This research is based on the investigation into the dynamic stability associated with seaplanes during takeoff. Various forces
acting on a hydroplaning hull form have been empirically defined. Such empirical data have shown that, under a certain set of
conditions, a hydroplaning hull will begin to porpoise: an instability oscillation in both the vertical direction and about the center of
gravity. To investigate the porpoising motion, a shallow water flume was used. It was the first time that such a facility had been used to
simulate the dynamic motion of hydroplaning hull forms. An experimental method derived from the store release experiments was
derived for the dynamics measurements. The equipment developed led to an analysis of a flat-plate hull porpoising in a supercritical
channel. The porpoising limit was then very well defined.