Seldom making the headlines, US submarines, mounting their long, arduous patrols into the Pacific from Australia, had a commanding influence on Japan's wartime fortunes. Japan depended totally on her merchantmen to sustain garrisons, supply the battle fronts and deliver raw materials. So it was that, alone or in groups, such as 'Blair's Blasters' or 'Park's Pirates', US submarines provided vital intelligence and stalked the hated merchantmen, sinking so many tankers that, by June 1944, the Japanese fleet's movements were already hobbled by an acute shortage of fuel. With Saipan as a base, the submarines continued in their disruptive role, one as effective as that of the U-Boat 'Wolf Packs' in the Atlantic. An officer in an American submarine scans the Pacific for signs of Japanese activity
