For Pearl Harbor shipyard’s first new dry dock since World War II, the Navy is reaching back in time and eyeing a pair of basins used during the war for ship work as the site for a huge new submarine repair facility.

Not only is the shipyard expected to get a massive waterfront production facility, it also may be able to perform work under wraps with a new adjacent covered dry dock being considered.

A Navy notice issued in May seeking industry feedback estimated the construction cost at between $2 billion and $4 billion.

Meeting ever-growing attack submarine needs in the Pacific to counter China requires four dry docks in Hawaii, the Navy said. Pearl has four, but Dry Dock 4 is used for surface ship work.

With the last work on older Los Angeles-class subs expected to end in 2022, the need becomes more acute.

Dry Dock 3, at only 497 feet, is headed for obsolescence because it can’t accommodate even the current fleet of newer Virginia-class vessels, according to officials.

And Virginia subs are growing in size.

Los Angeles subs are 362 feet and displace 6,900 tons. The 377-foot Virginia-class displaces 7,800 tons.

The newest Virginia vessels being built with what’s known as a “Virginia Payload Module” will have an additional 84-foot midbody section — meaning 460 feet in total length — with four vertical launch tubes capable of firing an additional 28 Tomahawk missiles.

The newest $3.4 billion Virginia subs, which are planned for delivery starting in 2025, displace 10,200 tons. The new USS Arizona, SSN-803, will be the first with the Virginia Payload Module. Navy plans call for delivery of the new Arizona in late 2025.

A next-generation attack submarine expected in the 2030s will have a wider hull than the Virginia subs, meanwhile.

Dry Dock 3 is relatively shallow and can only support Los Angeles-class submarines with the use of “buoyancy assist modules” to lift the submarines sufficiently to enter the dry dock, said shipyard spokeswoman Kate Necaise.

The lift modules do not have capacity or straps suitable for the bigger Virginia submarines, and as a result, a deeper dry dock is being pursued to service those subs, she said.

The Navy recently said it is preparing an environmental impact statement for a new 650-foot submarine dry dock and adjacent waterfront production facility at Pearl Harbor.

The notice issued in May sought industry input in packaging the two big projects into a single mega-contract with a multi-story production facility in excess of 500,000 square feet and either a covered or uncovered new dry dock.

Dredging in excess of 250,000 cubic yards and use of more than 200,000 yards of concrete was forecast.

Carl Schuster, a former director of operations at U.S. Pacific Command’s Joint Intelligence Center and an adjunct professor at Hawaii Pacific University, said enclosing the dry dock — which would require huge cranes to operate within the confines of the structure — may be to keep sub work from the prying eyes of satellites.

“That’s my assessment,” Schuster said. “It surely is not to protect the work from the environment.” It would be the first covered dry dock at Pearl Harbor.

The shipyard’s dry docks are arrayed near Hospital Point, with Nos. 1, 2 and 3 in close proximity and 4 on the opposite side of the point.

The oldest, Dry Dock 1, at 1,002 feet, was completed in 1919. Dry Dock 2, at 1,000 feet, was finished in 1941. The 497-foot Dry Dock 3 was completed in 1942, while Dry Dock 4, at 1,088 feet, was finished in 1943, according to the Defense Department.

The area eyed for a new dry dock and production facility is next to Dry Dock 3, and the Navy is considering filling in the old dry dock as part of the plan.

Two watery basins define the spot where the Navy wants to build the new facilities, meanwhile.

Jim Neuman, historian for Navy Region Hawaii, said that after the Japanese attack on Oahu, planners set out to develop “every available inch of shoreline” at Pearl Harbor for use as either docks, piers or other related facilities.

The manmade basins were a part of that expansion. The area closest to the existing dry docks was used for a floating dry dock to repair ships and submarines, Neuman said.

A basin next to it with rails that can be seen disappearing into the harbor was part of Marine Railway No. 2, completed in 1943, he said.

“That was also constructed to handle smaller ships and submarines, which allowed the dry docks to be freed up for larger projects,” Neuman said.

The railway was 399 feet long and was used to haul ships up out of the water. Neuman said the steel used in its construction was salvaged from the old coaling station that was located near the current site of Dry Dock 4.

Neuman said it appears the railway was still being used in some capacity into the late 1970s.

The modernization effort falls under the umbrella of the Shipyard Infrastructure Optimization Program, a 20-year, $21 billion effort to improve outdated infrastructure at the four Navy shipyards.

The four yards “need substantial recapitalization and reconfiguration in order to improve the timely return of ships and submarines back to the fleet,” said Naval Sea Systems Command, which oversees the shipyards.

The rise of China as a peer competitor has propelled the improvements at the Pearl Harbor shipyard, which will be the first to receive a waterfront production facility. The big complex is expected to bring workshops closer to submarines to improve efficiency.

More than 1,000 shipyard workers were added between 2010 and 2018. The yard now has approximately 6,000 civilian workers and 500 military workers. Contractors take care of surface ship work at Dry Dock 4 and are not counted as part of the civilian workforce.

The Navy’s environmental impact statement for the new dry dock and waterfront production facility will analyze a range of options, with a draft expected in the summer of 2021 and a final document in 2022.

A replacement dry dock is expected to be constructed first, followed by the adjacent production facility. The Navy previously talked about early 2028 for completion of the production facility.

But shipyard spokeswoman Necaise said “with preliminary alternatives and options still being analyzed, a completion date cannot be projected at this time.”