[KenB]

Maybe the question was: do you need a separate radar and GSP? Or can you use a combo unit?

A separate radar and GPS means that if one blows up you still have the other.

Combined can give you overlay (GPS and Radar on same screen), and if your console space is limited, only having one screen is a plus. Also, combined is cheaper.

I will probably go with a combo unit, yankee parsimony and all. Offshore you need the radar to find tankers and other big ships. You should not need a GPS to get home...