Back to the original point.......
Gingercoastie - We are just getting a C Series GPS/plotter/Fishfinder/radar fitted to our new boat (sorry Jon along with the new Raymarine Radio)
We have gone for the C80 - the numbers are just the screen size - same functions on all.
Apparently it will plot positions of ships sending distress calls on DSC - and you should be able to send a "location request" by DSC - and the response will be plotted on the screen.
I will let you know how I get on with it!
ps - ICOM IC-M1 portable always at hand - you must have something you can rely on!!