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Old 13-10-2010, 07:39   #166
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... Fewer people can treat me like an idiot ...
People can always treat others like an idiot. The difference is, given your accomplishments, most of us (less accomplished) would be idiotic in doing so.
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Old 13-10-2010, 12:01   #167
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The root interest in determining where you are is to avoid hitting anything not to determine your Lat/Lon.
eh no, Adeile, the main reason in determining where you are is to ensure that you can get where you want to go. Historical Navigators regulary navigated to their home ports, crossing uncharted areas, ( ie with unknown dangers) Charts are the primary method of determining not to hit things.

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That is the crux of the issue. GPS tells you where you are relative to the big wide world, visual and radar navigation tell you where you are relative to the things around you. In good datum areas the two co-incide well and there is no problem.
Radar is merely a form of a visual fix , ie a range and bearing. Again as a method of avoiding danger fixes are useless without reference to a chart. Errors in the chart ( such as a missing feature) cause the same problems irrespective of the fix method used. Datum errors are only one issue is a whole collection of possible errors, most of which effect all sorts of charts.


Secondly all fixes result in wrong information if the underlying chart is wrong, irrespective if its paper or digital. Radar, running fixes, visuals, GPS will not prevent you from running over an uncharted reef.

GPS and Digital charts are a convience and thats all.

What I was arguing is that paper charts are doomed becuase they cost too much to produce, are too exepensive to buy , too hard to come by and are generally surpassed by a cheaper easier to use digital alternative. This in no way invalidates paper, its just a fact of life however .

Just now the Uk HydroGraphic office, as a result of cuts and falling revenue, have discontinued the Lesiure Folio of charts around teh UK and Ireland, another body blow to teh widespread use of paper.

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Old 13-10-2010, 12:17   #168
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Don't know if anyone is familiar with them but RN lifeboats used to have a set of Ocean Charts for all seas... thats what I use for crossing and offshore passages... dated 1978... not too worried tho' as I doubt very much if Europe or the Atlantic islands or Caribbean have moved much since then.... this is turning into a load of bollox...lmao.
If you like watching TV while the boats moving... go for it... one owner on a UK - Portugal delivery was obsessed with his radar and chartplotter... to the extent we nearly rammed something on his watch... he was looking at the wrong thing to long and it slipped through... the screens were in the saloon... lucky for us I'd gone topsides for a smoke.
You'll never beat a good set of eyeballs
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Old 13-10-2010, 12:30   #169
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You'll never beat a good set of eyeballs
Quite right , but absolutely nothing whatso ever got to do with paper v digital debate. There are idiot navigators using both methods.

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1978... not too worried tho' as I doubt very much if Europe or the Atlantic islands or Caribbean have moved much since then.... this is turning into a load of bollox...lmao.
Yeah but a lot of the ATN's have

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Old 13-10-2010, 13:15   #170
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Quite right , but absolutely nothing whatso ever got to do with paper v digital debate. There are idiot navigators using both methods.

Yeah but a lot of the ATN's have

dave

Damn... n there was me thinking that was the point of the story.... Silly Me...
As for the ATN's... they can move em all they want... whatever they are...
Don't I just hate these abbreviations... real words are going the way of paper charts it seems
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Old 13-10-2010, 14:08   #171
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ATNs ( Aids to Navigation). ATN saves my finger tips AYSOS

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Old 13-10-2010, 19:39   #172
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Is a lightening strike likely to damage the battery powered hand held spare model at the bottom of the spinnaker locker? I hear even goats can get in them distant corners.
I don’t have a goat on this boat – if I do, he doesn’t seem to eat much. The last boat I had, did have a goat – used to nibble at various bits about the place and spill coffee on my charts – I never did find him.
I didn’t worry too much about the goat, but maybe I should worry about lightning strikes. My electronic charts seem to have no place on a boat because they are unreliable. They are powered by electricity and will fry. So I guess I should get rid of my AIS, Radar, GPS, wind/speed/depth instruments, autopilot, engine, watermaker, refrigeration, nav lights, bilge pumps etc etc etc as they presumably are unreliable too.
Oil lamps, salted beef and hard tack from now on for me. With a sextant in my hand and Bowditch in my pocket I could be a real sailor.
Arrrrr boys...man the pumps!!
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Old 13-10-2010, 19:44   #173
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I don’t have a goat on this boat – if I do, he doesn’t seem to eat much. The last boat I had, did have a goat – used to nibble at various bits about the place and spill coffee on my charts – I never did find him.
I didn’t worry too much about the goat, but maybe I should worry about lightning strikes. My electronic charts seem to have no place on a boat because they are unreliable. They are powered by electricity and will fry. So I guess I should get rid of my AIS, Radar, GPS, wind/speed/depth instruments, autopilot, engine, watermaker, refrigeration, nav lights, bilge pumps etc etc etc as they presumably are unreliable too.
Oil lamps, salted beef and hard tack from now on for me. With a sextant in my hand and Bowditch in my pocket I could be a real sailor.
Arrrrr boys...man the pumps!!
Now your talking....LMAO
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Old 13-10-2010, 22:02   #174
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Originally Posted by goboatingnow View Post
eh no, Adeile, the main reason in determining where you are is to ensure that you can get where you want to go. Historical Navigators regulary navigated to their home ports, crossing uncharted areas, ( ie with unknown dangers) Charts are the primary method of determining not to hit things.
Silly me, I always thought not getting dead was more important than getting to where I wanted to go. I suppose that comes from not having been in the military. I'll try and adjust my thinking.

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Radar is merely a form of a visual fix , ie a range and bearing.
I can see the similarities for this discussion so granted.

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Again as a method of avoiding danger fixes are useless without reference to a chart.
Granted for unseen dangers and without local knowledge.

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Originally Posted by goboatingnow View Post
Errors in the chart ( such as a missing feature) cause the same problems irrespective of the fix method used. Datum errors are only one issue is a whole collection of possible errors, most of which effect all sorts of charts.
Datum errors are a different catagory of error than misplaced or missing features. Datum errors affect every 'object' on a chart because every 'object' is 'misplaced' relative to lat/lon lines. Ignoring errors for individual features GPS produces a lat/lon position that can be 1nm or more in error relative to every danger around you. A good visual/radar fix will tell you where you are on the map within 0.1nm or so relative to features, dangers and your destination.

Lets assume that you use a mislocated feature as part of a visual fix. That will give you a larger 'cocked hat' for the result and you will know to take more bearings or to procede with more caution. Ignoring datum errors visual fixes have a slight advantage in that you know there is something in error around you.

Assuming a good datum and a hidden danger, such as a rock or wreck, that is not shown, then visual/radar and GPS are just as likely to run you over the danger.

Assuming a good datum and a hidden danger, such as a rock or wreck, that is misplaced, then visual/radar may have a slight advantage because the 0.1nm or so accuracy of the fix may cause you to pass a bit farther from the mapped position of the danger compared to the 5m accuracy of GPS.

Finally lets consider the case of poor datum and 10 of 1,000 dangers are misplaced/missing on the chart. Lets say your course take you within 1nm of 100 dangers. Your odds are better with a visual fix because only 1 or 2 are likely to be misplaced/missing, 3 or 4 if you are unlucky. With GPS all 100 dangers you pass by are a potential problem depending on which direction the datum error is and whether the dangers are taken down that side preferentially. Assuming dangers are taken randomly down both sides of the boat as you progress and the datum error is either left or right and not straight ahead or behind then 50 dangers will be a problem.

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GPS and Digital charts are a convience and thats all.
Agreed. And there is my arguement, they are such a convenience that people get out of the habit of checking the GPS results against the real world they can see. It's not an inherant advantage for paper charts, it's a human factors advantage, you are more likely to check your GPS fix against visual fixes so when you enter a poor datum area you will know and compensate.

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What I was arguing is that paper charts are doomed becuase they cost too much to produce, are too exepensive to buy , too hard to come by and are generally surpassed by a cheaper easier to use digital alternative. This in no way invalidates paper, its just a fact of life however .
I'm not sure they are doomed. Certainly it will be a long time before the military does away with them, so paper charts will be available for decades, even if they don't come in folios convenient for pleasure boaters.

I will grant you they are more expensive when buying charts to cover a large area.

Ease of obtaining them I would argue about, up until recently I was in Seattle where I had Captain's Nautical Supply. Here in San Diego, I can order anything I want from them and I have found at least one place to buy used. It's not instant internet service but it's fast enough for my needs.

Ease of use is arguable. You buy a system, you have to learn the user interface. You buy a new system from a different vendor and you have to learn a new interface. Worse, you upgrade your system with your original vendor and your user interface is almost the same but not quite so you are regularly making the the same mistakes because you didn't make a complete break from the old system. The aviation industry is dealing with this a bit right now, mucking around with a new or modified user interface while in flight has led to a couple of accidents and near misses so there has been some talk of mandating a consistent user interface for most GPS functions. Once you are up to speed with a user interface I can see it being faster unless there is some awkward physical problems with the plotter like an overly sensitive pointer stick or trackball.

Going back to the original question of plotter vs paper. Disregarding reliability and electrical consumption issues, in good datum areas plotters using GPS fixes have the advantage in speed, convenience and accuracy.

In poor datum areas paper charts have the advantage in that you are more likely to discover your GPS fixes are not relating well to your local world and take steps to compensate.
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Old 13-10-2010, 22:52   #175
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In poor datum areas paper charts have the advantage in that you are more likely to discover your GPS fixes are not relating well to your local world and take steps to compensate.
You're still making the assumption that the only position you can fix on an electronic chart is a GPS position.

That's not the case

You can take a fix with a hand bearing compass and plot it on an electronic chart in exactly the same manner as you would on a paper chart. With one you draw the bearings on the chart with a pencil, with the other you draw the bearings on the chart by using one of the many functions of the software.

Edit: Infact, I'd go so far as to say that you'd actually be far more likely to realise mis charted features electronically than you would using non-electronic means. Using the radar overlay would soon show up anomolies.
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Old 13-10-2010, 23:46   #176
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You're still making the assumption that the only position you can fix on an electronic chart is a GPS position.
No I'm not (or at least that is not the crux of my arguement. See below for a more nuanced response about plotting electronically)
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And there is my arguement, they are such a convenience that people get out of the habit of checking the GPS results against the real world they can see. It's not an inherant advantage for paper charts, it's a human factors advantage, you are more likely to check your GPS fix against visual fixes so when you enter a poor datum area you will know and compensate.
When was the last time you checked your GPS results against a visual fix and how often do you do so?

For those that don't have radar, can't get it to talk to the plotter or won't go to the hassle radar overlays don't do anything.

I don't dispute plotting fixes on a laptop is easy and fast. What about on stand-alone plotters with built in GPS's?
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Old 14-10-2010, 01:48   #177
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When was the last time you checked your GPS results against a visual fix and how often do you do so?
In Hong Kong - Never - because Hong Kong is charted very accurately.

In other places that I'm not familiar with, it's pretty much standard practice for me to get some comfort from another source - it may be the depth, it may be the radar, it may be a fix from a hand compass. It may be all 3.

In the Philippines for example, the GPS is the last thing I look at.

But this line of discussion isn't paper charts vs electronic charts. This is good practice vs bad practice.
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Old 14-10-2010, 02:17   #178
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I just spent 30 minutes getting caught up on this. It's always interesting to come back to a thread and read 50 posts or so in a row.

It struck me that the question is no longer "Who uses electronic charts?" The question is "Who does not use electronic charts?"

I really sympathize with the guys defending paper charts. The arguments are pretty much -

- Paper won't fail
- Paper is cool
- Celestial navigation is something everyone should know
- electronic charts are "inaccurate"

I think someone should start a poll.

A - I use electronics prime and paper backup
B - I use electronic only
C - I use paper prime and electronic backup
D - I use paper only
E - I do something else

I would be extremely surprised if anyone (honest) said they use paper only or even paper prime.

In regards to night blindness...

In 1942 airplanes had moon roofs to do star shots. Bombers flew at about 230 mph.

I have a few hundred air miles under my belt. I have flown GPS at night for years. Night blindness is a trade off and you dim instruments to protect yourself as much as possible. But every commercial jet now has 6 X 12+ inch CRTs on the flight deck. Trust me it's workable and the pilots don't wear sunglasses at night.

Now think about this. I have been in cockpits at night doing 500+kts. No one is doing star shots and plotting courses and fixes on paper. It ain't happening and no one is hitting anything solid or other airplanes (except for grevious errors).

We travel in boats at 5-10 kts. Trust me no matter how you are navigating, if you are hitting things you really just have lost the plot. Even a ship coming the other direction at 20 knots should be easily avoidable. The idea that a sailboater has his head in the cockpit and is at risk of hitting stuff as a result is ludicrous!

The same fear was held in airplanes - GPS will cause a lot of wrecks because pilots will have there head inboard. Yes it happens but the safety benefits of GPS outweigh that risk (and any other) risk by thousands to one.

Oh, yeah - almost nobody is using paper charts in airplanes after flight training. Makes no sense!

OK - rant over. I feel much better. Carry on.

(PS - I am totally in Mark's camp now that he is not an idiot and almost a circumnavigator - no paper for me...)
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Old 14-10-2010, 04:15   #179
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Ok.... 1st in poll...
Paper Charts + handheld GPS (10yr old non singing dancing Magellan) for position/sog/distance referall...

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Old 14-10-2010, 04:38   #180
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I would never use a paper chart. However just today I walked to the computer shop in Kudat, Sabah to have the geek there print out fifty (50!) pages of MacENC plotter printouts for my transit to Palau thru the reef adorned waters of the Sulu Sea. I'll never use them...except in the event I get smacked by a lightning bolt...or the far more likely event that the electrical system here packs it in.

They'll get used for shopping list scratch paper for a year.

I wouldn't bother with this on an open water passage.
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