Hull speed of Nowak & Williams Catboat
My husband and I sail a Tillosten/Pearson built 18' HA Catboat which is similar to what the Nowak & Williams built. The hull speed of the boat is 4.5. So when we researched putting a new motor on it we decided to go to a 6hp Tohatsu 4 cylinder which fits nicely into the well. The previous owners had a 9hp engine on it that was way to big for the boat and our thinking was that since the boat can't go above its max hull speed that a 6hp was sufficient.
Hope that helps.