Hydrostatically operated underwater pile driver and method of operating same

A device capable of being disposed a substantial distance below the surface of a body of water to drive a pile having an upper end by the hydrostatic force exerted downwardly on said device, said device including:

• a. a housing assembly that includes an elongate tubular member that has upper and lower open ends, said lower open end capable of slidably engaging said upper end of said pile when said device is vertically disposed and coaxially aligned with said pile;
• an anvil in said tubular member in contact with said upper end of said pile;
• a ram slidably movable in said tubular member, said ram capable of occupying either a first position adjacent said upper open end or a second position in contact with said anvil;
• and a stop that limits said ram from being moved upwardly above said first position in said tubular member, said ram having at least one opening extending transversely therethrough, said anvil, an intermediate portion of said tubular member and said ram defining a first confined space when said ram is in said first position, said tubular member having an opening therein;
• b. first means on said ram that when in a first position obstructs said opening and in a second position does not obstruct said opening;
• c. second means for raising said ram from said second to said first position;
• d. third means for removably supporting said ram in said first position;
• and
• e. fourth means in communication with said opening for evacuating water from said first confined space when said ram is in said first position and said first means in said first position, with said ram when released by said third means being driven downwardly in said tubular member by the weight of a column of said water thereabove to impact on said anvil, and the force of said impact being transferred from said anvil to said pile to drive the latter downwardly, with said first means being moved to said second position, said second means moving said ram to said first position with water from said body of water exerting equal but oppositely directed forces on the top and bottom of said ram, said support means removably engaging said ram when the latter reaches said first position in said tubular member with said ram being successively moved between said first and second positions until said pile has been driven to a desired depth.