Missing Titanic sub: what are submersibles, how do they communicate, and what may have gone wrong?

By Stefan B. Williams, University of Sydney

An extensive search and rescue operation is underway to locate a commercial submersible that went missing during a dive to the Titanic shipwreck.

According to the US Coast Guard, contact with the submersible was lost about one hour and 45 minutes into the dive, with five people onboard. The vessel was reported overdue at 9.13pm local time on Sunday (12.13pm AEST, Monday).

The expedition was being run by US company OceanGate as part of an eight-day trip with guests paying US$250,000 per head to visit the wreck site. As of Monday afternoon (Tuesday morning in Australia), US Coast Guard Rear Admiral John Mauger said the watercraft likely had somewhere between 70 and the full 96 hours of oxygen available to the passengers.

The Titanic’s wreck sits some 3,800 metres deep in the Atlantic, about 700km south of St John’s, Newfoundland. Finding an underwater vehicle the size of a small bus in this vast and remote expanse of ocean will be no small feat. Here’s what the search and rescue teams are up against.

OceanGate’s Titan submersible goes missing

Submersibles are manned watercraft that move in a similar fashion to submarines, but within a much more limited range. They’re often used for research and exploration purposes, including to search for shipwrecks and to document underwater environments. Unlike submarines, they usually have a viewport to allow passengers look outside, and outside cameras that provide a broader view around the submersible.

The missing submersible in question is an OceanGate Titan watercraft, which can take five people to depths of up to 4,000m. The Titan is about 22 feet in length, with speeds of about 3 knots, or 5.5km per hour. Although submersibles are often connected to a surface vessel by a tether, video and photos suggest the Titan was likely operating independently of the surface ship.

According to OceanGate’s website, the Titan is used “for site survey and inspection, research and data collection, film and media production, and deep-sea testing of hardware and software”.

Read Full Story https://theconversation.com/missing-titanic-sub-what-are-submersibles-how-do-they-communicate-and-what-may-have-gone-wrong-208100