A calculation I have never made before:
The speed that a yacht’s hull can be made to travel through water is related to waterline length.
The formula for an average sea-going yacht of conventional shape is:
Speed in knots = 1.4 x Square root of the L.W.L. in feet
The multiplier is altered according to the type of hull. It may range from 1.25 for a tubby hull to 1.5 for a large racing yacht.
Therefore Blue Mistress’ theoretical maximum speed at L.W.L of 19′ 8″:
= 1.4 x Square root of 19.66 ft
= 1.4 x 4.434
= 6.2 knots (Always remembering that speed through water is not the same as speed over the ground).
We were doing a little less in the clip below