Submarine maintenance delays have cost the Navy $3.4 billion over the past decade and could add $3.1 billion more as it prepares to retire aging Los Angeles-class attack submarines, a new Government Accountability Office (GAO) report finds.
In an analysis of attack submarine (SSN) data from fiscal years 2008 to 2025, GAO said it found “persistent depot maintenance delays, increased lengths of depot maintenance periods, and increased idle time.”
The report said the Navy incurred 3,040 maintenance day delays from 2016 to 2020 and another 3,454 delay days from 2021 to 2025 while the average deport-level maintenance period from 2016 to 2020 was 744 days versus 809 days for fiscal years 2021 to 2025. The Navy also only finished about 11 percent of SSN depot maintenance on time at the four public shipyards from fiscal 2016 to 2025.
Beyond delay days, GAO found the Navy incurred 8,906 active idle time days for active SSNs from fiscal 2016 to 2025. That peaked at 1,518 active idle time days in 2022 and that has lowered to 166 days in fiscal 2025. Active idle time is when the submarine and its crew have to remain pierside because it is not certified for normal operations and has to wait for its maintenance period.
Overall, GAO calculated this means the Navy lost over 15,000 operational days to the delay and idle time delays.
Another factor that pressure on the Navy is impending increases in inactive idle time, meaning submarines and their crews waiting years to be inducted into a public shipyard for decommissioning due to shipyard constraints. While idling, the boats and their crews cannot conduct normal operations and must remain pierside while certifications expire, but they are still fully crewed with sailors, including those who must maintain and supervise nuclear reactors.
Ultimately, those boats will have to wait until a shipyard has space for the submarine to dock and defuel the reactor. The four public naval shipyards’ priorities are conducting maintenance on the nuclear-powered aircraft carrier and nuclear ballistic missile submarines over active SSNs, let alone those due for inactivation services.
Then, once an inactive SSN is inducted into a dry dock, it still retains the crew and takes limited dry dock space away from operational vessels.
Exchange Monitor affiliate Defense Daily first published a version of this story.