Abstract: A pair of movable pistons are separated within an enclosed, submerged cylinder by an expansible combustion chamber. Piston rods extend from these pistons through the opposite ends of the cylinder. A pair of dish-shaped, circular plates are carried on the respective extremities of these two rods so that their convex surfaces face inwardly toward the ends of the cylinder in spaced relation. Expansion of an explosive gas mixture within the combustion chamber drives the pistons apart so as to accelerate the plates through the water, producing cavitation bubbles at their convex surfaces. Collapse of these bubbles combines efficiently to produce a single energetic acoustic pulse adapted for seismic prospecting.

Abstract: Condensate accumulating in the combustion chamber of a marine gas exploder of the cylinder and piston type is collected by gravity flow in a sump formed in a cylinder side wall or in a face of the piston, depending upon whether the cylinder is oriented horizontally or vertically. One end of an exhaust tube is positioned adjacent the base of the sump so that gaseous combustion products flow through the sump into the exhaust tube so as to collect and remove the accumulated condensate.