Enter the following values in to the calculator KV - The KV value of the motor Cell Count - The amount of cells in series Drive Motors - Single or Twin Drive System Select a prop from the list Select a Hull Type Power class is determined by unloaded RPM's only. Speed in km/h and mph is calculated based on the data entered. Performance levels are determined. SAW, is for expert boaters. It is important to have a lot of experience with Radio Control Brushless boats if using this type of setup. Range for error is extremely small. Visit Radio Control Boat Motor Selection for more details
Predicting speed is great for picking out components for a build but using a Bushnell Radar Gun 
Enter motor KV and Cell Count Prop Size in (mm) This Calculator is to provide a safe conservative prop selection. Please note: It should only be used to confirm predictions. It assumes proper hull size, weight and motor size selections with motors larger than the 540 size. Prop Selections will not be calculated for Unloaded RPM's that fall in to the SAW category. SAW, is for expert boaters. It is important to have a lot of experience with Radio Control Brushless boats if using this type of setup. Range for error is extremely small. Visit Radio Control Boat Motor Selection for more details.
Enter The Loaded RPM of the engine
Select the Prop to be used from the drop down menu.
Select the Hull type to represent slippage.