The Blue book is the yacht racing rule book and it stipulates windward performance under power.  And the requirement is that the boat can make the nominated speed into 12 knots of headwind.

Dash 750 - stock photo from Corsair

Waterline length (Lw) is the basis of the calculation and for the Dash 750 it is 7.32 and so that works out at 1.8 x √7.32 = 4.8 knots.  This afternoon the we have a nice breeze of 10-12 knots so its just what we need for this test. → Read more…