St John's ready to help in search for missing Titanic sub

The Polar Prince icebreaker, seen here off the coast of Newfoundland

A few days ago, British adventurer Hamish Harding wrote excitedly on Facebook about his upcoming journey to the bottom of the ocean to see the Titanic shipwreck.

It had been the worst winter seen in 40 years in Newfoundland, the Atlantic Canadian province where he was boarding the ship that would carry him to the wreck site.

But "a weather window has just opened up," Mr Harding wrote. "And we are going to attempt a dive tomorrow."

Mr Harding is one of five people now missing after their submersible lost contact with their mothership - a Canadian ice-breaker vessel called the Polar Prince - on Sunday.

The city of St John's, from where the Polar Prince set sail, towing the submersible behind it, has since become part of the massive search and rescue efforts to find the missing vessel.

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While the efforts are being spearheaded by the US Coast Guard in Boston, St John's harbour is where additional vessels will be based as that mission continues.

The city on the Atlantic coast is the closest to the site of the Titanic wreck, which lays at the bottom of the ocean around 600 km (372 miles) from shore.

The US Navy's Flyaway Deep Ocean Salvage System - capable of lifting and recovering large, bulky undersea objects - is scheduled to arrive in St John's on Tuesday evening, a navy spokesperson told the BBC's US news partner CBS.

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Canadian coast guard vessel CCGS Terry Fox is now in the harbour and the CCGS Ann Harvey is currently enroute. Both vessels are on standby, loading search and rescue equipment and personnel should assistance be required, Canada's defence department said.

Newfoundland Premier Andrew Furey told the BBC on Tuesday that he has been in contact with the US ambassador David Cohen to see how the province can further assist with the rescue mission.

"We're all very troubled with what is happening off our shores," Mr Furey said, but the wish is it will end with good news.

"We're not hopeless," he said. "We do hope that this rescue mission is fruitful."

On Canada's Atlantic coast and with important fishing and off-shore oil industries, Newfoundland and Labrador has a long and sometimes tragic history with the ocean, Mr Furey said.

Due of its proximity to the Titanic shipwreck, the province has become a centre for researchers and people interested in the voyage the Titanic took more than 100 years ago - an infamous maritime tragedy brought to renewed attention by director James Cameron's 1997 blockbuster film.

"St John's harbour has been a hub for expeditions for many years," said Larry Daley, a local who made an underwater trip to the wreck 20 years ago with Mr Cameron, told the BBC.

OceanGate, the company behind the missing submersible, had begun conducting trips from St John's to the Titanic since 2021, according to its website.

Mr Daley said that because of St John's history, the city has an array of trained mariners other technicians who have deep knowledge of the often temperamental Atlantic waters - expertise he believes could be helpful as the search for the missing submersible continues.