- author, Visual Journalism Group
- stock, BBC News
Rescue teams are in a race against time after a tourist submarine carrying five people went missing when the Titanic sank.
But how do rescue teams try to find the ship, which has been missing for nearly two days in the vast depths of the Atlantic Ocean, and what challenges will they face when they do?
Where does the research focus?
The crew of the submarine Titan lost contact with its surface vessel, the Polar Prince, 1 hour and 45 minutes after it went on a deep dive to view the wreckage on Sunday.
The submarine’s air supply is expected to run out at 10am GMT on Thursday.
The wreck of the Titanic lies about 700 kilometers south of St. John’s, Newfoundland, and several ships are assisting in the rescue effort.
U.S. and Canadian agencies, navies and commercial deep-sea companies are assisting in the rescue operations, which are operated from Boston, Massachusetts using military aircraft and sonar buoys.
Polar Prince has already been joined by the cable-laying vessel Deep Energy and three other vessels, with more on the way. Some carry remotely operated unmanned vehicles, which will be needed to clean the sea floor — the French research vessel L’Atlante is the only one capable of reaching the depths needed to reach the Titanic and is expected to arrive late Wednesday.
U.S. Coast Guard Capt. Jamie Frederick said crews from the U.S. and Canada were “working around the clock” during a “complicated search effort.”
Professor Alistair Gregg, a submarine expert at University College London, said a major problem was that rescuers did not know whether to look at the surface or the bottom of the sea – it was “very unlikely” they were in the middle – and warned not to look everywhere.
The most important challenges are:
- Search on the roof
The US Coast Guard said it was searching an area of about 20,000 square kilometres.
Besides the ships searching the search area, C-130 Hercules aircraft from the US and Canada are also trying to locate the submarine from the air.
But if for whatever reason you can’t send distress signals, Professor Craig says: “It’s about the size of a big pickup truck and painted white, so trying to see it from the air. It can be a real challenge.”
Changing weather and poor visibility are challenges the teams have to face.
- Search the depths of the ocean
Rescuers must also explore the depths – which the 6.7-metre-long submarine can reach almost 4 kilometers – because radio and GPS signals cannot travel through water.
Canadian P-3 Aurora aircraft are conducting sonar searches and sonar buoys are deployed in the area.
Sonar buoys detect and identify moving objects in water – often used to search for enemy submarines.
They can listen for sounds from propellers and passive detection of engines – which may include the crew banging against the submarine’s hull – or bounce sonar sound off the deck, i.e. active detection and listening for the return echo.
Description of ocean depths and submarine trajectories
The U.S. Coast Guard confirmed Tuesday night that a Canadian plane had heard underwater noises, and U.S. media reported an internal memo to the U.S. Department of Homeland Security said it detected underwater “clicking sounds” about 30 minutes apart.
Simon Boxall, an oceanographer at the University of Southampton, says underwater noise can motivate rescue teams. “There are a lot of sound sources in the ocean, but it’s really promising,” he says.
A submarine is different from a submarine. According to the National Oceanic and Atmospheric Administration, a submarine can launch itself into the ocean from a port, while a submarine has very limited energy reserves, so it needs a prime mover to launch and recover.
Last year, CBS’s David Bock joined a trip to the Titanic from Oceangate and was told the submarine had seven safety systems.
What are the emergency measures for a missing submarine?
- Tripods: Three lead tubes that can be dropped using hydraulics to gain buoyancy
- Rotating weights: If the hydraulic systems fail, those inside the submarine can tilt the submarine by releasing weights attached to each side by gravity by moving each side of the submarine.
- Ballast bags: Machines can be used to release bags filled with metal shot suspended from the bottom of the submarine.
- Fusible Joints: Joints that melt after 16 hours in seawater if electrical and hydraulics fail.
What will rescue crews do if the vehicle is under the sea?
If she can’t recover, additional expertise from the U.S. Navy and the private sector will be needed to salvage the vessel, according to U.S. Coast Guard Admiral John Mager.
According to Oceangate, Titanic is one of only five manned submersibles in the world capable of reaching Titanic, 3,800 meters below the ocean’s surface.
If Titan is at the bottom of the ocean and cannot return under its own power, the options are very limited, according to Professor Gregg.
If a submarine is more than 200 meters deep, there are very few ships that can go that deep, certainly not submarines.” .
Any attempt to search for a seabed in the area will be carried out by a remotely piloted unmanned vehicle.
A deep-layer power cable that arrived at the scene on Tuesday dispatched at least one vehicle, but it was unclear whether it could reach the required depth.
The U.S. Navy already has a remotely piloted drone capable of operating at that depth and last year used it to locate and recover a crashed fighter jet at a depth of 3,780 meters in the South China Sea.
In this case, the U.S. military used remote-controlled unmanned vehicles to attach the aircraft to a lifting hook that was lowered from a crane on a surface rescue vessel.
Ocean rescue expert David Mearns says that if remotely operated unmanned vehicles can find the Titan, they can recover it.
“A world-class remotely operated vehicle with dual processors could capture Titan or attach a lift line to it and slowly pull it to the surface,” adds Mearns.
