Submarines of the Imperial Japanese Navy
The IJN submarine arm did have a number of notable successes against American warships, however. During the Battle of Midway, administered the final "coup de grace" that sank the fleet carrier , as well as sinking the destroyer . A few months later, on September 15, 1942, with a single salvo of torpedoes, Japanese submarine sank the fleet carrier and damaged both the battleship and the destroyer . On November 13, 1942, the submarine torpedoed and sank the anti-aircraft cruiser , and a year later on November 23, 1943 the submarine torpedoed and sank the escort carrier , both with heavy loss of life. The had the distinction of both severely damaging the heavy cruiser , knocking her out of the war for a year, on October 20, 1942, and of also sinking (the only American submarine to be sunk by a Japanese submarine in the entire war) on November 16, 1943.
Allied submarines in the Pacific War
From 1943, Allied submarines waged an increasingly effective campaign against Japanese merchant shipping and the IJN. By the end of the war in August 1945, the Japanese merchant marine had less than a quarter of the tonnage it had in December 1941. Overall, U.S. Navy submarines sank around 1,300 Japanese merchant ships, as well as roughly 200 warships. Despite the need to maintain sea lanes for its empire, the Japanese never successfully developed a cost-effective destroyer escort better suited for convoy duties, while it also did not have the industrial might to replace the losses of its heavily armed destroyers, nor of its ill-protected merchantmen.