Titan sub implosion as quick as ‘turning on the light switch.’ What happened?

Investigators are turning their attention to finding out how a submersible carrying five people to the Titanic wreckage suddenly imploded.

All hopes for a positive outcome vanished Thursday when the U.S. Coast Guard confirmed it found debris belonging to OceanGate Expedition’s Titan near the famous ocean liner at the bottom of the North Atlantic.

The submersible’s disappearance Sunday set off an international rescue mission that captivated the world’s attention given its link to the Titanic. As well, the five passengers aboard the Titan were reported to have 96 hours of breathable air – an added element that led to the frantic search.

With its unfortunate demise and the death of those on board, investigators are focusing on how the Titan suffered a “catastrophic implosion,” as it was described Thursday by the U.S. Coast Guard.

First off, an implosion is a process in which objects are destroyed by collapsing on themselves.

It is the opposite of explosion, which is a rapid expansion in volume associated with an extreme outward release of energy.

“The implosion of the hull means the water pressure was greater than the strength of the material,” said Will Kohnen, president and CEO of submarine manufacturer Hydra Space Group, and chair of the Marine Technology Society’s manned underwater vehicles committee.

“When you reach the point where it doesn’t go anymore, all that stored energy goes into it and that’s what creates the inverse explosion, i.e., implosion, and it happens very fast.”

On Sunday, the Titan suddenly lost contact with Canadian research vessel Polar Prince roughly an hour and 45 minutes after it submerged to descend for a view of the Titanic. It takes more than two hours to get to the wreck.

The Titanic sits almost four kilometres below sea level. The U.S. Coast Guard said Thursday that the Titan’s debris had been found roughly 500 metres from the Titanic.

“The debris field is consistent with a catastrophic implosion of the vessel,” U.S. Coast Guard Rear-Adm. John Mauger told reporters in Boston.

Mauger initially described the Titan’s debris as “consistent with the catastrophic loss of the pressure chamber.”

Undersea expert Paul Hankin told reporters in Boston that searchers found five pieces of debris, including the nose cone, which was roughly 500 metres from the Titanic’s bow, and the front-end belt of the pressure hull.

The other end of the pressure hull was found in a second, smaller debris field nearby, Hankin added, which … basically comprised the totality of that pressure vessel.