Can a boat sail faster than hull speed and how good is the formula for calculation? If hull speed is calculated by the sqaure root of the lenght at the water line times 1.34 it does not seem right to me. My boat is 26 ft LOA but is 23 ft at the water line. The sqaure root of 23 is approximately 4.8 and if I multiply this by 1.34 I get a hull speed of 6.4. According to my knot meter I sail quicker than that on a regular basis. Is my formula wrong, is my math wrong, or is my knot meter wrong?