On Oct. 2, 2021, the USS Connecticut, one of only three Seawolf-class nuclear-powered attack submarines in the Navy, struck an unmapped seamount in the South China Sea. The incident, which Vice Adm. Karl Thomas subsequently described as avoidable with “sound judgment, prudent decision-making and adherence to required procedures,” also engendered not only a leadership shake-up but exposed systemic weaknesses in submarine operations, maintenance, and strategic readiness.
The official investigation, as detailed in the command report, concluded that the no single action or inaction caused this mishap, but it was preventable. It resulted from an accumulation of errors and omissions in navigation planning, watch team execution, and risk management. It was caused by an accumulation of errors and oversights in navigation planning, watch team performance, and risk management. The navigation team under estimated the risk of proceeding at high speed through unfamiliar waters, and ignored a number of warnings from the quartermaster of erratic fathometer readings. Seconds from impact, sonar operators got a read on a contact at the bow as an animal, instead of the underwater mountain approaching that it actually was.
This accident did more than incapacitated a $10 billion submarine. It removed an important asset for the U.S. arsenal when the Navy’s undersea force is already being stretched too thin. The Seawolf-class, which was designed toward the end of the Cold War to track Soviet submarines, remains unmatched in speed, stealth, and firepower. Capable of speeds in excess of 35 knots, operating in ice, and hosting up to 50 missiles ranging from Mk 48 torpedoes to Tomahawk missiles the Connecticut is a keystone of Indo-Pacific deterrence.
Restoring such a unique ship is an engineering achievement in itself. Since there are only three Seawolf-class subs to have ever been built, the industrial base for parts is practically gone. The bow and sonar dome, both badly damaged, have to be made to order at great expense and hassle. Congress allotted $50 million for initial restoration, with $10 million for the bow dome, but the cost of complete restoration is secret. The Connecticut started a Selected Restricted Availability (EDSRA) Extended Docking in February 2023 for the purpose of fixing damage and having a deep maintenance to update its systems. But the timeline slipped: what was initially a return by 2025 is now projected in late 2026, meaning the submarine will be out-of-service for over five years a delay that is representative of the bigger maintenance backlogs plaguing the Navy’s nuclear fleet.
The EDSRA process as such is a metaphor for the maintenance malaises of the Navy. These refits involve hundreds of thousands of man-days and the coordination of dozens of trades, all at shipyards themselves over a century on average. As one recent study noted, “at any given time, almost one-third of the submarine force is either in depot-level maintenance or idle and not available to operate.” The eroding industrial base, shortage of manpower, and the peculiarly specialized technical needs of nuclear vessels have led to recurrent delays Virginia-class submarines, e.g., spent an average of nine months behind schedule coming back into service following overhauls.
In the Seawolf-class, these problems are compounded. Repair to the Connecticut involves not only normal maintenance but also custom manufacture of obsolete parts, a process rendered more difficult by a lack of suppliers and the need for materials that are proven to be nuclear-grade. Cannibalization stripping parts from one boat to repair another is a last resort, but only contributes to the overall workload and risk of further delays.
On the strategic level, the Connecticut’s absence is acutely felt. The USS Seawolf will be having its own longer maintenance in 2026, and the USS Jimmy Carter, heavily modified to suit special operations, is not optimally suited to conventional attack roles. With the SSN(X) program delayed into the 2040s, the United States is now left with a growing capability gap at the very moment China’s navy is growing its undersea capabilities and regional presence. As a recent assessment noted, “the alarming trend of sending Los Angeles-class submarines to be decommissioned faster than the state-of-the-art Virginia-class boats are ready for service is a problem not just in physical operation; it reflects a much deeper disease at the heart of American naval shipbuilding.”
The Connecticut’s crash also illustrates the necessity of cutting-edge submarine technology in modern warfare. Seawolf-class subs are equipped with sophisticated sonar arrays, underwater mapping systems, and tough Arctic hulls the product of decades of development of how to drive and fight under ice. But the effectiveness of these technological marvels depends on the men and women who drive them and the support system behind them.
As the U.S. Navy works to return the Connecticut to action, the accident is a humbling reminder: where human error, technological complexity, and strategic imperatives converge, even the world’s most advanced submarines can be left exposed. In an era of rising great-power competition, every submarine and every day lost to maintenance has oversized consequences for American deterrence and maritime security.
