There seem to be a lot of freebie nav programs out there for a laptop, but then you need to find the necessary charts that will work with it. I want to add a computer nav program as a planning aid and also as a backup before I head south. I have found plenty of info on the GPS antennas, nav programs etc. But the problem is finding the charts to go with them. Seems like the charts for the Yucatan/Belize areas are not easy to come by. One will work with Sea Clear but not others. Some I found will work with Nobeltec, but not with Sea Clear. Can anyone point me in the proper direction. I want an easy to use, ( not very computer literate), not overly expensive, nav program for a laptop, running Windows 7. Charts for the southern US and the Carribean. Mostly the western part. Any and all advice greatly appreciated.