"It's probably a mercy": Expert says Titanic sub would have imploded instantly

A robotic diving vehicle deployed from a Canadian ship discovered a debris field from the submersible Titan on Thursday morning on the seabed some 1,600 feet (488 meters) from the bow of the Titanic, 2 1/2 miles (4 km) beneath the surface, in a remote corner of the North Atlantic, US Coast Guard Rear Admiral John Mauger told reporters.

The Titan, operated by the US-based company OceanGate Expeditions, had been missing since it lost contact with its surface support ship on Sunday morning about an hour, 45 minutes into what should have been a two-hour dive to the world's most famous shipwreck.

Five major fragments of the 22-foot (6.7-meter) Titan were located in the debris field left from its disintegration, including the vessel's tail cone and two sections of the pressure hull, Coast Guard officials said. No mention was made of whether human remains were sighted.

Even before the Coast Guard's press conference, OceanGate issued a statement saying there were no survivors among the five men aboard the Titan, including the company's founder and chief executive officer, Stockton Rush, who was piloting the Titan.

The four others were British billionaire and explorer Hamish Harding, 58; Pakistani-born businessman Shahzada Dawood, 48, and his 19-year-old son, Suleman, both British citizens; and French oceanographer and renowned Titanic expert Paul-Henri Nargeolet, 77, who had visited the wreck dozens of times.

Rescue teams from several countries had spent days scanning thousands of square miles of open seas with planes and ships for any sign of the Titan.

Intense worldwide media coverage of the search largely overshadowed the aftermath of a far greater maritime disaster stemming from the wreck of a migrant vessel off the coast of Greece last week, killing hundreds of people.

"It's probably a mercy": Expert says Titanic sub would have imploded instantly

Will Kohnen, chairman of the peer-review group Marine Technology Society's (MTS) committee on manned submersibles, said the implosion of the vessel would have happened instantly.

"It exploded inwards in a matter of a thousandth of a second. And it's probably a mercy because that was probably a kinder end than the unbelievably difficult situation of being four days in the cold, dark, in a confined space," he said.

"So, this would have happened very quickly. I don't think anybody even had the time to realize what happened," he added.

Kohned also said the location of the debris and the loss of communication with the vessel suggest the submersible imploded "early in the dive."

"It would indicate that it happened fairly early on. And from a technical point of view, I would speculate that something that puzzled me since Monday is how come they lost complete communication and tracking of the submersible right away on the way down. Because, you know, there's typically redundancy. You have communication through voice. It's all acoustic but you have a system for voice, you have a system for text. You have a system for a range finding, you have a system for sonar, and it's based so that you have a backup so that not everything fails at the same time all of a sudden," he said.

And it was curious that all systems stopped at the same time. Little did we ever suspect that... I mean that was one of the options, but it was pretty far down the line, but that would explain why all these systems stopped immediately and which indicates that would have happened on the way down early in the dive," he added.

'A very harsh environment:' Underwater researcher on Titanic submersible's implosion

After five people aboard a submersible died in a "catastrophic implosion," according to the US Coast Guard official on Thursday, an underwater researcher has underscored the unknown danger of the ocean’s deep depths.

“It is obviously a very harsh environment and it's got very little exploration, right?” said Nicholas Rotker, the lead underwater researcher and maritime leader of research nonprofit MITRE. “Obviously, the Titanic location itself has been explored several times, but ultimately, the wide swath of ocean that would need to be explored and surveyed to try to find an object that could have been gone missing is very vast.”

"These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world's oceans," OceanGate Expeditions, the US-based company that operated the Titan submersible, said in a statement. "Our hearts are with these five souls and every member of their families during this tragic time."

OceanGate cofounder learns about discovered sub debris during TV interview

The co-founder of the company operating the missing deep-sea submersible carrying five people to the wreckage of the Titanic was told debris had been discovered as he was giving a TV interview to the BBC on Thursday.

Hours later, the US Coast Guard said the vessel was destroyed due to a "catastrophic implosion" that killed everyone aboard, ending the multinational five-day search.

During the interview, Guillermo Sohnlein --who cofounded the US-based company OceanGate Expeditions with chief executive office Stockton Rush in 2009 -- did not comment on the news but went on to say an "instantaneous implosion" would've happened if there was a failure at 3,800 metres depth.

Sohnlein said he has not been involved with the company for 10 years, but media reports say he remains a minority shareholder.

Families of Titanic sub victims thank global search effort

The families of the passengers missing in a voyage to the wreckage of the Titanic in deep-sea submersible issued statements on Thursday following the news a "catastrophic implosion" destroyed the vessel.

The families of Harding and the Dawoods posted messages thanking the international rescue efforts for doing all they could.

British foreign minister James Cleverly on Thursday said the government was supporting the families of those lost on board the Titan submersible, expressing his condolences in a post on Twitter.