SS United States sunk off Florida as world's largest reef

The SS United States, the record-breaking ocean liner that once carried presidents, film stars and even the Mona Lisa, was deliberately sunk off the coast of Florida on Wednesday to become the world's largest artificial reef. The BBC reported that the ship was sent to the seabed in a precision operation that used no explosives.

The vessel, longer than the Titanic and once the fastest liner in the world, now rests on the sandy floor of the Gulf of Mexico about 40 kilometres southwest of Destin-Fort Walton Beach, according to AFP reporting carried by the Bangkok Post.

How the SS United States became a reef

Okaloosa County in Florida bought the long-retired liner from a conservancy group for $1 million in 2024. Local officials hope the huge new reef will draw divers and anglers and give tourism a lift.

The ship spent nearly 30 years tied up in Philadelphia before it was towed to Alabama last year for cleaning and environmental work. That year-long process included removing fuel, paint, wiring and other toxic materials, and the full project, including the sinking, cost about $13.5 million, AFP reported.

On Monday the liner made its final journey from Alabama towards Destin. Crews then opened valves to flood the hull in a controlled sinking on Wednesday.

A reef for beginner and expert divers

The wreck lies at a depth of about 180 feet (55 metres), but its top decks sit only around 55 feet (17 metres) below the surface, within reach of beginner divers. Deeper parts of the hull will suit more experienced divers.

Until now the largest artificial reef was an aircraft carrier sunk about 20 years ago off Pensacola, also in Florida. The liner joins dozens of other sunken vessels off Okaloosa County, including World War Two ships, tugboats and even a former casino boat.

Captain Tim Mullane of Alabama-based Coleen Marine, which led the work, has described it as an honour to give the ship a second life supporting marine life, diving and fishing.

A storied history at sea

The liner made its maiden voyage in 1952 and still holds a place in maritime history for its transatlantic speed record. It crossed the Atlantic hundreds of times before it was retired in 1969, when air travel took over long-distance trips.

Its passenger list reads like a who's who of the 20th century:

• US presidents Harry Truman, Dwight Eisenhower and John F Kennedy
• A young Bill Clinton, on his way to study at Oxford
• Stars such as Marlon Brando, Grace Kelly, Judy Garland and Cary Grant
• Artists and designers including Salvador Dali and Coco Chanel

Perhaps its most famous passenger was Leonardo da Vinci's Mona Lisa, which travelled to the United States aboard the ship in 1963, AFP noted.

Museum hopes that never came true

Campaigners spent years trying to save the ship as a museum or floating hotel, but those plans failed amid legal disputes and changes of ownership. A land-based museum telling the ship's story is now planned in Florida, the BBC said.

Susan Gibbs, president of the SS United States Conservancy, whose grandfather helped design the liner, told CBS News she was glad its story would live on.

Why artificial reefs matter

Sunken ships give corals, sponges and fish a hard surface to settle on, and they can take pressure off natural reefs by giving divers somewhere new to explore. Reef health is a live issue in Thailand too, where scientists are tracking coral bleaching, as covered in our report on Phuket coral reef sensors.

For readers who want to dive closer to home, our guide to diving in Phuket covers the best sites around the island, while fans of ocean travel may enjoy our look at luxury Mekong river cruises.

Image: The SS United States docked in Philadelphia before its final voyage. Photo by Reading Tom, CC BY 2.0, via Wikimedia Commons.