We're correcting all the time. When working really close, the charts are skewed from your actual position in both distance and direction. The chart is never exactly correct, ever. ( except by accident ) And,, it's not just because the charts are off. You have your own deviations on the fluxgate,, a couple of degrees here and there make things off. Only way to match is to continually correct.

We found the overlay good for finding out the position of boats anchored around you. I like to mark the position of the boats near me when I've set the hook down. In the middle of a moonless night when the boats shift with the wind and reposition themselves the overlay gives you a lot of information on the new relationships of boats and land.

Radar with overlay is as valuable at anchor as it is at sea.