Boat Speed Calculator & Formula Guide – Hull Speed, Power, and Real-World Examples

Boat Speed Calculator Calculate your boat’s speed based on engine RPM, gear ratio, and propeller pitch. Engine RPM: Gear Ratio: Propeller Pitch (inches): Propeller Slip (%): Calculate Speed Results Boat Speed: 0 knots Boat Speed: 0 mph Boat Speed: 0 km/h How to Use This Calculator Enter your engine’s maximum RPM (revolutions per minute) Enter […]

Boat Speed Calculator

Calculate your boat’s speed based on engine RPM, gear ratio, and propeller pitch.

Results

Boat Speed: 0 knots

Boat Speed: 0 mph

Boat Speed: 0 km/h

How to Use This Calculator

  1. Enter your engine’s maximum RPM (revolutions per minute)
  2. Enter your gear reduction ratio (if unknown, use 1:1)
  3. Enter your propeller pitch in inches
  4. Enter propeller slip percentage (typically 5-15%)
  5. Click “Calculate Speed” to see your estimated boat speed

Understanding the Calculation

The formula used is: Speed (knots) = (RPM × Pitch) / (Gear Ratio × 1056) × (1 – Slip/100)

This calculation provides an estimate of your boat’s maximum speed based on theoretical propeller advance with adjustments for real-world slip.

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