Submarine in World War II

During the Second World War, submarines comprised less than 2 percent of the U.S. Navy, but sank over 30 percent of Japan's navy, including eight aircraft carriers. More important, American submarines contributed to the virtual strangling of the Japanese economy by sinking almost five million tons of shipping—over 60 percent of the Japanese merchant marine. Victory at sea did not come cheaply. The Submarine Force lost 52 boats and 3,506 men.

USS Gato (SS-212), launched 21 August 1941, was the first of 54 submarines in her class. Gato-class boats carried the brunt of the U.S. submarine war early in World War II. Later in the war they were joined by the 122 boats of the similar Balao-class; the main difference was a thicker pressure hull for increased operating depth.

World War II submarines were basically surface ships that could travel underwater for a limited time. Diesel engines gave them high surface speed and long range, but speed and range were severely reduced underwater, where they relied on electric motors powered by relatively short-lived storage batteries. Recharging the storage batteries meant surfacing to run the air-breathing diesels. Even combat patrols routinely involved 90 percent (or more) surface operations.

Model of the USS Balao (SS-285) Fleet Submarine

Commissioned in February 1943, USS Balao carried 10 officers and 70 enlisted men in a hull 312 feet (95 m) long that displaced 2,415 tons submerged. Her armament included deck guns and 24 torpedoes. On the surface, powered by four diesel engines, the Balao had a top speed just over 20 knots (37 km/hr); cruising at 10 knots (18 km/hr) her range was 11,000 nautical miles (20,000 km). Two 126-cell battery groups gave her a submerged top speed of 8.75 knots (16.2 km/hr); holding her speed to 2 knots (4 km/hr), she could remain submerged for 48 hours.

"Execute unrestricted air and submarine warfare against Japan." Order issued by Admiral R. Stark, the Chief of Naval Operations in Washington, following the Japanese attack on Pearl Harbour, Hawaii, on 7 December 1941.

The Gato-class USS Robalo (SS-273) was launched in May 1943, 1 of 27 wartime boats built at Manitowoc Shipyard, Wisconsin. Submarines were normally launched stern first. This unusual sideways technique was necessary because the shipyard was on the banks of a narrow, winding river. The boat's test dives took place in Lake Michigan, before she was barged down the Mississippi to the sea. Courtesy National Archives

Mt. Fuji, Japan, was photographed through the periscope of USS Trigger (SS-237) on war patrol, 24 May 1943. Courtesy National Archives

Photographed through the periscope of USS Thresher (SS-200) in January 1944, a torpedoed Japanese merchant ship sinks in the Pacific. Courtesy National Archives

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