Undersea sounds become the focus of underwater rescue efforts

Unexplained noises detected beneath the waves of the North Atlantic Ocean became the focus of an urgent search on Wednesday for five people in a submarine that disappeared three days earlier while diving to the wreckage of the RMS Titanic.

The possibility that the sounds could lead to the lost craft offered a thin line of hope to an international team of rescuers who have scoured a stretch of the North Atlantic twice the size of Connecticut and two and a half miles deep. . A growing international force of planes, ships and underwater robots raced to find and bring the 7-meter ship known as the Titan to the surface before the pilot and four passengers run out of oxygen.

When the submarine, owned by OceanGate Expeditions, lost contact with a chartered vessel at the dive site on Sunday morning, it was believed to have been equipped with only four days of oxygen. Coast Guard officials said they operated on the assumption that they must reach the ship before Thursday morning to increase the crew’s chance of survival.

U.S. Coast Guard Captain Jamie Frederick said at a news conference that two remotely operated submarine vehicles were searching for the source of the sounds, and that a team of experts was studying recordings of the sounds to determine if they were a signal from the missing vessel. On Wednesday afternoon, however, that analysis remained “inconclusive.”

“This is a search-and-rescue mission, 100 percent,” said Captain Frederick. “When you’re in the middle of a search and rescue case, you always have hope.”

Canadian surveillance aircraft first detected the underwater sounds on Tuesday, using special listening buoys dropped in the search area, and the sounds prompted authorities to move the two remote-controlled vehicles to investigate, Captain Frederick said. They were unsuccessful.

The sounds were detected again on Wednesday by more Canadian planes flying over the area, he said.

Carl Hartsfield, an underwater vehicle designer at the Woods Hole Oceanographic Institution in Massachusetts who is part of the rescue team, said the sounds had been described as “bangs.” But he cautioned that some natural sounds from undersea animals could sound man-made and that acoustic experts were still analyzing the recordings.

Captain Frederick added, “We don’t know what they are, to be honest.”

Still, percussive noises from under the sea raised the possibility that someone in the ship was giving an “impromptu signal to locate the vehicle,” said Jeff Eggers, a retired naval commander with experience piloting compact submarines.

“There are a lot of things in the ocean that make sounds that can be heard on a sonobuoy, but very few things sound like just banging on metal,” he said.

Submarine crews unable to communicate with surface boats are taught to bang on the ship’s hull so they can be detected by sonar. Paul-Henri Nargeolet, a former diver and submarine pilot in the French Navy, was one of five missing passengers.

The Titan submarine – a cramped, cylindrical vessel with a single porthole, no seats, a small toilet with curtains and electric propellers – faced pitch-black, icy cold and crushing hull pressure during its descent to see the wreckage of the famed ocean liner which sank in 1912.

Passengers pay up to $250,000 for the experience, which is part of a booming high-risk travel industry. The others on board on Sunday were British billionaire adventurer Hamish Harding, 58, and a British-Pakistani businessman, Shahzada Dawood, 48, and his son, Suleman, 19, both science buffs.

According to the company, Stockton Rush, OceanGate’s CEO and a promoter of deep-sea tourism, piloted the submarine. Submarine industry leaders had warned of potential “catastrophic” problems with the Titan’s development.

Conditions inside the submarine — assuming the hull hadn’t been crushed — likely got worse on Wednesday as oxygen levels fell, medical experts said.

Captain Frederick said he did not want to speculate on when the search and rescue operation might turn into a recovery effort.

“Sometimes you’re in a position where you have to make a tough decision,” he said. “We’re not there yet.”