I have been using an open source (free) charting program that works incredibly well. It also has great support. You just need to upload your own electronic charts.
If you are interested and have a netbook or laptop for your boat: http://opencpn.org/
The program even has AIS compatibility.
If you are interested and have a netbook or laptop for your boat: http://opencpn.org/
The program even has AIS compatibility.