mold for scoop
He did not use a mold. He wrapped a large piece of arborite (later discarded) around the stern to get the interior shape of the scoop and then began fairing in the hull to below the winches. Vinylester was used underneath, then balsa core, then vinylester on top. The whole addition is out of the water when the boat is at rest. I don't know about micro knots of added speed, there is no way to compare. Also, with six golf cart batteries in my house bank, this is not a racer. However, I tell my wife that we are going faster and have calibrated the knotmeter to show a little more, that makes everyone feel better about the cost -- and she is the first one to disappear onto the "back porch" with her book on lazy days when the sun hits the stern.
Cheers, Duncan.