Two fold question, we were out in a 17 ft Crestliner that we did well on, but we had a few boat control issues...one the speed one the GPS jumped around quite a bit and when we had to net a fish the front end of the boat would start going way off course...would larger trolling bags help with this problem? Or is it normal for speeds to jump some? GPS is a lowrance elite 4.

Thanks !
Ben