1. What is Prop Slippage?

Prop slippage refers to the difference between the theoretical speed a propeller should produce and the actual speed achieved. It's expressed as a percentage and indicates the efficiency loss in the propulsion system.

2. How Does the Calculator Work?

The calculator uses the prop slippage formula:

Where:

• Actual Speed — Measured speed of the vessel (mph)
• Theoretical Speed — Calculated maximum speed based on propeller pitch and RPM (mph)

Explanation: The formula calculates the percentage difference between the expected and actual performance of a propeller system.

3. Importance of Prop Slippage Calculation

Details: Calculating prop slippage helps evaluate propulsion system efficiency, identify potential issues with propeller performance, and optimize vessel speed and fuel consumption.

4. Using the Calculator

Tips: Enter both actual and theoretical speeds in miles per hour (mph). Both values must be positive numbers, with theoretical speed greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is considered good prop slippage?
A: Generally, 10-15% slippage is considered good for most vessels. Lower percentages indicate more efficient propulsion systems.

Q2: What causes high prop slippage?
A: High slippage can be caused by propeller damage, incorrect propeller size, hull fouling, or improper engine trim.

Q3: How can I reduce prop slippage?
A: Regular maintenance, proper propeller selection, hull cleaning, and optimal engine trim can help reduce slippage.

Q4: Does prop slippage affect fuel efficiency?
A: Yes, higher slippage typically results in lower fuel efficiency as more energy is wasted in the propulsion system.

Q5: Can negative slippage occur?
A: No, negative slippage is not physically possible as it would imply the vessel is moving faster than theoretically possible.