From the earliest days of the war, the American submarine fleet was crucial to the success of interdicting Japanese convoys and defending strategic locations such as the Panama Canal. The factories in Japan were totally reliant upon the shipping of resources from remote parts of their empire, and as merchant ship losses to submarines grew, the Japanese war machine faced certain defeat. The crews undergo extensive training and maneuvers before their arrival in Hawaii. Admiral Lockwood, commander of the submarine forces in the Pacific realizes that use of American subs in coordinated Allied wolf packs and also single vessels will help bring the war to a close much faster. These underwater ships with names like Thrasher, Tang, Barb and Silversides help sink tens of thousands of enemy shipping all over the Pacific. Besides torpedoing the Japanese Fleet, the U.S. Submarine Force is also responsible for carrying out other secret and hazardous missions: mining enemy waters, photographing enemy shorelines for invasion, rescue operations of downed pilots and many other military operations.