1. What is Propeller Pitch Speed?

The propeller pitch speed calculates how fast a boat would theoretically move through the water if there were no slip (the difference between theoretical and actual speed). It's an important metric for propeller selection and performance analysis.

2. How Does the Calculator Work?

The calculator uses the propeller speed formula:

Where:

• \( RPM \) — Engine revolutions per minute
• \( Pitch \) — Propeller pitch in inches
• \( Gear\ Ratio \) — Gear reduction ratio
• 12 — Conversion factor (inches to feet)

Explanation: The formula calculates theoretical speed in feet per second based on how much distance the propeller would cover in one minute divided by time and gear reduction.

3. Importance of Propeller Speed Calculation

Details: Calculating theoretical speed helps in propeller selection, engine performance analysis, and identifying potential issues with your boat's propulsion system.

4. Using the Calculator

Tips: Enter RPM (engine speed), propeller pitch in inches, and gear reduction ratio. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is actual speed lower than calculated speed?
A: The difference is called "slip" which accounts for water resistance, hull design, and other factors that prevent the propeller from achieving its theoretical speed.

Q2: What is a typical gear ratio for boats?
A: Common gear ratios range from 1.5:1 to 3:1 depending on engine type and boat size.

Q3: How does pitch affect performance?
A: Higher pitch generally means higher top speed but slower acceleration, while lower pitch provides better acceleration but lower top speed.

Q4: What units does this calculator use?
A: The calculator uses feet per second (fps) for speed. To convert to mph, multiply by 0.6818.

Q5: Is this calculator accurate for all boats?
A: This provides theoretical speed only. Actual speed depends on many factors including hull design, weight, water conditions, and propeller efficiency.