Fishing structure with electronics.......

[hawgdog]

Being "dock shooter" mainly, i was just wondering how you would "know" you are on a brush pile or some sort of structure that you may have found with your electronics. I have really never tried to "jig" fish something that I may have trolled over.

I know this may sound "dumb" to most, but how do you know you are "hovering" over the pile , when your electronics will continue to scroll. I mean, you can't troll over a tree top , mark it, and go back and continually see it on your electronics......Can you?

Not sure if I am getting my point across, any information is appreciated. I have a hb 798 on console and terrova with a hb598, and just trying to learn how to use them.