The early Cold War years
During the end of the war the US Navy took twoGerman Type XXI boats and a handful of Japanese submarines for study. The out come was an ambitions program, to a fleet upgrade, launched to apply some of the lessons learned under the acronym GUPPY- Greater Underwater Propulsive Power.
Almost as soon as the Allies won their victory over the Axis power, another conflict, more sinister in character, started up between the Soviet Union and its former allies in the west. During the war the Russians had built the world’s largest force of submarines. With the coming of what came to be known as the Cold War, they continued to build even further. For the next forty-five years the western allies, formed into NATO, lived in deathly fear that the USSR would flood its force of over 300 submarines into the sea-lanes. This threat, that the Russians could repeat or even better the performance of the Germans during the World Wars, generated the main Cold War naval mission of the NATO forces, antisubmarine warfare.
The first decade of the effort was accomplished primarily by force of numbers. Despite the hopes that a decisive submarine technology would be found, none was. Improvements in submarine and ASW technology would evolve slowly. The major bottleneck was in the area of propulsion. Simply put, none of the different propulsion technologies, diesel, hydrogen peroxide, or gasoline, had ever provided the sustained high underwater speed. The answer to this problem was about to be found in the United States.