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Hull Speed Formula:
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Hull speed is the theoretical maximum speed that a displacement hull can efficiently travel through water. It represents the point where the wavelength of the boat's wake equals the boat's waterline length, creating increased drag that makes further speed increases difficult without significantly more power.
The calculator uses the hull speed formula:
Where:
Explanation: The formula is derived from wave-making theory, where the speed of a wave is proportional to the square root of its wavelength. For boats, this wavelength is approximately equal to the waterline length.
Details: Understanding hull speed is crucial for boat designers, sailors, and marine engineers. It helps in predicting performance characteristics, optimizing hull design, and estimating power requirements for displacement 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: Does this formula apply to all boat types?
A: This formula is primarily for displacement hulls. Planing hulls and semi-displacement hulls can exceed this theoretical speed with sufficient power.
Q2: Why is the coefficient 1.34?
A: The coefficient 1.34 is an empirical value derived from observations of wave-making resistance characteristics of typical displacement hull forms.
Q3: Can boats exceed their hull speed?
A: Yes, with sufficient power, boats can exceed hull speed, but it requires significantly more energy to overcome the increased wave-making resistance.
Q4: How does waterline length affect hull speed?
A: Longer waterline length generally means higher hull speed, as the relationship follows a square root function - doubling waterline length increases hull speed by about 41%.
Q5: Are there limitations to this calculation?
A: This is a theoretical maximum and actual performance may vary based on hull shape, weight distribution, sea conditions, and other factors.