I do the same in open water, then troll from one bouy to another. Some cases I use GPS, but normally just to get there. Once I'm there I use bouys. Most of the water I fish it is small enough to triangulate. I have run right up on a 4' shallow hump with logs laying accross each other. The water was clear and I could see the fish, so I dropped a bouy, backed off and used a slip cork, slayed'm.
This only my opinion, but nothing you can say will change my mind. That makes it a FACT.
Today is a Blessed Day and a Prosperous Day