The Navy has so many competing priorities that ship maintenance often gets short shrift when it comes to budget allocations, especially compared to new ship construction and operational deployments. However, in recent years, that has begun to change; maintenance is no longer the service’s red-headed stepchild. The former Chief of Naval Operations’ (CNO’s) Navigation Plan 2020 says the Navy will “prioritize readiness to keep forces forward deployed.” The Navy has begun taking actions to remedy the situation, including hiring at shipyards, the “Performance-to-Plan” initiative, and the long-overdue Shipyard Infrastructure Optimization Program (SIOP) for improving submarine maintenance.1 In a March 2023 interview with 60 Minutes, former CNO Admiral Michael Gilday said, “Our maintenance backlog is one of the primary things I’m working on to correct. Just three years ago we had 7,700 delay days and we have cut that down to 3,000. [But] I am not satisfied.”
Submarine maintenance receives a lot of attention because of the many delays the boats experience in shipyards—especially a few egregious maintenance delays such as that experienced by the USS Boise (SSN-764), a Los Angeles–class submarine that sat idle for more than five years waiting for a dry dock, among other things.
A ship in maintenance is one less ship available to the fleet. At any given time, almost one-third of the submarine force is either in depot-level maintenance or idle and not available to operate. Such low operational availability seriously degrades the Navy’s capability to penetrate contested zones and disrupt enemy operations. Recent wargames aimed at defending Taiwan from Chinese invasion indicate that submarines afford the United States an asymmetric and powerful advantage in any potential conflict.2
The Navy now struggles to complete on time what should be routine, scheduled, and predictable maintenance. If it ever faces battle damage and the need for quick repairs, it is doubtful shipyards would be able to handle the workload and turn submarines around in a timely, useful manner. Having excess or surge capacity to respond to such events will be vital to sustaining the Navy’s submarines and ships.
Any conflict that occurs in the next decade will largely be fought with the fleet the Navy has now. Or, more accurately, it will be fought with those ships that are not sitting in maintenance. It also will be maintained with the shipyards and expertise it has on day one. Having the ability to keep most of the fleet at sea is especially important given the Navy’s current low number of ships.
Ship Maintenance
Maintenance conducted at a shipyard is a complex and massive-scale industrial process. An “availability”—
depot-level maintenance—entails thousands of individual work tasks, conducted by workers organized into at least 20 different shops (welding, mechanical, etc.), and measured in thousands of man-days of labor. For instance, an extended selected docking restricted availability (ESDRA) for a Virginia-class submarine requires something like 8,000 individual work tasks and can consume 280,000 man-days of labor in its execution over about 24 months. These particular availabilities are among the most complex undertaken, thanks to the large scale, precedence relationships (i.e., the order of tasks is important), and high levels of skill and expertise required to perform the tasks. This capability and capacity cannot be built overnight, as Huntington Ingalls can attest. That company builds submarines, but it learned from experience that maintenance is very different. The result of its inexperience in maintenance was 22 months of delay in the USS Helena’s (SSN-725) 2017–20 availability.3
Shipyards
Naval shipyards have not kept pace with the complexity of the Navy’s ships. The four public shipyards are each more than 100 years old. Norfolk Naval Shipyard is the oldest, tracing its roots to 1767 when Virginia was still a British colony. The nascent Department of the Navy acquired it in 1801. Dry Dock Number One at Norfolk is registered as a national historic landmark and remains in use exactly as it was constructed between 1827 and 1834 (excluding the replacement of its caisson).4 The poor material condition of the shipyards impedes timely completion of maintenance. Indeed, this is why the Navy is embarking on an estimated $20 billion investment in the SIOP. However, the SIOP is expected to take almost 20 years to complete. It includes renovations, improvements, and extensions of existing dry docks to accommodate larger ships and rearranging facilities for more optimal flow of workers and goods.
Manage Utilization
There are two choices to manage utilization: the Navy can either increase capacity or decrease the demand for work.
Capacity increases are most effective when they address a bottleneck. Upgrading the existing dry docks is one way to do so, because many existing dry docks cannot accommodate large newer ships, and some have limitations because of tides and other factors.
After dry docks, the main bottleneck is the size of the workforce. The Navy has been hiring, but in 2022 it missed its goal by about a thousand workers. The shipyards must compete with private industry for highly qualified workers. Salaries for wage-grade employees are no longer competitive even with fast food restaurants, which offer comparable salaries and benefits. And a large proportion of the shipyard workforce has less than five years of experience and, as a result, is less productive than a more experienced cadre would be. It is likely the Navy will continue to struggle with workforce issues.
Demand for work at the public shipyards can be alleviated by sending work to private shipyards. The two private builders, Huntington Ingalls in Newport News, Virginia, and Electric Boat in Groton, Connecticut, potentially could perform submarine maintenance. But their capacity is already being stretched by construction of the Virginia- and Columbia-class submarines, the latter of which is already behind schedule.
And ship repair is different than ship construction, even if the equipment and workforce are the same. Huntington Ingalls’ then-CEO Mike Petters remarked in 2020, “Getting back into submarine repairs after about a decade of not doing the work was a challenge.”5 If the Navy pursues this course of action, it needs to communicate a regular plan of sending work to the private shipyards to incentivize the yards to make the investments necessary to improve their maintenance productivity.
Other ways to increase capacity include building or revitalizing a fifth public shipyard. The cost would be in the billions of dollars, but it would increase national capacity by 20 percent or more depending on its size. The Navy could also do more maintenance at forward bases or without dry docks. There are technical constraints on what work could be shifted, and doing so runs the risk of increasing the complexity of the whole submarine maintenance system.
Manage Variability
Variability in the arrival of work and its execution creates delays—more variability means greater delays. The scheduling of work with predecessor tasks and successor tasks creates delays. For example, painting cannot begin until welding is completed; if welding is delayed, painting, too, falls behind. With a network of thousands of tasks, it is difficult to ensure smooth flow of work. Moreover, unplanned work—“growth work”—increases variability and disrupts the planned execution.
By its nature, a maintenance availability will naturally see some growth work—at present, about a quarter of the work during a submarine availability is unplanned. Reducing growth work, which can be achieved up front by improving work estimates, will reduce variability and total workload.
Another approach could be to alter the maintenance plans for attack submarines (SSNs) to look more like those used for the Ohio-class ballistic- and guided-missile submarines. The Ohios undergo frequent but short maintenance periods called refits. SSNs undergo infrequent but long maintenance availabilities, which increase variability and cause delays. Shorter, more frequent maintenance refits for all submarine types would be a low-cost way to decrease variability and hence reduce delays, but they may not be compatible with attack submarine operations.
Shipyard Efficiency
The shipyards are not laid out as the result of some planned design, but rather because of a long, gradual evolution as shops were added, changed, and removed. The result is layouts less than ideal for the movement of workers and materials. The SIOP should modernize the shipyards, redesigning and optimizing their layouts to maximize efficiency. The Navy expects a 5 percent gain in efficiency, which—while it sounds small—would add up to some additional capacity.
Our backgrounds are in industrial engineering, i.e., as the efficiency experts companies hire to squeeze every bit of productivity out of a workforce. We believe in the power of lean production processes and continuous process improvement and recommend the shipyards continue implementing and promoting these concepts. The gains may be small, but, at a national level, they add up.
Parts Availability
The submarine industrial base has shrunk, and for many specialized parts, only one or a few suppliers exist. Limited parts availability can become a major bottleneck, especially when the lead times to build some parts can be measured in hundreds of days. The shipyards have turned to cannibalization—removing a needed part from one submarine entering the shipyard to get another submarine out. Cumulatively, this leads to a lot of extra work. The causes of not having needed parts on hand are many: inadequate planning, money issues before the start of the availability, and not knowing what parts will be needed because of growth work. Parts availability will continue to be an issue as long as the industrial base remains small.
Shifting Bottlenecks
As the Navy addresses any one cause of delay, other bottlenecks constraining throughput emerge. A common metaphor to explain the shifting production bottleneck problem is a ship floating on water above rocks. The rocks represent problems. As you work to remove the tallest rock impeding your progress, you can drop the water level, after which the next highest rock becomes the biggest impediment to your progress. Understanding how multiple bottlenecks throughout the process shift depending on conditions in the shipyard, the work being performed, and the stage of the maintenance availability informs a multiprong strategy to improve maintenance performance. The Navy should not expect that just addressing a single bottleneck such as the workforce will solve the problem. Fixing workforce issues and capacity will only expose the next prominent bottleneck. It is a never-ending battle.
Complexity Theory
Those in government tend to react to all system challenges as if more rules, policies, and planning can wring all the uncertainty and random events out of the system. These believers in more bureaucracy think the system can then tick away like clockwork to a known and predictable rhythm. More planning will only get the Navy so far, however. Maintenance work by its very nature will always entail some uncertainty. The process is stochastic, not deterministic. Stochastic systems are guided by the mathematics of queueing theory (see sidebar), and understanding those mathematical relationships can inform decisions on how to improve a process.
Shipyard maintenance challenges should be viewed through the lens of systems thinking: Ship maintenance involves both uncertainty and randomness, and neither can be eliminated by more and better planning. Through an understanding of queueing theory, the theory of constraints, and Lean Six Sigma, various strategies can be identified to improve the current situation. The Navy is making many strides, but, at some point, additional capacity will be required.
The Navy cannot plan its way out of a misalignment between work and capacity. Its submarines and ships are experiencing delays in scheduled maintenance now, during peacetime. What happens if the Navy must fight an adversary and ships are damaged and in need of immediate repair to return to the fight? What happens when four dry docks in Puget Sound Naval Shipyard are sidelined until the seismic risk is better understood and perhaps mitigated? Bringing additional capacity online is a long-term and financially expensive investment, and the Navy should not lose sight of planning to accomplish it even as the service must improve the capacities already in hand.
1. “Statement of Admiral Michael M. Gilday, Chief of Naval Operations, on the Posture of the U.S. Navy,” Senate Appropriations Committee, 26 May 2022.
2. David Lee Bergeron, “Fighting for Survival,” Naval History 33, no. 6 (December 2019).
3. Hugh Lessig, “Navy Cites Delays in Sub Maintenance at Newport News,” Daily Press, 16 April 2019
4. Cultural Resources Fact Sheet, Norfolk Naval Shipyard, www.navsea.navy.mil/Portals/103/Documents/SIOP/NNSY-History-FS.pdf.
5. Megan Eckstein, “Submarine Industrial Base Ready to Grow—But Only If Pentagon, Congress Send the Right Signals,” USNI News, 6 November 2020.