Those someone know it is possible to put some BlueChart map on StreetPilot III - like Adriatic coast
I had once tried them in my Street Pilot 2610 and the results were terrible. The color scheme was such that both the land and water were the same color blue so land boundries just looked like countour lines.
You could always download one and try it if you are curious, it certainly won't harm the GPS in any way. Your GPS will certainly recognize them as they are non-nt maps/charts.