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Old 30-01-2020, 17:37   #196
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Re: Traditional or digital navigation - which is safer?

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Sure you can see that there’s a reef somewhere out there, but not in enough detail to navigate near it in a yacht race. For that they needed to zoom way in from your “chart of the whole ocean” or have a whole lot of paper charts on hand that have a lot more detail than the whole ocean.
You realize that a stack of paper charts is pretty much the same thing as detail layers on a vector electronic chart. If you don't drill down the stack you won't see the detail.
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Old 30-01-2020, 17:47   #197
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Re: Traditional or digital navigation - which is safer?

The best option is to master both imo. I never rely on one of them, but if I had to I would always choose traditional navigation and paper charts. Always. I would never sail away with just digital maps. Lets say Im sailing in south eastern archipelago belt in Sweden of 100 000+ islands, full of rock gardens, and there is some issue with the electricity aboard. Nightmare.
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Old 30-01-2020, 18:28   #198
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Re: Traditional or digital navigation - which is safer?

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The best option is to master both imo. I never rely on one of them, but if I had to I would always choose traditional navigation and paper charts. Always. I would never sail away with just digital maps. Lets say Im sailing in south eastern archipelago belt in Sweden of 100 000+ islands, full of rock gardens, and there is some issue with the electricity aboard. Nightmare.
Wouldn't you be able to find a safe harbor with one general chart and a guide or pilot book?
No need to carry tbe full paper chart set for a very rare occurance.
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Old 30-01-2020, 23:57   #199
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Re: Traditional or digital navigation - which is safer?

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Sure you can see that there’s a reef somewhere out there, but not in enough detail to navigate near it in a yacht race. For that they needed to zoom way in from your “chart of the whole ocean” or have a whole lot of paper charts on hand that have a lot more detail than the whole ocean.

I can see that reef on my National Geographic Atlas of the World!

How much does one need to "zoom in" to see a reef that's 25 nautical miles across above the water? That reef isn't on top of a seamount where it would abruptly jut out of the water. There's declining depth for many miles approaching it. Even watching the depth sounder should have provided ample warning.

The prudent rule is to stay at least one mile way from such hazards, to accommodate charting errors and potential uncharted shoaling. Forewarned by what I saw on the chart, I would have been keeping a very close watch on the depth souder and not gone shallower than 20 fathoms. That precaution wouldn't even have required an accurate chart.

I realize that racers often violate rules of prudent seamanship by cutting the corners of safe navigation (that's why I don't sail with them), but I don't see how "racers take crazy risks" is a good excuse. Such behavior damages the sport and gives it the impression of being reserved for ultra-rich adrenaline-crazed imprudent lunatics. At least, that's my impression.

A moderately skilled mariner with paper charts and a depth sounder would not have run into that reef 50 years ago. I don't see how this is progress.
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Old 31-01-2020, 00:26   #200
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Re: Traditional or digital navigation - which is safer?

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I can see that reef on my National Geographic Atlas of the World!

How much does one need to "zoom in" to see a reef that's 25 nautical miles across above the water? That reef isn't on top of a seamount. There's declining depth for many miles approaching it. Even watching the depth sounder should have provided ample warning.

The prudent rule is to stay at least one mile way from such hazards, to accommodate charting errors and potential uncharted shoaling. I realize that racers often violate rules of prudent seamanship by cutting corners of safe navigation (that's why I don't sail with them), but I don't see how "racers take crazy risks" is a good excuse. Such behavior damages the sport and gives it the impression of being reserved for rich adrenaline-crazed lunatics. At least, that's my impression.
Prior to GPS... I would have said 50 miles as you didn't know what set you would be experienceing overnight... eg Runic on Middleton Reef...
Since GPS I would still allow a minimum of 10 miles as, esp in the SW Pacific, much is still 3 or more miles adrift in longitude.

PS ( not for you Pat... for tothers..) Beveridge Reef is on my BA chart of 'The World'.... its not named but is shown.... see pics below.


Any BA planning chart of the S Pacific, Indian Ocean, wherever ... will draw your attention to any offshore dangers in that ocean at a glance.. no rifling through masses of paper charts or layers of electronic charts required... its there... in your face....


And also , try finding that 3 fathom patch east of Beveridge on your electronic system...
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Old 31-01-2020, 03:32   #201
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Re: Traditional or digital navigation - which is safer?

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I can see that reef on my National Geographic Atlas of the World!

How much does one need to "zoom in" to see a reef that's 25 nautical miles across above the water? That reef isn't on top of a seamount where it would abruptly jut out of the water. There's declining depth for many miles approaching it. Even watching the depth sounder should have provided ample warning.

The prudent rule is to stay at least one mile way from such hazards, to accommodate charting errors and potential uncharted shoaling. Forewarned by what I saw on the chart, I would have been keeping a very close watch on the depth souder and not gone shallower than 20 fathoms. That precaution wouldn't even have required an accurate chart.

I realize that racers often violate rules of prudent seamanship by cutting the corners of safe navigation (that's why I don't sail with them), but I don't see how "racers take crazy risks" is a good excuse. Such behavior damages the sport and gives it the impression of being reserved for ultra-rich adrenaline-crazed imprudent lunatics. At least, that's my impression.

A moderately skilled mariner with paper charts and a depth sounder would not have run into that reef 50 years ago. I don't see how this is progress.


You can see this reef on your atlas but you couldn’t navigate near it on your atlas any more successfully than Vestra did by not zooming in on their digital charts like all the other racers successfully did. As a prudent cruiser I’d give it a wide berth too, but that’s not how you win sailboat races.

Nothing you wrote has anything to do with traditional vs digital navigation but rather is about this crews failure to use the tools readily available to them to keep their situation awareness. I agree that was their problem that caused them to go aground, NOT whether they were (not) using paper or digital charts. A navigator using ‘traditional methods’ would have had the same result if he were paying as little attention to where he was as this crew. I’m not trying to defend this crew at all, just pointing out that when you can’t even be bothered to zoom in on your chartplotter, why should we think you’d shuffle through a huge stack of paper charts in order to have a detailed chart of this reef on top to look at? This failure has nothing to do with their chartplotter but rather has to do with being too lazy or too undisciplined to use it.
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Old 31-01-2020, 03:47   #202
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Re: Traditional or digital navigation - which is safer?

Vestas is just a high profile incident...
Plenty of CDF sailors end up on reefs in the SWP and elsewhere due to undue relience on electronics.... they will believe the screen before the believe their eyes...

'But this thing is accurate to within 2 metres... what can ever go wrong...'

Wonkers...
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Old 31-01-2020, 03:48   #203
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Re: Traditional or digital navigation - which is safer?

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Simple fix... do not navigate near it......


Of course that’s true and it’s what I’d do too, but you’re missing the point that they had different priorities than you or me because they were trying to win a race, just like the rest of the fleet that successfully navigated near the reef, without going aground, who were also using digital navigation.

We could start another thread about the misplaced priorities and poor seamanship of these racers and we’d undoubtedly agree, but it has nothing to do with using traditional of digital navigation.
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Old 31-01-2020, 03:49   #204
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Re: Traditional or digital navigation - which is safer?

Vestas is just a high profile incident...
Plenty of CDF sailors end up on reefs in the SWP and elsewhere due to undue relience on electronics.... they will believe the screen before the believe their eyes...

'But this thing is accurate to within 2 metres... what can ever go wrong...'

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Old 31-01-2020, 12:01   #205
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Re: Traditional or digital navigation - which is safer?

CDF?
SWP? South West Pacific?
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Old 31-01-2020, 16:04   #206
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Re: Traditional or digital navigation - which is safer?

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CDF?
SWP? South West Pacific?
CDF cumulative distribution function
(It's something about the odds of running up on a reef)
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Old 01-02-2020, 04:01   #207
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Re: Traditional or digital navigation - which is safer?

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Vestas is just a high profile incident...

Plenty of CDF sailors end up on reefs in the SWP and elsewhere due to undue relience on electronics.... they will believe the screen before the believe their eyes...



'But this thing is accurate to within 2 metres... what can ever go wrong...'



Wonkers...


There was nothing wrong with the info on the digital charts any more than there’s something wrong with the info on your Atlas. But neither a zoomed out chartplotter or an Atlas showing the whole Southwest Pacific will show you enough detail to sail near a reef without hitting it. However, if you use either the properly scaled paper chart or the appropriately close range on your chartplotter, reefs can easily be avoided. It’s just a lot easier to zoom in on a plotter than it is to carry detailed charts of the whole Southwest Pacific and always have the right one out.

Plus, as you mentioned earlier, whether they were using paper or digital charts, even if they’d just paid attention to their depth finder, it would have given them some warning. But they were so intent on their position relative to the other boats in the race that apparently they forgot all about basic seamanship. They just weren’t paying attention and that’s not something new or.unique to just digital navigators.
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Old 01-02-2020, 06:27   #208
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Re: Traditional or digital navigation - which is safer?

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There was nothing wrong with the info on the digital charts any more than there’s something wrong with the info on your Atlas. .....


Actually there is in a lot of places, incorrect info on both digital and paper charts. Look up USS Guardian as an example:
https://en.m.wikipedia.org/wiki/USS_Guardian_(MCM-5)

There are plenty of places where both individual hazards are shown in an incorrect spot and where the maps show everything offset from GPS coordinates.

The high precision of chart plotters and GPS give people the expectation of high accuracy to and they become complacent about confirming what a chart plotter is showing them.

Visual navigation would not have helped the USS Guardian since the reef they hit was submerged but they knew that different maps showed the reef in different location (about 4nm I think) and made assumptions about which chart was more accurate.
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Old 01-02-2020, 07:05   #209
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Re: Traditional or digital navigation - which is safer?

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Originally Posted by Adelie View Post
Actually there is in a lot of places, incorrect info on both digital and paper charts. Look up USS Guardian as an example:
https://en.m.wikipedia.org/wiki/USS_Guardian_(MCM-5)

There are plenty of places where both individual hazards are shown in an incorrect spot and where the maps show everything offset from GPS coordinates.

The high precision of chart plotters and GPS give people the expectation of high accuracy to and they become complacent about confirming what a chart plotter is showing them.

Visual navigation would not have helped the USS Guardian since the reef they hit was submerged but they knew that different maps showed the reef in different location (about 4nm I think) and made assumptions about which chart was more accurate.
Interesting - navionics has the reef in different positions at different scales!



One matches well with bing satellite images, the other with yandex!
Cmap differs with scale as well but only a little.

Definitely somewhere to be very careful, easily enough info available to keep you on your toes though


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