# gps vs chartplotter



## ambianceack (Aug 27, 2006)

what are the differences and similiarities between a gps and chartplotter?


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## PBzeer (Nov 11, 2002)

As I understand it, a stand alone GPS merely gives you positional data (lat. long. speed, altitude, etc.) while a chartplotter puts that information onto a chart, giving you the ability to show a track, chart a course and use and enter waypoints. Or, in a different way, a GPS tells you where you are, a chartplotter tells you where you've been, and where you're going.


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## Freesail99 (Feb 13, 2006)

Both should be used as a back up to a paper chart.


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## Tubsmacker (Mar 5, 2007)

My boat has a GPS (old model), something that I avoided buying when flying aeroplanes around as an 'Old School' seat o the pants type of aviator. Now the boot is very much on the other foot as a 'greenhorn' sailor. I am thinking of buying one of the Yeoman plotters, rather than a colour chart plotter. seemingly they are supposed to be easy to use and as they use existing paper charts, they don't require database purchase. If one is going to have papercharts as a backup anyway, it seemed a logical solution.

Does anyone have any experience of these devices?


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## Freesail99 (Feb 13, 2006)

One major difference is that the Yeoman would be it is used at the navagation station, where as the chartpotter would be used at the helm.


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## TrueBlue (Oct 11, 2004)

A chartplotter depends upon coordinates provided by a Global Positioning System antenna/receiver. The chartplotter is integrated with and reliant upon the GPS to function properly.


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## camaraderie (May 22, 2002)

Tubsmacker...I tried one but took it back. My little W&P chart protractor and a paper chart are all I need. The yeoman was just a PITA to deal with in the cockpit and I like to do my navigating from there rather than down below. 
(I do have an electronic chartplotter...but I rely solely on paper in a lot of places as I am too cheap to buy more carts! )


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## camaraderie (May 22, 2002)

TrueBlue...even though it is paper chart based....the yeoman relies on GPS as well. Full details here:
http://www.yeomanuk.co.uk/prodmar/maxi.htm


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## Valiente (Jun 16, 2006)

The Yeoman was a very good idea for its time, and may still be for those with a certain discomfort with the technology of chartplotters or computers. But depending on where you sail, you can do quite well with a coastal navigation course, a decent handheld GPS with a 12 VDC plug (as they eat batteries), and updated and corrected paper charts.

Just be aware of tricky things like "does my GPS agree with the chart datum as listed on the chart I am using?" Going from a large-scale to a smaller-scale chart for the same area...and not noting the different datums...has put many a GPS-wielding sailor on the reef, for instance. Eyes, ears and even smell trump little flickering and occasionally fictitious numbers.

It's the habits of mind that cause navigational errors in most cases. The best way to use a paper chart is to read it and plot your course away from land and reefs, and then to note a couple of waypoints on your GPS that are free from obstruction. Account for lee and tidal effects (this can be noted in the useful cross-track or "XTE" function of even the cheapest handheld GPS), and you can sail safely in most situations, given an updated chart and the ability to coastal pilot.

Chartplotters are only as good as the charts they summarize, which in some cases are awful in detail and in others are outright wrong. Better in my mind is to use a PC laptop with a scanned or "raster" chart which is an exact representation of a real paper chart, rather than the "vector" charts that the chartplotters tend to use (although there are exceptions). Vector charts have their uses, however, due to the ability to zoom in to features that are easy to miss on a screen representation.

My choice is PC and paper and to avoid the proprietary cartridges of the chart plotters. My experience is that some skippers pay more attention to the creeping movement of the little boat icon of the chartplotter than they do to the sea around them. Needless to say, this is not only a grave navigational error, but also turns the experience of sailing into, in part, a glorified video game. 

No thanks.

Good luck. Play with these gadgets at West Marine, and view the simulations. But if you just coastal cruise, I think paper and GPS and plenty of practice alone will suffice.


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## TrueBlue (Oct 11, 2004)

Cam,
My post was responding to ambianceack's question, but that Yeoman device seems like an easy method of plotting your vessel's position on paper charts - if you lack a chartplotter. I do agree with your approach to navigating though. 

We keep our planned course, paper charts out on the chart table of the pilothouse, where we also have a chartplotter. But most of our navigating while sailing is done from the aft helm, where our 2nd plotter is located. Paper charts would be very inconvenient to use back there.


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## Maine Sail (Jan 6, 2003)

TrueBlue said:


> A chartplotter depends upon coordinates provided by a Global Positioning System antenna/receiver. The chartplotter is integrated with and reliant upon the GPS to function properly.


And paper charts and plottting are depend upon a human... Human error in todays day and age is far worse than computer error IMHO. Even doctors offices are moving towards EMR or electronic medical records due to human error. To assume that humans have less errors than computers is absurd.

I do know how to use a sextant and ded/dead reckoning and plotting yet, unless it's pea-soup fog, I don't normally pre-plot on paper. I'm a firm believer that one should know old school first, as a back up, but lets face it most new boaters won't ever learn this stuff and unfortunately a chart plotter is the next safest alternative to real seamanship.

I've been in situations, racing in fog, where there were three very seasoned, old school, ded reckoning type sailors, not including myself, all disagreeing upon our position each one insisting they were right. One loose halyard in a race, in thick fog, and all bets are off and positions get lost. So who was right? Since I was not the tactician I was unsure as were the other two. Fortunatley I had thrown my Garmin GPS Map 176 in my bag and pulled up our posiion in less that 30 seconds while the other guys were still arguing about how close we were to Half Way Rock! None of them had been right and the closest one, the tactician, had us off by over a half mile! He had looked at the wrong tide table when calculating drift! This is also a guy who has done Marion to Bermuda as a tactician so he was no spring chicken and a very competent sailor, it happens! In this situation it was human error times three!!! GPS error zero!

In 12 years of using a GPS, aboard a boat, I have had no situation, even in the days of SA, where I could not get a fix. Sure I've had times where my accuracy was more than 100 feet off but I can't draw a line on a chart, with a sharp pencil, 100 feet wide so that really is not a major concern.

To answer your question a chart plotter overlays your actual lat/long positionon a chart. If the charts were bad when they were made, like many Bahamas charts, then the GPS will still show you where you are but the chart is wrong so you could still hit bottom. Relying solely on paper charts is no safer in many areas than relying on any other form of navigation because many charts are just plain inaccurate and no matter howmuc you spend on a plotter it can't correct for poor data!

I know of no less than 30 uncharted rocks along the Maine coast, many them reported years ago yet no charts show them. if these charts are scanned into a GPS and used those rocks still won't show up!


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## camaraderie (May 22, 2002)

TB...sorry if I wasn't clear in my post. the yeoman plotting board requires input from a GPS to be properly set up to use on each paper chart you put on the board. Didn't know if you knew that so provided the link. Either with an electronic chartplotter or the Yeoman plotting board..you are ultimately relying on a GPS position fix. Now on to more important things:

*But most of our navigating while sailing is done from the aft helm, where our 2nd plotter is located. Paper charts would be very inconvenient to use back there.

*Are you saying you are sailing relying solely on a chartplotter for your position?? Do you not want your paper charts at your side? I understand you are using them for planning but I cannot imagine not using them while underway as well.


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## Tubsmacker (Mar 5, 2007)

Reading what you guys have written, It's all coming back to me now why I never fitted one in the Aircraft! I remember getting a rush out of Having to establish position when in doubt because of airspace restrictions etc. Doing things theb hard way was actually part of the fun. When GPS came out, you'd meet the village idiot flying around Europe,when previously he wouldn't make it past the tea bar door. But like I said earlier, The boot's on the other foot and I am now the 'village idiot' perhaps the difference is I will use manual navigation even though I'll have a GPS in every locker and enough Duracell batteries to power a Fridge Freezer!

I saw a mention of self scanned Raster charts. 
I found this programme which does that and provides lat long positioning from sextant sightings too. I have yet to learn how to use one though but it looks fun and a useful backup to my sackful of GPS devices/battery packs
http://www.tecepe.com.br/nav/


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## TrueBlue (Oct 11, 2004)

Cam,
I use paper charts for all our planned trips - have been for decades. As a result of years of plotting courses directly on paper charts and repeating the same routes over and over within our cruising range each season, these routes have become permanently penciled onto each chart - and we have amassed quite a collection.

We of course have GPS, in addition to separate but integrated chartplotter screens at both helms, plus a handheld backup. The paper charts are always out on the chart table and accessed frequently when either sailing from the aft cockpit helm or piloting from the pilothouse.

Here's a view of the pilothouse while in Block Island last season:










But having paper charts open on the aft deck is inconvenient during heavy weather and high winds. My point was, if we were to use the Yeoman device from the aft helm, the charts would be even more vulnerable.


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## camaraderie (May 22, 2002)

Ahh...ok...didn't sound like the usual TB ! Sorry for the misinterpertation.


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## Tubsmacker (Mar 5, 2007)

Virtual VOR/DME 

Just as an add on to the thread. I went on a sailing refresher course recently and was taken aback by the amount of time that people were taking finding position on a paper chart using lat longs from a gps. Particularly in view of the fact that the approx position was known. Time spent below was counter productive in a very busy shipping area I thought.

Coming from an aviation background, It occurred to me that whilst flying along at 130 kts I never had time to bugger around with lat longs and always used VOR/DME. What this system comprises of is a ground station (they are everywhere) that sends out 360 signals so you can always work out which spoke you are on from the compass rose on the map. DME is another signal that shows your distance from the station in miles. therefore you can now see where you are on the map very accurately.

Whilst in the cockpit on the sailing course I decided to make use of a virtual VOR on my marine chart. Of course they are there already. there are compass roses on all charts usually with the lat long shown. All you need to do is programme in chart compass rose as a waypoint on your handheld GPS, then with folded chart in hand, you can see where you are using a straight edge scaled with distance for your chart (if you use a scale distance ruler, you need to watch the scales of the charts of course) 

At any time, the gps will give you distance and bearing to your compass rose and you can see where you are.

Is this too simple and should I climb back in my cockpit, or is this idea of any use to anyone . Aviation shops sell those stick on compass roses so you can position them over any suitable waypoint and use the straight edge on that.


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## TSOJOURNER (Dec 16, 1999)

Tubsmacker said:


> Virtual VOR/DME
> 
> Just as an add on to the thread. I went on a sailing refresher course recently and was taken aback by the amount of time that people were taking finding position on a paper chart using lat longs from a gps. Particularly in view of the fact that the approx position was known. Time spent below was counter productive in a very busy shipping area I thought.


Tubs,
It appears as though you are throwing stones at an acceptable and encouraged method of safe and practicle navigation aboard a vessel? Evidentially you never lost your electrics whilst flying in controled airspace which can and does happen aboard a sailing vessel. The paper charts are a reference tool to the last known position and if taken every 30 minutes will provide a beginning point for dead reckoning if needed. "I rekon I'm dead right". This is not the forum for a replacement for a navigational class but there are many boat saftey classes available. Get into one for your own good, and maybe mine.


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## Tubsmacker (Mar 5, 2007)

Rick,
I think you misinterpreted my post, You are of course completely wrong in that I'm throwing stones at an acceptable practice. What i was saying was, if things are busy, plotting a gps position using lat long versus quick referencing using the chart compass rose. I never said anything about NOT using DR as a backup. That means you can have an accurate position easily whilst maintaining the position like the one in your photo above 

Cheers 
Tubs

I am familiar with DR and use it plus I have had total electrical failure that you describe. I had a backup and I used it!


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## TSOJOURNER (Dec 16, 1999)

ambianceack said:


> what are the differences and similiarities between a gps and chartplotter?


A GPS receiver and a Chartplotter use the United States buillt and maintained GPS Satelite system orbiting the earth. This stuff seems like voodo majic when it is studied and is absolutely awesome in its development and implementation. You are wise indeed to be considering its possible value to you. Those that thumb their noses to it's value are no different then those that refuse modern medical techniques due to their religious beliefs. Too bad, so sad. 
Similiarities
1.Both receive signals from orbiting satelites
2.Both need power to operate
3.Both are in a protective plastic enclosure
4.Both have a data screen that provides user feedback 
5.Both have many different models available
6.Both are WASS capable
 
Differences
1.Chartplotter is normally fixed in position. GPS receiver is normally handheld.
2.Chartplotter has a larger screen useful for using data to show real time position on a chart, GPS receiver displays raw numerical data.
3.Chartplotter software may be used on an onboard computer to enhance navigational information and is bad to the bone, whereas a handheld GPS receiver can be droped into a pocket when abandoning ship, or can be taken along on a hike, bike ride or whatever.
4.Electrical denmands on a chartplotter are greater then a handheld GPS receiver.

I use both types aboard as each serves it's own purpose. As long as you are considering a GPS receiver/Chartplotter why not consider a DSC VHF radio?

Got more questions? Look into a United States Power and Sail Squadron Electronics Course. The course is free, a nomial charge for the books.


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## TSOJOURNER (Dec 16, 1999)

Tubsmacker said:


> Rick,
> I think you misinterpreted my post, You are of course completely wrong in that I'm throwing stones at an acceptable practice. What i was saying was, if things are busy, plotting a gps position using lat long versus quick referencing using the chart compass rose. I never said anything about NOT using DR as a backup. That means you can have an accurate position easily whilst maintaining the position like the one in your photo above
> 
> Cheers
> ...


Tubs,
Whew, glad to read this! Was it the timing of the chart plotting that you were taken back by during the sailing refresher class?


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## TSOJOURNER (Dec 16, 1999)

Valiente said:


> My choice is PC and paper and to avoid the proprietary cartridges of the chart plotters. My experience is that some skippers pay more attention to the creeping movement of the little boat icon of the chartplotter than they do to the sea around them. Needless to say, this is not only a grave navigational error, but also turns the experience of sailing into, in part, a glorified video game.
> 
> No thanks.
> 
> Good luck. Play with these gadgets at West Marine, and view the simulations. But if you just coastal cruise, I think paper and GPS and plenty of practice alone will suffice.


After having using Maptech Chartplotting Software on a Compac laptop computer mounted at the inside helm for one year and a Raymarine Chartplotter for 4 years at an outside helm before that on a previously owned sloop I wish to offer an experienced opinion to add to your opinion about chartplotters. 
I have found them to be useful and costly. From a saftey point of view, they are useful. From the expense column, they are costly. Ray Marine that used C-Map chips was very expensive, but a laptop at an outside helm was out of the question at that time 6 years ago. Now with an inside helm the maptech chartplotter software has eliminated that expense with free electronic online NOAA chart downloads. The original maptech software package cost about $100 US last year with good tech support. 
I could explain of one instance where I have been at the helm and was able to pilot my vessel safely using a chartplotter through an unmarked channel at Rogers City, MI at night during restricted visability, where the buoys were removed "what a stupid city manuver and only the 2nd week of October" and I needed to stay inside of the channel due to draft restrictions. The chartplotter gave me the information that was needed and I made it to safe harbor, and made it out again the next day before light. Day or night would have made no difference as without a chartplotter I would have had to remain outside of the harbor in unprotected deep water. 
I would go again with a chartplotter if I had only an outside helm in a future vessel as they provide the same grapical information as does the PC ran chartplotting software. Of course the PC is much easier on the eyes, and can also provide real time satelite graphical XM Weather information.
As far as chartplotters cost, what is ones saftey worth? Does a skydiver look for a deal on equipment? Scubadiver? Home security? National Security? As long as it's afordable a sailor should have a saftey mindset and hopefully a safe vessel.


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## sailingdog (Mar 19, 2006)

Rick-

BTW, it is WAAS...not WASS...

I think Tubsmacker is dismayed by how much time it took for people to figure out where they were on the chart, based on the GPS coordinates.... Some people just have a tough time getting the X and Y coordinates down properly.

One thing that seems to be missing is that *all chartplotters are GPS units, with some additional graphical features. Not all GPS units are capable of displaying graphical chart or map data. *

_Also, I would emphasize that the GPS has to be *setup to match the Chart Datum*, or it will be wrong-and often wrong enough that you could lose your boat to the errors involved._


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## geary126 (Jul 11, 2006)

Backups are good. Critical, actually. And I'm all for paper charts. Actually, in the 70s, my parents and I had Loran and extensive chart / guides in 4 year circumnavigation (well, most of the way, anyway). Loran promptly crapped out, along with other electronics.

That being said, I just bought, for 550$, a sweeeeeeeet smallish chartplotter / sounder combo (bear in mind, the replacement cost on the mediocre depth gauge alone was $400), and this thing 1) doesn't wrinkle 2) doesn't require a flashlight. 3) is windproof 4) impresses at least other guys. 

Assuming I figure out how to mount it adequately, a 37% likelyhood, I'm going to be very, very happy.

I would say, on the chart side: waterproof paper, 15 x 22 books are super handy. Even on deck.


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## Tubsmacker (Mar 5, 2007)

Rick, It was the time taken to plot a lat long whilst on a night sail in a busy shipping area. We were using pilotage not DR as we were in the Solent UK and some people were using a lat long to check position. On this occassion I only used buoys lights and transits for my nav leg and didn't bother to use the GPS hardly at all. The Yachtmaster instructor liked the aviation VOR/DME concept though which is why i thought i'd share it on here. After all, handhelds are so cheap now that most people can justify having one.

Really it's just a fast reliable way of checking position accurately whilst on deck armed with just a folded chart and any gps.

Here's another possible Example that occurred to me whilst writing this.

Imagine sticking a compass rose on a transit line to your home port that you would normaly use visually. Under normal conditions, you can see the lighthouse is in transit with a church or whatever. (you can check the accuracy of this in good weather). If the vis then drops so you cant see the transit, the compass rose means that you can actually see your heading line on the paper chart using a straight edge rather than just relying on the info presented. you can also see (on the paper chart) any Xtrack error that a new gps bearing might indicate.
OK, if you have a c-map laded colour chartplotter in front of the wheel, then you might not be interested in this (unless it fails of course!)

I famous for boring fellow yachtspeople with aviation stories, but I actually like Navigation and never fitted a GPS or Decca Loran in any a/c I owned.
So if I'm boring anyone I apoloise for this.

PS. The reason that airliners always fly directly over your house/office, is that they in airways that usually have a VOR (VHF Omnidirectional Range) beacon at each end or leg. Modern GPS emulates the VOR positioning too I would suspect. 

PPS I used to fly low level below VOR reception using a compass+ stopwatch + Plastic ruler with knicker elastic (graduated in minutes for the map scale) it worked a treat and you always knew where you were going to be rather than just where you were. You cant get more DR and low tech than that!


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## Paysay (Apr 4, 2007)

This should stir things up: paper charts are very quickly becoming a thing of the past.

Quote from the NOAA website FAQ:"
Question - Do NOAA ENC®s enhance marine navigation and will they replace the paper chart completely?

Answer - NOAA ENC®s and RNCs will eventually replace paper charts for vessels using electronic navigation. NOAA will continue to produce paper charts for those users who do not choose to use electronic navigation. NOAA ENC®s and ECS are the greatest advancement in maritime safety since the introduction of radar to ships."

The US Navy is in the process of fitting out with chartplotters, ECDIS - N (Electronic Chart Display and Information System - Navy), and will be retiring paper charts (see: www.ukho.gov.uk/content/corpAttachments/AW/et9_web.pdf).

Advantages of electronic charts:
-Current, (Because of the logistics involved NOAA updates paper charts every two years while electronic charts are posted on the NOAA website with all current Notice to Mariners.)
- Free, (all you need is a high speed internet connection)
- Faster, more accurate plot (with GPS, or Loran). 
- Far more versital.

I still carry paper charts for the areas I cruise in, but I don't think I'll be saying that 5 years from now. I also carry three GPS receivers a chart plotter and a laptop with a full set of electronic charts and navigation software. I don't plot my position on a paper chart, but I do record the Lat/Long every hour (well, I try to remember to record it every hour.) If I ever find myself in a position where I cannot navigate electronically, I'll transfer the last several fixes onto a paper chart and navigate home the old fasioned way.

Paper charts are a dinosaur.


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## Tubsmacker (Mar 5, 2007)

Lol. I hope Rick isn't reading this or he'll be insisting on a course for you as well


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## jrd22 (Nov 14, 2000)

Dinosaur maybe, but until they make chartplotters that don't require electricity I think I'll keep mine on board as a backup. Besides, it's just not the same to huddle around the chartplotter screen at night and plot or dream about the next destination like we do with our "dinosaur" charts.


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## Boasun (Feb 10, 2007)

Chart plotters, laptops with charts are great. I use the latter with a GPS. But when you lose power you need to go back to the paper charts and plot your position quickly. So don't get me wrong in that you should have both on board. 
As when I finually get my next boat; Would have a GPS readout at the steering station with your way points plugged into along with paper charts, down below, backing up the GPS. 
The vessels I work on have their generators running 24/7 and we don't worry about having power. But most sail boats don't have the resource of that generator and rely on solar, wind gens and deep charge batteries. So you have to conserve your power resources


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## hellosailor (Apr 11, 2006)

Paper ain't dead yet. The electrical systems on small craft aren't quite as reliable as those on warships and commercial ships and I for one like the idea of knowing that even when all the toys are having hissy fits, I can find a sheet of paper and if it isn't as fast or elegant to use--at least it beats looking around and chanting "We're the Fugawi!"

I think I see what tubsmacker is getting at with stick-on compass roses, though. Instead of fumbling around and trying to plot lat/lon intersections on charts, all you need to do is find the compass rose, and measure off the same distance/bearing that your GPS is showing to it. One motion with a ruler, or one motion with a good eye, and you've got the distance and direction quickly. The downside is sticking on compass roses, but isn't there always a downside?<G> I'm not about to run out and buy (or print up) a pack, but I can see the point.


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## EscapadeCaliber40LRC (Sep 25, 2006)

In some parts of the world, neither paper nor electronic charts are sufficient. Once you leave the USA things seem to go downhill. On the leg down to Luperon the chart and the chartplotter both are in error. Eyeball navigation at close quarters is required. Don't try it at night and don't trust someone else's GPS coordinates. However back tracking on the chartplotter when heading back out is quite cool, so long as you didn't hit anything on the way in.


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## Cruisingdad (Jul 21, 2006)

Sailing offshore without paper backups and 30 minute PAPER plots verges on poor seamanship to me.

- CD


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## EscapadeCaliber40LRC (Sep 25, 2006)

I agree, just don't trust them. They are wrong. At the Eastern end of Hispaniola they are over a mile off, back at Luperon, you just end up sailing across a fair bit of land on the way in. Eyeball navigation is the only reliable tool. There's a good range guide in Van Zant's book, you just need to figure out where the turn is otherwise you'll find the mud on one side or hit coral on the other. The 84 Datum is off whether it is in electronic or paper form.


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## camaraderie (May 22, 2002)

EC40...had similar experience there...but to be fair the mapping there is way out of date and cannot be relied on...unlike the rest of the Caribe. 
I imagine someday I will get rid of paper (when I can have 3 battery operated chartplotters that cost the same as my GPS today!)... but for now...eyeballs first...paper next and chartplotter last.


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## EscapadeCaliber40LRC (Sep 25, 2006)

I agree, redundency in depth, all technology, but eyeballs for the last quarter mile. I like a chartplotter. I don't trust those "blue screens of death" Microsoft devices though but that's a personal quirk of mine. 

With a chartplotter, besides the chart you get way point and route planning, tidal charts for lots of places, a great anchor drag monitor, and a good night light. And it is great for backtracking once into a place like Luperon. 

I use a chartplotter at the helm, I have a spare unit, in case the first one craps out and I keep a good set of paper charts close at hand, plus a few other GPS tools including some nav software on my laptop just to have complete redundancy and immediate alternatives. I have a box of clear plastic garbage bags to protect the helm mounted chart plotter and I remove that plotter at the end of the sailing day and relocate it to a parallel hookup at the nav station for anchor watch/nightlight duty at night. The handheld gps is in my back pack which also serves as a ditch bag.
So for me it is eyeballs first, chartplotter second and paper last although I use all these tools interchangably throughout the trip.


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## hellosailor (Apr 11, 2006)

"In some parts of the world, neither paper nor electronic charts are sufficient. "
Heck, that even applies in reasonably well-known and populated parts of the world like NYC. The official NYC cartography goes back to pre-colonial Dutch maps of New Amsterdam, and I have no idea _what _that datum is called. But it is significantly off (1/4 mile and more) from the NAD and WGS datums with the sometimes infuriating result that land navigation packages are almost all off by 1/4 mile in NYC when they try to shift from pure GPS to street addressing (which comes form different tables) or vice versa. Google Maps and most car nav systems license from NavTeq, who feel the error is not worth correcting. (Other maps that use the free US Census "TIGER" map base suffer form the same problem, actually worse because the USC has updated only one of the four counties in NYC, leaving a split in their datum, which was never intended for navigational use anyhow.)

Even the USGS topo maps, which in theory would match the marine charts, mqanage to mislocate large structures on Jones Beach (Fire Island, LI, NY) by 1/3 mile if you miss the datum shifts--which sometimes do change. Maptech's online map server gives you no indication that the maps it is seamlessly shifting among, use different datums. Don't indicate datums on them at all.

So...cheap maps, GPSes and chartplotters, still don't make John Doe a naviguesser. Anywhere.


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## sailaway21 (Sep 4, 2006)

Tubsmacker brings up a good point in his story of a Solent passage. This passage is considered "piloting". Piloting involves the use, primarily, of visual aids to navigation, on land and a sea. The most commonly derived LOP is the visual bearing. The most important tool is the eye. Radar and soundings are also useful, if equipped. The use of GPS, Loran, celestial, or other offshore navigational devices in these situations is a dubious proposition. "Piloting" implies that there is a visual observation of position and the navigation of the vessel is conducted based upon it. The position may not even be plotted on the chart due to the exigencies of the situation. Radar is of such great use in such situations as it, more than any other navigational aid, mimicks the eyeball. As Tubsmacker intimates, a quick bearing and distance can be put down on the chart in a flash; plotting Lat/Long takes longer. Visual bearings, especially the use of ranges, are inherently better than any electronic aid. We're not as concerned with the fact that the lighthouse at Steppingstone is 0.1nm off in lat/long from it's charted position as we are with the fact that a million seamen have safely navigated it's waters by lining up on it and sailing a course leaving it a mile to port. If one wishes to glance at the GPS, in a piloting situation, for fun that's, of course, fine but there are usually more important navigational chores to be performed. A good fathometer will do far more to keep you off the hard stuff than a GPS in such situations. Tubsmacker's story illustrates two good points. A lot of sailors are not too proficient with the dividers, parallel rules, or triangles and their use with a paper chart. And secondly, they're in the chartroom when all the action is taking place between and beyond the anchors.(g)

After watching "The Hunt for Red October" perhaps one too many times, the novice navigator may be inclined to think that it is perfectly appropriate to navigate utilizing computer derived navigational information. As with all computer based systems-with a pencil and paper you can make an error but, to make a really big error you need a computer. The reason that piloting is done visually is that the human brain intuitively distills what the eye is observing without conscious thought. The GPS navigator pops out of the chartroom to report the vessel is setting down to port and the pilot replies, "yeah, I changed course for it a few minutes ago".

NOAA's assertion that electronic charts are the greatest advance since radar is rather bold, and probably hyperbole. Radio updates of Notice to Mariners is the primary advantage and it's not too big a chore to update those on a paper chart. As one who has had responsibility for maintaining a world wide chart catalog I can say that most corrections to the chart are not overly significant. Of course, one must go through all of the corrections, each and every time, to ascertain this fact. But, the point remains, it ain't like somebody up and moved Bishop Rock. For those reasons, I view radar and the fathometer as the two greatest electronic navigational tools yet invented. One could reasonably, if a bit haphazardly, circle the globe and various ports without charts if equipped with those two items. I am not advocating that, but merely illustrating how those two devices produce the most valuable information the pilot needs.

The weakness to NOAA's claim, as well as the use of chartplotters, to the small boat sailor is that it removes the human element from the navigational process. If you employ the humble paper chart, and religiously correct it via the NTM, you are subconsciously memorizing the chart. Every correction that is made to the chart will have been processed by the navigator's mind. As example, you receive a new edition of your old harbor chart. Can you espy each of the changes between it and the old chart? Of course not. And you need to sit down and examine it to ensure that nothing of great importance has changed since you last transitted it's waters. The automatic update of an electronic chart makes it more likely that you will not notice that buoy #10 has been repositioned or eliminated, until you go to make your normal course alteration off of what you thought was buoy #10. The potential for losing power, regardless of size of vessel, ensures that paper charts will be with the prudent navigator for many, many years to come. It is facile to say that computers do not make mistakes, only humans do. Where the computer and the human interface is the possible source of error and all computer derived solutions henceforth will reflect that error, often without the knowledge of the human. "Radar assisted collisions" are not necessarily a thing of the past. Computer assisted groundings are a thing of the present. In both cases, were the vessels not equipped with either device the navigator would have operated the vessel in a much different manner, the manner erring on the side of safety.

All navigational devices have their place, the great danger is in uneducated reliance upon them. The cruel irony is that the user does not know he or she is undeucated until disaster strikes. If you've got good water under the keel, and are a decent distance offshore, you may be lost, but you're pretty well safe. If you're motoring up a rock strewn channel in fog on GPS alone, you may know where you are, but you're probably not very safe.

For my fellow Luddites who utilize certain paper charts, and the same DR tracks on those charts, I have a suggestion. Scotch makes a tape that can be placed over your course plotted, usually two strips to either side works well. The tape is not removable but it can be written on nicely with a number 2 pencil and the pencil marks are erasible. It allows you to extend the life of the paper chart on that 1% of it that you are normally using. Most mates lay out their DR track in pencil, have it double checked, and then ink it in before applying the tape. The inexperienced mate decides that red ink would be the perfect color for his permanent DR track, only to discover that he can not see it under his red chart table lamp! And he has put the tape down before the realization.(g) Use black ink.


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## TSOJOURNER (Dec 16, 1999)

Cruisingdad said:


> Sailing offshore without paper backups and 30 minute PAPER plots verges on poor seamanship to me.
> 
> - CD


CD,
Would you agree that this also applies to nearshore or coastal cruising as well? It's comforting to know exactly where the heck our boat is, and by keeping an accurate log will help at least show where we have been. Aren't most Catalina owners nearshore sailors?


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## TSOJOURNER (Dec 16, 1999)

sailingdog said:


> Rick-
> 
> BTW, it is WAAS...not WASS...
> 
> ...


Certainly you are right on with your observations about the GPS and WAAS. Thanks for adding to the list of features.

On a lighter note, hav you herd of the Venicean Festival n Charlevoix? Do u sale in those watters?


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## TSOJOURNER (Dec 16, 1999)

Tubsmacker said:


> Rick, It was the time taken to plot a lat long whilst on a night sail in a busy shipping area. We were using pilotage not DR as we were in the Solent UK and some people were using a lat long to check position.


Tubs,
Sounds like there were different levels of navigational experience of the students aboard the school vessel? It sounds like a great oppurtunity for sailors to get real world experience. I have read about one fantastic sailing school in England that has an inside pool capable of making storm conditions for students to practice in life rafts. I found the info about it in Practical Boat Owner magazine, one of my favorite.


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## TSOJOURNER (Dec 16, 1999)

hellosailor said:


> I think I see what tubsmacker is getting at with stick-on compass roses, though. Instead of fumbling around and trying to plot lat/lon intersections on charts, all you need to do is find the compass rose, and measure off the same distance/bearing that your GPS is showing to it. One motion with a ruler, or one motion with a good eye, and you've got the distance and direction quickly. The downside is sticking on compass roses, but isn't there always a downside?<G> I'm not about to run out and buy (or print up) a pack, but I can see the point.


HS,
I also can see no useful purpose for a stick on "rosa dos ventos". The course should be ploted along with the navigational labeling written on the course line; heading, speed, distance before shoving off. If a GPS/Plotter is aboard then they also should be set up with the course information which has caught many of my charting errors before the trip began.  
I leave the cavalier attitude towards accepted navigational standards or piloting to another skipper to practice with.


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## PBzeer (Nov 11, 2002)

I find that my primary use of GPS w/software is when navigating shoal areas. To this point, it has pinpointed me very accurately for remaining within a channel or cut. It also gives me a look ahead at my course, so that when the eye says you're on a good line, it backs that up, or, shows your ranges were a bit off.

I also like that it keeps a track of where I've been, and of the mileage I've gone.

Yes, electronics can go down, but as long as I am near enough to land to see the shore, I have no difficulty, figuring out where I am. Another part of that, is understanding markers and their numbers, and even the orientation of the markers as you pass them.

Even if electronics were bulletproof, I would still carry paper charts.

_Currently at Dinner Key Marina, Florida_


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