gps signal

[joe7670]

My Garmin Marine unit has internal antenna and as Cam said since it's based on satellites, it should technically work anywhere on earth that it can see the satellites. I believe it needs 3 to pinpoint your location.

Not familiar with the nuvi, but i would think the main limitation between this and a marine unit is the maps they have. So basically the amount of info you will have about the waters such as markers, channels, depth...