I was given this unit which apparently can double as a small chartplotter. I know that one can purchase very expensive BlueChart cards for it, but I am wondering if there is another way to download charting data for it, or perhaps other mapping software is compatible with it. It came with all manuals and a mini card writer [I assume that's what it is]. I downloaded the manuals. It also came with a Streetmaps cd. I was thinking of getting a pedestal mount for it, and using my laptop as a backup.