Submarine warfare in WWII
Submarine warfare during World War II was a critical and complex theater of naval conflict, primarily involving German, Japanese, and American submarines. German U-boats initiated operations against Allied shipping in the Atlantic as soon as the war began, achieving significant early successes by sinking merchant vessels. However, by mid-1943, Allied countermeasures, such as improved convoy systems and advanced antisubmarine technologies, began to diminish the effectiveness of German submarine campaigns. In the Pacific, Japanese submarines conducted surprise attacks, notably during the Pearl Harbor assault, but their effectiveness waned as the war progressed, focusing more on disrupting American naval forces and transporting supplies. Meanwhile, American submarines played a pivotal role in the Pacific by targeting Japanese merchant shipping and warships, dramatically crippling Japan's supply lines. By the end of the conflict, while German and Japanese submarines inflicted considerable losses, they ultimately could not alter the war's outcome, as American submarine warfare proved decisive in undermining Japanese naval capacity and commerce. Overall, submarine warfare in WWII showcased a dynamic interplay of strategy, technology, and naval tactics that shaped the course of the conflict.
Submarine warfare in WWII
Submarines had a significant impact on naval operations during World War II and were used to sink major fleet units, especially in the Pacific, and to attack enemy commerce.
German submarine operations on the Atlantic Ocean convoy routes began as soon as Great Britain and France declared war on Germany in 1938 and continued until the end of World War II. However, after May, 1943, Germany’s submarine campaign was little more than a nuisance for the Allies. In response to the Germans, the British immediately started convoying merchant ships and building a growing number of escorts, ultimately including a few hundred crewed by the Royal Canadian Navy. German submarines also sank many British warships, including two battleships and three carriers, but these numbers were too insignificant to matter greatly in the large context of naval warfare. In the fall of 1941, the United States began to support antisubmarine operations, which led to a few shoot-outs between German U-boats and American destroyers, starting with the USS Greer in September, 1941, and culminating in the sinking of the destroyer USS Reuben James on the last day of October.
United States Against German Submarines
In January, 1942, the Germans launchedOperation Drumbeat, a submarine campaign aimed at shipping activities off the East Coast of the United States. Initially, only a small number of German submarines were used, but they achieved considerable success because American commercial troops were not traveling under convoy. The Germans soon increased their forces off the East Coast, sinking large numbers of ships off Cape Hatteras and elsewhere, sometimes within sight of the shore. American admiral Ernest King began to set up escorted convoys off the East Coast, until by late 1942 there were enough escorts to provide convoys on all major routes. The Germans sent their submarines to the West Indies and the Gulf Coast, where they continued to sink large numbers of ships.
Germany eventually resumed its campaign against the North Atlantic convoy route, initially helped by its code breakers who were able to decipher the convoy codes. The Allies fought back with increased escorts; greater use of airplanes, including escort carriers, mostly American-built, that provided protection in the middle of the ocean; new weapons; and a vast array of technological equipment. In order to locate submarines, code-breaking and direction-finding devices were used on communications between the submarines and their commanders, and sonar and centimetric radar were also employed. The climax of this battle came in 1943, when the Germans won a major convoy victory in March and the Allied defenses reached critical mass and won a decisive victory in May.
Japanese Submarines
Japanese submarine warfare against the United States began at Pearl Harbor, which was attacked by midget submarines. The attack accomplished nothing except to alert antisubmarine forces. As part of the Pearl Harbor assault, Japanese submarines tried to cut off sea access to Hawaii, sinking a number of merchant ships over a two-month period, though many ships survived because of the Japanese decision to strike nonwarships with no more than one torpedo. The Japanese also struck the American carrier Saratoga with a torpedo in January, 1942, but the ship was repaired and returned to service.
After the assault at Pearl Harbor, Japanese submarines were primarily used to attack warships or as transportation, the latter becoming an increasingly important function as many Japanese island garrisons were otherwise cut off. The Japanese sank the carrier Yorktown at the close of the Battle of Midway and the carriers Hornet and Wasp off Guadalcanal. Japanese submarines also sunk the Juneau in November, 1942, and the cruiser Indianapolis in June, 1945, right after it delivered atomic bombs to Tinian.
American Submarines in the Pacific
Initial problems with the Mark 14 torpedo hampered American submarine operations. These weapons accomplished little in the defense of the Philippines. Though mostly used against merchant ships, the torpedoes did sink many major Japanese warships, starting with the heavy cruiser Kako, which was destroyed as it returned from Savo Island in 1942. Submarines played important roles at the Philippine Sea, where the Japanese carriers Shokaku and Taiho were sunk, and the Leyte Gulf, where two heavy cruisers were sunk and a third was destroyed while the three ships were on their way to battle. The most spectacular warship sunk by an American submarine was the Japanese supercarrier Shinano in November, 1944.
Despite those attacks on warships, American submarines had greater success in sinking Japanese merchant ships. By the beginning of 1945, Japanese foreign trade was virtually strangled because the nation’s commercial shipping had declined by more than 60 percent. Admiral Chester W. Nimitz declared unrestricted submarine warfare as soon as he took command of the Pacific Fleet. Though problems with the Mark 14 torpedoes kept Japanese losses modest in 1942, in 1943 American submarines sank more than 1.5 million tons of shipping, and the following year this number doubled to about 3 million tons. Japanese antisubmarine efforts were hampered by the nation’s technological inferiority. Submarine patrols were also stationed in the Atlantic, but they had few opportunities for combat and accomplished little.
Impact
German submarines inflicted modest losses on the Royal Navy and heavy losses on Anglo-American shipping until mid-1943, but these victories did not enable Germany to win the war. Japanese submarines sank a number of major warships, including enough aircraft carriers in 1942 to nearly win the Guadalcanal campaign. American submarines played the key role in strangling Japanese commerce, and the United States’ sinking of Axis warships greatly aided American victories in two major naval battles in 1944.
Bibliography
Blair, Clay. Hitler’s U-Boat War. 2 vols. New York: Random House, 1996-1998. Extensive and detailed study of German U-boat operations from 1939 to 1945.
‗‗‗‗‗‗‗. Silent Victory. 2 vols. Philadelphia: J. B. Lippincott, 1975. Comprehensive examination of American submarine operations against Japan from 1941 to 1945.
Burlingame, Burl. Advance Force Pearl Harbor. Annapolis, Md.: Naval Institute Press, 2002. Careful study of the operation of Japanese submarines, both miniature and regular, during the Pearl Harbor attack.
Gannon, Michael. Black May. New York: Dell, 1999. A sequel to Operation Drumbeat, detailing the decisive defeat of the German submarine fleet in May, 1943.
‗‗‗‗‗‗‗. Operation Drumbeat. New York: Harper & Sons, 1990. Detailed look of German U-boat operations off the coast of the United States in early 1942, inspired by curiosity over a sinking that the author witnessed.
Hickam, Homer. Torpedo Junction. New York: Dell, 1991. Examines German U-boat operations off the American coast in the first half of 1942.
Padfield, Peter. War Beneath the Seas. New York: John Wiley & Sons, 1995. Describes submarine operations by both the Allies and Axis Powers in the Atlantic, Mediterranean, and Pacific theaters.