If I mount on the bow and use the trolling motor mount, do I have to turn off every time I pull up to go to a new spot? Which would also mean I can't use when big motor is on! Right?And if these units work best under a couple miles of speed unless I have 2 units this unit should be at helm w/ ducer on the transom, guidance is needed as electronics in my New Years resolution! Learn how to use efficiently!! Thanks in advance for any recommendations!