Murphy was one of a very small number of volunteer pilots who, with their flight crews, started bombing at low altitudes in B-17 flying fortresses in the Southwest Pacific. The aircraft were flown at a 200-foot altitude and at 250 miles per hour at night. One-thousand pound bombs, equipped with four-to-five second fuses, were dropped from the B-17s. On March 3, 1943, the Japanese made a desperate move to re-supply their forces on New Guinea. Twenty-two cargo, transport, and war ships proceeded toward New Guinea using bad weather for cover. They were found in the Bismarck Sea. The Allied Air Forces--using skip bombing--sank all twenty-two Japanese ships. Murphy was credited with sinking nine Japanese ships during his year of combat, including one in the Bismarck Sea battle. Skip bombing became a tactic that helped the U.S. win the war in the South Pacific.