A new report by the US Government Accountability Office (GAO) found that the overall physical condition of the country's four public shipyards and their equipment are in poor condition.

The US watchdog revealed that the previously identified poor conditions remained, despite the service committing to increasing capital investment and creating an improvement plan in 2013.

The four public shipyards highlighted in the study are Norfolk Naval Shipyard, Portsmouth Naval Shipyard, the Puget Sound Naval Shipyard and Intermediate Maintenance Facility, and the Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility.

These sites are intended to help maintain fleet readiness, as well as support various naval operations being carried out by the US Navy's nuclear-powered aircraft carriers and submarines.

GAO analysed the navy data and found that the cost of backlogged restoration and maintenance projects at the shipyards had grown by 41% over a period of five years to a navy-estimated $4.86bn, which would require at least 19 years to clear.

It also found that the average age of the shipyards' capital equipment currently surpasses the expected useful lifespan.

In addition, the US Navy estimates that it will fail to carry out 73 of 218 maintenance periods over the next 23 fiscal years due to lack of capacity and other deficiencies.

"GAO analysed the navy data and found that the cost of backlogged restoration and maintenance projects at the shipyards had grown by 41% over a period of five years."

The navy is expected to require at least $9bn in capital investment over the next 12 fiscal years.

However, this estimate does not include all expected costs, including those for planning and upgrading the shipyards' utility infrastructure.

GAO recommended that the US Navy adopts a comprehensive, results-oriented approach to meet its shipyard capital investment requirements, as well as conduct regular management reviews and report to Congress on progress in addressing the facilities' requirements.

The watchdog further specified that the plan should establish a desired goal for the shipyards’ condition and capabilities, provide an estimate of the costs to be incurred to implement the plan, and address all major requirements, external risk factors and associated planning.

It should also provide metrics for evaluating progress toward meeting the highlighted goals.

Additionally, GAO noted that US Navy needs to conduct management reviews that include all relevant stakeholders involved in overseeing the implementation of the plan, in addition to reviewing metrics, assessing the progress made toward the goal, and making necessary adjustments to ensure that the goal is achieved.