How did the submarine get lost in the first place? 10 questions and answers about the submarine drama Knock sounds: possible trace in submarine search

The “Titan” was on its way to the wreck of the famous luxury ship “Titanic” with five people on board. The submarine has been missing since Sunday morning (local time). About an hour and 45 minutes after the start of the dive, contact with the mothership “Polar Prince” was lost.

Are there any signs of life from the prisoners?

Search teams recorded a knocking sound every 30 minutes Tuesday in the region where the Oceangate vehicle is suspected, according to an internal memo from the US government, which broadcaster CNN and Rolling Stone magazine quoted Wednesday night. .

Hours later, additional sonar devices were deployed and the knocking could still be heard. The memo did not specify exactly when and for how long the sound was heard. CNN reported more noises in an update Tuesday night, but they were no longer described as “knocks.” However, the sounds indicated that there was still hope for survivors.

The US Coast Guard later tweeted that a Canadian search aircraft heard “underwater noise”. Underwater robots have been sent to the area to investigate the source, but so far without success.

How long can the occupants survive in the submarine?

Time is of the essence: Authorities estimate that the oxygen is allowed alone until Thursday afternoon (CEST) are sufficient. According to the operator Oceangate Expeditions, the 6.70 meter small “Titan” has enough oxygen to supply five people with oxygen for 96 hours. Conditions are extremely harsh near the “Titanic”, some 684 kilometers south of the Canadian island of Newfoundland. It is pitch dark and the water pressure is high. Retired British Vice Admiral Chris Parry told LBC:

How to search for the submarine?

Radio, GPS, satellite phone, radio. However, all this no longer works at a certain water depth. Contact with the outside world is only possible at sea tube depth – about twelve meters below the surface of the water.

As John Mauger of the US Coast Guard explains, the search initially focused on the surface of the water by systematically flying aircraft over a wide area. Underwater vehicles are said to have arrived by now. The rescuers mainly used sonar to locate the “Titan”.

The word sonar is an abbreviation of SoAnd n/anavigation and ranging, which stands for sonic navigation and range finding. Sonar devices emit sound energy — known as a “ping” — then wait for the echo from an underwater object. The distance to the other object can be estimated from the echo transit time.

Sonobuoys are an important aid in underwater searches. The devices are dropped from an aircraft and descend to the desired depth. A surface float with a radio transmitter provides communication between the sonar and the aircraft. Once the device picks up the echo, it sends the information back to the surface buoy and then to the aircraft. Sonobuoys are used by the military to pick up the sounds of enemy submarines, for example.

The US Coast Guard said on Twitter that an area of ​​about 26,000 square kilometers had already been searched. For comparison: Switzerland has an area of ​​41,285 square kilometers.

How could the submarine be “lost”?

No one knows exactly what happened to the submarine in the first place. The best-case scenario is if the “Titan” becomes entangled in the wreckage of the “Titanic,” marine researcher Tim Taylor told NBC News. Because in this case the boat would be the easiest to find.

However, experts have put forward several theories about what could have happened. Initial hopes that the submarine might have floated to the surface following a power or communications failure appear to be unfounded. In such a case, the crew could actually have used a radio to make contact.

If the “underwater noise” recently picked up by a Canadian search plane was actually from the “Titan,” early theories that the submarine may have ruptured would be obsolete.

Another concern is that the hull is damaged and there may be a leak.

Can the submarine come to the surface on its own?

The boat does not appear to be able to rise from the seabed under its own power. So it should probably be pulled up. “Even though the submarine is still intact, if it’s deeper than 200 metres, there are very few ships that can go that deep, let alone divers,” said the university’s submarine expert Alistair Greig to BBC College London.

The wreck of the Titanic, which broke in two, lies at a depth of about 3,800 meters.

Would it even be possible to salvage the submarine?

The experts disagree on that. Greig said he doubted rescuers could be attached to the submarine’s hatch. On the other hand, marine researcher Taylor stressed:

Meanwhile, the US Navy sends a device to the region to recover the submarine. As a spokeswoman for the German news agency said, the “Fadoss” deep-sea disposal system should arrive Wednesday evening (local time) in St. Johns in Newfoundland, Canada, and then be transported further out to sea. The Navy describes it as a “portable boat lift system that provides reliable deep-sea lifting capacity of up to 27 tons for recovering large, bulky, and heavily sunken objects such as aircraft or small ships.” It can be installed on ships with its winch and rope. A rescue – with or without “Fadoss” – can only be undertaken once the boat has been located.

Are tourist trips to the wreck generally dangerous?

In any case, the American physicist Michael Guillen warns the British broadcaster Sky News against such tourist trips.

Guillen dived to the famous wreck aboard a Russian boat in 2000 – saying he was in mortal danger. At the stern, the submarine got caught in a fast underwater current, which slammed it into the Titanic’s massive propellers, the scientist said. “Our submarine was like a giant mosquito compared to the propeller. Huge chunks of Titanic fell on us and I knew we were in trouble.”

He has already begun to process his death, Guillen said. “There was a voice in my head. I will never forget the words, ‘So this is how it will end for you.’ I thought of my wife, whom I would never see again.” But in the end everything turned out fine. The pilot succeeded in freeing the boat.

What do submarine experts say about the “Titan”?

Meanwhile, according to an article in the New York Times, submarine industry executives were concerned about Titan’s safety years ago. “We are concerned that Oceangate’s current experimental approach could lead to adverse outcomes (ranging from minor to catastrophic),” they wrote in a 2018 letter published by the paper. It accuses Oceangate of misleading marketing. Boss Stockton Rush was asked to have the “Titan” tested by an independent party.

That fits the impression of reporter David Pogue of American broadcaster CBS, who took part in the trip last year. He told the BBC the vehicle appeared to him to be improvised. Part of the ballast consists of construction tubes. If the boat gets stuck or leaks, “there’s no backup, no escape pod.”

On Tuesday, the American tech blog The Verge pointed to a technical feature: the submarine is controlled by a game controller from the well-known Swiss manufacturer of computer accessories Logitech.

Recent reports (including from the Keystone-SDA news agency) incorrectly spoke of an Xbox controller. However, a video screenshot clearly shows that it is a Logitech device.

Since when is the submarine missing?

The vehicle has been missing since Sunday morning (local time). About an hour and 45 minutes into the dive, which was to last about seven hours, contact with the escort boat “Polar Prince” was lost. According to the provider Oceangate Expeditions, the nearly seven meter small “Titan” has enough oxygen for a total of 96 hours.

Who’s in the sub?

On board the submarine “Titan” is the French researcher Paul-Henri Nargeolet (77), who is considered one of the best-known experts on the wreck of the luxury liner that sank in 1912 and is therefore nicknamed “Monsieur Titanic” has got. Other prisoners include veteran British adventurer Hamish Harding (58) and British-Pakistani business adviser Shahzada Dawood (48) and his 19-year-old son Suleman. As the “Oberbayerisches Volksblatt” reported, Dawood’s wife is from Germany. According to the Oceangate operating company, the fifth missing is company manager Stockton Rush, 61, who acted as captain of the boat.

Oceangate offers wealthy clients an adventure trip – the cost for the eight-day expedition is approximately $250,000. The dive itself only takes a few hours.

The Titanic sank in the North Atlantic in 1912 on her maiden voyage from Southampton to New York. More than 1,500 of the 2,200 people on board were killed. The remains of the famous luxury liner were discovered in 1985. (saw/sda/dpa)