Missing Titanic sub updates: Desperate search as oxygen expected to run out in hours

Rescue efforts to find the missing Titanic submersible are entering their decisive hours on Thursday. The vessel, named Titan, lost communication with tour operators on Sunday, June 18, while about 435 miles south of St John's in Newfoundland, during a voyage to the Titanic shipwreck off the coast of Canada.

On board the Titanic sub is the British billionaire adventurer Hamish Harding as well as UK-based businessman Shahzada Dawood, his son Suleman Dawood, and OceanGate's chief executive and founder Stockton Rush, reportedly with French submersible pilot Paul-Henri Nargeolet.

Rescuers are searching an area 2.5-miles below the surface of the sea. The temperatures are freezing cold and it is too deep for light to penetrate. In these pitch black conditions, it is easy to hit the ocean floor suddenly as subs have only a limited field of vision from their lights.

As of Wednesday afternoon, it was believed that just 20 hours of oxygen remained in the vessel, which meant it would run out at some point on Thursday morning. The 6.7m (22ft)-long OceanGate Expeditions vessel, which has British billionaire adventurer Hamish Harding on board, reportedly had a 96-hour oxygen supply in case of emergencies.

The BBC has reported that the US Coast Guard has estimated oxygen could run out for those on board at 07:18am eastern time in the US, which is 12:18pm here in the UK. Ten extra ships and several remote submarines are said to be joining the search on Thursday, which will more than double operations.

The search now covers an area twice the size of US state Connecticut, and a sub-surface area 2.5 miles (4km) deep. But it's not clear whether the noises came from the submersible. The Polar Prince, which is the research vessel the Titan was