USS Massachusetts (SSN 798) Virginia-Class Submarine

History

USS Massachusetts (SSN 798) is a Block IV Virginia-class nuclear-powered fast-attack submarine of the United States Navy. It was commissioned on March 28, 2026, and is the seventh Block IV submarine of the class.

The submarine was built under the Virginia-class teaming arrangement involving General Dynamics Electric Boat and HII Newport News Shipbuilding. HII delivered Massachusetts to the Navy on November 21, 2025, after the submarine completed its initial sea trials in October 2025.

In August 2026, Massachusetts completed its shakedown trials and was cleared to continue toward fleet tasking without the previously planned post-shakedown shipyard availability. The decision was intended to make the submarine available for fleet preparations sooner while avoiding an additional shipyard period.

Construction and commissioning

Massachusetts was included in a United States Navy contract for ten Virginia-class submarines. The name Massachusetts was announced in 2015. The keel was laid at Newport News Shipbuilding on December 11, 2020, during a virtual ceremony held during the COVID-19 pandemic.

The submarine was christened at Newport News Shipbuilding on May 6, 2023, with Sheryl Sandberg serving as ship sponsor. It completed initial sea trials on October 7, 2025, and the Navy accepted delivery on November 21, 2025. These milestones are recorded in a published vessel chronology.

USS Massachusetts was commissioned at Boston Harbor on March 28, 2026. The U.S. Navy commissioning record identifies Massachusetts as the seventh Block IV Virginia-class submarine and the 12th Virginia-class submarine delivered by Newport News Shipbuilding.

Available source material contains conflicting class-sequence descriptions. One supplied news headline describes Massachusetts as the 26th Virginia-class submarine, while the same report later calls it the 25th. The vessel chronology identifies it as the 25th submarine of the class. The official Navy commissioning release does not use either sequence number but describes Massachusetts as the newest fast-attack submarine.

Shakedown trials and fleet transition

After commissioning, Massachusetts underwent shakedown trials. These at-sea evaluations are used to test propulsion, navigation, sensors, communications, combat systems, safety equipment, and supporting machinery under operating conditions.

The Navy announced on August 17, 2026, that Massachusetts would move toward fleet tasking after completing the trials without entering its planned post-shakedown shipyard period. Normally, deficiencies identified during shakedown testing may be corrected during a post-shakedown availability. Waiving that period allowed the submarine to continue training and preparations for operational assignments rather than immediately returning to a shipyard.

Design

USS Massachusetts belongs to Block IV of the Virginia class. Virginia-class submarines are nuclear-powered attack submarines designed for missions that include anti-submarine warfare, anti-surface warfare, intelligence collection, surveillance, land attack, and support for special operations.

The class combines acoustic stealth, advanced sensors, and nuclear propulsion. Its reactor plant is designed to operate without refueling during the planned service life of the submarine. This removes the requirement for a midlife reactor refueling overhaul and is intended to increase the amount of time available for operations.

Block IV configuration

Block IV submarines were developed with an emphasis on improved operational availability. The configuration reduces the number of major maintenance periods expected during the life of each submarine, allowing more time to be allocated to deployments and other fleet activity.

For Massachusetts, bypassing the planned post-shakedown shipyard period extended this emphasis on availability into the beginning of the submarine's fleet career. The supplied source also notes that avoiding an additional shipyard period could reduce demand on specialized submarine maintenance labor and shipyard capacity.

Sensors and missions

Virginia-class submarines use passive sonar and other undersea sensors to detect, classify, and track submarines and surface vessels while limiting their own acoustic signatures. Their surveillance capabilities also support intelligence collection during extended submerged operations.

The class is intended to operate covertly in contested waters and can support anti-submarine warfare, anti-surface warfare, surveillance, intelligence collection, and land-attack missions. The supplied source states that the submarines can employ heavyweight torpedoes against surface targets and use cruise missiles for land-attack missions.

Operational history

Following commissioning in March 2026, Massachusetts entered a period of testing, training, and preparation for fleet use. By August 2026 it had completed shakedown trials and was cleared to continue toward fleet tasking without the planned post-shakedown shipyard availability.

The decision did not by itself document a completed combat deployment. Instead, it allowed the submarine to proceed more directly into training and preparations for operational assignments. The available sources describe this as an increase in potential fleet availability rather than evidence of combat operations.

Specifications (USS Massachusetts SSN 798)

General characteristics

• Class: Virginia class, Block IV
• Type: Nuclear-powered fast-attack submarine
• Displacement: Approximately 7,800 tons
• Length: 114.9 m (377 ft)
• Beam: 10.4 m (34 ft)
• Propulsion: Nuclear reactor plant designed to operate without refueling during the submarine's planned service life

Mission systems and armament

• Primary missions: Anti-submarine warfare, anti-surface warfare, intelligence collection, surveillance, land attack, and support for special operations
• Weapons described in the supplied sources: Heavyweight torpedoes and cruise missiles