1. What is a Boat Prop Pitch Calculator?

Definition: This calculator estimates the ideal propeller pitch for a boat based on its speed, engine RPM, and propeller slip.

Purpose: It helps boat owners and marine professionals select the proper propeller for optimal performance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Pitch — Propeller pitch (inches)
• S — Boat speed (miles per hour)
• RPM — Engine revolutions per minute
• Slip — Propeller slip factor (decimal, typically 0.05-0.15)

Explanation: The formula calculates how far the boat would move forward with each propeller rotation if there were no slip, then adjusts for real-world slip conditions.

3. Importance of Proper Prop Pitch

Details: Correct propeller pitch ensures optimal engine performance, fuel efficiency, and prevents over-revving or lugging the engine.

4. Using the Calculator

Tips: Enter your boat's speed in mph, engine RPM at that speed, and estimated slip factor (default 0.12). Speed and RPM must be > 0, slip between 0-0.99.

5. Frequently Asked Questions (FAQ)

Q1: What is propeller slip?
A: Prop slip is the difference between theoretical and actual boat movement per propeller rotation, caused by water resistance and other factors.

Q2: What's a typical slip factor?
A: Most boats have 5-15% slip (0.05-0.15). High-performance boats may be lower, while heavily loaded boats may be higher.

Q3: How do I measure my boat's speed and RPM?
A: Use your boat's speedometer and tachometer at cruising speed with normal load conditions.

Q4: What if my calculated pitch isn't available?
A: Choose the nearest available pitch, or consult a propeller specialist about custom options.

Q5: Does this work for all boat types?
A: This works for most planing hulls. Displacement hulls may require different calculations.