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Hull Speed Formula:
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Hull speed is the theoretical maximum speed that a displacement hull can achieve without planing. It represents the speed at which the wavelength of the vessel's wake equals the waterline length, creating significant wave-making resistance.
The calculator uses the hull speed formula:
Where:
Explanation: The formula is derived from wave theory, where the speed of a wave is proportional to the square root of its wavelength. For displacement hulls, the maximum efficient speed occurs when the hull creates a wave with length equal to the waterline length.
Details: Understanding hull speed is crucial for boat designers, sailors, and marine engineers. It helps in predicting vessel performance, fuel efficiency, and determining the appropriate power requirements for displacement hull vessels.
Tips: Enter the waterline length in feet. The value must be greater than zero. The calculator will compute the theoretical hull speed in knots.
Q1: What types of hulls does this formula apply to?
A: This formula applies specifically to displacement hulls. Planing hulls and semi-displacement hulls can exceed this theoretical maximum.
Q2: Why is the coefficient 1.34?
A: The coefficient 1.34 is an empirical value derived from wave theory and practical observations of displacement hull performance in various sea conditions.
Q3: Can vessels exceed their hull speed?
A: Yes, with sufficient power, displacement hulls can exceed hull speed, but it requires exponentially more power and becomes increasingly inefficient.
Q4: How does hull shape affect hull speed?
A: While the basic formula uses waterline length, hull shape, beam, and displacement can affect the actual maximum efficient speed a vessel can achieve.
Q5: Is this formula used for all boat types?
A: No, this formula is primarily for traditional displacement hulls. Modern planing hulls, multihulls, and other hull forms have different performance characteristics.