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Hull Speed Formula:
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Hull speed is the theoretical maximum speed that a displacement hull boat can achieve without planing. It represents the speed at which the boat's bow and stern waves synchronize, creating increased drag that makes further acceleration difficult without excessive power.
The calculator uses the hull speed formula:
Where:
Explanation: The formula calculates the speed at which the wavelength equals the waterline length, creating optimal wave formation for displacement hulls.
Details: Understanding hull speed helps boat designers and operators optimize vessel performance, fuel efficiency, and power requirements. It indicates the practical speed limit for displacement hull vessels.
Tips: Enter the waterline length in feet. The value must be greater than zero. The calculator will provide the theoretical hull speed in knots.
Q1: What's the difference between hull speed for power boats vs sailboats?
A: Power boats typically use a coefficient of 1.5, while sailboats may use 1.34. Power boats can sometimes exceed hull speed through planing.
Q2: Can power boats exceed hull speed?
A: Yes, many power boats are designed to plane, allowing them to rise over their bow wave and exceed theoretical hull speed.
Q3: How does hull shape affect hull speed?
A: Fine-entry hulls may slightly exceed calculated hull speed, while full-bodied hulls may struggle to reach it. Modern hull designs can modify these limitations.
Q4: Is hull speed relevant for planing hulls?
A: Hull speed is primarily relevant for displacement hulls. Planing hulls are designed to operate above their hull speed once they transition to planing mode.
Q5: How accurate is the 1.5 coefficient?
A: The 1.5 coefficient is a general rule of thumb. Actual performance may vary based on hull design, weight distribution, and sea conditions.