 chronometers and 6 copies of the chart to sea with you, the GPS users are much better off than you Beardy types with your pipes and your walker log's. So we can discard the "What if we lose power" argument against GPS.

Now for some fun.

 

 

 

'What if the Chinese blow up all the GPS satellites?" What are you smoking? Let me tell you a little story. In China there is a Mr Chow. He is the manager of 'The Peoples power station No 126' Mr Chow needs lots of cheap coal to run his power station so he can keep his boss Mr Chew (Controller of the Peoples power stations in onebungthong province) happy. If Mr Chew is happy he gets to keep his job and flash apartment with the inside toilet. He also needs to keep Mr Lee happy. Mr Lee is a local 'Businessman' and party member and Mr Chow keeps him happy by giving him free power. If Mr Chow keeps Mr Lee happy Mr Lee supplies Mr Chow with girls and doesn't have him pushed into the coal furnace.

 

Now in the Australian outback there is a chap named Kevin. Kevin used to drive a digger at the blue sky coal mine but since he was replaced by a robotic GPS digger, he just sits in the pub all day. With Wayne who used to drive the trucks and Frank who used to drive the trains. But thanks to GPS the cost of digging up the coal and sending it to China is cheaper. So Mr Chow can make enough power to keep both Mr Chew and Mr Lee happy and keep playing the beast with two backs with Ling May in his office each Tuesday night. In other words WHY THE FUCK WOULD CHINA WANT TO DIS ABLE THE GPS SYSTEM?

 

Do you also lose sleep at night worrying about a Zombie Apocalypse? It's much more likely.

 

And as for jamming the system, mate you really got to stop reading so much Clive Cussler. All that pot is making you paranoid dude.

 

 

 

GPS is the new Harrisons Clock mate. It’s better than what came before and you should embrace it. If it makes you beardy types happy, then wave your sextants in good health.

 

But drop the crap about GPS not being as reliable as Celestial Navigation.

 

End rant.

 

Slow day at work LB??



#61 Recidivist

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Posted 30 January 2014 - 04:52 AM

OK, I admit it.  When I was cleaning out the nav table so the new owner could take possession of my boat, I came across the RDF and headphones. 

 

I left them there in case he needs them one day.



#62 Life Buoy 15

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Posted 30 January 2014 - 05:16 AM


 


So for hundreds of years those navigating solely buy celestial nav were not being prudent?

 
Nobody ever navigated solely by celestial.
 
They were doing DR, observing physical features of the sea and wind and land and bottom (when close enough).
 
Celestial has always been one more tool in the kit.
 
 
Really? Nobody ever navigated solely by celestial? Well I certainly crossed several oceans back in the day doing just that. Yes and the least accurate of all navigational techniques, the DR, was part of that. Not having a 4000 meter lead line and eye sight that could make out coastal features from 1000 miles out that was all we had. But the world has moved on. As I said before, why start using this newfangled compass when the good old lodestone has served us so well.[/size][/size]
 
 
 
I have taught navigation for the last 20 years, and the 20 years prior to that I, like most people of my age used celestial navigation for fixing our position in the absence of anything else. Personally it I found it to be a pain in the arse, standing there holding a 1.5 kilo weight up to your eye on a rolling yacht, then having to fuck around at the chart table to pot a dot on the chart. Some of you beardy types might have (and still do) enjoy that kind of thing but the convenience of fixing the position instantly with a degree of accuracy never before known, well, only a dickhead would chose to rely on a more tedious and less accurate method. Yes we are talking only about fixing position - all that celestial navigation does - not shaping a safe course to steer. (Of course you can do this quickly and safely on a chart plotter if you have the computer skills of a retarded 7 year old)[/size][/size]
 
 
 [/size][/size]
 
 
GPS is safe and reliable, in the right hands. I firmly believe in and teach a thorough understanding of chart knowledge, tides, tidal streams, shaping a course to steer and pilotage techniques. I don't bother dwelling too much on 'doubling the bow angle' or 'distance of by vertical sextant angle' anymore. And the last thing I want my students doing is fixing there position by DR (or EP for that matter) alone when a glance at their phone will be much more accurate for fucks sake. [/size][/size]
 
And once they get that I show how to use their chart plotter. The redundancy example is a no brainer. Even most shorthanded offshore yachts these days have a hard wired unit, a battery operated hand held, a laptop, an IPad and 2 IPhone.[/size][/size]
 
That's 6 chart plotters- all independently fed amps. (You can cross an ocean on two double A batteries after all. you only need to turn it on once a day!) Put one in a Faraday cage if you must, wrap one in the Koran or sheep’s entrails, whatever turns you on. Since you didn't take 6 sextants, 6 almanacs, 6 chronometers and 6 copies of the chart to sea with you, the GPS users are much better off than you Beardy types with your pipes and your walker log's. So we can discard the "What if we lose power" argument against GPS. [/size][/size]
Now for some fun.[/size][/size]
 
 [/size][/size]
 
'What if the Chinese blow up all the GPS satellites?" What are you smoking? Let me tell you a little story. In China there is a Mr Chow. He is the manager of 'The Peoples power station No 126' Mr Chow needs lots of cheap coal to run his power station so he can keep his boss Mr Chew (Controller of the Peoples power stations in onebungthong province) happy. If Mr Chew is happy he gets to keep his job and flash apartment with the inside toilet. He also needs to keep Mr Lee happy. Mr Lee is a local 'Businessman' and party member and Mr Chow keeps him happy by giving him free power. If Mr Chow keeps Mr Lee happy Mr Lee supplies Mr Chow with girls and doesn't have him pushed into the coal furnace. [/size][/size]
 
Now in the Australian outback there is a chap named Kevin. Kevin used to drive a digger at the blue sky coal mine but since he was replaced by a robotic GPS digger, he just sits in the pub all day. With Wayne who used to drive the trucks and Frank who used to drive the trains. But thanks to GPS the cost of digging up the coal and sending it to China is cheaper. So Mr Chow can make enough power to keep both Mr Chew and Mr Lee happy and keep playing the beast with two backs with Ling May in his office each Tuesday night. In other words WHY THE FUCK WOULD CHINA WANT TO DIS ABLE THE GPS SYSTEM?[/size][/size]
 
Do you also lose sleep at night worrying about a Zombie Apocalypse? It's much more likely.[/size][/size]
 
And as for jamming the system, mate you really got to stop reading so much Clive Cussler. All that pot is making you paranoid dude.[/size][/size]
 
 [/size][/size]
 
GPS is the new Harrisons Clock mate. It’s better than what came before and you should embrace it. If it makes you beardy types happy, then wave your sextants in good health.[/size][/size]
 
But drop the crap about GPS not being as reliable as Celestial Navigation.[/size][/size]
 
End rant.
 
Slow day at work LB??

Yeah. Hurt my foot so I am stuck in the office. People are working all around me. Gives me the creeps.

#63 Steam Flyer

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Posted 30 January 2014 - 02:28 PM

ok, so all electronics are fried, but you have your sextant and up to date tables and charts. How do you do your DR without the boatspeed log? guestimate? Make an actual log out of a cocnut and Ginger's underwear? I actually know the fundamentals, thanks to flying, for DR (using a mechanical computer, E6B, doing it all by hand is not something i've done), but thei seem to recall that speed is rather important part of the calculation... 

 

With airplanes, things are bit more urgent & fast-paced. And I have a hard time envisioning an accident that would fry the electronics but leave the rest of the plane undamaged. Maybe the copilot hit "reset all" on the master computer, and the GPS isn't fried but is going to be busy for the next 3 hrs downloading it's ephemeris?

 

Actually, I used to fly on Piedmont... the original "fly low enough to read the road signs" airline. Does that count?

 

Back to boats- you can improvise a lot with sticks, string, & paper. A speed log is relatively easy. However, as mentioned earlier, having a good DR plot already in place is really the best way to pick it up after the chartplotter blue-screens. IMHO it's silly to put some kind of demand on sailors to be "real navigators" but this kind of thing is a good learning exercise, and who knows, you might figure out something new.

 

FB- Doug



#64 mustang__1

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Posted 30 January 2014 - 02:58 PM

in planes it was more of a learning exercise as well. However, if you dont have GPS installed (or it craps out),  then you gotta be able to spatially orient yourself on the chart. 

 

 

You still have to know your speed for DR. I guess if the stuff crapped out halfway you can estimate based on feel, but then what the  point, might  as well rely on the sextant... 



#65 Steam Flyer

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Posted 30 January 2014 - 04:11 PM

 

... ...
Slow day at work LB??
Yeah. Hurt my foot so I am stuck in the office. People are working all around me. Gives me the creeps.

 

Ah so... sympathy, get well soon

 

Personally, I am fascinated by people working. I could watch it all day

 

;)

 

FB- Doug



#66 Life Buoy 15

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Posted 30 January 2014 - 07:37 PM

No worries then. Now about those Chinese.....

 
I don't like 'em.

Have you tried one roasted? The traditional owners of this land used to cook them over an open fire. They called them the other white meat.

#67 Somebody Else

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Posted 30 January 2014 - 09:36 PM

no_little_asian_dont.jpg



#68 Somebody Else

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Posted 30 January 2014 - 11:03 PM

How did the ancient Scandinavians navigate?

 

Specifically, how'd these two navigate back to their car?

 

0757_the_olympic_horn_800x600.jpg



#69 pipe dream

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Posted 31 January 2014 - 08:50 AM

Has anyone mentioned the fact that there are three (soon to be four) gps systems operating.

GPS (USA)
Glonass (Russia)
Beidou (China)
Galileo (Europe) (only 4? sats in space at the moment, tested ok but not operationally useful as yet)

Do any marine units recieve signals from anything other than GPS?

I can but buy a surveying unit at the moment that reads all four.

#70 Life Buoy 15

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Posted 31 January 2014 - 09:08 PM

You can buy GPS that receives signals from hundreds of sources- satellites, designated dGPS stations and commercial radio stations.
These give a accuracy to a few millimetres - quite useful when plotting on a chart of a scale where your pencil line is about 1/2 mile wide!

#71 pipe dream

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Posted 31 January 2014 - 11:44 PM

You can buy GPS that receives signals from hundreds of sources- satellites, designated dGPS stations and commercial radio stations.
These give a accuracy to a few millimetres - quite useful when plotting on a chart of a scale where your pencil line is about 1/2 mile wide!


Sorry that wasn't quite the point I was trying to make. People further up the thread seemed to be concerned as to what would happen if China blew the gps sats out of the sky.

My point that I should have said in the earlier post was that there would be redundancy in a unit on a boat if it received signals from three or four systems rather than just one.

#72 jerryj2me

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Posted 01 February 2014 - 10:13 PM

Also storing them in a metal box or wrapping in foil, then putting into watertight container. I've known lightning to fry everything electrical on a boat, much less all the electronics.

 

No, not foil. A steel box.

 

Why?

 

A huge current surge (lightning strike) causes a huge magnetic field.

Huge magnetic fields induce currents in other conductors.

 

In a lightning strike, electronics can get fried due to this, even if the lightning strike current did not go straight through the device.

 

You only got to induce a low voltage (1-5 volts) in certain types of electronics to fry them. 

 

Now, the steel box vs. aluminum foil thing?

 

Magnetic fields go straight thru aluminum but not steel.



#73 Life Buoy 15

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Posted 01 February 2014 - 10:41 PM

People further up the thread seemed to be concerned as to what would happen if China blew the gps sats out of the sky.

Or if there is a Zombie Apocalypse.

#74 Steam Flyer

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Posted 01 February 2014 - 10:53 PM

Also storing them in a metal box or wrapping in foil, then putting into watertight container. I've known lightning to fry everything electrical on a boat, much less all the electronics.

 

No, not foil. A steel box.

 

Why?

 

A huge current surge (lightning strike) causes a huge magnetic field.

Huge magnetic fields induce currents in other conductors.

 

In a lightning strike, electronics can get fried due to this, even if the lightning strike current did not go straight through the device.

 

You only got to induce a low voltage (1-5 volts) in certain types of electronics to fry them. 

 

Now, the steel box vs. aluminum foil thing?

 

Magnetic fields go straight thru aluminum but not steel.

 

 

Doh!

 

Thanks for the correction

 

FB- Doug



#75 Life Buoy 15

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Posted 01 February 2014 - 11:20 PM

How did the ancient Scandinavians navigate?
 
Specifically, how'd these two navigate back to their car?
 
0757_the_olympic_horn_800x600.jpg

As I understand it they used a lodestone, saga telling and a sun compass.
The two above I am sure got some nice lads to walk them back to their car. Well the back seat anyway. What they are is summed up nicely by the colour of the box followed by the word printed on it.




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