Seeing as this question comes up often in many related topics, here are some formulae to enable you to
work out the
Hull speed of your
displacement vessel.
Please Note: This is the theoretical speed. It does not take into account certain variables.
Rule of thumb would say that you will not reach theoretical
hull speed in normal circumstances.
S = 1.34 x (square root of waterline length in feet )
Hull speed = 1.24 * LWL^1.433 / Disp.^.311
Hull speed (Vk)=[square root (LWL in ft x 0.3034)] x 2.5