We have several layers of navigation redundancy - always a good idea....
The Raymarine E7 with Navionics charts is theoretically our primary tool (the reality is different). We then have both Garmin Bluecharts and Navionics charts on an iPad and Garmin charts on an iPhone. We also have a handheld Garmin GPS. We can get GPS position from our AIS/radio and our satphone and we have waterproof large area charts for general plotting. We also have a plethora of cruising guides with small detail charts. The iPhone and iPad get accurate GPS position from a Bad Elf Bluetooth GPS.
We have Activecaptain data on all our Garmin charts. Navionics decided to go it alone with a social information layer that is proving to be completely useless. I suspect they will end up with Activecaptain before long as it definitely has the momentum. Activecaptain has proven to be remarkably useful for up to date information about anchorages and locations generally. It is constantly being added to and can be downloaded for offline access. The green anchor symbol in the Garmin chart above is an Activecaptain marker. Clicking on it provides both information and reviews. I make a point of contributing whenever I think I can add value.
I said the E7 was theoretically the primary tool but the reality is that the Navionics charts are so appallingly bad for the Bahamas that we barely look at them. The image above shows a typical chart detail for both the Garmin and the Navionics. The highly detailed Garmin data (Explorer charts) has proven to be astoundingly accurate. We anchored happily at this location. Would we have done so without the Garmin charts? I seriously doubt it.
Last year we did at least use the Raymarine for passages because we could create a route on the iPad Navionics app and sync it to the plotter (creating routes on the plotter is a real pain). Anyway, Navionics updated their app and that capability has been removed. Now we barely use the plotter at all. If I could start again I would not buy a Raymarine plotter for these reasons alone - there are others that will be documented later.