SSGN

SSGN is the United States Navy hull classification for a class of nuclear-powered, guided-missile submarines. The designation applies to Ohio-class submarines that were converted from ballistic-missile submarines to conventional, multi-mission platforms. The conversions began in the early 2000s as part of a shift toward flexible, long-range conventional strike and special-operations support without maintaining a large number of land-based missiles.

During the program, four Ohio-class submarines were converted to SSGNs. The process removed or repurposed the strategic missile systems and repurposed the hulls to carry a large payload of Tomahawk cruise missiles and advanced mission-systems equipment. The submarines were also modified to support special operations forces, notably through the addition of Dry Deck Shelters that enable rapid deployment of personnel and equipment, as well as improved berthing and support facilities for crews and mission teams.

Armament and capabilities focus on conventional strike and precision targeting. Each SSGN can conduct long-range Tomahawk land-attack missions, providing a covert and persistent weapon system capable of rapid, distributed strikes from undersea. In addition to weapons, the SSGN platform supports special operations by transporting and deploying personnel and equipment with stealth and reach.

Operational history notes that the SSGNs have served in various theaters, delivering conventional missiles, gathering intelligence, and supporting special operations missions while maintaining the stealth and endurance characteristics of submarine platforms. As of the 2020s, the four SSGNs remain in service, contributing to U.S. naval capabilities through flexible, multi-mission undersea operations.