I've got an 18' Deep V also, with a full windshield so the boat catches a lotta wind. The only time it would get outside it's advertised radius was when the cord wrapped around the shaft and it would take a "break" to spin itself back around and regroup.
I thought I was passing along a good fishing tip, but I guess the secret's out.
I guess the next logical step is for them to combine your locator and trolling motor electronics so you can mark a spot on your fish finder and your trolling motor will take care of the rest. Or maybe it can already do that, and I just need a new locator...:D
I am just pullin' your leg.:D