Thanks. I was hoping someone had hacked or cracked the format. Don't get me wrong, I don't want to steal a chart vendors intellectual property, I just want to use my own data in the plotter.
Incidentally, Raytheon/Raymarine made products that used Navionics and C-Map chart cards. I have an old Navionics card for my area, but the unit I am interested in, the SL70C/RC uses a C-Map card. The C-Map card of interest in about $300.
jv