Can you explain how to use a back trolling technique and provide a few scenarios when it would be the best choice?

Back trolling is a tried and true technique where the boat goes against the current at the same speed as the water. The boat remains in a constant position with lures situated downstream to the lead of the boat. Traveling along the bottom is the bait that remains at least 18 inches away from a weight attachment. Utilizing a back trolling technique gives an angler the opportunity to maintain greater control over fishing lines. Anglers are able to pull two sets of lines, shorter live bait or jig line and a lower line along the surface bottom, without the two lines tangling into one another. An angler also gains suitable boat control when passing over water breaks and structures. If the boat is small, back trolling cuts speed down to the bare minimum. If weather conditions produce choppy water, back trolling is fantastic. Here the choppy motion of the water causes lines to jerk back and forth which will cause fish to strike twice as often. An ideal scenario for back trolling is when searching for walleye and sauger in wing dams and dike fields. Here you would use a minnow plug lure or night crawler and remain approximately 30 feet above the desired structure. Use the bare minimum in terms of weight. You want enough weight to reach the structure but not enough to allow the line to sink past that mark. Once you feel the bait reach the bottom surface, upward sweep the rod and let it sink back down. Keep performing this motion several times back and forth across the structure. Once 15 minutes passes with no response from the fish, move along to another location.