Titanic tourist sub: What is a ‘catastrophic implosion?’

The OceanGate submersible Titan that was carrying five people to the wreck of the Titanic Sunday likely suffered “a catastrophic implosion,” destroying the vessel and killing all those onboard, the U.S. Coast Guard said Thursday.

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Rear Adm. John Mauger confirmed during a news conference that a remotely operated vehicle found parts identified as those of the Titan about 1,600 feet away from the bow of what remains of the Titanic.

Contact with the sub was lost shortly after it began its descent from the surface of the Atlantic Ocean to the Titanic site on Sunday morning. The Titan was reported overdue Sunday afternoon with a last known position of about 435 miles south of St. John’s, Newfoundland.

It’s likely that that is when the implosion happened, not days later, according to a story from the Wall Street Journal. The Journal reported that a top-secret military acoustic detection system the U.S. Navy uses to track enemy submarines detected what the Navy suspected was the implosion of the submersible on Sunday morning.

On board the vessel was OceanGate CEO Stockton Rush, 61; French Navy veteran Paul-Henri (PH) Nargeolet, 77; British billionaire Hamish Harding, 58; Pakistani businessman Shahzada Dawood, 41; and his son Suleman, who was 19.

What is an implosion and why did it happen? Here’s what we know now.

An implosion happens when something collapses inward because the external pressure on the object is greater than the internal pressure of the object.

The implosion – which is the opposite of an explosion – is a violent inward burst of energy. In an explosion, the energy burst outward.

What does the level of pressure inside a vessel have to do with implosion?

When a submersible goes into the water to dive, it is pressurized, meaning that the atmospheric pressure inside the vessel is made higher than that of the surroundings, or the water outside the vessel.

Because a craft is pressurized it can dive to great depths such as the resting place of the Titanic which is 12,000 feet below the surface of the ocean. Under tons of water, the water pressure where Titan is believed to have been destroyed is between 5,500 and 6,000 pounds per square inch. Compare that to the atmospheric pressure at sea level which is 14.7 pounds per square inch.

What caused the implosion?

While it is not yet clear what caused the Titan to be destroyed, it is likely that something caused the hull to be breached, causing the vessel to lose pressure.

Roderick Smith, an engineering professor at Imperial College London, told Agence France Presse that the implosion was likely due to a “failure of the pressure hull” but debris must be recovered to carry out a full investigation.

“The violence of the implosion means that it may be very difficult to determine the sequence of events,” Smith explained.

How can you avoid an implosion?

To keep a vessel from imploding at great depths, it would need to be built out of strong materials and have a shape that allows it to withstand equal pressure on all sides, according to Scientific American.,

Deep-sea submersibles are often spherical, Scientific American explains, because the shape helps evenly distribute pressure. If it is not evenly distributed, the hull can become compromised. Even a tiny crack can de-pressurize the craft leading to an implosion.

What happens during an implosion?

A catastrophic implosion is “incredibly quick,” taking place within just a fraction of a millisecond, Aileen Maria Marty, a former Naval officer and professor at Florida International University, told CNN.

“The entire thing would have collapsed before the individuals inside would even realize that there was a problem.”

Likewise, Dr. Dale Molé, the former director of undersea medicine and radiation health for the US Navy, told that the men would have died almost instantly because of the extraordinary forces exerted by the ocean at depth.

‘It would have been so sudden, that they wouldn’t even have known that there was a problem, or what happened to them,” Mole said.

In addition to being quick, it is incredibly violent, scientists say. The force involved in an implosion has been described as one that “shreds” everything in its path.

In Titan’s case, the water outside flooded in, shearing off the rear cover and landing frame, and ripping apart the sub’s hull where the five men were.

“At those intense pressures, your life ends in a second,” said Dawn Wright, an oceanographer and chief scientist at a mapping company called Esri.