Rescuers Ramp Up Efforts to Find Titan Craft Missing en Route to Titanic

With alarm rising and air supply onboard the missing watercraft dwindling, a growing array of international rescuers ramped up their search on Tuesday for the submersible carrying five people that disappeared on Sunday while en route to the wreckage of the Titanic.

U.S. Coast Guard commanders described a complex and highly challenging search mission over an area the size of Connecticut, some 900 miles off Cape Cod in the North Atlantic. Officials said it was complicated by the vast distances that vessels must travel to get to the site, and the logistical complexity of a combined surface and undersea search for the privately owned, 22-foot submersible, called Titan, which disappeared in the midst of diving two and a half miles deep to view the sunken ship.

“We are doing everything possible,” said Capt. Jamie Frederick, response coordinator for the First Coast Guard District, based in Boston. He estimated on Tuesday afternoon that the five people on the submersible had 40 hours of breathable air left.

Yet as the Coast Guard continued its “unwavering effort” to find the lost Titan, troubling questions emerged about the safety practices of the company that built it, OceanGate Expeditions. In a letter sent in 2018 to the company’s chief executive, Stockton Rush, industry leaders warned of possible “catastrophic” problems from its “experimental” approach and its failure to follow established safety guidelines. The company, based in Everett, Wash., argued in response that such regulations stifled innovation.

“The letter was basically asking them to please do what the other submarines do,” said one of its signers, Bart Kemper, a forensic engineer.

Mr. Rush, the vessel’s pilot, was among those missing. Others include Hamish Harding, 58, a British explorer; Paul-Henri Nargeolet, 77, a French maritime expert who has made over 35 dives to the Titanic wreck site; a British businessman, Shahzada Dawood, 48, and his 19-year-old son, Suleman.

Mr. Harding, who previously set a Guinness World Record for deep ocean diving, had acknowledged in the past just how perilous deep-sea exploration was.

“If something goes wrong, you are not coming back,” he told an Indian newsmagazine in 2021, after his record-setting trip to the Mariana Trench, seven miles deep in the western Pacific.

Search crews stymied by dense fog on Monday gained better visibility on Tuesday, a Coast Guard spokesman, Chief Petty Officer Robert Simpson, said. But some vessels steaming toward the area, including one from France equipped with an exploration robot that can dive to 13,000 feet, faced trips as long as three or four days to reach the site, he said.

Another vessel on its way on Tuesday, from the Royal Canadian Navy, is equipped with a hyperbaric recompression chamber, used to treat diving-related illness.

The Titan is classified as a submersible and not a submarine, because it is not autonomous and requires a support platform to deploy. It is built of titanium and carbon fiber, weighs about 21,000 pounds and offers 96 hours of “life support” for five people, according to the OceanGate website.

The submersible has been missing since Sunday, when it lost communication with the Canadian research ship MV Polar Prince, which helped it to deploy. The last communication was about one hour and 45 minutes into its dive, according to the Coast Guard.

But even that narrow 96-hour window for survival may be too generous. Some experts have questioned whether travelers can survive that long, citing the risk of carbon dioxide buildup in the submersible if it is not equipped with a system to remove it.

Rachel Lance, a biomedical engineer at Duke University who has studied submarine disasters and built underwater breathing systems, said she had not seen evidence of such a system in publicly available photos of the Titan’s interior.

Without removal of carbon dioxide, she said, the survival limit for people inside would likely be closer to “one or two days, max, for five people in a space that small.”

Dr. Lance said the U.S. Navy established rigid standards for carbon dioxide management in submarines after disasters including the H.M.S. Thetis, in 1939, where 99 crew members died from carbon dioxide buildup.

“We have learned these lessons,” she said. “You can’t buy your way out of safety precautions, and you can’t negotiate with respiratory physiology.”

A submersible traveling to the depths of the Titanic would face soaring increases in pressure during its long descent. At the ship’s resting place, it would experience pressures equal to those beneath a 100-story tower of solid lead — the height of the Empire State Building.

Founded in 2009, OceanGate Expeditions sought to increase access to deep-sea exploration, organizing expeditions for paying tourists to visit shipwrecks, part of a rising trend in high-risk excursions. The Titanic, which sank in the North Atlantic in April 1912 after colliding with an iceberg, killing 1,500 passengers, has drawn intense interest since its wreckage was discovered in 1985, and since the blockbuster 1997 film about it imbued the tragedy with a new aura of romance.

By the early 2000s, scientists were warning that visitors were a threat to the wreck, saying that gaping holes had opened up in the decks, walls had crumpled, and that rusticles — icicle-shaped structures of rust — were spreading all over the ship.

According to the tech news site GeekWire, the Titan was “rebuilt” after OceanGate determined through testing that the vessel could not withstand the pressure of a 12,000-foot dive. Trips to the Titanic started in 2021, at a cost of $250,000 per person.

Mike Reiss, a passenger who traveled on the same OceanGate trip last year, told the BBC that the mission was an “adventure” and a “very serious expedition,” not a “tourist trip.” He said that the submersible was small but comfortable — “spa-like” — but that people on board were well aware of the dangers. “You sign a waiver before you get on that mentions death three different times on Page 1,” he said. “It’s a beautiful, moving experience,” he added.

Numerous factors could hinder the ongoing rescue operation, including weather conditions, darkness, the state of the sea and water temperature. For an underwater rescue, the degree of difficulty is even greater than on the surface. First, though, rescue crews must locate the submersible.

Many underwater vehicles are fitted with an acoustic device, often called a pinger, which emits sounds that can be detected underwater by rescuers. But it remains unclear whether Titan has one on board.

The U.S. Navy has one submarine rescue vehicle, although it can reportedly reach depths of just 2,000 feet. For recovering objects off the sea floor in deeper water, the Navy relies on what it calls remote-operated vehicles, such as the one it used to salvage a crashed F-35 Joint Strike Fighter in about 12,400 feet in the South China Sea in early 2022. That vehicle, called CURV-21, can reach depths of 20,000 feet.

Mr. Nargeolet, the French adventurer among the Titan’s passengers, who once served as a mine-clearing diver in the French Navy, tried to explain in an interview last year why the mysteries of the Titanic beckoned, in spite of the danger.

“Once you’ve gotten your head into the Titanic, it’s hard to get it out,” he said.

Reporting was contributed by Anna Betts, Christine Chung, William J. Broad, Emma Bubola, Vjosa Isai, Jenny Gross, Ben Shpigel, Alan Yuhas, Amanda Holpuch, Anushka Patil, Jesus Jiménez, Aurelien Breeden, Derrick Bryson Taylor, Salman Masood, John Ismay and Nicholas Bogel-Burroughs.