Cast & Crew
During a U.S. Naval deep sea operation, medical officer Lt. Cmdr. William Arnold and Adm. Ashton anxiously await the overdue return of divers Cmdr. David Forest and sailor Joe O'Brien. When O'Brien surfaces with the unconscious Dave, Arnold quickly has the men placed in a decompression chamber. Dave revives momentarily, then collapses into the severe muscular spasms associated with oxygen poisoning. Concerned over Dave's condition, Arnold reflects upon their twelve-year association: A year after America's entry into World War II, Arnold is a recruiter at Fort Pierce, Florida for the Underwater Demolition School, part of the new Naval branch of amphibious warfare. Dave, a former cargo officer on a munitions ship, applies and Arnold hesitates because Dave is slightly older than the usual recruits. Dave declares his belief in the future of the new branch, then confesses that his only apprehension is his inability to swim, which he intends to learn during an upcoming thirty-day leave. Impressed by Dave's enthusiasm, Arnold agrees to consider Dave for a position after he takes swimming lessons. Dave's dedication pays off and he is accepted into the school, where he trains intensely for several months. Despite being older than the other recruits, Dave is at the top of his team in training, which includes rigorous physical work at sea conducting mock rescues and demolition missions. During an exercise using live ammunition, Dave rescues sailor Joe O'Brien from inadvertently wandering into the detonation area, and the men become friends. Due to the newness of the Underwater Demolition Team, training is continually extended. As Dave and the team finally set out for their first mission, they receive news of the Japanese surrender. Although dismayed, Dave tells Joe he intends to remain with the UDT. Many months later, Dave goes to Adm. Ashton to present his plan for developing a device to allow divers to breath underwater, which would allow the UDT to retain the element of surprise so vital to their operations. Ashton is skeptical when Dave asserts that divers can be launched from submarines, thus evading sophisticated sonar and radar tracking. Ashton advises Dave that the Navy accepts new ideas slowly, but offers his support, allowing Dave to gather eleven volunteers for a month of testing off the coast of the Caribbean during Naval maneuvers. In the Caribbean, during the testing of the underwater breathing devices, Dave and several men begin to descend to fifty feet, but most of the men cannot go beyond thirty feet due to difficulties from extreme water pressure. Although Dave and Joe launch from a submerged submarine successfully, the captain criticizes the action for placing his submarine in unacceptable danger because the boat must remain still for a long period of time while the divers recover. Later while off-duty, Dave and Joe meet Americans Anne Whinmore and Maria Teresa Valdez and the couples become friends. Midway through the testing, Arnold tells Dave that the submarine captain turned in a negative report on the UDT trial, but Dave is undaunted. During war games, Dave and Joe use the breathing devices to swim undetected between their lead ship and a ship on the opposing side. They then place a sack, representing explosives, on the ship's hull and report to the "enemy" ship's captain that his battleship has been destroyed. Stunned, the officer is angered, then impressed by a covert attack made by only two divers. After the tests, Dave continues dating Anne regularly. Later, upon receiving confirmation of the government's unconditional support for UDT operations, Dave proposes to Anne. Anne is filled with doubts about Dave's safety, however, especially when he relates the news of an updated breathing device called "underwater lungs" developed by the French that allow divers to descend to great depths. Fearful of Dave's commitment to the UDT and the looming threat of war with Korea, Anne turns down his proposal. Although saddened, Dave remains in the Caribbean, testing the new French oxygen tanks over the next two months with Joe. One afternoon, Anne meets Dave at the base and agrees to his suggestion that she start diving so that she might better understand his work. During their dive, Dave mimes another proposal and Anne accepts. On their honeymoon, Dave admits to Anne that he has received transfer orders to Coronado, California and then on to Korea, where the war has begun. After settling Anne in California, Dave joins the UDT in Korea. During a mission detonating mines along the coast to clear beaches for landing craft, Dave is wounded by enemy fire from the shore and is saved by the team. Dave is then sent stateside to recover and joins Anne just after the birth of their son, Davey, Jr. Over the next several years, the UDT matures into a full-fledged arm of the Naval forces. Pleased, Ashton summons Dave to inform him that the Atomic Energy Commission has requested the UDT inspect bomb damage and recover unexploded enemy bombs at underwater crash sites in the shark-filled Pacific. After Dave participates in a number of recruiting films shot in the dangerous shark-infested Marshall Islands, Anne pleads with him to accept a desk job as they are expecting a second child. Dave agrees, but soon after an Air Force jet filled with top secret equipment crashes at sea and is ordered destroyed for national security. When Army deep sea divers are unable to reach the plane because of strong currents, the UDT is summoned. Knowing of Dave's experimentation with a new oxygen mix that works below 200 feet, Ashton asks Dave to make the dive. Dave agrees and with only Joe for support, makes the dive. Dave insists that Joe remain at 200 feet while he mines the plane another 100 feet below, but as Dave completes the job, his oxygen hose is torn when it becomes caught on a wire. Joe rescues Dave and the men make the difficult ascent sharing Joe's oxygen tank. In the present, eight days after the dive, Dave, still in the ship's decompression tank, revives as Arnold admires his bravery and love of exploration. Although weak, Dave recovers and, as he goes to greet Anne, who is waiting on deck, tells Joe that they are bound for desk duty.
Commander Francis D. Fane U.s.n.r.
Harry Redmond Jr.
The working title of the film was The Amphibian. The film closed with the following written acknowledgments and dedication: "To the Department of Defense and the Department of the Navy, for their cooperation in the filming of this motion picture, the producers wish to express their sincere gratitude. To the Navy Men of the Pacific Fleet, without whose help this picture could not have been made, our heartfelt thanks are extended. And to the divers of the Underwater Demolition Teams of the United States Amphibious Forces, whose story is told here, this picture is respectfully dedicated." Although the openings credits read: "And introducing Claire Kelly," Kelly had appeared in a bit role in The Best Things in Life Are Free and also in Scandal Incorporated, both released in 1956. Underwater Warrior was based upon the experiences of Cmdr. Francis D. Fane. A written prologue reads: "The unusual experiments in shark-infested waters were conducted in the Marshall Islands by Commander Francis D. Fane, U.S.N.R. Technical Advisor for this production, whose life and adventures inspired our picture." For more information about the Underwater Demolition Teams (UDT), see the entry above for the 1951 film The Frogmen.
Jon Lindbergh, son of famed aviator Charles Lindbergh, appears in a small role as a deck officer; this was his only film. Lindbergh spent three years as an ensign with the UDT and spent most of his life involved in underwater studies. The film was shot on location at San Clemente Island, Coronado, CA and in the Hawaiian and Marshall Islands. Hollywood Reporter production charts add Steve Litchell, Art Marshall, William Vaughn, Mike Steen, Arvid Nelson, Leo Needham, Mike Dugan and Thomas McBride to the cast, but their appearance in the released film has not been confirmed.