Electronic Navigation; the Downside

Spirit of Glenans said:
The sad fate of the Team Vestas VOR contestant is an object lesson on the pitfalls of relying solely on the chartplotter. See the link below, and on Twitter; #VOR


http://afloat.ie/sail/events/volvo-...il&utm_term=0_56cc7c153a-311dca7d90-405525094
Click to expand...


Sounds like as much operator error as a fault of the system itself.

Team navigator Wouter Verbraak blamed their failure to "zoom in" on their electronic charts.
"Not doing so is the big mistake that I made," he said,
Click to expand...
 
Spirit of Glenans said:
The sad fate of the Team Vestas VOR contestant is an object lesson on the pitfalls of relying solely on the chartplotter.
Click to expand...

Is it? Do you know for sure that they didn't have any paper charts on board? As I understand it, they weren't using electronic charting as well as they might have; but then they might not have been using paper charts as well as they might have, either.
 
Spirit of Glenans said:
The sad fate of the Team Vestas VOR contestant is an object lesson on the pitfalls of relying solely on the chartplotter. See the link below, and on Twitter; #VOR


http://afloat.ie/sail/events/volvo-...il&utm_term=0_56cc7c153a-311dca7d90-405525094
Click to expand...

When I came up the Red Sea all my charts both paper and electronic were up to 100 metres incorrect. The reefs were not in the places they were supposed to be. In the pacific the entrance to the lagoon of Suverof was nearly 200 metres out of position. I think that once you leave European - North American waters most charts will be dodgy when used with GPS as they have not been re-surveyed by satellite as that costs the local country lots of dosh.
michael
 
Paw Paw said:
When I came up the Red Sea all my charts both paper and electronic were up to 100 metres incorrect. The reefs were not in the places they were supposed to be. In the pacific the entrance to the lagoon of Suverof was nearly 200 metres out of position. I think that once you leave European - North American waters most charts will be dodgy when used with GPS as they have not been re-surveyed by satellite as that costs the local country lots of dosh.
michael
Click to expand...

Completely missing the point in this case - the charted position of the reef was in fact entirely accurate. The problem was that it wasn't displayed on the charts until quite a close zoom level. As discussed at great length in the main thread, I don't know why the OP felt the need to start another one.

Interestingly, Navionics seem to have fixed the issue. I was about to suggest you go and look at http://webapp.navionics.com, which used to exhibit the problem very clearly, but I checked myself before posting and found that the reef is now clearly visible! That's been altered in the last couple of weeks.

Pete
 
Paw Paw said:
When I came up the Red Sea all my charts both paper and electronic were up to 100 metres incorrect. The reefs were not in the places they were supposed to be. In the pacific the entrance to the lagoon of Suverof was nearly 200 metres out of position. I think that once you leave European - North American waters most charts will be dodgy when used with GPS as they have not been re-surveyed by satellite as that costs the local country lots of dosh.
michael
Click to expand...
This guy wasn't even aware of the reef! He must have zoomed out to plan his Course to Steer for the next period and left it zoomed out. At the speed they were achieving this could have been over 100nm for a 4-hour watch. At that zoom level the reef was hidden. It's a no-brainer that, at any speed, the chartplotter should have been zoomed in, and monitored, to reveal hazards to be given a wide berth in the boat's immediate path.
 
Spirit of Glenans said:
It's a no-brainer that, at any speed, the chartplotter should have been zoomed in, and monitored, to reveal hazards to be given a wide berth in the boat's immediate path.
Click to expand...

I think we'd all agree with that, but that's rather different from your original assertion that the crash was "an object lesson on the pitfalls of relying solely on the chartplotter."
 
pvb said:
I think we'd all agree with that, but that's rather different from your original assertion that the crash was "an object lesson on the pitfalls of relying solely on the chartplotter."
Click to expand...

I like to think that the cartographer assembling a paper chart would have included some indication of an obstacle, but I must admit I've never really seen charts of remote places like that.

The navigator explained the problem - he'd examined the whole of the planned route closely before departure, but then shortly before the start the planned route was changed. He intended to repeat the exercise for the new route once they were under way, but didn't get round to it before they reached the reef.

Pete
 
prv said:
Completely missing the point in this case - the charted position of the reef was in fact entirely accurate. The problem was that it wasn't displayed on the charts until quite a close zoom level. As discussed at great length in the main thread, I don't know why the OP felt the need to start another one.

Interestingly, Navionics seem to have fixed the issue. I was about to suggest you go and look at http://webapp.navionics.com, which used to exhibit the problem very clearly, but I checked myself before posting and found that the reef is now clearly visible! That's been altered in the last couple of weeks.

Pete
Click to expand...

Have a look at these two items from Navionics near Patmos, Dodecanese as 2 examples of some of the real dangers within Navionics. The Web app does not seem to have a facility to look at object information which on Navionics PC Plotter is right click and look at the object info.

This example is just NW or Leros - Look at the small dotted ring in 8 meters.
https://chris-robb-btconnect.tinytake.com/sf/MjQwMzVfMjE3NDc4
The depth is marked as 8 meters -its not its 4 meters

This example is on the SE coast of Patmos -IF KELHIA
https://chris-robb-btconnect.tinytake.com/sf/MjQwNDFfMjE3NDk2
The depth is marked at 3 meters, but it is infact less than 1.3 meters measured by lead line.

This is a dangerous rock, marked on paper charts clearly with a +. Even if you zoom in on Navionics you do not see any sign of a rock, you just see a series of round dots -- for which you have to right click to get the info on it (which was rubbish)

Both these were reported to Navionics - the second twice as its dangerous. They would not accept my report and said there was no rock there - so I had to send a google earth picture on which it showed as clear as a daisy and copies of paper charts.

They told me that it had been updated - clearly looking at the web app it has not.

Navionics whole method of NOT showing dangerous rocks sucks.
 
pvb said:
I think we'd all agree with that, but that's rather different from your original assertion that the crash was "an object lesson on the pitfalls of relying solely on the chartplotter."
Click to expand...
What I'm saying is that he did rely solely on the chart plotter to plan the Course to Steer. He would have seen the reef in good time if he had used a paper chart. If he didn't have a paper chart, he could have examined the area ahead at a level of zoom likely to reveal isolated rocks. He then compounded the error by not monitoring the plotter.
 
Last edited:
Spirit of Glenans said:
...he could have examined the area ahead at a level of zoom likely to reveal isolated rocks. He then compounded the error by not monitoring the plotter.
Click to expand...

That sounds to me almost like a definition of operator error.
That said, the invisibility of the reef at some levels of zoom is unacceptable. But surely that's a Navionics issue, not one of chart plotters per se. (And guess what charts I have, although I was already aware of its phantom hazards...)
 
My main electronic navigation uses admiralty charts. I can still miss detail if I select the wrong chart.
That's nothing to do with electronic navigation. It's my competence as a navigator.

M
 
A split screen display used to be offered, I always thought this was a vital feature..

...Though I contradict myself by not buying one, because of the expense - however I normally carry charts so am absolved.

I am out of touch, are plotters with a split zoom screen still available?
 
Kerenza said:
My main electronic navigation uses admiralty charts. I can still miss detail if I select the wrong chart.
That's nothing to do with electronic navigation. It's my competence as a navigator.
M
Click to expand...


I looked an electronic chart of the spot in question. At one zoom level there was nothing, not a dot or pixel; at the next level the island appeared in it's fullest detail.

It seems to me that even larger scale paper charts draw attention to important hazards even if the scale itself might not seem to warrant it.
 
You must log in or register to reply here.

Share this page

Top