I got to thinking about the theory behind some of those old sailing hull designs. The length at the waterline was short to minimize wetted surface, and therefore friction, in light air. Heavier air would heel the boat over and increase the water line, thereby raising the hull speed when power is available to drive the boat faster. Doesn't it stand to reason that a boat with a sugar scoop stern will be slower than a boat with a traditional stern in light winds, all other things being equal? Then again, all other things are rarely equal. Modern hull design, with its greater form stability, will tolerate the greater heeling moment of more sail area, which increases driving force. The force of greater sail area will probably overcome the extra friction of the sugar scoop.
What I can't imagine the modern sugarscoop hulls doing, however, is producing a ride as comfortable as that of the traditional hull with overhangs when beating into the wind and seas.
T. P. Donnelly
S/V Tranquility Base
1984 Islander 30 Bahama