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The 'F-22' of Submarines: Why America Built Only 3 of the Deadliest Submarines Ever
In the late 1980s, the U.S. Navy was faced with a crisis. In 1980, the Soviet Union had received information from the Walker family spy ring that the Navy could track its submarines through excessive propeller noise. As a result, the Soviet Union went looking for advanced Western machinery to make better propellers. In 1981, the Japanese company Toshiba sold propeller milling machinery—now relatively common nine-axis CNC milling machines—to the Soviet Union via the Norwegian Kongsberg corporation.
By the mid 1980s, the Soviet Union’s new machinery began to make itself felt. The new Akula-class submarines had a “ steep drop in broadband acoustic noise profiles ”. One government source told the Los Angeles Times , “the submarines started to get silent only after the Toshiba stuff went in.” On top of running silent, the Akula class could dive to depths of up to two thousand feet—while the U.S. Navy’s frontline submarines, the Los Angeles class, could dive to only 650 feet.
To combat the threat of the Akula class, the U.S. Navy responded with the Seawolf class of nuclear attack submarines. The Seawolf submarines were designed with HY-100 steel alloy hulls two inches thick , the better to withstand the pressures of deep diving. HY-100 steel is roughly 20 percent stronger than the HY-80 used in the Los Angeles class. As a result, the submarines are capable of diving to depths of up to two thousand feet, and crush depth estimates run from 2,400 to 3,000 feet.