I gather some electronic cartography doesn't work some gps recievers. I would guess this one would work with Garmin Blue chart. I was looking at another reciever.
http://www.amazon.com/Dual-Electronics-XGPS150-Universal-Smartphones/dp/B004M3BICU
I'm trying to figure out which would be easiest to keep charged, best signal, etc. Let me know what you find out. Thanks.