Thread: Marine e-charts.

Navionics app doesn't require a phone signal to work. It's actually quite good and the map is not different from what you would get on a chartplotter. Some people have dedicated phone/tablet holders on their boat which makes life easier. Having said that, it's nicer to have the maps on your chartplotter and no concerns about waterproofing. If you want a map on your fish finder unit, then either Navionics or C-Map on an SD card will do the job.