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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's determined by the waterline length of the vessel and represents the point where the vessel's bow and stern waves synchronize, creating increased drag that makes further speed increases inefficient.
The calculator uses the hull speed formula:
Where:
Explanation: The formula calculates the speed at which the wavelength of the vessel's wake equals the waterline length, creating the most efficient wave pattern for a displacement hull.
Details: Understanding a vessel's hull speed is crucial for predicting performance, fuel efficiency, and determining the practical limits of a displacement hull design. Exceeding hull speed requires exponentially more power for minimal speed gains.
Tips: Enter the waterline length in feet. The value must be greater than zero. The calculator will provide the theoretical maximum efficient speed for a displacement hull vessel.
Q1: Can boats exceed their hull speed?
A: Yes, but it requires significantly more power and is generally inefficient for displacement hulls. Planing hulls are designed to exceed this limitation.
Q2: Does hull speed apply to all types of boats?
A: No, it primarily applies to displacement hulls. Planing hulls, semi-displacement hulls, and multihulls have different performance characteristics.
Q3: How accurate is the 1.34 coefficient?
A: It's an empirical value that works well for most displacement hulls, but actual performance may vary based on hull shape, weight distribution, and other factors.
Q4: Why is waterline length used instead of overall length?
A: Waterline length determines the wave-making characteristics of the hull, which is what creates the hull speed limitation.
Q5: Can hull speed be increased by modifying the hull?
A: Minor improvements are possible through hull refinements, but the fundamental relationship between waterline length and maximum efficient speed remains.