Elkhunter- Thank You very much for the reply. I am, however talking about navigation, not sonar.
I was fooling with it this morning and found it shows contours of other lakes, so I assume I need a map to show Chaumont Bay. It shows Seneca Lake, but not Cayuga, Otsego, but not Canadarago, Lake Ontario - near Buffalo, but not the East end and not Lake Erie out of Buffalo -- there are soundings, but not the actual contour lines. UGGGGHHHHH!
Trying to research map cards, fun wow, Humminbird Lakemaster does not show a coverage map, just a list of lakes. Brutal. You would think that when you buy a unit you could get the areas with a few hours of you or something like that!!
Anyway- any recommendations on Map chip for Chaumont -Lake O (Niagara River end) and Lake Erie - Buffalo end (likely 2 different maps).