Drawbacks of using a smartphone as a chartplotter

[er9]

Originally Posted by hpeer

And what charts can you get for the Bahamas?

Look, if it works for you, for your cruise style, for your area, then fine, great, good for you.

There is no single best solution for everyone.

The Dragonfly's support NOAA raster charts. you have to pay for them and I don't know how much of the planet is available yet.

I agree though. I don't dislike iPads and tablets. I think like you mentioned they have their place and can be very usefull. I want to add a tablet eventually for the reasons you cite but it would be only used as a tool to enhance my navigation and plot a course.

I could even see using one to navigate but I would absolutely have the course plugged into a plotter first and probably a second one as well and the chartplotter would be ready to go on standby in an instant if the tablet malfunctioned etc....

sorry I still think they are risky as primary navigation instruments....

[hpeer]

I want to change the course of this discussion a little bit, change the focus.

The purpose of a CHART PLOTTER is to provide you with information that was previously supplied on paper charts. Secondarially it also gives you an indication of where the GOS thinks you are on the chart. It also provides additional information.

The paper charts were developed over many decades and have a pretty consistent format. It changes a bit between agencies, but is stable within agencies.

I like my electronic charts to look just like my paper charts. Less room for confusion. I HATE raster charts first because they “declutter” and thus hide important info but also because I now have to be familiar with multiple presentation formats.

Also, paper charts have information about their Provence and other neat little notes. Like what datum was used, if the datum can be identified, what year the survey was done, and all kinds of other useful stuff. That may not show up on my raster plotter but it does show up on my paper charts which look just like my plotter. So, for instance, if the datum is unknown and ther 1/2 mile discrepencies between the plotter and Chart, I want to know that. If the data on the chart was taken from a French survey in 1887 I want to know that.

So I try to keep both paper and vector charts. Why? Because the PRINCIPAL reason for anchart plotter is navigation and all that fallderall is related to understanding what your chart means.

I think folks forget that. They see the pretty colors and nifty graphics and think “Wow, this is COOL!” What is missed is those charts are no more accurate than the raster charts but give you little or no clue of what the inaccuracies may be. All the examples I’ve given are real life.

Now if you are in a small cruising area, you can verify the accuracy of you chart plotter, then the risks are minimum and these devices can perform fine. When you venture further afield things change.

Raster charts can and do mix and match data inputs. One supplier provides Bahamian charts with data from at least two different sources. They provide little lines indicating an established route. Sometimes these routes lead over coral reefs and cause boats to wreck. Raster charts can lead you to giving the data more credence than it deserves.

Try running two or three chart plotters using different data sources against one another. A real eye opener. There is an abandoned light house we platform on the Delaware River. No lights. Three foot depth all around. But that’s at low tide with a 7’ range, so 10’ at high tide. It declutters on the 3 mile range of my plotter, which is a perfectly reasonable range setting for running up river. I can see a fast motor boat plowing into that thing never knowing it is there.

My MAIN MESSAGE here is that chart COMPREHENSION is the PURPOSE of a plotter.
It can only be fully appreciated when compared to the source material, ie: the paper chart. Anything that detracts from that comprehension is taking away from the primary mission.

Sorry for sounding preachy. I’ve learned the hard way, fortunately I’ve a tough boat and have survived my mistakes while learning. Good luck.

[Bleemus]

OpenCPN on a laptop down below and currently testing Seapilot app on phone or tablet as a quick check. Impressed so far.

[hpeer]

Agreed. I’ve used Fugawi and now OpenCPN. I like both except tlfor the weakness of the laptop.

Interestingly when we bought the big boat the chart plotter was mounted below. Why?

[er9]

Originally Posted by hpeer

I want to change the course of this discussion a little bit, change the focus.

points taken, your experience is very much appreciated. thank you for taking the time to switch gears and offer a little education on the subject. its nice to get that perspective...hopefully will keep one or two of us off the rocks. I love paper charts but admittedly know little about them at the moment.

[hpeer]

Nigel Calder wrote a great little book called Reading a Nautical Chart or some such thing.

Just wonderful. Great birthday present.

[conachair]

Originally Posted by hpeer

I like my electronic charts to look just like my paper charts. Less room for confusion. I HATE raster charts first because they “declutter” and thus hide important info ....

Sure you have that the right way round? Raster charts are just an image of what a paper chart looks like. Vector charts create the image on the machine you're using with data contained in the chart file.

Personally I prefer vector but each to their own

[hpeer]

Originally Posted by conachair

Sure you have that the right way round? Raster charts are just an image of what a paper chart looks like. Vector charts create the image on the machine you're using with data contained in the chart file.

Personally I prefer vector but each to their own

Yup wrong way round. I hate VECTO charts.

See why? I’m easily confused!

[JimsCAL]

There is no single correct answer to this. Each has to find what works for them, where they sail, etc.

I sail on Long Island Sound and the southern New England Coast. Primary GPS is an old 5 inch Garmin chartplotter with a handheld Lowrance GPS (with chart chip) as the backup. I have a power cable for the Lowrance so battery life is not an issue. I carry paper charts (Maptech chartbook) as I really can't get the big picture on either GPS screen. My usual mode of navigation when cruising is to plan the route on the paper charts, lock in the next waypoint on the chartplotter, and then navigate using the waypoint course and distance info on the chartplotter. I don't bother using routes on the chartplotter.

[transmitterdan]

Hpeer,

The data that you complain is missing on raster charts (date of survey, cartographer's notes, etc) are all contained within vector charts. There is a lot more information available within vector charts that can ever be displayed on raster charts. I would say in the US the vector charts contain 10 times more info than raster. One thing that is frustrating to me is when a vector chart is missing data that is on the paper charts. There is no reason vector charts cannot have all the raster data. For some unknown reason they don't though.

[Dockhead]

Originally Posted by hpeer

I want to change the course of this discussion a little bit, change the focus.

The purpose of a CHART PLOTTER is to provide you with information that was previously supplied on paper charts. Secondarially it also gives you an indication of where the GOS thinks you are on the chart. It also provides additional information.

The paper charts were developed over many decades and have a pretty consistent format. It changes a bit between agencies, but is stable within agencies.

I like my electronic charts to look just like my paper charts. Less room for confusion. I HATE raster charts first because they “declutter” and thus hide important info but also because I now have to be familiar with multiple presentation formats.

Also, paper charts have information about their Provence and other neat little notes. Like what datum was used, if the datum can be identified, what year the survey was done, and all kinds of other useful stuff. That may not show up on my raster plotter but it does show up on my paper charts which look just like my plotter. So, for instance, if the datum is unknown and ther 1/2 mile discrepencies between the plotter and Chart, I want to know that. If the data on the chart was taken from a French survey in 1887 I want to know that.

So I try to keep both paper and vector charts. Why? Because the PRINCIPAL reason for anchart plotter is navigation and all that fallderall is related to understanding what your chart means.

I think folks forget that. They see the pretty colors and nifty graphics and think “Wow, this is COOL!” What is missed is those charts are no more accurate than the raster charts but give you little or no clue of what the inaccuracies may be. All the examples I’ve given are real life.

Now if you are in a small cruising area, you can verify the accuracy of you chart plotter, then the risks are minimum and these devices can perform fine. When you venture further afield things change.

Raster charts can and do mix and match data inputs. One supplier provides Bahamian charts with data from at least two different sources. They provide little lines indicating an established route. Sometimes these routes lead over coral reefs and cause boats to wreck. Raster charts can lead you to giving the data more credence than it deserves.

Try running two or three chart plotters using different data sources against one another. A real eye opener. There is an abandoned light house we platform on the Delaware River. No lights. Three foot depth all around. But that’s at low tide with a 7’ range, so 10’ at high tide. It declutters on the 3 mile range of my plotter, which is a perfectly reasonable range setting for running up river. I can see a fast motor boat plowing into that thing never knowing it is there.

My MAIN MESSAGE here is that chart COMPREHENSION is the PURPOSE of a plotter.
It can only be fully appreciated when compared to the source material, ie: the paper chart. Anything that detracts from that comprehension is taking away from the primary mission.

Sorry for sounding preachy. I’ve learned the hard way, fortunately I’ve a tough boat and have survived my mistakes while learning. Good luck.

This is a great subject; thanks for bringing it up.

I would politely disagree with one aspect of this -- in my opinion there is nothing to hate about vector charts, if you would only use them for their correct purposes.

Vector charts are no good for passage planning -- you can't get a good overview; important details drop out at lower zoom levels; much useful data included in a normal chart is omitted.

For passage planning and navigation, paper or raster (on a large, high resolution screen) is supreme.

But electronic plotting is not intended for this purpose primarily anyway -- electronic plotting is a killer app for pilotage. And for pilotage, you can't beat vector charts, which are much easier to understand on small plotter screens, and which instantly adjust zoom level according to your needs.

So I (for one) use raster charts (and paper) at the nav table, for navigation and passage planning. But at the helm, I use vector charts. I actually have one raster chart card for my B&G Zeus system, and I was surprised at how bad it is on small (8") plotter screens, at how awkward it is to switch between zoom levels, at how much you miss the infinite gradation of zoom levels to suit a given situation.

I used to insist on paper for all complicated passage planning jobs, but after filling the space beneath every bunk on board with paper charts, I finally gave up on that. Covering large cruising areas with paper charts, acquiring them ($$$), storing them, not to mention (!) keeping them properly and responsibly updated, is just not practically feasible on a cruising sailboat, even a large one. So now I use paper when I have it, but mostly use raster charts (including the brilliant VisitMyHarbour charts of UK and Northern European waters, kept up to date and official "for navigation" charts) on a large 4k monitor at the nav table.

[Stu Jackson]

Originally Posted by er9

>>>>>
>>>>>>>>>>


>>>>>>>>>>>>>>>>
it slips out of your hand and goes overboard etc...etc...etc...

>>>>>>>>>>>>>>>>>>>>>>>>

There is a great amount of validity to this statement. When we headed north from SF to BC two years ago, I had just received a free smart phone from AT&T to replace our old Motorola black dumb phone; it would no longer be supported.


Until I got a case for it (after the trip, of course!!!). I was forever bumbling and fumbling with the thing. It was thin. It was slippery. It wanted to go swimming, all the time. There were altogether too many times when it did drop on a deck or a dock and literally teetered on the edge.


My son still does the "Watch how clutzy my dad is with his phone" comedy routine. I never could really juggle, but it sure looks like I was trying. My son was the wonderful fella who bought me the case for it. I think it was out of sheer pity for me, 'cuz he knows that when my old boat stereo died I replaced it with a Bluetooth unit and the phone has ALL my music on it.


I tried Navionics on it but was not pleased with it. Since I grew up navigating before electronics, I have had no trouble learning my new cruising grounds the old fashioned way: paper charts. I can even figure out ETA - something like that old sawhorse: SDT.


My Garmin 76Cx still works fine, it's that we're just off the edge of the charts I purchased with it in 2008.

[hpeer]

Transmitter,

How are you getting that data? Especially on my Raymarine C80 plotter. Can you show an example?

Dock,

It’s funny but I use a silly Aquamap application for planning. I has “charts” but nothing suitable for navigation. It does show the islands, anchorages, and has Active Captain. I can run a route and get mileage.

Here is a sample. Has 2 routes, the trip we just finished and a potential run to Cartagena from Grenada with leg miles shown.

As said above, numerous times, there is no single “best” answer. I find using different tools for different jobs works for me.

[hpeer]

Screen shot of a place I want to go maybe this year

[hpeer]

Cabo Samana, DR