Capacity of the Navy's Shipyards to Maintain Its Submarines: Presentation at the Annual Conference of the Western Economic Association International [presentation] [open pdf - 554KB]
From the Summary: "Delays at the shipyards adversely affect 'operational readiness'. Maintenance delays have 'idled expensive ships' and their skilled crews and reduced the number of submarines that the Navy can put to sea. The Navy's four shipyards have experienced significant delays in completing maintenance on its submarines. Two main factors have caused the delays:  The amount of maintenance required for each overhaul has increased.  The Navy has not hired enough new workers to keep pace with the workload. CBO [Congressional Budget Office] projects that the submarine 'fleet's size will exceed the yards' capacity' to maintain it over the next several years and in '25 of the next 30 years'. Changing the shipyards' capacity or the size of the fleet would take several years, so delays would continue in the 2020s even if new policies were adopted."
Congressional Budget Office: http://www.cbo.gov/