Titan submersible's support ship returns to Canadian harbour following fatal implosion

Investigation begins amid questions over future of deep-sea expeditions

Officials from Canada's Transportation Safety Board go on to the Polar Prince, the main support ship for the Titan submersible, at St John's in Newfoundland. PA

The Titan submersible's main support ship, the Polar Prince, has docked at St John's, Newfoundland, following the loss of the submarine with five people on board.

A catastrophic implosion destroyed the Titan during a descent to the wreck of the Titanic last Sunday.

On Thursday, debris was found 4km beneath the surface of the North Atlantic, close to the liner that struck an iceberg and sunk in 1912.

As the support ship arrived in the Canadian port on Saturday morning, flags were seen at half-mast to mourn the victims.

Those killed in the accident were Dubai-based British businessman and adventurer Hamish Harding, father and son Shahzada and Suleman Dawood, Stockton Rush, chief executive of OceanGate – the company behind the submersible – and French Navy veteran Paul-Henri Nargeolet.

Clockwise from top left, Hamish Harding, Stockton Rush, Shahzada and Suleman Dawood and Paul-Henri Nargeolet, who died aboard the Titan. AFP

Safety investigators begin scrutiny of Polar Prince

The Polar Prince is set to become the subject of a safety investigation led by the Transportation Safety Board of Canada.

A team of TSB investigators boarded the ship upon its arrival at port in order to gather information, conduct interviews and assess the occurrence, in accordance with the Canadian Transportation Accident Investigation and Safety Board Act and international agreements.

The TSB, which will not determine civil or criminal liability, said its investigations are carried out with the primary objective of advancing transportation safety.

This comes in the wake of reports by the BBC suggesting that OceanGate's chief executive, Mr Rush, had previously dismissed safety concerns over the Titan submersible in an email exchange with deep-sea exploration specialist Rob McCallum.

What happens next for the Titan submersible tragedy?

The focus now shifts to the possible recovery of the submersible's debris and the remains of the deceased.

The Canadian Coast Guard confirmed that one of its vessels would remain at the scene to provide support and assistance to the recovery and salvage operations, as co-ordinated by the Maritime Rescue Co-ordination Centre Boston.

Although there is currently no definitive time frame for recovery efforts, there have been doubts raised about the prospects of successfully retrieving the bodies.

This follows a statement by Rear Admiral John Mauger from the US Coast Guard, citing the unforgiving environment of the sea floor and the evidence of a catastrophic implosion of the vessel.

Meanwhile, debris from the implosion is anticipated to be gathered for further investigation.

Ryan Ramsey, a former submarine captain in Britain's Royal Navy, compared the process to a plane crash investigation, given the absence of a black box for the submersible.

Questions are also surfacing about the legal implications of the incident, especially regarding any potential lawsuits against OceanGate from the families of the deceased.

Though the passengers signed waivers acknowledging the risk of serious injury or death, the validity of these waivers may be challenged if there is evidence of gross negligence or undisclosed hazards.

The outcome of these legal considerations, however, remains uncertain until the results of the continuing safety investigation are made public.