Boat Speed Calculator
Calculate boat top speed using Crouch's formula based on horsepower, displacement, and boat type
Boat Performance Calculator
Calculation Mode
Engine power delivered to the propeller
Weight of water displaced by the boat
Speed Results
Crouch's Formula: S = √(P / D) × C
Displacement: 0 lbs (0 kg)
Crouch Constant: 150 (Cruisers, Average Runabouts, Passenger Vessels)
Power-to-Displacement Ratio: 0 hp/1000 lbs
Performance Analysis
Example Calculation
Racing Hydroplane Example
Boat Type: Racing Hydroplane
Engine Power: 3,000 hp
Displacement: 6,800 lbs
Crouch Constant: 220 (for hydroplanes)
Calculation
S = √(P / D) × C
S = √(3000 / 6800) × 220
S = √(0.441) × 220
S = 0.664 × 220
S = 146.1 mph
Crouch Constants by Boat Type
Factors Affecting Boat Speed
Engine horsepower and efficiency
Boat weight and displacement
Hull design and type
Water conditions and waves
Wind resistance and direction
Propeller design and condition
Understanding Boat Speed Calculations
What is Crouch's Formula?
Crouch's formula is a widely used equation in marine engineering to estimate the top speed of powerboats based on their engine power and displacement. It provides a quick and reasonably accurate method for preliminary speed calculations.
Why Use This Formula?
- •Quick estimation for boat design analysis
- •Helps determine engine requirements
- •Widely accepted in marine industry
- •Accounts for different boat types
Formula Explanation
S = √(P / D) × C
- S: Boat speed (mph)
- P: Shaft horsepower (hp)
- D: Displacement (pounds)
- C: Crouch constant (boat type specific)
Note: This formula gives theoretical maximum speed. Actual speeds may vary due to sea conditions, propeller efficiency, and hull condition.