An international search for a missing submersible took a tragic turn Thursday when the vessel was found scattered in pieces in icy darkness on the ocean floor.
A remotely operated vehicle discovered the nose cone of the Titan submersible about 1,600 feet from the bow of the Titanic, authorities said. At least four other large pieces were found nearby, including the front and rear sections of the sub’s pressurized chamber, said Paul Hankins, a director of salvage operations and ocean engineering with the Navy.
The world watched as a growing team of search and rescue experts tackled their complex and dangerous mission at extreme depths in a remote location 400 miles east of Nantucket. Here’s a look at the difficult task the team faced, the technology used and conditions that may have led to “a catastrophic implosion.”
What happened to the Titan submersible?
Anyone who’s traveled in the mountains or by airplane understands how air pressure changes, but it’s difficult to comprehend the forces straining at every inch of the submersible as it descended the nearly 2.5 miles toward the ocean floor on Sunday.
“Pressure is enormous down there,” said Nikolas Xiros, professor of naval architecture and marine engineering at the University of New Orleans.
On the ocean floor at the depth where the Titanic rests – 12,500 feet – the pressure is nearly 380 times greater than at the surface, said Luc Wille, professor and chairman of physics at Florida Atlantic University.
It’s a familiar concept to divers, who feel the pressure when they descend, breathing air regulated to match the pressure around them. The deeper you go, the higher the pressure climbs.
“People always underestimate that impact,” Wille said. At 12,500 feet, the pressure is more than 4,400 pounds per square inch. With that kind of force, he said any defect in the Titan’s hull could have triggered an implosion.
What is a water column implosion?
When search and rescue teams refer to “the water column,” they mean in the water between the surface and the bottom. An implosion is the opposite of an explosion. Rather than pressure building on the inside and causing something to explode, the ocean generates incredible pressure on the outside of a vessel and collapses the walls inward.
A crack, a defect in the hull materials or design or a structural failure could have imploded the Titan sub, experts told USA TODAY.
How large was the initial search area?
Twice the size of Connecticut, about 12,000 square miles, Coast Guard officials said. And it extended as much as 2.5 miles deep.
By Tuesday, about 10,000 square miles had been searched. On Wednesday, one North Carolina-based HC-130 Hercules plane alone searched an area spanning 879 miles.
When asked before the debris were located, Jim Bellingham, a Johns Hopkins University expert on deep-sea operations said, the submersible could be floating on the ocean’s surface, drifting anywhere between the surface and the bottom or stuck on the sea floor.
Did the Navy detect the sound of the implosion?
Yes, though not definitively, the Coast Guard said. The Navy’s analysis of acoustic data collected in the vicinity on Sunday morning found an “anomaly” that could have been an explosion or an implosion around the time the sub lost contact.
It’s likely that other monitoring equipment also may have picked up the sound, said Eric Fusil, a submarine expert and associate professor in the University of Adelaide’s School of Electrical and Mechanical Engineering. The Navy and others monitor sound offshore to assist with endangered species research.
What does debris field mean?
A term used by rescue and recovery specialists that became all-too familiar for some after 9/11 and the Space Shuttle Columbia disaster. It refers to an area that contains pieces of buildings, aircraft, vehicles or vessels after they explode, implode, crash, sink or otherwise break apart.
Where is the Titan debris field?
Search and rescue crews remotely operating an underwater vehicle discovered a large debris field about a third of a mile from the Titanic while looking for the missing Titan submersible, the Coast Guard said. The ROV later found another smaller debris field nearby.
According to court documents filed with the U.S. District Court in Eastern Virginia that oversees operations around the Titanic, the Titan was to descend downstream away from the wreck and navigate against the current to approach the vessel that sank 111 years ago.
The debris was discovered by an ROV associated with the Canadian vessel Horizon Arctic, which reached the area and began searching early Thursday.
How did rescuers search for sounds deep in the ocean?
In several ways, including aircraft sonar, buoys equipped with sonar and acoustic monitoring used to help research endangered whales.
A look at the search patterns
Search crews worked by taking last-known positions – whether through a signal or sighting – and calculated currents, winds, sea states and other factors to determine the search radius, said Chris Boyer, executive director of the National Association for Search and Rescue, a non-profit education, training and advocacy group.
Planes and ships used a wide variety of sensors: radar, sonar, infrared cameras and night vision systems were deployed to detect any trace of the missing submersible.
How many ships, submarines and airplanes were searching for the missing sub?
At least five vessels searched the ocean’s surface, with another five on the way, Capt. Jamie Frederick, the First Coast Guard District response coordinator, said Wednesday. Also on scene were several private vessels including the Horizon Arctic, which found the wreckage, and Bahamian and French research vessels.
What type of airplanes were searching for the submersible?
Three C-130 aircraft and three C-17 transport planes from the U.S. military were scouring the sea in addition to Canadian military aircraft with sound-sensing equipment.
Grace Hauck, Shawn J. Sullivan, and Javier Zarracina contributed to this report.
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