Huntington Ingalls Industries (HII) has joined the hull sections of the US Navy's Virginia-class submarine, Washington (SSN 787), into a single, watertight unit.
Washington will be the 14th Virginia-class vessel and the seventh to be delivered by HII's Newport News Shipbuilding division.
Newport News submarines and fleet support vice-president Jim Hughes said: "Pressure hull complete is an exciting step toward the boat's completion because it's the point when the submarine really starts to take its final shape and is the last major construction milestone before christening and delivery next year.
"As with all of our Virginia-class submarines, Washington represents a true team effort that involves our partners at General Dynamics Electric Boat, the navy, our suppliers and the Washington crew."
The 377ft-long submarine is capable of diving to more than 800ft and can cruise at maximum speeds of 25k when submerged. It can also operate for 33 years without being refuelled.
The vessel incorporates new Virginia payload tubes that are aimed at lowering expenses while improving missile-firing payload capabilities.
HII completed the keel laying of the submarine in November last year and the vessel is currently 83% complete.
Washington submarine commanding officer commander Jason Schneider said: "I can truly say Washington now looks like a submarine on the outside.
"I look forward to seeing the systems that make up the internals of the submarine continue to come together as we approach launch and delivery."
The Virginia-class submarines are capable of executing anti-submarine, anti-surface ship, strike, intelligence, surveillance and reconnaissance operations, in addition to special operation forces and irregular and mine warfare.
Image: The US Navy's Virginia-class submarine Washington (SSN 787) achieved 'pressure hull complete'. Photo: courtesy of Ricky Thompson / HII.