The families of Shahzada Dawood, his son Suleman, and Hamish Harding have paid tribute after they died in the Titan submersible’s catastrophic implosion.

The US Coast Guard confirmed the tail cone of the deep-sea vessel was discovered around 1,600 ft from the bow of the Titanic wreckage during a press conference in Boston.

Rear Admiral John Mauger said further debris was also found, in the North Atlantic Ocean off the coast of Newfoundland, that was “consistent with a catastrophic loss of the pressure chamber”.

Undersea expert Paul Hankin said five major pieces of debris helped to identify it as from the Titan submersible – including the vessel’s nose cone and the front end bell of the pressure hull.

The Dawood family released a statement on Thursday night, mourning the loss of the father and son.

“Our beloved sons were aboard the OceanGate’s Titan submersible that perished underwater,” the statement said.

“Please continue to keep the departed souls of our family in your prayers during this difficult period of mourning.

The family statement said they are truly grateful to those involved in the rescue operations and the “untiring efforts” brought strength to the family.

“We are also indebted to our friends, family, colleagues and well-wishers from all over the world who have stood by us during our hour of need,” the statement said.

“We extend our heartfelt condolences to the families of the other passengers onboard the Titan submersible.”

The sister of Shahzada Dawood and aunt of Suleman, Azmeh Dawood, told NBC News in the US that the 19-year-old was terrified about going on the trip.

“I feel disbelief… It’s an unreal situation,” she said.

“I feel like I’ve been caught in a really bad film, with a countdown, but you didn’t know what you’re counting down to. I personally have found it kind of difficult to breathe thinking of them.”

Shahzada Dawood’s company paid tribute to him and his son after their deaths.

In a statement, Engro Corporation, the Pakistani conglomerate that Mr Dawood was vice chairman of, said: “With heavy hearts and great sadness, we grieve the loss of our vice chairman, Shahzada Dawood, and his beloved son, Suleman Dawood.

“We extend our heartfelt condolences to the family, colleagues, friends and all those around the world who grieve this unthinkable loss.”

Meanwhile, the family of a British billionaire adventurer who died have paid tribute to their “dedicated father”.

Hamish Harding was described as “a guide, an inspiration, a support, and a living legend” following the news of his death on Thursday.

In a short statement, Mr Harding’s family said: “He was one of a kind and we adored him.

“He was a passionate explorer – whatever the terrain – who lived his life for his family, his business and for the next adventure.

“What he achieved in his lifetime was truly remarkable and if we can take any small consolation from this tragedy, it’s that we lost him doing what he loved.”

Mr Harding’s family said his death has left a “gap in our lives that can never be filled”, and that they were “united in grief” with the families of the others who had died.

“We know that Hamish would have been immensely proud to see how nations, experts, industry colleagues and friends came together for the search and we extend our heartfelt thanks for all their efforts,” they said.

Mr Harding was remembered by friend Richard Garriot de Cayeux, who is the president of the Explorers Club, which Mr Harding helped found.

“Hamish Harding is a dear friend to me personally and to The Explorers Club,” Mr Garriot de Cayeux said.

“He holds several world records and has continued to push dragons off maps both in person and through supporting expeditions and worthy causes.”

Rear Admiral Mauger said there did not appear to be any connection between the underwater noises detected during the search and rescue mission and the location of the debris on the seafloor.

“This was a catastrophic implosion of the vessel which would have generated a significant broadband sound down there that the sonar buoys would have picked up,” he said.

The Wall Street Journal reported the US Navy said they detected a sound in the search area for the submersible on Sunday that was consistent with an implosion.

Titanic director and submersible expert James Cameron told the BBC he predicted the outcome days earlier.

“I felt in my bones what had happened,” he said.

“For the sub’s electronics to fail and its communication system to fail, and its tracking transponder to fail simultaneously – sub’s gone.

“I knew that sub was sitting exactly underneath its last known depth and position. That’s exactly where they found it.”

According to court documents, safety concerns had previously been raised about the Titan submersible by a former employee of OceanGate.

The filings said David Lochridge, OceanGate’s former director of marine operations, claimed wrongful dismissal after flagging worries about the company’s alleged “refusal to conduct critical, non-destructive testing of the experimental design”.

Court papers suggest Mr Lochridge “identified numerous issues that posed serious safety concerns” but he was allegedly “met with hostility and denial of access” to necessary documents before later being fired.

Foreign Secretary James Cleverly described the update as “tragic news” and said the UK Government is closely supporting the British families affected.

Pakistan’s foreign ministry released a statement, sharing their condolences.

“Our deepest condolences to the Dawood family and the family of other passengers on the sad news about the fate of Titanic submersible in the North Atlantic,” the statement said.

The White House said the families of those who died had “been through a harrowing ordeal over the past few days, and we are keeping them in our thoughts and prayers”.