Another foundering how do chart plotters get it wrong

[Wotname]

Shorter post

Question for Mark (Colemj). As it seems that you don't agree with much of the criticism on this thread, what in your view are the limitations of GPS and the limitations of electronic charts?

[Mirage Gecko]

Already commented I like the electronic alternative in preference to paper and although I have a few paper charts never seem to use them in fact I am not even sure where they are but clearly each to their own choice but it is nearly always the human element that creates any of the associated navigational problems with the use of either medium.
However in my opinion which is based on what I see happening around me I reckon we may have reached a point where paper charts are virtually already dead for the majority of non professional sailor/cruisers with only those who still feel strongly about using or learning the older or should I say more traditional methods.
Chris

[Wotname]

Originally Posted by Mirage Gecko

Already commented I like the electronic alternative in preference to paper and although I have a few paper charts never seem to use them in fact I am not even sure where they are but clearly each to their own choice but it is nearly always the human element that creates any of the associated navigational problems with the use of either medium.
However in my opinion which is based on what I see happening around me I reckon we may have reached a point where paper charts are virtually already dead for the majority of non professional sailor/cruisers with only those who still feel strongly about using or learning the older or should I say more traditional methods.
Chris

I think you are probably correct and certainly the electronic chart has many advantages but for safe navigation we must be aware of and remember it's limitations.

[carstenb]

Originally Posted by Wotname

Well, what an eye opener - not sure if I would trust you as navigator, I mean "Barcadi", really - what sort of sea dog are you

Officers (including the "pencils" and 'sparks" and so on) drink gin and the ratings - rum.

yep - we only carry gin

[FamilyVan]

I don't consider myself a traditionalist, I've gone to west marine or whatever a few times with the intention of buying an electronic charting system and I've just never been able to justify the $800+ to myself. It always seems that something else is more important like a new stove, or alternator.
I know several full time live board's around these parts who don't have ECSs.
Having said that, I do have a beautiful and carefully accumulated (paper) chart folio including 5 great lakes, gulf of st Lawrence, icw, us east coast Bahamas and caribean as far south as the grenadines. So- if I were a new boater and had no chartfolio, I'm guessing that $800 would be a fraction of the cost of my paper charts.

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[weavis]

Originally Posted by FamilyVan

I don't consider myself a traditionalist, I've gone to west marine or whatever a few times with the intention of buying an electronic charting system a couple of times and I've just never been able to justify the $800+ to myself. It always seems that something else is more important like a new stove, or alternator.
I know several full time live board's around these parts who don't have ECSs.
Having said that, I do have a beautiful and carefully accumulated (paper) chart folio including 5 great lakes, gulf of st Lawrence, icw, us east coast Bahamas and caribean as far south as the grenadines. So- if I were a new boater and had no chartfolio, I'm guessing that $800 would be a fraction of the cost of my paper charts.

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Yup.
Charts are expensive to make and print.

[FamilyVan]

Originally Posted by weavis

Yup.
Charts are expensive to make and print.

Well- I'm a navigator by trade, so when whatever ship I happen to be on receives a new edition chart, rather than throw out the old one- I just take it home, the charts are all up to date the day I take them home- usually corrected by me, so I have some insight into the quality and nature of the corrections.
Not really a viable option for most cruisers.

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[Jon Eisberg]

Originally Posted by weavis

Yup.
Charts are expensive to make and print.

Not to mention, bulky, and heavy, as well...

For my cruise last summer in Atlantic Canada, my charts folded into quarter formed a stack just under a foot in height, weighing a total of about 70 pounds... Not inconsequential, aboard a 30-footer...

At $20 apiece for CHS charts, I don't even want to know the total cost :-) Fortunately, I obtained most of my stuff years ago for Nova Scotia and Newfoundland used by another cruiser, at a fraction of the cost...

Still, money and space well spent, at least for me... And, the CHS charts are, literally, cartographic Works of Art... :-)

[rwidman]

The people complaining about the "newfangled electronic charts" are the same ones who complained when people started driving cars instead of horses.

My chart plotter has never led me into trouble but I'm sure I would have found trouble without it.

[boatman61]

Sometimes wonder how some of these ardent defenders of CP's would actually fare following a catastrophic electrical failure.. else why would it get so up their butts when someone says they have flaws.. don't take it so personally guys...

[FamilyVan]

Originally Posted by rwidman

The people complaining about the "newfangled electronic charts" are the same ones who complained when people started driving cars instead of horses.

My chart plotter has never led me into trouble but I'm sure I would have found trouble without it.

I'm not sure that's the case. I think the people identifying weaknesses in electronic charts are extremely experienced and therefore have had more exposure to electronic chart failures, and have had a higher level of training with electronic .navigational instruments, so are more aware of there inherent flaws.
I assure you, I am not afraid of developing technology.
I have spent thousands of hours using electronic charts- some of the very best available, and had hundreds of hours in formal institutional training in there use.
Either because I'm unlucky- or because of my exposure to the technology, I have had the occasion to really scare myself while using them, either because they failed, or because the mere presence of the technology emboldened me to be out in conditions, or travel faster, or have fewer look outs then I would have had I only had RADAR, depth and Gyro.
I remember a particular occasion when a young second mate argued with me that it wasn't raining outside because he couldn't see any clutter on his RADAR overlay on his ECDIS.
As is my habbit, I was looking out the bridge window and could clearly see there was a thunder shower outside- lightning and all.

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[Suijin]

About 10 years ago I was out striper fishing on the Chesapeake Bay in my center console early one spring morning. I decided to cross the Bay around the Choptank river, west to east in search of a good rip. The eastern shore was shrouded in fog and as I entered it I was seriously alarmed to see the southern shoreline of the river's mouth looming up, much closer than my chart plotter said it should be. I poked around as the fog burned off and found that the entire point of land was off by at least 1/4 mile.

The Chesapeake is one of the most heavily trafficked bodies of water on the east coast, yet outside of the main channel the vast majority of it has not been surveyed since before World War II.

I think what gives people false confidence in in their plotter is their experiences where it IS accurate. Juxtaposed against my experience in the fog, the plotter and chart was so accurate around my marina that I could actually find my way in through the breakwater, in pitch dark, make a right and then a left, right to the boat ramp without ever looking out of the boat, if necessary. People have experiences like that and just assume as a result that it's accurate everywhere.

[onavegador]

Hi
there are many reasons why a boat may hit a small island. I would just tell some story about my experiences with electronic charts, GPS and Sat Nav.

1) electronic charts may be vector charts digitalized from paper sources. As with every thing what is not done copy paste where may go parts forgotten ore misreported.
When sailing years ago using c-map for navigation from Fiji to Australia one morning, when looking around with the binoculars I saw something that was looking definitely like waves but something something solid. It was a tiny sandbank with mangroves and small palms. Controlling my chartplotter there should be open sea, on my paper chart I saw a really tiny island. As I was a little lazy the noon before I did'nt marked my noon position as normal in my paper chart. Not in immediate danger but really good luck that I could realize just in time the small bank in front of me. In NZ I heard from other cruisers that this error on c-map is known and that an other guy hit the bank and was salvaged only several days later.
The mentioned error does not exist any more. I have here no chart ready to name the object.

2) The setting for the chart datum was wrong. That may happen, because not all charts are on WGS 87. For instance in the Red Sea you have very accurate electronic charts showing you the coves (called marsas) there you can anchor, often with every detail. But you cannot steer in with GPS and electronic charts as you will not find a corresponding chart datum. The entrances to the marsas are in some cases even some miles away from your GPS Position. The charts are mainly designed using surveys from the Portugese navigators of the 16th century.

3) Charts for New Caledonia are based an a datum you would only have (2010) on a French GPS.

4) On delivery of a boat to from Europe to St. Lucia, after a stop in Barbados I realized during our sail to Martinique that the position of the boat on our Sat Nav was one degree (wrong) to that I had plotted. I'm pretty sure that this error was due to playing with the device by someone of my crew.

Fair winds.
James

[colemj]

We have been struck by lightning taking out all fixed electronics, burned electrical wiring and boiled half of our house battery bank. We fared very well navigating for three weeks to a place to effect repairs because we had backup and standalone electronic systems - and our brains.

A catastrophic electrical failure would have to be enormous, to take out tablets, phones, computers, handheld devices, etc. Not only taking out the main house batteries, the start batteries, and any other auxiliary batteries like genset and dinghy, but also all of the AA and AAA dry cells on board. This type of failure would probably be part of losing the boat completely, and such a low probability occurrence as to be silly to worry about. For sure, the probability of losing all your paper charts overboard would be higher.

For those enamored with paper charts, there are places in the world where the paper charts are decades, or centuries, older than the electronic versions. We are in one of these places now. The current paper charts are so far out that navigation is almost impossible using them. The electronic charts are much better and able to be used for pretty close navigation with eyeball help around reefs. We just had the 5th boat this year lost on the reefs here - all five of the boats were navigating solely with paper charts and had no electronic navigation on board. Two years ago, 4 boats piled onto the reefs the same way. Last year, several others also piled onto the reefs, but we were not here so I don't have any info on their navigation status.

For those who think that one's physical senses trump all, here is a personal story. Back when LORAN was the state of the art, my friend and I were at the end of a 20hr bash upwind into a large storm and were approaching our home port waters around midnight. We knew these waters like the back of our hand and were navigating with our senses and experience. Our LORAN started beeping at us as being off course, but we could easily see the navigational lights and markers, as well as the point of the shoal we needed to round. Because we did not have trust in the LORAN (they did have a lot of error in those days), we checked our bearings and consulted each other and convinced ourselves that the LORAN was wrong, so we turned it off.

We then proceeded to run right up on that point of shoal because our senses transposed two navigational aids in the dark to the wrong relative distances and our knowledge and experience told us we were correct. I bet this has happened to hundreds of boats throughout history.

The datum argument is silly - that exists regardless of chart format.

As for the people here identifying weaknesses having "extremely experienced and therefore have had more exposure to electronic chart failures, and have had a higher level of training with electronic .navigational instruments, so are more aware of there inherent flaws", I need to point out that several of them specifically said in their posts that they had very little experience with electronics, and almost no training or history with them. They do seem aware of a lot of flaws with them - mostly having to do with those evil things burrowing into people's minds and wreaking havoc with the universe - but they also don't seem to see the similar flaws in other types of navigation and related tools.

Everyone has anecdotal stories of the type of knowing "people who ran right into land because they had their heads buried in a chartplotter" - but I fail to see how this is the chartplotter's fault. Same with all of the examples of "I had brand X of an electronic chart and it was missing something".

One could provide an encyclopedia of examples of people going aground using DR or sextants, being mislead by paper charts, etc. In fact, throughout history, far more people have come to grief without chartplotters, GPS and/or updated electronic charts than with them. I would venture that many of these people would not have come to grief if they did have them.

Mark

[rgscpat]

I'm sure that it would be a huge sacrifice for a race boat to plot a prudent rounding distance around a small island, even post-race, given that it could have cost them a crucial 10 boat lengths in the race back to the tavern; the risk of losing a boat or of risking lives pales in significance compared to that of being late to get to the rum. Sigh.

There are old pilots,
and there are bold pilots,
but not so many old, bold pilots.