LONG BEACH, Calif. — The Queen Mary is so corroded that it’s at urgent risk of flooding or collapse, and the price tag for fixing up the 1930s ocean liner could near $300 million, according to a survey done by experts.

It would likely take five years to rehab the ship, a tourist destination docked permanently in Long Beach Harbor south of Los Angeles, according to documents obtained by the Long Beach Press-Telegram.

During its heyday, the Queen Mary carried Hollywood celebrities, such as Bob Hope and Elizabeth Taylor, royalty, such as the Duke and Duchess of Windsor, and dignitaries, such as Winston Churchill. It also spent several years ferrying 765,000 Allied troops during World War II, when it was nicknamed the “Gray Ghost.”

But now, naval architects and marine engineers who compiled the survey warn that the vessel is probably “approaching the point of no return.”

The hull is severely rusted and certain areas, including the engine room, could be prone to flooding, according to the newspaper report published Monday. And because the bilge system is inoperable, large amounts of water can’t be pumped out and could cause the ship to sink to the lagoon floor.

In addition, the pillar supports for a raised floor in an exhibition space are corroded throughout and could face “immediate collapse” under the weight of just a few people, the survey said.

Roughly 75 per cent of the repairs were deemed “urgent.”

The Queen Mary made Long Beach its permanent home in 1967. Now a floating hotel with shops, restaurants and event spaces, the ship attracts some 1.3 million visitors annually.

City officials said the findings are being discussed with the ship’s current leaseholder, Urban Commons, and both sides are committed to preserving the historic asset and making sure it can safely remain open to the public. In November, Long Beach approved $23 million to address the ship’s most urgent repairs, and Urban Commons is working to secure additional funding.

“We have a timeline in which the engineers believe they can complete those immediate projects,” said John Keisler, economic and property development director. “These are major challenges we can only address over time; it can’t all be done at once.”

The condition has become so dire that politicians in Scotland, where the Queen Mary was built, have called for an international fundraising campaign to restore the former Cunard liner. They’ve urged Prime Minister Theresa May to put pressure on the U.S. government to step in and save their architectural treasure, according to a recent report in Scotland’s national newspaper.