KITTERY, Maine — The U.S. Navy returned the Virginia-class attack submarine USS North Dakota (SSN 784) to the active fleet on August 29 after Portsmouth Naval Shipyard in Kittery, Maine, completed an Extended Drydocking Selected Restricted Availability. The Virginia-class attack submarine received major maintenance and modernization work and completed the project ahead of its rebaselined schedule.
40-Month Maintenance Period
North Dakota arrived at Portsmouth Naval Shipyard on April 28, 2023, and entered Dry Dock No. 2 in September 2023. It undocked on February 26, 2026, before undergoing nearly six more months of pierside work, system integration, testing and certification.
The submarine began sea trials on August 20, 2026, and arrived at Naval Submarine Base New London in Groton, Connecticut, on August 27. The availability formally ended on August 29, bringing the total maintenance period to about 40 months.
The original plan called for about 33 months of work valued at approximately $347 million.
First Block III Availability
The project was Portsmouth Naval Shipyard’s first Chief of Naval Operations availability for a Block III Virginia-class submarine. Shipyard workers and North Dakota’s crew worked together to integrate new maritime technologies and complete several technical modifications on a Block III submarine for the first time.
The work included structural inspections, repairs, replacement of key mechanical and electrical systems, and upgrades involving the submarine’s bow-array technologies.
The Navy said the submarine progressed through its testing program, including its final phase, at a historically rapid pace. The experience gained from the project is expected to help guide future maintenance work on other Block III Virginia-class submarines.
Block III Design
USS North Dakota is the 11th Virginia-class attack submarine and the first of eight Block III boats. The submarine is 114.8 meters long, nuclear-powered and based at Naval Submarine Base New London.
The Block III configuration introduced a redesigned bow with a Large Aperture Bow (LAB) sonar array and two large-diameter Virginia Payload Tubes. These replaced the 12 individual vertical launch tubes used on earlier Virginia-class submarines.
Navy and Shipyard Statements
“Executing this complex work package on our first Block III submarine was a demanding task, but this team met every challenge head-on with tenacity and selflessness,” said Capt. Jesse Nice, shipyard commander. He said the team’s work created a foundation for future Virginia-class maintenance projects.
Capt. Mike Poplawski, commodore of Submarine Squadron TWO, said the technological capabilities integrated during the availability provide an immediate operational benefit and strengthen the readiness and resilience of the submarine force.
Andrew Stark, North Dakota’s project superintendent, credited the submarine’s crew and Portsmouth’s civilian workforce for their coordination throughout the project. He said the team executed the “fastest, most aggressive end game in recent history” on a major availability at Portsmouth Naval Shipyard.
USS North Dakota
General Dynamics Electric Boat built North Dakota in Groton, Connecticut. Its contract was awarded on August 14, 2003. The keel was laid on May 11, 2012, the submarine was launched on September 15, 2013, christened on November 2, 2013, and commissioned on October 25, 2014.
The submarine supports missions including anti-submarine warfare, intelligence gathering and special operations support.
With North Dakota back in the fleet, Portsmouth Naval Shipyard has completed its first major maintenance project involving the Block III Virginia-class configuration. The experience is expected to support future modernization and maintenance work on other submarines in the block.
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