This is also from Gerr's work. He has determined that the classic formula for Hull Speed ( 1.34Sqrt(LWL) ) does not always apply, the 1.34 is not a constant, leading to, in some cases, much higher speeds. However, Gerr observes:
"For instance, a boat with a DL or 80 might have a SL multiplier of 2.11, but it couldn't achieve that speed under sail unless it had not just sufficient sail area, but the stability to stand up to such a sail area in the wind strengths needed to deliver the required power. Not an easy task!"
The maximum speed under motor power calculated below depends on the ratio of 'weight' to 'horsepower'. The weight of a given boat does not directly appear in the database and is reverse calculated from the 'figures of merit' which can lead to a round off error of generally 1-2 % but errors of up to 4% have been detected in some cases.