A pneumatic catapult accelerated sled on rails was decelerated by water inertia in a total of 40 experiments with 28 human volunteers and two anesthetized black bears to evaluate effects of four different pitch orientations of the seat on impact tolerance.

All subjects were restrained by dacron webbing 2-7/8 inches wide, 6,000 pounds tensile strength in a harness consisting of shoulder straps converging on a chest belt, then diverging to a common attachment at each side with the seat belt, so that an "X" configuration from shoulders to hips was applied to the front of the torso;​ the chest belt buckle being at the center of the "X."