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Old 02-12-2014, 12:59   #61
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Re: Team Vestas hits reef

All this talk about errors in the charted position of the reef... the point of impact is roughly 6 miles from the end of the reef. SIX MILES!

I don't think one can chalk this one up to positional errors in their charts.

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Old 02-12-2014, 13:13   #62
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Re: Team Vestas hits reef

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Originally Posted by Jim Cate View Post
All this talk about errors in the charted position of the reef... the point of impact is roughly 6 miles from the end of the reef. SIX MILES!

I don't think one can chalk this one up to positional errors in their charts.

Jim
They said it was a "mistake". I agree on that, a big one.
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Old 02-12-2014, 13:13   #63
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Re: Team Vestas hits reef

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That question can be answered by the question "To those who rely on non-electronic navigation, what do you do when your charts and sextant are lost overboard". Or some other equally hypothetical situation.

It is a HUGE leap to start a hypothetical argument with the assumption that all electronic navigation aids have ceased working. We have freaking cameras on board that can be used for navigation. We have taken a direct lightning strike that has shorted batteries and charred navigation instruments and still had plenty of electronic navigation aids to make due with. By my last count, we had 11 GPS's, 7 independent devices that can display and navigate with electronic charts, 4 devices that can navigate to waypoints, and three devices that provide position fixes. Many of these can use the Russian system if the US one goes down (a hypothetical that is always good for a facetious argument here).

Most of these devices were acquired over the years without even attempting to bring a navigation device on board. It is almost impossible not to get a GPS inside most things you buy today. There are Casio watches that can navigate! And most of us can figure out which direction the sun rises and sets.

You are correct that this is groundhogs day!

Mark
As an engineer who has several decades in using, engineering and certifying mission critical systems I'm always amazed by the ability of the human brain to be deceived by technology. When testing and certifying the most important test is the 'holy ****' test. In a controlled environment this is simple to implement. Turn off all systems. This leaves you with the five senses. Sight, sound, feel, taste and smell.

The universal observation from commercial users of heavily integrated navigation and communication systems to the holy **** test is how little situational awareness they have. We've all experienced this at one time or another. It's when our fight or flight instincts take over.

When my wife and I took are ASA basic keelboat course we were on a 50' yacht in the San Juans with a skipper who was shall we say best suited to bar room sail training. We were transiting the main shipping channel when we were enveloped in fog. The skipper clearly had no situational awareness and I had the helm at the time. I had studied my charts the night before, I had my own compass and I had been watching the large ship traffic closely. I was able to steer us on a safe course and maintain that course because I still had sufficient situational awareness. My basic sense of sound was all I had. (the large ship fog horns) I replaced my loss of visuals of land and ships with sight of my compass.

The first lesson I teach engineers is situational awareness. Always refer to your five senses before trusting any technology. I'm always checking my five senses while sailing and then I check the instrumentation. Do they correlate. If not, am I wrong or is the instrumentation wrong. We engineers naturally think like this. Many of my non engineering friends don't.

Most GPS devices now rely on an internet connection to help with position resolution. They may also take several minutes to provide a position. They may also be using less than an ideal number of satellites resulting in less than accurate readings. Also many hazards move or were originally plotted with unknown calibration sensors. We engineers understand the multitude of errors in any digital and converted data. Unfortunately the general public don't understand, tolerance, drift, bias and the multitude of errors that compound many readings and they don't question them. A GPS reading won't help you if your chart is wrong and you may not know. That's why I always include detectability along with the common severity and occurence in all risk assessments.

We have many great technologies now like GPS but my trust in technology hasn't changed in decades.

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Old 02-12-2014, 13:50   #64
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Re: Team Vestas hits reef

Map errors in both electronic and paper charts are not uncommon, especially in remote areas.

Traditional navigation techniques such as clearance bearings can be a much more reliable way of avoiding obstructions if there is a map error. However, these techniques can also be used on electronic charts. There seems a mistaken belief that this sort of check is only possible with a paper chart.

If radar is available a radar overlay is a very powerful tool for picking up map errors.

However, in this case it sounds from the preliminary reports like map error was not a factor.

On this sort of boat navigators devote a great deal of effort to weather routing and race tactics. I wonder if this distracted from the primary role of avoiding hitting the bricks, but this is pure speculation.
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Old 02-12-2014, 14:12   #65
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Re: Team Vestas hits reef

"That question can be answered by the question "To those who rely on non-electronic navigation, what do you do when your charts and sextant are lost overboard". Or some other equally hypothetical situation.

It is a HUGE leap to start a hypothetical argument with the assumption that all electronic navigation aids have ceased working." Colemj


Mark,
I think Left Brain is correct and your above statement represents flawed logic. When speaking scientifically/philosophically about "Chance"--which is implicit in your above remarks, we know that chance is an unknown yet, concurrent with that unknown, is a quantifiable possibility/probability which, based upon experience, implies a greater or lesser percentage of occurrence. Simply stated, if we were to determine the "chance" of paper charts being lost overboard or electronics that cease to function, one with considerable experience in sailing would conclude that there is a higher probability/possibility of losing ship's power through lightning strikes, ingress of water below or catastrophic power failure than losing one's charts overboard--perhaps caused by sinking(most logical where navigation ceases and struggle for survival ensues) or throwing them overboard(unlikely). I think the point being argued is that logic, reason and experience would dictate a greater chance/probability for electronic aids to malfunction/abort than the possibility of a ship's charts going overboard. Therefore, given the element of chance as prefigured by a rational, reasonable calculation of probability, one would certainly choose paper charts over electronic charts(if you had to choose one) as the most reliable and dependable method of navigation. That is, of course ,if you are a rational person. Good luck, good sailing, and may your life be blessed with an abundant and never ending flow of electrons.
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Old 02-12-2014, 14:30   #66
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Re: Team Vestas hits reef

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Originally Posted by leftbrainstuff View Post
Most GPS devices now rely on an internet connection to help with position resolution.
Some GPS chips (A-GPS) will use triangulation from the phone towers, but this is only used when the satellite signal is lost such as in a building, or occasionally to speed up the initial fix from a cold start.
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Old 02-12-2014, 14:38   #67
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Re: Team Vestas hits reef

..clear case of icing on wings....: facepalm:
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Old 02-12-2014, 14:40   #68
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Re: Team Vestas hits reef

Paper charts are only as good as the position data used. In that regard electronic systems are many orders of magnitude more accurate and reliable than DR or sextant data plotted on paper charts. It is a trivial matter today to have multiple electronic methods of finding precise position all with different power sources. The odds all of them will fail simultaneously is so small as to be negligible. There is no factual basis to argue that electronic navigation is unreliable or otherwise not dependable enough to require old school methods. If all else fails the sun will always rise in the east...until it doesn't.
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Old 02-12-2014, 14:51   #69
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Re: Team Vestas hits reef

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There is no factual basis to argue that electronic navigation is unreliable or otherwise not dependable enough to require old school methods.
I agree with you about the reliability, but it is important to realise that traditional navigation methods such as clearance bearings and a three point fix will often give you a more accurate relative position to obstructions than the GPS when there is a map error.

GPS position errors are very rare with a well installed system, but map errors are not uncommon.
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Old 02-12-2014, 15:04   #70
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Re: Team Vestas hits reef

Noelex, I agree with you that GPS is not a full replacement for your own eyes (aided by magnification), a radar and hand bearing compass when within range of obstacles. But fretting that all the satellites will stop one day is pointless.
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Old 02-12-2014, 15:20   #71
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Re: Team Vestas hits reef

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Originally Posted by Jim Cate View Post
All this talk about errors in the charted position of the reef... the point of impact is roughly 6 miles from the end of the reef. SIX MILES!

I don't think one can chalk this one up to positional errors in their charts.

Jim
Yep, looking at the tracks in post #12, their track needed to be at least 6 miles further west or 10 miles further east to miss the reef.
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Old 02-12-2014, 18:08   #72
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Re: Team Vestas hits reef

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There are some cheap e charts and some good e charts. Regarding good e charts I don't know of what you are talking about regarding "often errors on electronic charts that are not on paper charts, and there are differences in data quality/inaccuracies ". The differences regards the presentation and some port and anchorage spot details. We are talking about very big scale data, not any difference in what regards data used for any navigation, except presentation, that can be customized anyway.
Polux- Sujin is exactly right when he says that there are "often errors on electronic charts that are not on paper charts, and there are differences in data quality/inaccuracies". Navionics in particular is RIDDLED with really quite dramatic errors. For example their data entry for notices and information contained in the "see lower zooms" notes is so bad that it can only be described as having been entered by someone for whom English is a THIRD language, who cannot even copy by sight., and I have actually rarely seen a fully accurate text. I have complained of it many times, with pictures, to no avail. There are often the most astonishing errors on E-charts that have nothing whatever to do with use of outdated bathymetry copied from the paper or whatever. For example I passed a series of lateral marks in the middle of the Coral Sea, on the Navionics charts, which were not there on the C-charts, certainly absent on Admiralty paper, and for damn well sure not there in reality! Apart from anything else, the depths were in the several thousand meter range… Look, on this one you are just wrong. Paper equally affords a FAR more detailed representation of small features on small scale charts, and offers quick and stable reference to them without "zooming". I use electronic charts all the time, and they are exceedingly useful tools. But you really overstate yourself here. Sujin is simply correct.
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Old 02-12-2014, 18:15   #73
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Re: Team Vestas hits reef

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As an engineer who has several decades in using, engineering and certifying mission critical systems

….
Most GPS devices now rely on an internet connection to help with position resolution.
I'm sorry, but your latter statement makes your first statement hard to believe.

Of the 11 GPS's on our boat, not a single one of them requires an internet connection. Almost all of them do not have the ability to connect to the internet in any fashion even if it was available.

Please point me to a single marine gps system that requires an internet connection, or even uses one in any aspect of providing a position fix. Point me to a single consumer electronic device that requires an internet connection.

In fact, simply explain to me how connecting to the internet could even allow a gps device to get greater position resolution. For example, if my gps connected to my internet right now, it would think I was in Panama City. I am hundreds of miles away from Panama City, but that is the first node in the network from me.

I don't think you understand how GPS or the internet works.

The rest of your posting has absolutely nothing to do with electronic navigation and more to do with individual people (or maybe just a drunk sailing teacher). Situational awareness is not acquired by looking at a paper chart anymore than it is lost by looking at an electronic one. Any cartography errors don't magically disappear because they are printed on paper, and a sextant used for position fixes will not magically keep you off them.

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Old 02-12-2014, 18:17   #74
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Re: Team Vestas hits reef

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Paper charts are only as good as the position data used. In that regard electronic systems are many orders of magnitude more accurate and reliable than DR or sextant data plotted on paper charts. It is a trivial matter today to have multiple electronic methods of finding precise position all with different power sources. The odds all of them will fail simultaneously is so small as to be negligible. There is no factual basis to argue that electronic navigation is unreliable or otherwise not dependable enough to require old school methods. If all else fails the sun will always rise in the east...until it doesn't.
How odd that you seem to assume that you cannot plot GPS position onto WGS84 data paper. Of course you can. Electronic charts are frequently more inaccurate due to often staggering errors in data entry which often seems to have been farmed out to drones in some third world location where they neither understand navigation nor speak English. E-charts are very useful, and I navigate with them constantly, though ALWAYS use at least two separate chart systems (vis Navionics and C-maps- which interestingly very frequently contradict each other), as well as refer to imagery from Google Earth. But it is vital IMHO when sailing long range to have paper. It is very easy to lose your major plotter systems. Currently I am in Singapore preparing to head up the Malacca Straits, and every afternoon here there are intense lightning storms. That they would take out the plotters and the tough book in a direct strike is likely, but the spare gps handhelds in the grab bag and oven not so. With these I can plot directly to paper. (Not to mention the fact that, yes, I still carry a Sextant and tables and enjoy practising eyeball and hand alone astronav). Further, paper is a superb reference which displays small hazards in small scale (so grand scale) chart areas, allowing for really useful quick reference when crossing areas such as the Coral Sea, which is simply NOT possible on the fiddly zoom system of electronic. They both have their uses but really your disdain for paper is neither warranted nor correct.

That said, the smacking into a reef much larger than Manhattan has nothing to do with poor charting!
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Old 02-12-2014, 18:35   #75
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Re: Team Vestas hits reef

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"That question can be answered by the question "To those who rely on non-electronic navigation, what do you do when your charts and sextant are lost overboard". Or some other equally hypothetical situation.

It is a HUGE leap to start a hypothetical argument with the assumption that all electronic navigation aids have ceased working." Colemj


Mark,
I think Left Brain is correct and your above statement represents flawed logic. When speaking scientifically/philosophically about "Chance"--which is implicit in your above remarks, we know that chance is an unknown yet, concurrent with that unknown, is a quantifiable possibility/probability which, based upon experience, implies a greater or lesser percentage of occurrence. Simply stated, if we were to determine the "chance" of paper charts being lost overboard or electronics that cease to function, one with considerable experience in sailing would conclude that there is a higher probability/possibility of losing ship's power through lightning strikes, ingress of water below or catastrophic power failure than losing one's charts overboard--perhaps caused by sinking(most logical where navigation ceases and struggle for survival ensues) or throwing them overboard(unlikely). I think the point being argued is that logic, reason and experience would dictate a greater chance/probability for electronic aids to malfunction/abort than the possibility of a ship's charts going overboard. Therefore, given the element of chance as prefigured by a rational, reasonable calculation of probability, one would certainly choose paper charts over electronic charts(if you had to choose one) as the most reliable and dependable method of navigation. That is, of course ,if you are a rational person. Good luck, good sailing, and may your life be blessed with an abundant and never ending flow of electrons.
I think he is wrong, and that your assumptions and premises here are flawed. This is another example of starting out with a gamed, but unexamined, premise as a non-debatable standard to compare to. But it is a red herring.

We aren't talking about a single electronic device here. In our case it is 11 of them. And many of them do not rely on the ship's batteries to begin with. To completely lose GPS navigation, we would have to have 11 separate and non-connected devices destroyed outright, or we would have to lose the entire house battery bank, two separate starting battery banks, the dinghy battery, the solar panels, the generator, two alternators, the internal batteries of the devices themselves, all of the AA and AAA dry cells we have on board (there are literally hundreds of these), and we would have to wait probably a week before all of the devices ran out of juice.

Will you wager an estimate of this probability? I have lost a chart overboard. I have never had the above happen.

We have been struck by lightning, suffering a complete outage of main electronic navigation and even our house batteries. This didn't stop us for a minute from using electronic navigation devices and charts for the next 3 weeks until we pulled in to effect repairs.

I do think that the probability of losing all our electronic navigation ability is as low as losing a chart and sextant. I think it is lower than falling overboard while trying to get a sextant fix. And I have considerable experience in sailing and navigating. Most importantly, I have eaten this dog food and know what I am talking about. You may think that logic, reason and experience says otherwise, but I suggest you aren't thinking hard enough, or are refusing to open yourself to the possibility that things are not what you believe.

If something so catastrophic happened to cause us to lose all electronic navigation ability the probability is very high that we would have greater issues to overcome than navigation. Not even paper charts and a sextant would be of much help because the boat would likely be sinking or on fire.

How many people out cruising do you think are proficient in a sextant and can whip one out immediately and get a good fix? And can keep doing this? In other words, even if there are paper charts being used, how many cruisers do you think will be able to use them if they don't have a gps?

I'm a rational person and I don't use paper charts. We do have a chart of the entire Caribbean Sea somewhere, but I don't know where it is.

I do know which direction the sun and moon rises and sets.

Mark
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