Just bought a boat, has the active target and 2 12s… Believe they are gen 3… Do they not come with detailed mapping for bigger lakes? I see my map, but very little details… I guess I need to buy a Cmap card for detail? Or is there a better chip, I’m in the Midwest… Mostly fish lake of the Ozarks… I guess I assumed there would to detailed mapping all ready on the units… any input or suggestions would be greatly appreciated…thanks