Los Angeles-class (SSN-688)

The Los Angeles class, also designated the 688 class, is a series of nuclear-powered fast attack submarines operated by the United States Navy. Development began in 1967 as a response to Soviet submarine technology. The class succeeded the Sturgeon class and was designed with increased speed and stealth to maintain pace with carrier battle groups. Construction was shared between Newport News Shipbuilding and General Dynamics Electric Boat between 1972 and 1996. This class transitioned the naming convention for attack submarines from marine life to American cities.

The class consists of three production flights. Flight I vessels established the baseline design. Flight II introduced a dedicated vertical launch system (VLS) for cruise missiles and an updated reactor core. The final group, designated 688i, featured noise-reduction technology and relocated diving planes from the sail to the bow to facilitate under-ice operations. Internally, the vessels use two watertight compartments: a forward compartment for living and control spaces, and an aft compartment for engineering systems.

Propulsion is provided by an S6G pressurized water reactor powering steam turbines. Control systems transitioned from the analog-digital hybrid Mk 113 to the digital Mk 2 Combat Control System. The sensor suite initially utilized the AN/BQQ-5 sonar system, later replaced by the AN/BQQ-10, which uses an open architecture to integrate commercial hardware. Some units were configured to carry Dry Deck Shelters or the Advanced SEAL Delivery System for special operations.

The lead boat entered service in 1976. Operational lifespans have varied; some hulls exceeded 40 years of service, while others were retired due to the cancellation of midlife reactor refuelings. One vessel, USS Miami, was lost during an overhaul because of arson. Retired vessels are processed through the Ship-Submarine Recycling Program, with two units currently serving as moored training ships for the Nuclear Power School. Retirements accelerated in 2026, with Newport News withdrawn in January, Boise in April, Alexandria in June and San Juan in August, as the Virginia class replaces the type.