Planar boards are designed to spread trolling lines out away from the boat. This is achieved by water ‘pushing’ the board away from the boat. The more line you let out the further out the board goes. Equipped with a strike indicating flag this allows you to troll more lines at a safe distance from each other and makes for wider trolling swaths to cover more water. An In-Fisherman tip is to use planer boards to work bait through water that is too shallow for the boat to enter.