221 champ. Tried doing a search, had not luck. Upgrading to a unit at the console with side scan, I am assuming I need to locate on the back of the transom and not through, correct? Where and how to mount? Also assuming I need to drill through the transom? Seams like it would be a straight forward question on line, lots of mixed results. Help/photos appreciated.
Dazed and confused in Detroit.
Garmin 93sv