Home
Back
Crouch's Formula:
| From: | To: |
Crouch's Formula is a mathematical equation used to predict the theoretical speed of a boat based on its horsepower and displacement. It's widely used in marine engineering and boat design to estimate performance characteristics.
The calculator uses Crouch's Formula:
Where:
Explanation: The formula shows that boat speed is proportional to the square root of the power-to-weight ratio, with the Crouch constant accounting for hull efficiency.
Details: Accurate speed prediction helps in boat design, engine selection, performance optimization, and safety planning. It allows boat builders and owners to estimate how different configurations will affect performance.
Tips: Enter the Crouch constant (typically 150-250 for planing hulls), horsepower, and displacement in pounds. All values must be positive numbers.
Q1: What are typical Crouch constant values?
A: Common values range from 150-250: 150 for heavy displacement hulls, 180-200 for average planing hulls, and 220+ for high-performance racing boats.
Q2: How accurate is Crouch's Formula?
A: It provides good estimates for planing hulls but may be less accurate for displacement hulls or unusual hull forms. Real-world factors like sea conditions affect actual speed.
Q3: What is displacement in boat terms?
A: Displacement refers to the weight of water displaced by the boat, which equals the total weight of the boat including fuel, gear, and passengers.
Q4: Can this formula be used for all boat types?
A: It works best for planing monohulls. Multihulls, sailboats, and displacement hulls require different calculations.
Q5: How does hull design affect the Crouch constant?
A: More efficient hull designs (better hydrodynamics) have higher Crouch constants, meaning they achieve higher speeds with the same power-to-weight ratio.