Kittery shipyard delivers attack sub back to Navy after overhaul

Photo / Courtesy of Portsmouth Naval Shipyard The yard’s service life extension program started with Cheyenne, establishing the successful execution of a Los Angeles-class submarine refueling, overhaul and modernization of a submarine that is later in its service life.

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By Laurie Schreiber

Portsmouth Naval Shipyard in Kittery recently completed an engineered refueling overhaul on Los Angeles-class attack submarine USS Cheyenne (SSN 773).

The project distinguished Cheyenne as the first submarine to undergo an overhaul as part of a program that extended its total service life beyond 44 years, according to a news release.

The project was the latest step in the yard’s program to extend the sub’s service life.

Complexities

Cheyenne underwent major repairs, structural inspections and replacements of mechanical and electrical systems that enhanced the submarine’s capabilities, according to a separate news release earlier this year.

That work was noteworthy considering the ongoing construction of the shipyard’s dry dock project as part of the Navy’s Shipyard Infrastructure Optimization Program. Dry Dock No. 1, which dates to World War II, is undergoing a seven-year renovation that, once complete, will allow the yard to accommodate three Los Angeles- or Virginia-class submarines for repair, maintenance and modernization.

A flag flies in the foreground and a sub is in the water in the background.

Photo / Courtesy of Portsmouth Naval Shipyard

Portsmouth Naval Shipyard in Kittery recently completed an engineered refueling overhaul on Los Angeles-class attack submarine USS Cheyenne (SSN 773).

“The efforts on Cheyenne are even more impressive as the team executed their highly complex work amid an active construction zone for our multi-mission dry dock,” the shipyard’s former commander, Capt. Michael Oberdorf said in February. “It’s like cooking Thanksgiving dinner while renovating your kitchen — it requires thoughtful planning, coordination and superb execution.”

Last of its class

Attack submarines are designed for anti-submarine warfare, anti-ship warfare, strike warfare, special operations, intelligence, surveillance and reconnaissance, irregular warfare and mine warfare.

The Los Angeles class forms the backbone of the U.S. Navy's submarine force, according to the Cheyenne’s website. More than 60 submarines of this class have been completed; 33 are still in active service. The class contains more nuclear submarines than any other class in the world.

Based in Groton, Conn., Cheyenne was built by Newport News Shipbuilding and Dry Dock Co. in Newport News, Va., launched in 1995 and named for the capital city of Wyoming.

Cheyenne is the 62nd and the last Los Angeles-class attack submarine.

Blazing a trail

The shipyard’s project team for the refueling overhaul encompassed various trade workers, engineers and material support personnel, who worked alongside the ship’s crew.

The service life extension program started with Cheyenne and is considered “critically important to the overall health of the attack submarine community and the strength of our Navy for any future conflict,” said Capt. Jesse Nice, who assumed command of the shipyard from Oberdorf in June.

“The Cheyenne project team has blazed the trail for us as a shipyard, establishing the successful execution of a Los Angeles-class submarine refueling, as well as the overhaul and modernization of a submarine that is later in its service life,” Nice said.

The project was completed nearly two months ahead of the delivery date. The sub was refueled, overhauled and upgraded with the latest sonar and combat control equipment, allowing it us to remain at sea for months at a time, said Cmdr. Mark Rostedt, Cheyenne’s commanding officer.

The overhaul followed a similar project on the USS Hampton (SSN 767), a Los Angeles-class attack submarine that arrived at the shipyard in November 2024.

Commissioned in 1993 and homeported in San Diego, Hampton was due to undergo maintenance and system upgrades.

“SSN” is a U.S. Navy hull classification that denotes “ship submersible,” or submarine, and nuclear power.

Portsmouth Naval Shipyard repairs and services the U.S. submarine fleet. Located on a 300-acre complex on Seavey Island in the Piscataqua River, the yard employs nearly 7,500 civilians. It’s one of four such Navy-operated facilities in the country and the second-oldest, founded in 1800.

The yard plays an important role in employment and payroll throughout the region, including Maine, New Hampshire and Massachusetts.

In 2024, the shipyard injected $1.6 billion into the region's economy, up from $1.54 billion in 2023, $1.46 billion in 2022 and $1.32 billion in 2021.

Most of the shipyard’s civilian workforce hails from Maine, with 4,252 employees, up from 4,194 in 2023.