The US Navy has installed high-frequency sonar for safe Arctic operations and the Raytheon Deep Siren acoustic communications system.
There was a plan to build 29 of them but only three were built
USS Jimmy Carter, third Seawolf commissioned in 2005 is roughly 100 feet (30 meters) longer than the other two boats of her class due to the insertion of a section known as the Multi-Mission Platform (MMP), which allows launch and recovery of ROVs and United States Navy SEALs forces. The MMP may also be used as an underwater splicing chamber for tapping of undersea fiber optic cables.
Compared to previous Los Angeles-class submarines, Seawolf submarines are larger, faster, and significantly quieter; they also carry more weapons and have twice as many torpedo tubes, for a total of 8. The boats are able to carry up to 50 UGM-109 Tomahawk cruise missiles for attacking land and sea surface targets. The boats also have extensive equipment to allow shallow water operations. The class uses the more advanced ARCI Modified AN/BSY-2 combat system, which includes a new, larger spherical sonar array, a wide aperture array (WAA), and a new towed-array sonar. Each boat is powered by a single S6W nuclear reactor, delivering 45,000 hp (34 MW) to a low-noise pump-jet.
Seawolf class hulls are constructed from HY-100 steel, which is stronger than the HY-80 steel employed in previous classes, in order to withstand water pressure at greater depths
American Seawolf class are estimated to have a test depth of 490 m (1,600 ft), which would imply a collapse depth of 730 m (2,400 ft).