RE: The Furuno rep laughed at me
It hasn't been great boating weather, but I did get to the boat last week and deleted all tracks again. I also changed the color of all the depth contour lines. It appears that 2 or maybe all 3 of the three automatic lines (less than 10', etc) were being drawn in the same color as the course track. That doesn't explain the apparent different slips in my marina, but it might explain the "tracks" to the marinas i have never visited. The area of the bay where I have been boating can be quite shallow, so there are "less than 10' ", "less than 20'" contour lines all over the place.