Phone with Navionics
As long as you download the area you’re going to you don’t need cell signal to use it, and its only like $15 I believe.
The phone works in some applications as mentioned by reloading the maps. A phones GPS will not track as easily and accurate as the Garmin units. If you go to remote places like I do, I urge you to invest in a good unit. All it takes is getting twisted around in snow covered limbs in dark woods…and your lost. I know, I’ve been there more than once.