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Old 07-04-2010, 10:51   #181
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Originally Posted by osirissail View Post
One major advantage of paper charts over electronic charts [...] It is the placement of the "little boat" symbol over the chart that results in many unfortunate incidents.
[...]
Or more simply said - the charts generally accurately show the land masses and underwater obstacles, but the Lat/Long registration is often different and sometimes very different from real GPS derived Lat/Long's. This is called "offset".
[...]
You see the shore features visually and then look at your paper chart and see the relative positions of features on the chart. You brain can make subconscious corrections for minor errors in the drawings of the features on the chart.
- - But with a GPS integrated e-nav computer system or GPS plotter you are presented with this little symbol of your boat and its position and you assume you are "right there" on the chart when in most cases your are not "right there" but offset somewhat.
From all your posts I know that you understand navigation but you take a very different approach to this offset. If the electronic and paper chart are the same chart, the errors are the same too and you can do the comparison between chart and shore features with the electronic chart just as well as with the paper chart. Same for plotting bearings etc.

Most users of paper charts do use a GPS to find their position and will plot that position on the paper chart. The position can be checked with a couple of bearings to shore features but remember that the difference is the error of the chart, not an error of the GPS position.
When you use a digital chart you can do the same check with bearings to find the same error. Your statement is basically that people who use electronic charts are too lazy to do that and that is not true. Like I wrote before, there may be people who don't know how to navigate or plot bearings on a chart but that has nothing to do with paper vs electronic charts. Every traditional navigation method can be done with electronic charts and in a faster and easier way.

Now let me tell you how we deal with offsets: we approach an unfamiliar shore and I see our boat on the electronic plotter approaching our destination, hooray! I paint the shoreline with the radar and drop that image over the chart. Errors are immediately visible and I adjust the electronic chart offset so that chart matches radar image (because the radar is right and the chart is wrong).... done. There is no way that you can deal with the situation better using paper charts. But there are many people who don't even know that their plotter has that offset feature because they block out all modern techniques that can only be done with electronic navigation. Electronic navigation introduced new, additional methods that are not possible with paper navigation.
If you can't drop a radar image over your electronic chart you can still use the chart offset correction in the plotter... it's just not as quick/easy.

Quote:
- - Another major hazard of e-charts when using GPS integration is "over-zooming." [...]The accuracy of the different "scale" charts is lost when you over-zoom. With paper charts the only way to over-zoom is to use a very large magnifying glass.
I don't agree. When you zoom beyond the chart resolution (digital zoom / over-zoom) and plot your position it is just as accurate than on any other zoom level. Also, distances and bearings to markers or shore features will be just as accurate. But you do loose overview when you zoom in.

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Old 07-04-2010, 14:35   #182
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Not all plotters and/or e-nav computer programs will allow you to change the Lat/Lon registration (offset) of the loaded chart. If your systems will allow you to do that then you have one of the "latest and greatest" systems. The early "radar overlay" systems did not allow you to adjust the underlying map to the radar image which led to much frustration and confusion.
- - As to taking bearings and transferring them to your e-nav system display - yeah - a good navigator will do that - but - 9 times out of 10 - (people are born lazy) they will not and just accept the position of the little "boat" symbol as the true position. Or, just compensate in their mind by adjusting your real position to be a "little to the left and forward of the boat symbol." That gets confusing when you are trying to do ten things at once while under sail in seas and entering an new harbor. I just turn the little boat symbol "off" and use the display as a regular "paper chart" and rely on radar to locate me with reference to the real visible "hard stuff" out there. Keeping your brain "in the loop" is the key to safe and successful navigation.
- - I would suggest that real time cruisers do use GPS Lat/Lon to plot their position on a paper chart. Taking bearing sights at sea in unfamiliar areas is rarely successful as landmarks/objects shown on the charts are normally grossly out of date, non-existant or lost amongst "new" objects built since the chart was originally surveyed.
- - Example: 6 years ago while first arriving at St. Georges Grenada I had the latest e-chart up and it was showing me 3 nm from the entry channel abeam a mountain - but - radar had a "hard" return that resembled the mountain at 1.5 nm ahead. A couple of circles later trying to determine the source of the discrepancy revealed that they had built a new cruise ship pier out ahead of the mountain. My personal navigational philosophy is to not proceed into "uncharted" waters until I know what is really out there and all systems agree to a reasonable degree.
- - There are numerous comedic and tragic stories of sailor/cruisers trying to sail through a mountain/shore/island/obstacle just because it does not appear on their $6K Plotter system. I would be all for the "Darwin" elimination principle in these cases except that their wreckage now presents a new obstacle for me that is not on the chart.
- - The problem with "over-zooming" is that when on a regional chart/large area chart, many of the details that are displayed on a harbor chart, are omitted for lack of space. Over-zooming gives the novice the false sense that nothing is there when if they switched to a close-in chart they would see an obstacle. Many "vector" chart systems now in use will not allow you to "over-zoom" and will automatically switch to a closer-in more detailed vector display as you zoom-in.
- - Raster electronic charts - are - paper charts. They are scanned (photo) images of the original chart. But that process consumes many times the storage space of a vector-ized chart. Vector charts are simplified human interpretations of the original original "paper/acetate" charts. The first vector charts were horrible and dangerous because too much important data from the original was left off the chart. But now the transfer systems are light-years better and they display most if not all of the same data as on the original chart. But still the richness of the color shadings and shore line details that are found on paper charts is still not available on vector plotting systems. I would suggest that is one major reason some posters have commented that they like/love the "big picture" presentation of a paper chart versus a Plotter chart is the amount of "details" you get on a paper chart. Granted that a lot of the "richness" of the drawings is of no real navigational value, but it is still a "nicer" presentation than monochrome, straight line shorelines. Simply put, paper charts are prettier. Kind of like, a "weight-challenged" (fat) lady in a bikini looks a lot better when she is wearing a baroque ball gown with lots of frills and feathers. Same data, easier on the eyes presentation.
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Old 07-04-2010, 15:01   #183
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Originally Posted by osirissail View Post
Not all plotters and/or e-nav computer programs will allow you to change the Lat/Lon registration (offset) of the loaded chart. If your systems will allow you to do that then you have one of the "latest and greatest" systems. The early "radar overlay" systems did not allow you to adjust the underlying map to the radar image which led to much frustration and confusion.
My RL 80 C plus RL 70C C plus (circia 2004) will allow an offset. As Nick says alignigning the chart with the radar image provides a poverfull navigation tool.
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Old 07-04-2010, 15:19   #184
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"As you become experienced in e-nav/e-chart systems the GPS derived little boat symbol becomes a "suggestion" of where you might be as opposed to definite "I'm there, period""
Osiris, I've maintained for years that the way most gps software shows position (by a crosshair or spot) is simply WRONG and BAD DESIGN. The "spot" can only be correct when the size of it, or the outline of it, reflects the position undertainty. So if the position uncertainty is +- 50 feet...you need a circle 100' across, not a pinprick two feet wide. Or, a pinprick two feet wide to show where the software thinks you are, but a graduated cloud 100' wide around it, to indicate the fuzzy nature of the position.

"- what you care about is that there is a submerged rock say 10 degrees to port about 1/8 nm ahead. You see the shore features visually and then look at your paper chart and see the relative positions of features on the chart. You brain can make subconscious corrections for minor errors in the drawings of the features on the chart."
if I understand you, I have to disagree most vehemently. The first time I rounded Long Island in the dead of a moonless night, it was damn black out. I wanted visual confirmation of where I was, because we were racing and yes, going to thread some rocks. All I could see was black, blacker, and blackest with so much shore clutter there was no way to use any of the lights for reference. We didn't have a chartplotter, just the paper charts and the GPS, and you know, you try to put those numbers on a chart while you're at the helm. The off-watch needed their sleep, the crew on deck with me was the cook, I wasn't going to bet the boat on their opinion.

Paper charts? Damn, a chartplotter would have been nice! At least to start a guestimate with.

Running down my list of options and lack thereof...I finally figured out that the depthsounder meant "Too deep for me to count!" when it said "_ _ _" and that put me over the deepwater channel (199+ feet) so I finally got some solid feedback from something and started connecting the dots. Go figure, the instrument that says "I can't help boss!" turns out to be the most helpful one on board. Everything else fell into place, on the paper charts, after that.
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Old 07-04-2010, 15:38   #185
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Some posters have expressed the opinion that paper charts are superior for planning a passage. Although I a am fan of electronic charts I have to agree.
Paper charts contain 10x the information, at a glance, that (currently) the electronic displays contain. Yes you can zoom in on the electronic chart and get all the information, perhaps more, but when planning a passage the big picture is best supplied by paper charts.
If however you are navigating into an unfamiliar anchorage in the middle of the night, give me an electronic chart (preferably with radar overlay) every time.
The real time update is invaluable.
If both options are available use paper charts for planning and electronic charts for real time navigation
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Old 08-04-2010, 12:00   #186
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I was just thinking about one day when I was doubling as rail meat with a waterproof paper (aka plastic) chart in my hands. And sometimes teeth as a 40mph front line moved through on a dead air day.

Or as Jon Stewart said earlier this week "One thing they don't tell you about the iPad, it's NOT DISHWASHER SAFE. Don't ask me how I know this."

Give it time, the paper and plastic will meet. There are prototype screens that are in fact close to being "thick paper" and can be rolled up, although not folded. Dishwasher safe surely will come.<G>
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Old 08-04-2010, 12:09   #187
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Originally Posted by noelex 77 View Post
Paper charts contain 10x the information, at a glance, that (currently) the electronic displays contain. Yes you can zoom in on the electronic chart and get all the information, perhaps more, but when planning a passage the big picture is best supplied by paper charts.
Ah... you mean that the paper chart is bigger than the screen that is used for the electronic chart! I agree, the silly small screens on some plotters are not worth much for planning. Basically, you will have to roughly plot a route and then zoom in on each waypoint and move it to the correct position.

For passage planning, you can use a big LCD screen to compensate for that. Also, with vector charts, you can change the configuration to leave out some data that is not important for overview, like spot soundings.
For passage planning, I use a 24" LCD screen that doubles as part of our entertainment system.

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Old 09-04-2010, 05:25   #188
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the silly small screens on some plotters are not worth much for planning. .
Yes... sometimes you are a bit righter that other times and I may compliment you on your rightness, imho, in this instance.

Paper chart folks will happily spend $500 on one region of charts (I notice a post here in classifieds for $495 for old charts of one region) and say they are better than a GPS. Mate a GPS ain't nothin without a decent size screen!
Ours is a tidgey little thing the size of a postage stamp... one really needs to get a decent size chart plotter screen and do the passage planning on a laptop.

As for paper charts having more information, thats ludicrous because in the modern lapTop world you are but a click away from Google, Wikipaedia, Google Earth and all the information that a bit of paper can't have.

I understand not to be too critical, its a generational change that takes time. Computers to be easier to use than paper takes time. Recently I had to write something with a pen.... and found it strange and difficult! The physical nature or writing is slowly disappearing from me!!!!!! Now thats scary!!!!!!!!


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Old 09-04-2010, 06:17   #189
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My primary means of navigation and piloting (until I get close enough to use my eyes) are electronic, my laptop and e-charts for planning , gps and radar for getting my boat to where I can use visual references.
Compared to my parallel rule and dividers finding courses and distances on my laptop takes a lot less time and is much more accurate. On my best day I could never get positions using a sextant and sightreduction tables that are anywhere near as accurate as those with my GPS.
However, I would never, ever cruise anywhere without also having a full set of paper charts and my courses, distances and bearing angles for my trip pencilled in on them. (I do the work on the laptop and then transfer it to paper.)
A few reasons, I have at least six laptops just die on me over the course of the years, two of those on my boat. I'm not sure why -- maybe old age or maybe laptop abuse, but they were gone, dead, not resting, RIP. And this does not count the times that I've just run out of battery.
Paper charts are just there -- no batteries required. As long a you keep them up they'll always be there when you need them. Of course out in the wind we've sometimes had to chase them around the cockpit when someone picked up the winchy handle that was keeping them in place (never lost one over the side though). That brings me to a second reason. I take the chart up into the cockpit and check landmarks and bearings. I'd never taken my laptop up into the cockpit unless I was anchored, moored or tied up. First I probably couldn't see it too well, and second any errant spray could put paid to the thing.
Finally a full-sized chart give me a much better 'sense of place' than my 17-inch laptop screen. Maybe its just my old eyes.
Don't see why a sailor would not use all the useful tools available and I think that even though I do almost all my navigation and piloting electronically, paper charts are still a useful tool.
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Old 01-11-2010, 07:52   #190
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For those of you that debate the need of paper charts in this GPS Enabled Age, we have just returned from a two week cruise along Florida's southwest coast (see http://www.cruisersforum.com/forums/...s-14448-2.html ). Our primary navigation device is a Garmin 2006C chartplotter that has worked faultlessly for 6 years. Never-the less we maintain a paper plot which is updated hourly or whenever we make a course change.

As it occers, after the second day out we began to have periods when our GPS indicated "Lost Satellite Reception". These outages were intermittent and lasted anywhere from a few seconds to a few minutes but occured with greater frequency over the days. Finally, after 3-4 days, the GPS quite entirely simply indicating "Searching for Antenna". While we do have several back-up GPS devices and quickly shifted to an older GPSMap 162 connected to our lap-top running nRoute, had we not, and had we not kept our paper plot, we would have been in poop city negotiating our way from 20 miles north of Smith Shoal light to Key West. (Although we did have our trusty Sextant and tables and could have shot a morning round of stars for a fix had that been necessary.)

A word to the wise--FWIW!

s/v HyLyte
The foregoing post on June 16, 2008 launched this thread and the subsequent discussion. As noted later in the thread, we discovered the failure of our GPS and corrected it.

As if to reinforce my penchant for keep paper charts, and plots, yesterday on a return to our Club we lost the GPS/Chart-plotter at our helmstation. It would initialize but then display a message "Antenna Cable Short Detected". No worries, we have multiple back-ups including a GPSMap 76 and Magellan DX5000, both of which I had put fresh batteries in and tested on September 1st. Lo and behold, however, neither of these devices would work either, even after I again replaced the batteries and fiddled with the machines.

I do not yet know the cause of these failures although I suspect a nearby lightening strike may have a hand in it as, upon our departure we discovered our masthead wind instrument was also malfunctioning, which usually only happens after a close lightening strike. (It's happened twice before when boats close to us were hit. Welcome to Florida sailing).

Lesson learned... Again.

FWIW...

PS: It is interesting to note how much more carefully a helmsman watches a range in a narrow channel when he/she cannot glance down to see one's position on a chart display.
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Old 01-11-2010, 11:38   #191
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As if to reinforce my penchant for keep paper charts, and plots, yesterday on a return to our Club we lost the GPS/Chart-plotter at our helmstation. It would initialize but then display a message "Antenna Cable Short Detected". No worries, we have multiple back-ups including a GPSMap 76 and Magellan DX5000, both of which I had put fresh batteries in and tested on September 1st. Lo and behold, however, neither of these devices would work either, even after I again replaced the batteries and fiddled with the machines.

I do not yet know the cause of these failures although I suspect a nearby lightening strike may have a hand in it as, upon our departure we discovered our masthead wind instrument was also malfunctioning, which usually only happens after a close lightening strike.
There is no need to loose GPS position with a few precautions. A handheld backup GPS in a waterproof box wrapped in aluminum cooking foil or a metal box, or both! (2 units if your really paranoid) should survive anything and is not expensive.
Don’t forget the batteries lithium if compatible have a long life or fresh alkaline. Test the backup every so often.
Unless the GPS system goes down which is highly unlikely or there is temporary local jamming you should always have a GPS position.
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Old 06-11-2010, 21:12   #192
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It's a no brain er- don't go anywhere without real charts and its a good idea to double check your nav. instruments against the charts. I and I am sure many others have had instrument failure- if you are checking against charts you are not badly inconvenienced.
Good point.

I too like most people, keep paper charts on hand. The costs can be rather high though. I've had good success filling in gaps in my chart packs by printing my own charts using a Xerox Phaser color printer and my MacENC and Visual Navigation Suite software. The wax surface helps protect the paper. I give them away to my guest as memento's of our trips. If Xerox made a larger format printer, like an 11x14, I'd be right on it. The normal page size can be a little small, so I find I print various magnifications for harbor approach and entrances.

Another advantage is I have notes printed on these self-printed charts--things like buoy's missing, warnings not to trust radio towers where one is plotted and three are visible, lights not functioning, or those notorious for not working, etc. These are particularly useful for harbor entries and my secret anchorages--I have many that I seem to be the only person using, and for emergency bail out route options--if I'm concerned I need to find my way into a specific nearby port in an emergency.

Some harbors have limited detail. Knowing exactly where I anchored at a secret harbor, on successive trips, allows me to note better places to drop the hook next time--for the perfect spot. Having one or two small self printed charts in the cockpit has been a big help for me, with no worries about the chart getting trashed, blown overboard, drinking spilled on them, or pages torn out of the binder because of the wind. I keep my good charts safe at the chart table. While these chart are not good for plotting purposes, they are ideal for comparing landmarks and depth readings.
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Old 06-11-2010, 21:18   #193
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There is no need to loose GPS position with a few precautions. A handheld backup GPS in a waterproof box wrapped in aluminum cooking foil or a metal box, or both! (2 units if your really paranoid) should survive anything and is not expensive.
Don’t forget the batteries lithium if compatible have a long life or fresh alkaline. Test the backup every so often.
Unless the GPS system goes down which is highly unlikely or there is temporary local jamming you should always have a GPS position.
You are making an assumption that the satellites themselves will be functioning.

On deliveries I commonly have 3 GPS's of my own with me, plus whatever is on the boat. That number does not matter if the GPS Satellite network is down. What if a major war occurs and the President makes the decision to interupt GPS service? A good navigator would not rely on it, yet everyone I know does.

As for me, I bring a Sextant with me because I'm worried one big solar flare will wipe out the GPS satellite network. Google 'CME Sun"
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Old 06-11-2010, 23:15   #194
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...I'm worried one big solar flare will wipe out the GPS...
Would that be similar to one week of unbroken haze and cloud cover wiping out celestial navigation?
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Old 06-11-2010, 23:51   #195
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Would that be similar to one week of unbroken haze and cloud cover wiping out celestial navigation?
No of course not, on day 8 the sun comes back out.

Somewhere between month 12 & 24 enough replacement satellites have been launched to acheive periodic GPS coverage over part of the globe. (insert thumb twiddling smiley here) By the end of the 5th year the full constellation should be up and running giving complete and uninterrupted coverage.

A really good solar flare is not just going to fuzz up reception, it's going to fry the orbital hardware. Or China decides to test a few more A-sat missiles leaving a lot more space junk flying around. Or the US gets into a spat with somebody that has A-sats. Or we get really unlucky and something medium sized hits a large existing satellite leaving a lot of space junk.

Just because a piece of high technology has worked well so far doesn't mean it will continue to do so indefinitely.
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