Death to PAPER ! More Nails in the Paper Chart Coffin . . .

[boatman61]

Originally Posted by doug86

"Not to be used as sole means of navigation".... what a ridiculous label. You could justifiably put that sign under the wet compass and be just as correct. What good is a knowing your mag heading if you don't know where you are going and where you started from? Or how fast you are going?

Can you use a paper chart as the "sole means of navigation"? Without looking outside? Without a compass? How can you plot your position on paper chart without some other piece of equipment, like a pencil? How will you determine your speed? Does a flashlight to illuminate the paper in the dark constitute an additional piece of technology? That the CanCG feels the need to put those words under a chart plotter doesn't say much about how they train their coxswains. Nothing should be your sole means of navigation.

No one proposes to use an electronic chart or a chart plotter as the "sole means" of navigation. We all have compasses and binoculars and depth sounders and eyeballs and so forth.

However, consider this hypothetical: you are entering a strange harbor at night, known for its strong cross currents and tightly marked channels. You can choose only one means of navigating from the following two choices:
A) a GPS chartplotter with up to date charts, mounted right next to the helm or;
B) a paper chart, latest edition.

That's it. No flashlights, no binoculars, no spotlights, no depth sounders, no pencils, no knotlogs. No other technology. I.E, you are actually faced with choosing what that ridiculous little label proposes: a single source of navigation. Just ONE THING.

I choose the chart plotter every time.

How about you?

I'd choose the Chart.... every time.... it gives more information...
as for "The GPS CAN give accuracy to 6ft".... there's a lot of difference between what it can and what it does....

[doug86]

Originally Posted by boatman61

I'd choose the Chart.... every time.... it gives more information...

How is it possible that a paper chart gives more information than an exact digital duplicate of that same chart?

[GordMay]

Originally Posted by doug86

"Not to be used as sole means of navigation".... what a ridiculous label. You could justifiably put that sign under the wet compass and be just as correct …

Unlike a chart plotter, a compass doesn’t claim to tell you exactly where on the planet you are.

[boatman61]

Originally Posted by doug86

How is it possible that a paper chart gives more information than an exact digital duplicate of that same chart?

One example... new CP on a boat with latest chip... going up the Kanakalle the CP showed me on a ridge 1.5km away... and this is a very busy route well marked...
My chart and Mk 1's had me right where I wanted to be...
Its all very well in your local US areas but some of us are operating in more distant parts of the world...
Oh... another thing... the theoretical 6' accuracy is only possible if your stationary... otherwise its inaccurate... your moving and theres a time lag...

[doug86]

Originally Posted by GordMay

Unlike a chart plotter, a compass doesn’t claim to tell you exactly where on the planet you are.

Gord, knowing where you are on the planet is just the first step in navigating to someplace else on the planet.

[s/v Jedi]

Originally Posted by hummingway

Surely you didn't mean to sat auto-pilot? You would use your auto-pilot to enter a strange harbour at night?

Yes, we use AP in these situations because we are short handed. With a single press of a button, the AP will eliminate drift caused by currents or wind, giving the helmsman time to observe and plan next course change.

The 2nd person operates radar and chart plotter. We never used way points fed to the AP but with the new electronics package we might test that with a familiar approach soon.

If you do not use the AP (or if your AP does not have the function to eliminate drift, ie only heading and waypoint modes), the helmsman needs full attention to steer through the cross currents, meaning you loose a pair of eyes.

ciao!
Nick.

[doug86]

Originally Posted by boatman61

One example... new CP on a boat with latest chip... going up the Kanakalle the CP showed me on a ridge 1.5km away... and this is a very busy route well marked...
My chart and Mk 1's had me right where I wanted to be...

In this example, it was your eyeballs that saved the day, not the fact that you had a paper chart instead of an electronic one. The information on the two charts is the same. You haven't answered my question:
How is it possible that a paper chart gives more information than an exact digital duplicate of that same chart?


You are merely reinforcing the fact that one must rely on more than one tool to determine one's position. GPS is pretty darn reliable in most cases for that, but should always be confirmed with eyeballs and other things. Just as you would suspect your wet compass if it was reading N and you were sailing into the sunset on the Equator.

[doug86]

Originally Posted by s/v Jedi

Sorry but I would choose to stand off and not enter... .

Which is an absolutely fine choice!

[osirissail]

Originally Posted by hummingway

Surely you didn't mean to sat auto-pilot? You would use your auto-pilot to enter a strange harbour at night?

It depends upon the quality of the autopilot you have installed and how much you "know" that autopilot and its characteristics. A quality autopilot has an adjustment to turn off "sea-state" and turn on very tight "compass heading" following. Doing such allows the autopilot to maintain a compass heading within a degree or two versus the "sea-state" function that allows ten or more degrees of compass swing before the autopilot brings the boat back to the commanded heading.
- - Using a quality autopilot set for "tight" heading control allows you to concentrate your attention on the chart and the actual conditions outside rather than having to constantly worry about what your heading is and the rudder position.
- - If you do not have such an autopilot then using an autopilot to enter any harbor, strange or familiar is a recipe for some exciting unintended "experiences."
- - As to nautical paper charts and e-nav systems there is a lot of history involved in their development.

[conachair]

Originally Posted by boatman61

I'd choose the Chart.... every time.... it gives more information...

I'd choose all of them

You are allowed more than one

Chart first, but laptop with digi charts and google earth both running is very nice to have. Google earth is free (after the laptop) and I found it a very useful tool, 3d view is handy to see just which hill is beside bay you're going to, great to find paths for a nice walk in the morning. All the tools are useful. Just remember they might not be right and might break.

[osirissail]

**Part two**
- - There are basically two different chart systems in use - "Raster" e-charts that are nothing more than scanned photos of real paper charts/acetates and "Vector" charts that are human interpreted copies of real paper charts.
- - The original e-charts were all Raster and the files were enormously large. If you have ever seen the computer directories of the original Maptech digital charts you will see up to a hundred subdirectories each with megabytes of chart data. This first format of e-charts consumed so much hard drive and CD space that only a few charts could be stored and used.
- - Then the "Vector" chart format was invented where instead of recording/storing every little pixel of a scanned paper chart, only the screen locations of significant points on the chart were recorded and straight lines connected these points. You can observe this system on the little GPS displays with mapping. As you zoom in your will see shorelines depicted as straight lines with one shade/color on the land side and another shade/color on the water side. Virtually no shoreline detail is present. The file size of Vector charts is dramatically smaller than Raster.
- - In order to get hundreds, even thousands of charts on a CD, chart producers hired people to sit at a desk with a paper chart and use a plotter stylus to "pick" significant points which the computer connected with a straight line. Unfortunately, the "boss" kept bugging the worker to hurry up and get the chart done. This lead to the omission of quite an amount of significant data in the finished Vector chart.
- - An article in Ocean Navigator about a decade ago outlined the problem when an ocean liner ripped a long tear down it hull because of lack of complete information in the existing Vector charts. The chart translators were seeing a square of 4 or so depth sounding that were numerically equal and then placing only one data point in the center of the group. That can be an expensive and fatal mistake as each sounding on a paper chart is specific to the exact Lat/Long of its placement. What the depth is in between is unknown as the two equal depth readings could be on the sides of a sea mount with the peak of the mount uncharted.
- - Fortunately, the process of transcribing the original paper/acetate nautical chart to a Vector format has significantly improved since those days so more data from the original chart is being shown on the Vector version. However, if you really Zoom in on a Vector chart you will see the large loss of detail that is present on paper or Raster charts.
- - It was just a marketing decision that in order to make compact Chart Plotters both small and economical only the Vector chart system could be used for chart data storage. Trying to store terabytes of raster chart information on a little handheld GPS plotter or any other size plotter was a non-starter.
- - So, Yes, Chart Plotters cannot contain the detail and mass of content that a paper chart conveys to the nautical navigator. Whether you actually need all that extra detail that paper charts present is a different discussion.

[doug86]

Originally Posted by osirissail

Chart Plotters cannot contain the detail and mass of content that a paper chart conveys....

Perhaps you should modify that to say "stand alone chart plotters generally only display Vector charts, and cannot show the detail...."

I have 3 computer based chart plotters that all display Raster charts, so I am seeing everything that would be on a paper chart.

[boatman61]

[QUOTE=doug86;700788]In this example, it was your eyeballs that saved the day, not the fact that you had a paper chart instead of an electronic one. The information on the two charts is the same. You haven't answered my question:
How is it possible that a paper chart gives more information than an exact digital duplicate of that same chart?
QUOTE]

I will confess my knowledge of CP's is limited... this occasion was prompted as my somewhat inexperienced crew was taking over in busy waters and I figured the TV at the helm might help so I switched it on for her to follow the markers...
One other thing I noticed... not all the bouys are shown and those that are do not show the light sequence... although they were on the chart.... maybe there's a way to bring them up.. I don't know...
and to be honest am not really interested...
I have my own style and techniques... just as you do... I'm happy with mine TY...

[doug86]

Originally Posted by boatman61

I will confess my knowledge of CP's is limited... this occasion was prompted as my somewhat inexperienced crew was taking over in busy waters and I figured the TV at the helm might help so I switched it on for her to follow the markers...
One other thing I noticed... not all the bouys are shown and those that are do not show the light sequence... although they were on the chart.... maybe there's a way to bring them up.. I don't know...
and to be honest am not really interested...
I have my own style and techniques... just as you do... I'm happy with mine TY...

Boatman, I think you're system is fine and I would not accuse you of being a lesser navigator for doing things "old school".

I hope that, with your very limited understanding of the CP technologies, you will not accuse those of us who choose to exploit the technical advantages of CP's of being fools.

[boatman61]

Originally Posted by doug86

Boatman, I think you're system is fine and I would not accuse you of being a lesser navigator for doing things "old school".

I hope that, with your very limited understanding of the CP technologies, you will not accuse those of us who choose to exploit the technical advantages of CP's of being fools.

Doug... I would not dream of calling someone who used the CP a fool...
until after being called a fool for not using one....