How well does this work, when out of cellular range?
I was thinking of just replacing the old garmen chart plotter with my iPad
we used an iPad with the NavX app in the virgin islands with great success, it also depends on which iPad you have, wifi alone or an iPad with GPS assist.
I currently use my IPad with INavX for my navigation. It works great and an be integrated to receive input from various systems on you boat if those systems are modern enough. I use a GPS receiver (dualGps) and link my IPad to it via blue tooth. Downfall is that the IPad battery only last about 6 hours when running the INavX. I will be eventually running 12v to my binnacle so I can keep my iPad charge while sailing. The DualGps receiver is also rechargeable and last for about 18 hours on a charge.