Offline maps are useless with apps that phone home

[Jammer]

I recently moved away from the Navionics mobile app because I had problems with it failing during extended cruising in remote areas. It would periodically attempt to contact Navionics for some sort of authorization token and would refuse to display its charts if it couldn't connect.


Turns out that C|Map does the same thing (see photo). I had painstakingly downloaded offline charts for the area I would be in, and they worked for a day or two. A restart of my phone triggered the authentication cycle. No internet to be had at that particular island so I used other chart sources for a day.



These problems are hard to smoke out because the app vendors appear to use long delays (days) and combinations of events (actually using the app, restarts) to trigger reauthentication, which is silent if successful.


Cruisers who frequent remote areas and use any of the mobile charting applications should take this as a warning.

[SailingHarmonie]

This is not always a problem. If the app can connect with your MFD on the local wireless network, and it sees the appropriate chart there, it is "authenticated" and useable. Many boats also have starlink, so the authentication process is invisible to them.

This can be problematic if you use your iPad on a delivery, as I often do.

It's why my primary tablet navigation program is iSailor. None of these games. And you buy the charts forever, even if you cancel the update subscription. Finally, the charts come from a different source (in most places) than the Navionics charts I use on my MFD, so I have a "second independent opinion"

[Tin Tin]

Try switching off wifi and data on your device, works on my ipad. Still get all the maps stored offline from years ago.


So if you have moved away from Navionics what have you moved to that is better with offline maps and no internet?

[Jammer]

Originally Posted by Tin Tin

So if you have moved away from Navionics what have you moved to that is better with offline maps and no internet?

At this point I'm looking at options and am thinking about going through the complex steps required to update the charts on my 15 year old but working Raymarine C90w chartplotter. I can't replace the chartplotter without also replacing the radar, making it an expensive undertaking.


My strategy up until now has been to use the C90w mainly for radar and use a phone for charting, particularly in areas where high-resolution depth data is important.


To update the charts on the C90w would require me to purchase a CompactFlash interface for my PC, and a CompactFlash card, then download the charts of interest, and hope that they actually work when I put the card in the chartplotter. Reports have been mixed from people who have done this.