Fuente: WIPO "rice" A measuring device is provided for use in a method for determining the depth of a trolled lure. The measuring device has an angular scale divided into degrees to measure a dive angle and a bubble level affixed thereto for calibrating the angular scale relative to the horizon. A register pin affixed at a fulcrum of the angular scale forms a center point for a fishing line to rotate about in order to measure a dive angle. The register pin further includes a flange to ensure the fishing line is retained on an outer diameter of the register pin while the dive angle measurement is taken. A mounting device is provided adapted for affixing the measuring device within a boat in a manner that allows for leveling or calibrating.