1. What is a Propeller Pitch Calculator for Boat?

Definition: This calculator determines the ideal propeller pitch based on boat speed, engine RPM, and propeller slip factor.

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Pitch} \) — Propeller pitch (inches)
• \( S \) — Boat speed (miles per hour)
• \( \text{RPM} \) — Engine revolutions per minute
• \( \text{Slip} \) — Propeller slip factor (decimal)

Explanation: The formula calculates how far the propeller would move forward in one revolution if there were no slip.

3. Importance of Proper Propeller Pitch

Details: Correct propeller pitch ensures optimal engine performance, fuel efficiency, and prevents over-revving or under-powering your engine.

4. Using the Calculator

Tips: Enter your boat's speed in mph, engine RPM at wide-open throttle, and typical slip factor (default 0.12). Slip must be between 0 and 0.99.

5. Frequently Asked Questions (FAQ)

Q1: What is propeller slip?
A: Slip is the difference between theoretical and actual distance traveled per propeller revolution, typically 10-20% for most boats.

Q2: Why 1056 in the formula?
A: This constant converts mph to inches per minute (1 mile = 63,360 inches, 1 hour = 60 minutes → 63,360/60 = 1056).

Q3: How do I measure my boat's speed?
A: Use GPS for most accurate speed measurement at wide-open throttle.

Q4: What's a typical slip factor?
A: Most boats have 10-15% slip (0.10-0.15). High-performance boats may be lower, while heavily loaded boats may be higher.

Q5: Can I use this for inboard and outboard motors?
A: Yes, the calculation works for all propeller-driven boats, though slip factors may vary.