Author Topic: Tablet for navigation  (Read 1057 times)

Morski Krastavac

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Tablet for navigation
« on: August 06 2019, 13:57 »
Not necessarily Bavaria specific:
I am considering to use the Navionics "Boating App", download the charts and software onto a tablet and use it for navigation on my BAV40. My question is if anyone has done something like this and specifically which tablet is most suitable. Obviously full sunlight readability is important, so would be water proof and power consumption.
Any suggestions?
Morski

SYJetzt

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Re: Tablet for navigation
« Reply #1 on: August 06 2019, 15:33 »
depends on the price you want to pay!
I purchased this spring a Samsung Galaxy Tab A10.1 in a waterproof armor-x case and a docking cradle for the helms place on deck.
Works fine with navionics and opencpn too.
Readability beneath bimini is good, but in direct sunlight (mediteranean) not really usable.
For use in direct sunlight you need a brightness of 1000 nits or more, which no (consumer) tablet will reach. 
New marine chartplotters or mfd´s reach that brightness, but will cost much more and are proprietary closed systems.
The biggest advantage of the tablet is imho the price for (european) charts. But for US this is another story.i
 

Morski Krastavac

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Re: Tablet for navigation
« Reply #2 on: August 07 2019, 14:14 »
Thanks for the info, does your tab have a built in GPS and if so, is it compatible with the Navionics App and/or Open CPN? How much memory does your tablet hold, obviously enough to download the charts off Navionics and OpenCPN. I want to make sure my new machine has enough brain to hold the information.
Currently I run CPN on a laptop with GPS mouse. That works fine but it must stay at the nav station due to poor daylight readability, which is an obvious pain in the rear.
After your post I looked at the Samsung website and specifically both at the A 4 and S 4 series. Not sure if a 200 Dollar price difference justifies the S over the A. Opinions?
Morski

SYJetzt

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Re: Tablet for navigation
« Reply #3 on: August 07 2019, 14:54 »
tablet is like this:
https://www.samsung.com/us/mobile/tablets/galaxy-tab-a/galaxy-tab-a-10-1-2019-32gb-black-wi-fi-sm-t510nzkaxar/#specs

Memory is sufficient for holding all kind of charts (there are models with up to 128GB memory, enough for the whole world) and extendable with additional sd cards (but not sure, if navionics can deal with that sd cards).
Navionics and Opencpn can deal with the built-in gps, but i have established a connection to my seatalk1 network over a wifi multiplexer, so i can get all info from the raymarine world on the tablet and vice versa on opencpn.

Check the availability of an exactly fitting waterproof case carefully, if ordering a tablet. Without a real tough waterproof case i think there is no adaequate lifespan for this equipment.

The built-in battery provides operation over 4 hours of service with full brightness of screen, so I fitted an additional qi-Charger and receiver for the tablet, so there is no need to open the usb-slot in the waterproof case for charging, if there are harsh conditions on deck.

I spent a little more money for all the additional equipment (case, cradle, charger, software and charts) as for the tablet itself, but i think the price is very reasonable for the whole stuff.


Rampage

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Re: Tablet for navigation
« Reply #4 on: August 10 2019, 08:00 »
I use Navionics on an iPhone and iPad, neither are easily readable in bright sunlight but fine under the bimini.  I’ve got a lot of charts downloaded on to them, as I use the app in UK and in the Med: I have a total of 2.16gb of storage dedicated to the app.  That’s to give you some idea of the storage needed.

Provided you’ve got a source of position data from a built in gps the app will work fine.  Using an external gps may need some specific settings but most tablets these days come with built in gps.

When using the iPhone in the cockpit, I use a simple waterproof case and a car holder to stop it going walkabout.  I use it for approaching new places where I’m uncertain about the accuracy of the plotter charts, so I don’t need to use it for long periods, so no charging required.

Final point, if you’re thinking of an iPad, be aware that only the ones that have a sim slot have a built in gps.

Salty

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Re: Tablet for navigation
« Reply #5 on: August 11 2019, 13:02 »
I use Navionics on an iPhone and iPad,

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.

When using the iPhone in the cockpit, .....
................  I use it for approaching new places where I’m uncertain about the accuracy of the plotter charts, ........

.
.

With respect, what makes you think that Navionics charts on your iPhone or iPad are any more accurate than the electronics charts in your plotter.

My plotter uses Navionics charts, but one of the first things I noticed very shortly after buying a brand new multifunction chart plotter complete with a new Navionics chart was that a wreck located a short distance outside of the harbour was incorrectly marked in that it was depicted using a combination of symbols. The references I am about to refer to are those shown in the United Kingdom Hydrographic Office (UKHO) and internationally approved Admiralty Chart 5011, namely the list of “Symbols and Abbreviations used on Admiralty Charts.”

In the instance I am referring to the Navionics chart depicted the wreck using a combination of the following symbols:-
IK28 which is the symbol for a dangerous wreck where the depth of water over the wreck is unknown, but is considered to be 28 metres or less on UKHO charts (it used to be a lesser depth on U.S. charts and on those of many other countries that didn’t have VLCCs within their national fleets), and
IK2 which refers to a symbol used to indicate a depth cleared by a wire drag sweep

Interrogating the symbol on the chart that Navionics have used, indicated that the wreck had been swept with a wire and that there was a clear depth of 14 metres above the wreck.

The symbol they should have used is shown at
IK27 which notes the clear depth surrounded by a dotted circle with the wire swept symbol directly under the dotted circle.

The combined symbol that Navionics had used was entirely wrong and misleading, and were it not for the interrogation facility provided by the plotter software it would not have been possible to figure out with certainty, what their combined symbol may have meant. It may be that you don’t have such interrogation facilities on your iPhone or iPad and I agree that a 14 metre depth in the vicinity of a port entry is hardly likely to worry you, except that without the interrogation facility there was no indication of what the depth of water was over the dangerous wreck. All you would know from the List of Chart Symbols waould be that it was 28 metres or less. How much less is the unknown bit that you would want to steer clear of.

The fact that I can find such a simple error in the production of Navionics chart software means to me that the possibility of further errors is real, but I would also like to make clear that it doesn’t mean that any of the other electronic charts sold to yachties are necessarily any better, or worse, but see the next paragraph.

Unlike Merchant Ships which have to use SOLAS approved electronic chart software or carry and use paper charts provided by an approved Hydrographic Office, our little boats can use chart software produced by anybody and irrespective of whether it is approved by SOLAS or not. Unless there has been a recent change in regard to their approval, I am pretty certain that Navionics charts fall into the “or not” area.

In regard to the accuracy of Hydrographic Office paper charts, it is highly unlikely that the electronics charts that we yachties use are any more accurate than the paper charts produced by the leading Hydrographic Offices of the world from which that data has been copied in the assembly of those electronic charts. Unfortunately in making those copies, errors can and do creep in, and without the SOLAS approval, it cannot be assumed that the electronic charts most of us use are as good as the paper charts they were derived from, but they should be better than nothing at all.

Lastly in regard to that accuracy, on most British Admiralty charts there is a small inset showing different areas of the chart along with the dates that those particular areas were surveyed. Many of those areas depend on surveys carried out many years ago, some going back to the mid 1800s or earlier.
So consider for a moment the kind of navigational equipment carried on ships back then,
A sextant - depends on having a good eye and a clear horizon etc.
A Chronometer - depends on having a periodic radio signal time check, but radio wasn’t invented until     the early 1900s so back then they had to have a pretty good idea of how their chronometer was behaving, and a fifteen second error meant a one minute of longitude error in position, one mile at the equator.
A hand lead line - so any depth soundings were spot depths where it was easy to miss an under water mountain peak.
The EchoSounder was invented somewhere around 1917 and would give a line of soundings which was infinitely better than the spot depth from a hand lead line. But underwater cliff edges or mountain peaks could still be missed if not exactly on your course line, and it still had to wait until it was universally fitted aboard survey vessels.
The next improvement on sounding depth came around 1970 when side scan sonar was invented enabling a large area of the sea bed to be checked for depth.
Finally if it doesn’t say on the paper chart that full sea floor coverage has been achieved, then there may be some depth surprises to upset you.
Satellite photography will change things in due course as far as the land masses are concerned as will crowd surveying of depths from ships and yachts, but sending out a survey vessel is an expensive option that doesn’t happen all that often.

Oh, and one other point, don’t be fooled into thinking that just because you have GPS that has a read out to multiple decimal points that knowing exactly where you are puts you in safe water, it doesn’t if you don’t know if the nearby land masses and underwater dangers were accurately positioned on your charts in the first place. You could be a lot closer to something damaging than you think.

Yngmar

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Re: Tablet for navigation
« Reply #6 on: August 11 2019, 14:16 »
I think I've posted this before, so you've probably already found it by searching, but just in case here's our setup in 2017: https://sdfjkl.org/blog/2017-09-12-opencpn-in-practice/

It has evolved a bit since. We're now in warm climates and have the bimini up 99% of the time, so screen readability is no longer really a problem. We've given up on the sealable plastic bag and instead just taped over the edges of the tablet - DIY ruggedized and has withstood saltspray aplenty. Bit of silicon grease in the USB charger plug seals that up too and prevents any corrosion on the connectors.

The tablet runs OpenCPN (on Windows - Linux sadly lacked drivers for the hardware) with C-Map charts. The phone, which is now a rugged waterproof model runs Navionics. The charts work well in tandem. OpenCPN is vastly superior as navigation tool and all long-term planning is done here, plus it drives the autopilot along the route. Navionics has great detail in many out of the way anchorages with its Sonarchart, that C-Map lacks with its commercial shipping focused charts that have nothing in areas where yachts like to explore but ships do not. All charts are of course wrong occasionally and it's always good to rely on your eyes, brains and depth sounder and be careful when something seems off. On the upside, we've discovered some wonderful and isolated anchorages because the charts had them as 0.5m deep when in fact they were 8m and thus other yachts didn't even consider them :kewl (and we turn off our AIS when we find such a place).

OpenCPN is also available on Android, although with more limitations than on a desktop OS.
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SYJetzt

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Re: Tablet for navigation
« Reply #7 on: August 12 2019, 10:50 »
I agree with Salty and Yngmar.
I also checked the brightness of an Ipad, which brightness wasn´t better than the android ones. I purchased the android because of the availability of navionics AND opencpn due to the adavantages of both c-map and navionics chart worlds, as Yngmar mentioned. 

I also had a look at a IP65 pc touchscreen (with a NUC-system below deck), because there are excellent brightness values (>1000nits). But there i had to change my (old) pc system, run new HDMI-cables trough the boat and invest far more money than for the tablet solution (and cannot run the navionics stuff on the same system).

@ Yngmar: i think i need to fit a AIS-off-switch-in-the-sheltered-bay too ;D

Rampage

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Re: Tablet for navigation
« Reply #8 on: August 15 2019, 18:12 »
Salty, I’m well aware of the limitations of the data that just about any electronic chart is based on.  However, the reason I use the iPhone and Navionics when approaching somewhere unfamiliar if that the small scale charts on my plotter have often been compiled using a slightly different datum than WGS84, so the plotted position doesn’t match the ground reality.  I’ve found, so far, that Navionics is not prone to this problem.
We’re all (I hope) aware of the limitations of electronic charting available to leisure sailors and the need to consult a decent pilot book and other references to ensure safe navigation.

Salty

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Re: Tablet for navigation
« Reply #9 on: August 15 2019, 21:38 »
My chart plotter is a Raymarine A77 model that was new in 2014, and this has a facility to enable a host of different chart datums as well as that of WGS84 to be properly displayed where the relevant datum can be selected from the plotter itself. Talking to a friend a few minutes ago, and he has an elderly Raymarine RL70c chart plotter, as also did I before getting the A77, and we are both fairly convinced that RL70c also had a similar facility to enable the correct display of different chart datums. So it may be that you need to check whether your plotter also has that same facility.
Although my present plotter has a Navionics chart fitted, the previous plotter had used C-Map.
I’m fairly sure that C-Map chart data was obtained from Transas which is a Russian firm that has fairly recently been granted approved status in order to meet the requirement of SOLAS and the IMO for the production of approved chart software for use on merchant ships. The source data for the original non-approved electronic charts they used to produce was from Russian charts for areas off the coast of Russia that their own vessels had surveyed, whilst for much of the rest of the world they had taken the data from charts sourced from the United Kingdom Hydrographic Office (UKHO). Whether the information being converted to electronic charts was all then reduced to WGS84 datum, I wouldn’t like to say. However I do know that at that time only those UKHO charts where the wording on the chart stated specifically that it was at WGS84 datum were actually guaranteed to be at that datum. So it is possible that mistakes may have been made before Transas achieved their approved status.

Rampage

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Re: Tablet for navigation
« Reply #10 on: August 16 2019, 19:34 »
Salty,
I know that there is the facility to change the datum. However, it’s only for small areas such as a small Greek town quay where the datum hasn’t been properly transposed when the chart was compiled.  Why go through a series of menu options to change the datum when there’s a ready made fix of using the iPhone?  Most of the chart is fine, just some small areas aren’t right, so I stick with WGS84 and recognise that occasionally it’s worth having the iPhone there.

Salty

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Re: Tablet for navigation
« Reply #11 on: August 17 2019, 23:01 »
Hmmn, rather you than me

Morski Krastavac

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Re: Tablet for navigation
« Reply #12 on: August 24 2019, 11:58 »
First off: Thanks for all the info, I much appreciate the help.

One more question came up recently: Speaking with a boat neighbor I was told that one can not download OpenCPN onto a tablet. Is there any truth to this?
Morski

Salty

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Re: Tablet for navigation
« Reply #13 on: August 24 2019, 20:14 »
First off: Thanks for all the info, I much appreciate the help.

One more question came up recently: Speaking with a boat neighbor I was told that one can not download OpenCPN onto a tablet. Is there any truth to this?

None whatsoever, I have it on a Samsung android phone, and the guy who installed it for me had it on an android tablet. Also I’m sure I’ve read within this forum of people who have it installed on iPads and other tablets.

Mirror45184

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Re: Tablet for navigation
« Reply #14 on: November 23 2019, 07:52 »
Paper, eyeball, sounder and good seamanship.....
Mark Hutton
SV SYnergy
B40 Cruiser 2009

Odysseus

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Re: Tablet for navigation
« Reply #15 on: November 23 2019, 11:01 »
Good to read this discussion, I have worked in and on electronics since 1963 and the rate of change is growing rapidly year on year with all electronics, the big mover and shakers are only just keeping pace with change and this is done  by expensive  R&D and acquisitions at the cost of not supporting legacy products. (When they have gone they have gone. )
So, any sensible sailor should be keeping up with what is out there on the WEB as a way of making sure they have a way forward when kit fails.

What do I have.

I have run TRANSAT on an old laptop for 19 years, the kit started as  commercial  shipping  software in Southampton I believe,  then the leisure market,  they moved to Ireland 10 years ago. I find it exceptionally good in port areas around the Biscay as I can puddle hop using this data. It shows much  more detail than my C80 plotter which I do not switch on apart from in fog.

NAVIONICS is a good system, does lack some definition can be used on a lot of hardware, however as I said above, it has now been acquired by Garmin, what happens next I think is predictable,  less development,  higher costs, which has already begun.  But as of now 2019  reasonable prices.

OPEN CPN is growing rapidly, especially in America,  as this is open software  we have a number of developers working on software hardware conectability,  PCs, laptops, tablets etc.
This year I have put it on my Android Samsung 10"  tablet and Samsung phone, I also joined Dave's forum at a cost of £6 ish. They are a group of people developing the addons for this application. However there is not a lot of info out there at the moment and it took me a fair time to get started and loading charts, even now not sure how I got it all working but the future's in this software.

SAILGRIB is a weather routing app I use on my tablet the developer is a French man and it works very well, again you need to persevere getting it working but is well worth the effort.

I believe  that our sailing technology will see more expensive kit being sold as throwaway commodity,  don't expect to get anything repaired by the seller's they will not support you, once a product finishes its production run, so look to the future and support yourself.

Hope this helps

Odysseus
Bav 38


Odysseus

Clivert

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Re: Tablet for navigation
« Reply #16 on: November 29 2019, 15:05 »
We came up from Gib a year or two back doing two to three day passages around Portugal,Spain and France visiting various little harbours on the way.
We used C120 over the chart table and a C80 in the cockpit.
These were backed up by mark one eyeball and we had no problems at all.
I understand that updates on Navionics by Garmin do lack some important info.
I had to point out the the forts in the solent should be displayed as such rather than just bouyage and they did indeed update the charts.
Ipad was useful crossing the channel as I don't have AIS and I had a good signal with shipfinder so you pays your money and pick you options.
How we did it 40 years ago I don't know !!!!

Clivert

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Re: Tablet for navigation
« Reply #17 on: November 29 2019, 19:24 »
As a rider to my comments, returning from Cherbourg to Portsmouth in May this year with first time channel crossers in board, I noticed that the mail guest sailor kept referring to navionics on his phone.
My C80 lost signal ( faulty ariel ) and his first response was " don't worry, I have Navionics on my phone ".
My reply, " there's Bembridge Ledge, there are the forts and there is the Spinney Tower " !!!!!
Nuff said !

Bavaria 34

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Re: Tablet for navigation
« Reply #18 on: December 10 2019, 01:15 »
As a rider to my comments, returning from Cherbourg to Portsmouth in May this year with first time channel crossers in board, I noticed that the mail guest sailor kept referring to navionics on his phone.
My C80 lost signal ( faulty ariel ) and his first response was " don't worry, I have Navionics on my phone ".
My reply, " there's Bembridge Ledge, there are the forts and there is the Spinney Tower " !!!!!
Nuff said !

I've been in The Solent three times this year with 0.0 viz at The Brambles yet no fog in the forecast.

Nuff said?

Clivert

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Re: Tablet for navigation
« Reply #19 on: Yesterday at 10:31 »
Last sail of the season in 1979 from Chichester to the Nab.
Forecast; fog early clearing mid morning.
Fog on drive down but clear at Emsworth so headed out in our 19ft Prelude.
Reached Harbour entrance and fog.
Forecast that it would clear.
Set a course using dead reckoning and with foghorn at the ready set out.
Found the Nab surrounded by people fishing in open boats.
Sun came out so set course for home but fog came down again.
Reached Chichester entrance as fog cleared and but we had wait for the tide.
Eventually set off up harbour to Emsworth and the fog rolled up behind us.
Found our way with one crew in the bowb knowing boats on moorings.
Got up to Slipper Mill ready for haul out in the morning.
Nuff said

Dance Lightly Too

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Re: Tablet for navigation
« Reply #20 on: Yesterday at 17:52 »
I love Navionics on the iPad as a back-up to the chart plotter for many reasons.

The only problem I have had with the software is incorrect time zone resulting in an incorrect current calculation for slack current and tide height calculation for our location.

We boat on the west coast of B.C., Canada, a area of sometimes large tidal flows where a missed timing of hour can be critical for our size of sailboat. This problem only occurs as we get progressively closer to Northern B.C. and Alaska. I have mentioned this to the old parent company and the new corporation for the past 2 years with no responses.

Other then that issues I have been a satisfied user for the last 10 years with improvements happening regularly.