This diagram explains how albatross accelerate so quickly when in flight- very applicable to the the manner in which displacement hulls pick up speed...."Dynamic soaring -- Albatrosses perform a fascinating and complicated flight maneuver called dynamic soaring, in which energy can be extracted from horizontally moving air and transferred to the bird so that an energy gain is achieved which enables it to fly continuously without flapping. Dynamic soaring is possible when the wind speed changes with altitude. This type of wind, which is called shear flow, exists in the boundary layer above the ocean surface in areas in which albatrosses are found. Dynamic soaring consists of periodically repeated cycles, with one cycle illustrated to the left: 1 - climb (windward flight); 2 - upper curve (change of flight direction to leeward); 3 - descent (leeward flight); & 4 - lower curve (change of flight direction to windward) (Sachs 2005)."
