## What are the variables in a propeller calculator?

You can use this boat propeller calculator to determine one of five variables: boat speed, propeller slip, propeller pitch, engine gear ratio, or engine revs. To use the calculator, input four of the five variables.

**How to use the boat prop calculator tool?**

HOW TO USE THE BOAT PROP CALCULATOR TOOL Knowing the theoretical speed for your boat can help you select the proper pitch. To use our boat prop calculator, you need four inputs:

**When to recheck your propeller Calculator before flight?**

Before flight recheck your max. current! If your Current, el. Power or RPM are over the manufacturers limits your motor, controller and/or battery may take damage! Verify before flight by measurment!

### How to calculate the slip speed of a prop?

Got it! Loading… Use this calculator to figure out just about anything in regard to propeller, ratio, RPM and speed. You can change one parameter and recalculate the rest. Use the CalcT button to figure the theoretical speed from the actual speed and slip.

**How is the pitch of a boat propeller calculated?**

A propeller pitch can be understood by considering the action of a screw. The pitch indicates the distance that each rotation contributes to the extent to which the boat moves forward on each rotation. For instance, if the propeller moves forward 15 inches every time it completes a full turn, the nominal propeller pitch is 15 inches.

**What should propeller ratio be for 200 hp engine?**

As such, if an engine has a gear ratio of 2:1, the engine drive shaft will turn twice for every propeller revolution. It is common for 200-HP engines to have a ratio of 1.86:1. Engines that have a smaller horsepower will have a higher ratio in the region of 2.33:1. The following equations are used within this calculator:

## What’s the slip rate on a boat propeller?

The slip can be much higher at lower speeds, often above 50%. Typically, the slip reduces as the speed increases, generally diminishing to under 10%. ‘Gear ratio’ defines the number of drive shaft revolutions per propeller revolution.

**Where can I find a free propeller calculator?**

Those wanting to actually size a propeller for a boat (determine the best diameter and pitch) may find a free downloadable Propeller Calculator program from Castle Marine in the U.K. helpful. We (Polson Enterprises) do not provide assistance in sizing propellers. We suggest you: Try the Castle Marine program above

**How is wave speed calculated in a calculator?**

The calculator will evaluate and display the total wave speed. The following formula is used to calculate the speed or velocity of a wave. Wave speed, also known as wave velocity, is a term used in physics to describe the speed at which a wave is propagating.