PEARL HARBOR — A top Navy official said yesterday that he expects the service to budget hundreds of millions of dollars in coming years to modernize Pearl Harbor Naval Shipyard.

John S. Thackrah, acting assistant secretary of the Navy for research, development and acquisition, said studies are under way to see if calls by some to preserve historic buildings at the shipyard can be accommodated by plans to make the shipyard's facilities more efficient.

"I've been in conversations with the secretary of the Navy, where, yep, we're going to invest, we're going to bring modernization," Thackrah told The Advertiser. "But we may have to do it behind the facade of a very 1940s-looking building. OK, if that's what we've got to do, that's a little more challenge, a little more expense. It's going to take us a little more time, but we're going to do it."

Thackrah, who is speaking today at the shipyard's 100th anniversary "birthday bash," acknowledged that the modernization plan could be altered by the next presidential administration.

But Thackrah, who also is deputy assistant secretary of the Navy for management and budget, said that, after a series of studies, the Navy has committed to invest in the shipyard.

Officials at the shipyard have said it needs $2 billion in repairs over the next 20 years to update infrastructure built for World War I- and II-era needs and to remain competitive with other Navy yards.

"We've got a lot vested here. We want to stay here, (and) a lot of good work is going on here," Thackrah said. "This is kind of our key to the Pacific."

Pearl Harbor shipyard workers have complained about a lack of money in Navy budgets for shipyard modernization.

Modernization efforts would follow studies of historic structures.

Kiersten Faulkner, executive director of the Historic Hawai'i Foundation, said the Navy has undertaken an examination of all historic assets in what's known as the Pearl Harbor National Historic Landmark District — a departure from past history reviews that were tied specifically to one project.

The study, which Faulkner said is unprecedented in its scope, will look at historic buildings not only in the shipyard, but on the Navy base and other areas within the Pearl Harbor landmark district.

Lt. Cmdr. Majella Stevenson, the shipyard's staff civil engineer, said there will actually be three studies.

Stevenson said a shipyard modernization plan — part of a naval base "shore infrastructure" needs review — is due out in September.

A contract has also been awarded for a cultural landscape assessment to determine which buildings are historic, Stevenson said. A historic asset management plan, meanwhile, will overlay on the cultural landscape assessment, and is due in a couple years, she said.

Faulkner said the broader historic look at the landmark district "is something Historic Hawai'i Foundation and the other historic partners have been advocating for a couple of years now."

"It's really very forward thinking and very exciting that they (the Navy) are able to say, 'We have a military mission, but we also have a responsibility to be stewards of our historic assets. How can we marry those two things together?' " Faulkner said.

Faulkner added that the shipyard also is moving forward on a project for a new facility to support the basing of Virginia-class submarines at Pearl Harbor.

That plan calls for the rehabilitation of one building, "adaptive reuse" of two buildings, and the proposed demolition of a fourth building, she said.

Faulkner said the Navy initially wanted to rehabilitate one building and demolish the other three, but shipyard commander Capt. Gregory Thomas "sent them back to the drawing board and asked them to do adaptive reuse compared to demolishing the buildings."

"I'm cautiously optimistic," Faulkner said of the overall plan. "I think the planning efforts are really strong steps in the right direction."