1. What is the Boat Speed Calculation?

The boat speed calculation estimates vessel speed based on engine RPM, propeller characteristics, and gear ratio. This formula helps boat owners and marine engineers optimize performance and efficiency.

2. How Does the Calculator Work?

The calculator uses the boat speed formula:

Where:

• \( V \) — Boat speed (mph)
• \( RPM \) — Engine revolutions per minute (rev/min)
• \( PP \) — Propeller pitch (inches)
• \( PS \) — Propeller slip (%)
• \( GR \) — Gear ratio (dimensionless)
• 1056 — Conversion constant

Explanation: The formula calculates theoretical speed based on propeller pitch and engine RPM, then adjusts for real-world propeller slip through water.

3. Importance of Boat Speed Calculation

Details: Accurate speed prediction helps in propeller selection, fuel efficiency optimization, engine performance analysis, and trip planning.

4. Using the Calculator

Tips: Enter RPM (typically 1000-6000), propeller pitch (common range 10-30 inches), propeller slip (typically 5-25%), and gear ratio (common range 1.5-3.0).

5. Frequently Asked Questions (FAQ)

Q1: What is propeller slip?
A: Propeller slip is the difference between theoretical and actual distance traveled per revolution, caused by water displacement and efficiency losses.

Q2: How do I find my gear ratio?
A: Gear ratio is typically specified in your engine or outboard manual, or can be calculated by dividing propeller shaft RPM by engine RPM.

Q3: What is a typical propeller slip percentage?
A: Most well-matched propellers have 10-20% slip. Lower slip indicates better efficiency.

Q4: Can this formula be used for all boat types?
A: This formula works best for planing hulls with conventional propellers. Displacement hulls and specialized propulsion may require different calculations.

Q5: Why is propeller pitch important?
A: Pitch determines how far the boat moves forward with each propeller revolution, directly affecting speed and engine loading.