Home
Back
Hull Speed Formula:
| From: | To: |
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 the most efficient wave pattern for the hull length.
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 interference for displacement hulls.
Details: Understanding hull speed helps boat designers and owners determine the maximum efficient speed for displacement vessels, optimize fuel consumption, and set realistic performance expectations.
Tips: Enter the waterline length in feet. The waterline length is the length of the boat at the water's surface, measured from bow to stern. All values must be valid (LWL > 0).
Q1: What types of boats does this formula apply to?
A: This formula applies primarily to displacement hull boats such as sailboats, trawlers, and traditional motor yachts that move through water rather than on top of it.
Q2: Can boats exceed their hull speed?
A: Yes, some boats can exceed hull speed through planing, surfing waves, or with sufficient power, but it requires significantly more energy and may not be sustainable.
Q3: Why is the constant 1.34 used?
A: The constant 1.34 is derived from wave mechanics and represents the speed in knots when the wave length in feet equals the boat's waterline length.
Q4: Does this apply to planing hulls?
A: No, planing hulls (like speedboats and powerboats) can exceed hull speed significantly as they rise up and plane on the water's surface.
Q5: How accurate is this calculation?
A: It provides a good theoretical estimate for displacement hulls, but actual performance may vary based on hull shape, weight distribution, and sea conditions.