Propeller calculator for speed (knots) and pitch bases on a number of values from the user. A tool for motorboat and boat motor enthusiasts. The user inputs values via "sliders". Make fine adjustments via plus and minus buttons. The app will calculate speed and the raise of the boat, based on the input. These inputs about the boat and engine are needed for all calculations: Length, Weight, HorsePower, Rpm and Propeller Slip.