Missing submersible: The science behind the search
US and Canadian crews are working “around the clock” to search both on the surface and under the sea. But efforts to locate the boat are extensive and difficult
This is your chance to step outside of everyday life and discover something truly extraordinary” — that’s the slogan OceanGate Expeditions uses to advertise its tourist expeditions to the Titanic shipwreck. The price of a ticket for a trip to the deepest parts of the sea: $250,000. Not a price that would be affordable for ordinary tourists, but acceptable for wealthy vacationers. On board the currently lost tourist vessel Titan are, among others, British billionaire businessman and adventurer Hamish Harding, along with the British-Pakistani management consultant Shahzada Dawood and his 19-year-old son. An intensive, multinational rescue effort is now underway.
US and Canadian crews are working “around the clock” to search both on the surface and under the sea. But efforts to locate the boat are extensive and difficult. According to US Coast Guard reports, an area “the size of Connecticut” has already been flown over to look for signs that the aircraft has surfaced, while military aircraft and commercial vessels have also joined the search.
Difficult conditions prevail at the site where the Titan is missing. The Titanic shipwreck lies at a depth of around 3,800 meters (more than 12,400 feet) in almost complete darkness. The water pressure is high and the temperature close to freezing.
“Techniques vary, but in this depth of water, a sonar search system would have to specialize in a very narrow beam but a high enough frequency to resolve a small submersible. The search for Emiliano Sala’s plane a few years ago, an object of similar size, took less than three days, but in shallower water,” Jamie Pringle, a forensic geoscientist at Keele University, England, told reporters.
In Titan’s case, there are only two possibilities. “If, contrary to expectations, the boat drifts to the surface and cannot be located due to the low freeboard [distance from the water to the upper deck — Editor’s note], the chances of being found are realistic,” the German Navy estimated. “This is countered by the fact that a distress signal would have been sent in such a case.” If the submersible has sunk to the seabed, this would make finding and rescuing the vessel particularly difficult. The seafloor is much more rugged than on land, with many stratifications and continental shelves, as well as ocean currents.
Light does not travel easily through water, blocking most communications. “Unfortunately, the seawater below the surface blocks the propagation [of electromagnetic waves] very quickly: no radar, no GPS, and spotlight or laser beams are absorbed within a few meters,” said Eric Fusil, director of the Shipbuilding Hub for Integrated Engineering at the University of Adelaide, Australia. Because of the submersible’s design, it’s not possible to deliver fresh oxygen from the outside, according to the German Navy.
The water pressure 3,800 meters down at the site of the Titanic wreck is roughly 400 atmospheres (6000 PSI) — about the same as having 35 elephants on your shoulders. This makes deep-see exploration a major technological feat, requiring submersibles and submarines capable of withstanding huge amounts of pressure over long periods of time. “Any deep divers know how unforgiving the abyssal plain is: going undersea is as, if not more, challenging than going into space from an engineering perspective,” said
