Trying to get the correct answer of determining the hull speed of a catamaran. I know the hull speed of a monohull is S=LWL squared x 1.34. Does that also apply to cat's? Do you simply double the LWL for them? If that is so than what about tri's? Same thing, add up all the waterline and finish the equation?
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Correction, hull speed is...
... 1.34 x square-root(LWL). Makes a big difference! Now, if only we could change physics to make your formula correct... I could cruise at about 1200 knots
Derek
... 1.34 x square-root(LWL). Makes a big difference! Now, if only we could change physics to make your formula correct... I could cruise at about 1200 knots
DerekHull speed
As a boat moves through the water it creates a bow wave and a stern wave from the displacement of the water. As the speed increases the "wavelength" increases until a situation is reached where there is a crest at the bow and stern and a hollow between. To go faster the boat must climb up and over its bow wave, and that requires a lot of power. This argument applies strictly to "displacement" hulls typical of the cruising sailboat. Long narrow hulls, such as a catamaran do not displace as much water as a displacement hull, the size of the bow wave is smaller, and the boat is able to "climb over" the bow wave, thus exceeding the standard formula for hull speed.
As a boat moves through the water it creates a bow wave and a stern wave from the displacement of the water. As the speed increases the "wavelength" increases until a situation is reached where there is a crest at the bow and stern and a hollow between. To go faster the boat must climb up and over its bow wave, and that requires a lot of power. This argument applies strictly to "displacement" hulls typical of the cruising sailboat. Long narrow hulls, such as a catamaran do not displace as much water as a displacement hull, the size of the bow wave is smaller, and the boat is able to "climb over" the bow wave, thus exceeding the standard formula for hull speed.
yeah, typo error in my formula
Meant to type square root, oh well. I'm familiar with the formula but appariently not the key board. Guess the typo makes a nice differance huh?
Meant to type square root, oh well. I'm familiar with the formula but appariently not the key board. Guess the typo makes a nice differance huh?
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