At a joint meeting of the U.S. Senate Armed Services Committee’s Seapower and Readiness Subcommittees held this week, officials addressed an ongoing struggle to modernize the Navy’s aging shipyards, including Pearl Harbor facilities.

For decades the Navy has sought new vessels and weapons but hasn’t invested proportionally in facilities to maintain them. Now the service is in the midst of implementing a $21 billion Shipyard Infrastructure Optimization Program, which aims to upgrade shipyards over a span of 20 years.

But a Government Accountability Office report released Tuesday found that the Navy’s price estimates for SIOP dry dock projects have increased by 400% since 2018.

Pointing to cost overruns, including one that forced Congress to increase the program’s budget for a dry dock on the southern boundary of Maine by $250 million, Hawaii’s U.S. Sen. Mazie Hirono, who chairs the Seapower subcommittee, said, “We need to understand what steps the Navy has taken to make sure we have better cost estimates of the projects we are undertaking.”

She added, “This will be important as the Navy turns to the dry dock replacement at Pearl Harbor naval shipyard, which is the next dry dock to be constructed and will require significant dredging and filling to extend the existing dry dock.”

The Navy is crafting its environmental impact statement for Pearl Harbor’s proposed Dry Dock 5. It’s slated to replace Dry Dock 3, which was installed in 1942 and is too small to accommodate the service’s new and larger Virginia-class subs.

Naval Facilities Engineering Systems Command Pacific spokesperson Kirsta Cummins said, “The Navy is continuing with design process, and current estimates indicate a cost between approximately $3 billion to $4 billion” for Dry Dock 5, which is expected to be completed in 2028.

On Friday the Navy announced it will also make repairs and safety upgrades to its other Pearl Harbor dry docks. In a news release from Naval Facilities Engineering Systems Command Hawaii, the service said it awarded an $8.8 million contract to California-based Insight Pacific LLC on May 4. The Navy estimates that work will wrap up by February 2024.

The Navy views its Pearl Harbor shipyard as a critical mid-Pacific repair station for vessels, particularly submarines. The yard is also the state’s top industrial employer, with as many as 6,000 civilian workers and 500 military workers. Additional contractors work on surface ships that aren’t included in the workforce tally.

Diana Maurer, the GAO report’s author, testified at the hearing held Tuesday that workers across the country overhauling and repairing submarines “often perform that work in facilities that are in poor condition, using equipment that’s well past its expected service life.”

Given that the shipyards were built well over a century ago to repair wind- and steam-powered ships, Maurer said, “their layout is far from efficient to maintain nuclear-powered vessels.”

A 2021 GAO report warned that facilities like Pearl Harbor, which are struggling to meet regular maintenance demands, might not be capable of repairing battle- damaged ships in the event of an armed conflict. In that case, ships would have to travel to the mainland for extensive repairs.

Maintenance of submarines is particularly challenging. A significant portion of the Navy’s fast-­attack submarines are both behind schedule on maintenance and have also lost critical dive certifications. Demand for modernization is set to grow in the Pacific region.

In September the United States, United Kingdom and Australia announced the signing of the “AUKUS agreement,” a trilateral security pact aimed at checking China’s growing navy. The pact centers on cooperating on submarine technology and operations, and includes a provision through which the U.S. would open its shipyards to Australian and British vessels for maintenance and repairs.

During the hearing Sen. Josh Hawley, R-Mo., asked Navy officials whether meeting that commitment is realistic given the maintenance backlog.

In response, Deputy Assistant Secretary Frederick Stefany said the “AUKUS effort, frankly, is 15 to 20 years out” before it would require opening U.S. shipyards to its partners for maintenance and repairs. By then, he said, “we expect that the SIOP-type efforts will have have matured.”

However, Maurer said SIOP’s maturity will likely hinge on whether it secures additional funding.“We found that initial cost estimate was unrealistically low. … Among other things, that $21 billion price tag did not factor in inflation and did not include the cost to improve underlying utilities,” she said.

Additionally, Vice Adm. William Galinis pointed to recent struggles with shipyard staffing at some locations, telling lawmakers, “Our attrition rates are higher than what we had planned, our recruitment rates are lower than what we what we had planned.” But officials at the Pearl Harbor yard said retention and staffing haven’t been problems in Hawaii.

“We have experienced slightly lower attrition this fiscal year than previously planned — to date, losing only 192 people as opposed to the projected 201 — and have also had higher hiring numbers than previously planned this fiscal year,” said Pearl Harbor Naval Shipyard spokesperson Marc Ayalin.

He added that the shipyard anticipates hiring 379 people by the end of September and plans to expand its apprenticeship program.