TOPDAL is a ship navigation tool for measuring distance traveled based on the rotation of its propeller, which is then transmitted to a counting bell to show the total distance and enable calculation of the ship's speed using the formula \(v=s/t\). This device needs to be maintained by washing the propeller with fresh water after use, drying it, and lubricating it with grease, as well as checking and cleaning the moving parts of the counter bell.