Your fish finder already tells you how deep the fish are... but how do you know how fast you should troll so that your lure rides at that depth? Wonder no longer! This handy calculator will recommend a speed based on information you provide. The advanced algorithm takes into account several variables which can affect the depth of your lure as you move across the water, including: - the type of line; some lines are more buoyant than others - the diameter of the line; thicker lines have more drag in the water, and will ride higher as speed increases - the amount of line you have in the water; longer lines allow for deeper trolling at higher speed - the weight of the lure; heavier lures sink further than lighter ones at a given speed Once you enter this information, and tell it how deep you want to fish, the app can estimate a trolling speed to allow you to fish at your desired depth.