If you are just learning to fish brushpiles and you cannot get your spot lock to work like you want it. Use an anchor, but do it properly.
Don't use a river anchor or just a heavy weight. Get an anchor with chines that sets.
Find your brush pile and mark it with a bouy. Go up wind from your bouy about 30 yards and drop your anchor where it will not be near the brush pile to risk tearing it up. Drift back until you get in line with your bouy and tie off to set the anchor and stop your drift.
If you are off mark by a little bit, drop your trolling motor and use it manually to move your boat over to the brushpile.
That way you only have to worry with the yaw of your anchor set and not having to worry with all dimensions of space to control. This is a good way to get practice with your trolling motor control skills and still be able to enjoy fishing. As you get a little practice, youll be able to not have to set an anchor.
Whatever you do, do not set the anchor in the pile and ruin it for you and everyone else.
So, this is sound advice on anchor use.
Depends on your relative skill on the troller...if you get can the nose pointed in the wind and the proper speed setting on your troller, you can sit in one place without spot lock...with spot lock, you have to dial in the speed setting to aid the GPS, instead of hindering it (which can be a trial and error process) or just get a newer version troller that has a tighter GPS positioning...I don’t know the technicals, but Wayne P. can advise you.
If I can’t stay on a pile, with spot lock, I will just manually sit on it...NOW if it is a PLUM TREE...I am gonna drop anchor, and put spot lock on a really low speed.