I recently bought a Garmin 93sv with 2017 maps and a 73dv with a 2016 map. The navigation chart on the 93sv is white with one dotted navigation line and buoys. The 73dvs navigation chart is full of contours, depths and shading on the same lake same spot. 5 calls to Garmin support they are trying to tell me the 2017 map update took all the pertinent information off the navigation chart and added it to the fishing chart in effect rendering the navigation chart useless. Any one else have this problem or know what to do? I’m regretting Garmin and wishing I had gone with Lowrance!!!