In the United States, the established tradition of engineering was explicitly competing with the rising discipline of physics for World War I military largess. A host of inventors, led by Thomas Edison and his newly created Naval Consulting Board, cranked out thousands of inventions to solve military problems and aid the war effort, while academic scientists worked through the National Research Council (NRC) led by Robert Millikan. Submarine detection was the most important problem that both the physicists and inventors hoped to solve, as German U-boats were decimating the crucial naval supply lines from the U.S. to England. Edison's Board produced very few useful innovations, but NRC research resulted in a moderately successful sound-based methods for locating submarines and hidden ground-based artillery, as well as useful navigational and photographic equipment for aircraft. Because of the success of academic science in solving specific military problems, the NRC was retained after the war's end, though it gradually decoupled from the military.