Image source, Kenny Sharpe

Image source, Kenny Sharpe

Only a few days ago, CBC journalist Kenny Sharpe took these photos at St John's.

Writing on Twitter, Sharpe says he didn't know what he was photographing at the time.

It turned out to be the Titan submersible being towed out to sea.

The images show the small sub being pulled along by the Polar Prince ship, as the crew heads towards the site of the Titanic wreck.

The US Coast Guard has just shared a brief update on the search for the missing Titan submersible.

Today, an HC-130 Hercules aircraft has travelled 879 miles (1400km) over the search area.

Aircraft from partner agencies are also scheduled to search.

Tiffanie Turnbull
reporting from London

News that noises have been picked up in the hunt for a missing submersible has offered a glimmer of hope that the five men on board are alive.

Frank Owen, from the Submarine Institute of Australia, says he is confident - based on the information available - the sounds are coming from inside the vessel.

"If there was a 30-minute interval, it's very unlikely to be anything but human-related," he told the BBC.

Frank says the noises "smack of advice" coming from the fifth man inside - 77-year-old Paul-Henry Nargeolet, a former French navy diver and renowned explorer.

"He would know the protocol for trying to alert searching forces… on the hour and the half-hour, you bang like hell for three minutes," Frank added.

• You can read more here about what happens after the sounds are detected

Image source, Reuters

We've had two press conferences in the last two hours.

First we heard from the US Coast Guard in Boston who said the operation to find the tourist submersible has been expanded.

Capt Jamie Frederick said the surface search was an area equivalent to twice the size of Connecticut and 4km deep as he confirmed more surface vessels and remotely operated vehicles (ROVs) will be joining the search.

Although experts estimate the five men on board would have less than twenty hours of oxygen left, Capt Frederick said that it remained very much a rescue operation.

Then over in Newfoundland, Canada, we heard from Horizon Maritime Services and Miawpukek Horizon reps - the groups behind the Polar Prince ship which launched Titan submersible into the sea.

Horizon chairman Sean Leet said the marine industry in this part of the world is no stranger to responding to tough situations.

"I've been in the marine industry since a very young age and I've never seen equipment of that nature move that quickly," he said.

Conditions have at times been difficult over the past day, with clouds bringing showers and thunder storms.

However, BBC Weather presenter Ben Rich says clearer conditions appear to be on the way.

Several journalists have been asking questions at this press conference, and Sean Leet is asked by the BBC whether families of those on the Titan are on board the Polar Prince vessel which is searching for the missing sub.

He tells our reporter "that's a question I can't answer".

Asked whether there was anything capable of lifting the Titan from such depths, he says: "The equipment that is on site and coming to site... is certainly capable of reaching those depths."

The equipment being used in the search is the "finest in the world, the most capable in the world", he says, adding that it was mobilised "flawlessly".

And that's the end of the press conference.

Leet says the Polar Prince remains at the Titanic site supporting the sub rescue efforts.

And his group's rescue ship, The Horizon, was sent back to the port to get more equipment.

"We will be at the Titanic site at 5am tomorrow morning. We are aware of the time sensitivity around the mission. We remain focused on the search of the Titan and for the crew and keep hope they will be found safely."

Beginning the press conference, co-founder and chairman of Horizon Maritime Services, Sean Leet, says their thoughts and focus remain with the crew of the Titan and their families.

The marine industry in this region is no stranger to responding to difficult incidents, he says, adding that all of us are "unified" in the work to find the Titan.

He says "our critical role remains in a support capacity".

And he confirms the company has been supporting the Titanic expeditions for several years.

We're set to hear from Horizon Maritime Services and Miawpukek Horizon representatives.

These are the groups behind the Polar Prince ship, which the Titan submersible launched from.

We're expecting a brief statement and will bring you updates as they happen.

The Titan submersible could be in ultra deepwater - the craft is capable of reaching 4,000m in depth.

It was on its way to the site of the Titanic wreck, which lies on the ocean seabed at a depth of 3,800m.

A little earlier we heard from Captain Jamie Frederick from the US Coast Guard, who said the search area for the sub was "expanding every hour" because of environmental factors.

Image source, PA Media

The BBC has spoken to Oisin Fanning, who has been on a deep sea voyage to the Titanic wreck before and knows a few of the people on board the missing submersible.

He said there is a lot of training beforehand. You wake up at 04:00 and safety procedures are ongoing for about four to five hours before it even descends into the water.

Fanning thinks those onboard would understand how to maximise their oxygen supply.

"They will immediately look to conserve oxygen straight away," he said.

"They will do everything to keep themselves calm, breathe shallowly and preserve the oxygen for as long as possible.

"I think they’ll last with oxygen for longer than people think."

With about 20 hours of oxygen left, more ships have joined the expanded search in the North Atlantic.

The new ships will join the Polar Prince, which deployed the Titan submersible on Sunday, as well as Deep Energy, a pipe-laying vessel flagged in the Bahamas.

Three other Canadian vessels are also involved

• The area of the search has expanded - the surface search is now twice the size of the US state of Connecticut, and the sub-surface search is approximately 2.5 miles (4km) deep
• Capt Frederick says "We have to remain optimistic and hopeful when we are in a search and rescue case."
• A French team is bringing some "state of the art equipment" to help in the search

The press conference largely focused on the mysterious 'banging' noises. This is what we know about these noises:

• The first noises were heard by a Canadian P-3 aircraft yesterday
• The Coast Guard sent teams to search the area where the noises were detected
• More noises were heard today as well
• Unfortunately, the ocean is a noisy place and it remains unclear what the sounds are

The media update is over, but we are going to bring you some more details of what was said.

One important line came from Capt Frederick when he was asked if he was still optimistic.

"We have to remain optimistic and hopeful when we are in a search and rescue case," he replied.

"We are in the middle of the search and rescue case. Sometimes we don't find what we're looking for and you have to carefully consider all of the factors.

"There are a lot of factors you have to consider. After considering all those factors, sometimes you're in a position where you have to make a tough decision. We're not there yet.

"If we continue to search, potentially we could be at that point... And that's a discussion we will have with the families long before I am going to discuss here publicly."

Capt Frederick ends the update after saying his team are "not in the business of speculation".

"We are in the business of searching," Capt Frederick adds.

He says he plans to keep the media and the public informed with developments.

We're now hearing there is a lot of equipment flowing in from St John's.

The French team coming in is bringing some "state of the art equipment".

The US Coast Guard plans to have more assets in the area soon, which will be placed in the spots they determine to be best for the search.

Capt Frederick says it is his understanding the Canadian P-3 aircraft heard some noises today as well.

He now introduces Carl Hartsfield for his expertise in this area.

Hartsfield tells reporters it is very tough to discern what the noises are.

His team has "multiple sensors in the area taking the data back to the best people in the world and feeding this back to the team so they can make decisions".

"They have to eliminate potential manmade sources other than the Titan," he adds.