Huntington Ingalls Industries’ (HII) Newport News Shipbuilding division has reached the pressure hull complete stage in the construction of the US Navy’s Virginia-class submarine Massachusetts (SSN 798).

The pressure hull complete signifies that all the hull sections of the submarine were joined to form a single, watertight unit.

This marks the last major construction milestone achieved before the launch of the submarine.

The keel-laying for the 25th Virginia-class submarine, Massachusetts, was performed in December 2020.

Newport News Shipbuilding Virginia-class submarine construction vice-president Jason Ward said: “Our highly skilled shipbuilders are driven to serve the nation by delivering great submarines that help ensure America’s undersea superiority.

“Reaching this point in construction demonstrates our commitment to getting Massachusetts ready as soon as possible to become part of the US Navy fleet.”

The Virginia-class fast attack submarines have been designed to replace the US Navy’s Los Angeles-class submarines as they retire.

The US Navy’s fleet of attack submarines is deployed to identify and destroy enemy submarines and surface ships.

Other functions performed by the attack SSNs include intelligence, surveillance, and reconnaissance missions; power projection; support battle group operations and engaging in mine warfare.

The next-generation Virginia-class vessels will provide advanced capabilities, including increased firepower, manoeuvrability and stealth.

It will also provide improved warfighting capabilities in both littoral and coastal operations.

Virginia SSNs feature a fly-by-wire ship control system, which aims to enhance the shallow-water ship handling capability.

As many as 19 submarines of this class have been commissioned to date.

The company has recently delivered the submarine USS Montana (SSN 794), which was commissioned in June.

Earlier in April, HII launched New Jersey (SSN 796) submarine.