KITTERY, Maine (AP) — The Navy says it has received more than one proposal in its latest attempt to enlist the private sector to redevelop the Portsmouth Naval Shipyard’s shuttered prison.

It isn’t saying much else, though, because the proposals are cloaked in secrecy.

Tom Kreidel, spokesman for the Naval Facilities Engineering Command in Virginia, which is overseeing the effort, said the responses are being reviewed.

The Navy is trying for a third time to breathe life into the fortress-like structure that has priceless views of the Atlantic Ocean but also needs millions of dollars of repairs.

It’s been an albatross ever since it closed in 1974: It’s too expensive to repair and too costly to tear down, partly because of the environmental abatement of asbestos and lead paint.

The first redevelopment attempt in the late 1990s proposed transforming the prison into premium office space. But that plan ended with the death of New Hampshire developer Joseph Sawtelle in 2000.

Another redevelopment attempt by the Navy was abandoned in 2009.

For the latest effort, the Navy said its goal is to maximize value to the taxpayers, either through rent, in-kind services or property improvements that could save money for the Navy over time.

Proposals were submitted in July. Kreidel said there’s no firm timetable for completing the review and narrowing the focus to a single proposal for exclusive negotiations. The original request for a proposal called for a 50-year lease.

More than 80,000 inmates spent time in the prison, which was known as the Navy Brig.

Former guards who will gather for a reunion and lobster bake on Thursday are among those who are interested in seeing if the third time’s a charm for the Navy.

“I wish they would’ve done it years ago,” said Tom Guillory of Mariaville, Maine, who retired from the Marines after serving as a prison guard in 1967-68. “It’s a piece of history.”

The structure is eligible for listing in the National Register of Historic Places, and renovations would have to comply with standards for historic preservation.

Besides costs, security is another obstacle. The Navy would have to approve the type of development since the prison is located on an active-duty Navy shipyard. Security is especially strict because the yard overhauls nuclear submarines.