well the facts are in!!!! After having a 6 page long thread on The Hull Truth about the Navionics USA app, I have found out that yes it will work out of wifi and cell range. here are a few comments from some electronic geeks over there.
#1 The iPad 3G or iPhone 4/4S GPS receiver does not need a cell or WiFi service/subscription/connection to function. Apps such as iNavX and Navionics store the charts locally on the iDevice so they only need to be downloaded once.
#2 The HTC Evo has an internal GPS. I use it quite frequently while flying where there is no cell phone or wi-fi signal. The phone specs (
http://www.htc.com/us/products/evo-sprint#tech-specs) show it has GPS and aGPS. aGPS stands for Assisted GPS which means it can use a cell or wi-fi signal to lock faster on satellites.fshmn,
#3 I have an iPhone 4 with the Navionics app. The chart plotter works in the North East canyons 90-100 miles offshore.
I can't tell you how it works, just that it does.
Originally Posted by
fshmn 
just so I "throughly" understand....
If I download the Navionics App to my Iphone 4S, then I will have a working marine gps even when I'm 20+ miles offshore?
Yes
Does the Navionics App connect to the Iphone internal GPS receiver?
Yes
Again, assuming from your statement that the Iphone has a GPS receiver.
Yes
Or will I have to integrate the Navionics maps into the Iphone GPS App?
?? Plug n play, download the app, use the app on a wifi connection to download section(s) of the chart(s) you require...
If so, $10 is a cheap backup GPS on my boat. -
Yes!