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Catamaran Hull Speed Formula:
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Hull speed is the speed at which the wavelength of a vessel's bow wave equals the waterline length, creating increased drag. For catamarans, this theoretical maximum speed is typically higher than monohulls due to their design characteristics.
The calculator uses the catamaran hull speed formula:
Where:
Explanation: The formula accounts for the relationship between waterline length and wave-making resistance, with the catamaran factor adjusting for the reduced drag of twin hulls.
Details: Understanding hull speed helps in sailboat design, performance prediction, and efficient operation. Exceeding hull speed significantly increases power requirements.
Tips: Enter waterline length in feet and the appropriate catamaran factor (typically 1.1 for cruising catamarans, up to 1.3 for high-performance designs). All values must be positive numbers.
Q1: Why do catamarans have a higher hull speed factor?
A: Catamarans experience less wave-making resistance due to their narrow hulls and wide spacing, allowing them to exceed traditional hull speed more easily.
Q2: What's a typical catamaran factor value?
A: Most cruising catamarans use 1.1, while performance catamarans may use 1.2-1.3. The exact factor depends on hull design and weight.
Q3: Can catamarans exceed their hull speed?
A: Yes, many catamarans can significantly exceed their theoretical hull speed, especially when planing or in favorable conditions.
Q4: How does weight affect hull speed?
A: Increased weight lengthens the waterline (increasing hull speed) but also increases drag. The calculator assumes typical loading conditions.
Q5: Is this calculation accurate for power catamarans?
A: The formula works for displacement-mode operation. For planing power cats, different calculations apply at higher speeds.