The search continues for a missing submersible near to the wreck of the Titanic in the North Atlantic Ocean.
On Tuesday evening the five people onboard, which includes a London businessman and his son - had roughly 40 hours of breathable air left, according to the US Coast Guard.
Shahzada Dawood, 48, a Pakistani-born global board member of the Prince’s Trust charity, and his son Suleman, 19, are with British billionaire explorer Hamish Harding and two others on the tiny vessel that set off on Sunday to see the famous wreck at a depth of 12,500 feet in the Atlantic.
Captain Jamie Frederick of the US Coast Guard explained the deadline rescuers face as they try to trace the lost men who have been missing since the last “ping” connecting the submersible with its mother ship was heard yesterday afternoon above the wreck site.
He told a press conference in Boston on Tuesday: “So, first of all, it’s an estimate, right?
“We know from the data we were using, a starting point was 96 hours.
“We know at this point we’re approximately about 40/41 hours (of oxygen left).”
He added: “We know there’s about 40 hours of breathable air left, based on that initial report.”
The amount of oxygen left gives the rescuers a deadline of midday on Thursday if they want to be sure of finding those inside while it is still possible for them to breathe.
Officials said the search covering 10,000 square miles had turned up no signs of the lost sub known as the Titan, but they planned to continue looking.
Captain Frederick said the “complex search effort” required “multiple agencies with subject matter expertise and specialised equipment”.
He said: “While the US Coast Guard has assumed the role of search and rescue mission coordinator, we do not have all of the necessary expertise and equipment required in search of this nature. The unified command brings that expertise and additional capability together to maximise effort in solving this very complex problem.”
On Tuesday rescuers said they were expanding their search into deeper waters.
Coast Guard Rear Admiral John Mauger told CNN: “As we continue on with this search ... we’ve been working through the night with a broad group of partners to bring all capabilities to bear looking on both the surface and now expanding to a subsurface in the area.”
As the race to find the five passengers — who are also thought to include Stockton Rush, the American chief executive of the OceanGate firm running the trip and the French explorer Paul-Henry Nargeolet — continues, the Dawood family released a statement praying for a safe end to the drama.
“Our son Shahzada Dawood and his son, Suleman, had embarked on a journey to visit the remnants of the Titanic in the Atlantic Ocean. Contact has been lost with their submersible craft and there is limited information available,” the statement said.
“We are very grateful for the concern being shown by our colleagues and friends and would like to request everyone to pray for their safety while granting the family privacy at this time.
“The family is well looked after and are praying to Allah for the safe return of their family members.”
Mr Dawood, who is understood to live in Surbiton, south-west London, with his wife Christina, Suleman and daughter Alina, comes from one of Pakistan’s wealthiest and most well-known business families.
He moved to Britain as a student to study law at the University of Buckingham and later studied for a masters degree in textile marketing at the University of Philadelphia.
His father Hussain, 79, is the chairman of the Dawood Hercules Corporation, which makes chemicals, and the Engro Corporation, which makes fertilisers, food and energy. Mr Dawood is the vice-chairman of both companies.
He is also in the founder’s circle of the British Asian Trust and a board member of the Prince’s Trust, the charity set up by King Charles in 1976 to help disadvantaged young people.
As the Dawood family clung to hope that the Mr Dawood and his son will be rescued, friends of the British billionaire Hamish Harding spoke of their fears for those on board.
Jannicke Mikkelsen, a Norwegian explorer, said: “My biggest fear is knowing that they are trapped, without being able to get help.
“My fear is that they didn’t make their last ascent window. We are starting to make worst case scenarios.” Patrick Woodhead, the founder of White Desert Antarctica, which organises polar expeditions, said Mr Harding was a “true friend” and “incredible” explorer and that he was praying that he and the other passengers will survive. “Hamish is a great advocate for exploring the globe and discovering new pathways to help make the world a better place,” Mr Woodhead added.
“Our thoughts are with his wife Linda and his sons at this anxious time, and may Hamish and the crew be located quickly.” The wreck of the liner Titanic, which sank on its first voyage to the US, is located about 370 miles off Newfoundland and was discovered in 1985, prompting tourist trips to see it in recent years. The US Coastguard has warned that locating the submersible would be difficult in such a remote part of the ocean.
Harding’s stepson, Brian Szasz, who was one of the first people to reveal the veteran explorer was on the craft later told friends he was going to a Blink-182 concert despite the crisis unfolding.
Writing on Facebook, he said: “It might be distasteful being here but my family would want me to be at the Blink-182 show as it’s my favorite band and music helps me in difficult times.”
It has deployed two C-130 Hercules aircraft to search the surface in case it has emerged undetected. A Canadian Hercules aircraft and a P8 aircraft equipped with underwater sonar capability have also joined the search, while sonar buoys are also being deployed to try to detect the vessel. Even if the submersible is found in time, it might still be a challenge to save those inside.
Frank Owen, a former submarine officer and director of an Australian escape and rescue project, said those on board also faced the challenge of maintaining composure to avoid consuming too much oxygen.
He told the BBC that if “they start panicking or moving around too much they could exceed those rates” [of normal consumption of oxygen] with the result that the time available to the stricken passengers is shortened.
He added that it would be easier to find the submersible on the surface of the water, but that it would be difficult if it was trapped or entangled.
The vessel weighs 23,000 lbs (10,432 kg), measures 6.7m (22ft) in length, and can hold five people for 96 hours. Called Titan, it is made of “titanium and filament wound carbon fibre” and has proven to “withstand the enormous pressures of the deep ocean”, OceanGate said.
