Electronic Charts

[jtulls]

I know there are a ton of threads out there on this, but Team Vestas Wind put out their independent report on the grounding (they wrote the book | Sailing Anarchy).

Reading through, it talks about how C-Map/Expedition didn't show the shoal, unless you zoomed in to a certain level and even then you need the detailed charts installed. They show screen shots of the maps on Pg 36-37 and I also attached a screen shot -- the map shows hardly any detail.

I took at look at the Navionics webapp and barely had to zoom in to see the shoal (see attached image -- look for the shallow blue/green) and when I zoomed in the level of detail was insane for such a remote location!

I was wondering what your experience is with electronic charts. What software do you use and have you run into lack of detail?

[colemj]

The report stated that they were using only the base world map of their CMap charts, and did not even load the actual charts into their computers. They had those detailed charts, they just didn't load/unlock them. The picture shown is from the base world chart (basically, a plotting sheet).

They also deliberately turned off all the textual and visual warnings and safety systems on their charting program that would have alerted them to the fact that land existed in that area, and that there was a more detailed chart available.

In addition to their 2 computers (which they did not load detailed charts onto), they had 2 B&G chartplotters on board. The base world map on these chartplotters showed land existing on those shoals on all zoom levels. They were using one of the chartplotters to control their lights, and did not look at the other chartplotter until they were on the bricks.

The CMap charts of that area are not the best, but they do contain information on that shoal sufficient to keep even an amateur, half-asleep, navigator from bricking on it.

As you show, Navionics are even better, as are the official HO ENC vector charts - which show that land at all zoom levels.

So to sum up, they were not even using their electronic charts - instead relying simply on a world base map plotting sheet. They had deliberately turned off all warning and safety-checking systems in their navigational software. They had FOUR chart plotters on board, two of which clearly and unambiguously showed the dangers. They chose only to use/look at one of them (and picked the wrong one). They did not choose to use official HO ENC charts on their software, which show these dangers at all levels, although it seems in hindsight that they wouldn't have been anymore successful if they did.

So, while I expect that most here will see in this report a damning of electronic charts, I see absolute navigational idiocy - lower than amateurish. If I were the navigator of this boat, I would be deeply ashamed and embarrassed by the findings. I certainly would not continue to hang on the "electronic charts were the problem" excuse.

Let me state this again: two of the four chart plotters on board clearly showed the land and shoals at all levels (on only their world base map, no less!), while they failed to even load the electronic charts they did have into the other two computers being used as their "main" chart plotters. Failed to load the charts!

One has to work very hard in contortions to blame this on electronic charts.

Mark

[denverd0n]

Originally Posted by colemj

One has to work very hard in contortions to blame this on electronic charts.

I agree completely. This was nothing more nor less than a catastrophic error in navigation.

[jtulls]

Originally Posted by denverd0n

I agree completely. This was nothing more nor less than a catastrophic error in navigation.

My intention was to stay away from focusing on the errors leading to the grounding but to focus on the maps. I was hoping to start a discussion on quality of the electronic charts.

I've been running Navionics and have never found detail to be an issue. What are the opinions of the electronic charts you use? I don't have much experience with CMaps -- are the detailed charts a separate package? Can you do any real/safe navigation on the base maps alone (excluding maybe ocean-crossing where there shouldn't be many obstacles)?

[Stu Jackson]

Originally Posted by jtulls

My intention was to stay away from focusing on the errors leading to the grounding but to focus on the maps. I was hoping to start a discussion on quality of the electronic charts.

I've been running Navionics and have never found detail to be an issue. What are the opinions of the electronic charts you use? I don't have much experience with CMaps -- are the detailed charts a separate package? Can you do any real/safe navigation on the base maps alone (excluding maybe ocean-crossing where there shouldn't be many obstacles)?

That's an unrealistic expectation or premise.

Why? Because of what Mark said.

It's simple, if you have a tool and you misuse it, you can't blame the tool.

The base maps don't have the detail. Wrong tool.

[El Pinguino]

Originally Posted by jtulls

Can you do any real/safe navigation on the base maps alone (excluding maybe ocean-crossing where there shouldn't be many obstacles)?

Not in my opinion because its the 'few obstacles' that will bring you undone.

[Albro359]

One real problem with electronic charts, particularly in remote areas like the Pacific Islands is that the vector charts are based on the paper charts and some of these paper charts have not been updated for 100 years. Most of them are not WGS84. Often the latitude is more or less correct but the longitude isn't.
And they vary between C-Map and Navionics.
We have both and sometimes the Navionics is "more correct" than C-Map and vice-versa, and sometimes they are both just plain wrong.
One cannot rely solely on electronic charts.
Many do, believeing that because they are electronic that they must be right, but sadly this is often not the case.
Paper charts, Mark I eyeball and a caution are the navigator's best tools.

[colemj]

Originally Posted by Albro359

One cannot rely solely on electronic charts.
Many do, believeing that because they are electronic that they must be right, but sadly this is often not the case.
Paper charts, Mark I eyeball and a caution are the navigator's best tools.

I don't understand this. You made the argument that electronic charts can be in error because they are based on the paper charts containing these errors. Then use this to argue for paper charts being more "safe".

Why not "electronic charts, Mark I eyeball and caution are the navigator's best tools"?

Mark

[colemj]

Originally Posted by jtulls

Can you do any real/safe navigation on the base maps alone (excluding maybe ocean-crossing where there shouldn't be many obstacles)?

The same as you can with paper plotting sheets (actually, a bit better than that). But I don't understand why someone would use electronic charting and not buy any electronic charts.

Mark

[StuM]

Originally Posted by Albro359

One real problem with electronic charts, particularly in remote areas like the Pacific Islands is that the vector charts are based on the paper charts and some of these paper charts have not been updated for 100 years. Most of them are not WGS84. Often the latitude is more or less correct but the longitude isn't.
And they vary between C-Map and Navionics.
We have both and sometimes the Navionics is "more correct" than C-Map and vice-versa, and sometimes they are both just plain wrong.
One cannot rely solely on electronic charts.
Many do, believing that because they are electronic that they must be right, but sadly this is often not the case.
Paper charts, Mark I eyeball and a caution are the navigator's best tools.

You can rely on electronic charts in this situation in exactly the same way as you can rely on paper charts. Just don't assume that that you are where the "little boat" is shown in relation to features. If you mark your GPS "fix" to your paper chart, you will have exactly the same offset as the plotter.

In fact, many plotters allow you to adjust the chart offset - so the plotter can be more accurate than the paper they were copied from. (In one area where the boat was to be located for a while, I offset a plotter by about 700m after carefully sailing close to a reef channel marker to determine the discrepancy)

[nautical62]

When I sailed my boat solo from he BVIs back to Florida last summer I used the Garmin app and charts. which by license I could put on both my iPad and iPhone. The whole Caribbean and U.S was $50.

I was very pleased. I couldn't tell any difference between the quality of the charts on the app vs. those on a dedicated GPS. The iPad screen size was of course much bigger than many GPS chart plotters, I found zooming and moving the map with my finger, much easier than using the cursers on GPS units I've used. The app does not include a few features that most marine GPS units have but it gives a great chart, shows you where you are, and allows you to measure distances and bearings quickly, which for the most part is all I need.

A downside is reading it in full sun which was not a problem for me under the Bimini. While I had no problem, obviously an iPad or iPhone is does not have the same level of weather resistance, though water proof cases are affordable.

[lonesoldier0408]

I like the versatility of electronic charts in principle as my experience is limited, however power loss would render them useless. Again with the deviations found in magnetic North, which affects chart accuracy, proximity becomes an issue as well. Proximity is what will cause the on the bricks situations. Just 2 cents, and worth what you paid for it. 😬


Sent from my iPhone using Cruisers Sailing Forum

[MarkJ]

1) Learn to zoom in

2) Dont go over the top of a place called 'shoals'

3) Don't go over an area mid ocean which has a 20 meter line. Thats shallow.

[ranger58sb]

Originally Posted by jtulls

My intention was to stay away from focusing on the errors leading to the grounding but to focus on the maps. I was hoping to start a discussion on quality of the electronic charts.

I've been running Navionics and have never found detail to be an issue. What are the opinions of the electronic charts you use? I don't have much experience with CMaps -- are the detailed charts a separate package? Can you do any real/safe navigation on the base maps alone (excluding maybe ocean-crossing where there shouldn't be many obstacles)?

We use NOAA raster and vector charts, and we also use C-Map vector charts. In our area, both vector charts are at least as good as the the NOAA raster charts (which on our systems would be almost as current NOAA paper charts, although not as updated as a print-on-demand paper version printed just yesterday). The C-Map vector charts have slightly more info in some areas: marina info. And then we've also got ActiveCaptain markers (and marina info) overlaid on all that.

Three separate electronic charts -- plus Mk I eyeballs -- serve us well.

Can't speak to trying to "navigate" using only "base maps" but near as I can tell they're useless for actual navigation. OK for locating continents, but we rarely lose those.

-Chris

[MarkJ]

NOAA charts? Do you know where the subject location of this debate occured?


700nms further into the ocean from Madagascar.