Despite the Navy’s plans to improve its public shipyards, the four facilities and their equipment remain in “poor condition,” featuring drydocks that are more than 100 years old and other shortcomings that will take decades to fix, according to a government watchdog report released Tuesday.

The naval shipyards in Norfolk, Virginia, and Kittery, Maine, and the shipyard and intermediate maintenance facilities at Puget Sound, Washington, and Pearl Harbor, Hawaii, are vital to maintaining the nuclear fleet, the Government Accountability Office report states.

But while they are critical to maintaining the Navy’s nuclear-powered fleet — 10 carriers and 70 boats — “their overall condition remains poor,” according to the report.

Backlogged maintenance and restoration projects for the facilities have grown by 41 percent over the past five years, the report states.

Fixing them will cost roughly $4.86 billion and won’t be completed for nearly 20 years, according to the GAO.

A Navy analysis found that shipyard capital equipment has an average age that now exceeds its expected useful life, the report states.

The shipyards are not fully meeting the Navy’s needs, partially due to these poor conditions, according to the GAO.

Inadequate facilities and equipment have led to maintenance delays that contributed to more than 1,300 lost operational days for carriers and 12,500 lost operational days for submarines from fiscal year 2000 to 2016, the report states.

As a result of the ongoing problems, the Navy will be unable to conduct more than a third of its 218 planned maintenance periods over the next 23 fiscal years, according to the GAO.

The report found that the average age of the 18 drydocks used to perform maintenance is about 89 years, with the oldest completed in 1891 and the newest completed in 1962.

Several drydocks can’t support existing boat classes, while others can only support vessels when assisted by equipment or tidal schedules, the GAO reports.

As existing carriers and boats are retired and new classes come into the fleet, use of the existing drydocks will become even more limited, the report states.

Drydock flooding “during certain delicate depot maintenance tasks” risks worker safety, ship damage and potential environmental impacts,” according to the GAO.

Shipyard equipment features submarine shaft lathes built in the 1930s and plate rollers built in the 1950s, and requests for repair have jumped about 28 percent from 2008 to 2016.

“The actual need for repairs may be greater than the number of repair requests indicates, according to shipyard officials, because shop-level employees are reluctant to submit repair requests when there is little hope of obtaining funding for a repair,” the report said.

Navy data shows that 48 buildings across the four shipyards have been condemned or are unusable for ship repair, including some that are on the waterfront and could be used to improve the repair process, the report states.

“Shipyard officials noted that the shipyards were not designed for their current mission and that the layout, size of facilities, pier space, utilities, and safety systems contribute to reducing the efficiency of the shipyards for repair work,” according to the GAO.

While the Navy has developed capital investment plans for shipyards and equipment, the sea service’s approach does not fully address the problems because plans are missing key elements, according to the report.

Missing parts of the plans include no full assessment of the shipyards’ resource needs, regular management reviews of progress, analytically based goals and reporting on progress to Congress, according to the GAO.

“Unless it adopts a comprehensive, results-oriented approach to addressing its capital investment needs, the Navy risks continued deterioration of its shipyards, hindering its ability to efficiently and effectively support Navy readiness over the long term,” the report states.

The GAO recommends the Navy develop a comprehensive investment plan, conduct regular management reviews and regularly report to Congress.

The Pentagon concurred with the recommendations and noted planned actions to address the issues.