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Navy Readiness: Actions Needed to Address Costly Maintenance Delays Facing the Attack Submarine Fleet

GAO-19-229 Published: Nov 19, 2018. Publicly Released: Nov 19, 2018.
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Fast Facts

Navy shipyards have been unable to keep up with maintenance demands for attack submarines. As a result, the Navy has spent $1.5 billion since 2008 to support submarines that it could not deploy.

For example, the USS Boise has been docked for over 2 years while waiting for maintenance—with the Navy paying to support it.

The Navy has begun to hire more workers at its shipyards and, in some cases, has shifted more work to private shipyards.

We recommended the Navy assess how to best use public and private shipyards to achieve the full benefit of the nation’s investment in these submarines.

A Virginia Class Attack Submarine

This is a photo of a submarine that is underway.

This is a photo of a submarine that is underway.

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What GAO Found

The Navy has been unable to begin or complete the vast majority of its attack submarine maintenance periods on time resulting in significant maintenance delays and operating and support cost expenditures. GAO's analysis of Navy maintenance data shows that between fiscal year 2008 and 2018, attack submarines have incurred 10,363 days of idle time and maintenance delays as a result of delays in getting into and out of the shipyards. For example, the Navy originally scheduled the USS Boise to enter a shipyard for an extended maintenance period in 2013 but, due to heavy shipyard workload, the Navy delayed the start of the maintenance period. In June 2016, the USS Boise could no longer conduct normal operations and the boat has remained idle, pierside for over two years since then waiting to enter a shipyard (see figure). GAO estimated that since fiscal year 2008 the Navy has spent more than $1.5 billion in fiscal year 2018 constant dollars to support attack submarines that provide no operational capability—those sitting idle while waiting to enter the shipyards, and those delayed in completing their maintenance at the shipyards.

USS Boise Idle Pierside

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The Navy has started to address challenges related to workforce shortages and facilities needs at the public shipyards. However, it has not effectively allocated maintenance periods among public shipyards and private shipyards that may also be available to help minimize attack submarine idle time. GAO's analysis found that while the public shipyards have operated above capacity for the past several years, attack submarine maintenance delays are getting longer and idle time is increasing. The Navy may have options to mitigate this idle time and maintenance delays by leveraging private shipyard capacity for repair work. But the Navy has not completed a comprehensive business case analysis as recommended by Department of Defense guidelines to inform maintenance workload allocation across public and private shipyards. Navy leadership has acknowledged that they need to be more proactive in leveraging potential private shipyard repair capacity. Without addressing this challenge, the Navy risks continued expenditure of operating and support funding to crew, maintain, and support attack submarines that provide no operational capability because they are delayed in getting into and out of maintenance.

Why GAO Did This Study

According to the Navy, its 51 attack submarines provide the United States an asymmetric advantage to gather intelligence undetected, attack enemy targets, and insert special forces, among others. These capabilities make attack submarines some of the most–requested assets by the global combatant commanders.

GAO was asked to review the readiness of the Navy's attack submarine force. This report discusses the extent to which the Navy (1) has experienced maintenance delays in its attack submarine fleet and costs associated with any delays; and (2) has addressed any challenges and developed mitigation plans for any maintenance delays. GAO analyzed readiness information from fiscal years 2008-2018, operating and support costs, maintenance performance, and other data; visited attack submarines and squadrons; and interviewed public and private shipyard and fleet officials.

This is a public version of a classified report issued in October 2018. Information the Department of Defense deemed classified or sensitive, such as attack submarine force structure requirements and detailed data on attack submarine maintenance delays, has been omitted.


GAO recommends that the Navy conduct a business case analysis to inform maintenance workload allocation across public and private shipyards. The Department of Defense concurred with GAO's recommendation.

Recommendations for Executive Action

Agency Affected Recommendation Status
Department of the Navy The Secretary of the Navy should ensure that the Chief of Naval Operations conducts a business case analysis to inform maintenance workload allocation across public and private shipyards; this analysis should include an assessment of private shipyard capacity to perform attack submarine maintenance, and should incorporate a complete accounting of both (a) the costs and risks associated with attack submarines sitting idle, and (b) the qualitative benefits associated with having the potential to both mitigate risk in new submarine construction and provide additional availability to the combatant commanders.
Closed – Implemented
The Department of Defense concurred with this recommendation. In December 2018, the Navy issued a five-year submarine maintenance plan citing our report and stating that the Navy will take several actions to reduce submarine idle time and maintenance delays that address our findings. These actions include moving two additional attack submarine maintenance availabilities to the private shipyards, with the possibility of moving additional availabilities to the private sector over the next five years.

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Attack submarinesInternal controlsMaintenance costsMilitary forcesMilitary readinessNaval operationsNaval shipyardOperating and support costsSchedule slippagesSubmarinesWorkforce shortages