Difference between a submersible and a submarine

June 20, 2023

The tourist vessel that went missing on its way to the Titanic wreckage is a submersible, not a submarine — and the difference is key to why it has disappeared.

A submersible, unlike a submarine, doesn’t have enough power to launch itself into the ocean and return on its own, the National Oceanic and Atmospheric Administration explains on its website.

Instead, a submersible relies on a support ship to launch it and recover it.

The procedure is similar to a boat that takes scuba divers out to sea with their gear, allowing them to jump for their underwater adventure and then climb back onboard for the trip back to shore.

OceanGate Expeditions’ Titan — a Cyclops-class submersible designed to carry five people to depths of up to 13,123 feet — uses the Polar Prince, a former Canadian Coast Guard icebreaker, as its support ship.

The missing Titan — The Titan, a tourist vessel that went missing on its way to the Titanic shipwreck, is a submersible — not a submarine.

Royal Australian Navy submarine Rankin — Unlike submersibles, submarines like the Royal Australian Navy’s Rankin, above, have enough power to get to and from their destinations without the need for a support ship.

But the Titan lost contact with the Polar Prince 1 hour 45 minutes into its dive on Sunday afternoon, according to the US Coast Guard, leaving it missing in the depths of the North Atlantic Ocean.

Nuclear submarines can remain underwater for months, however, David Concannon, an adviser to OceanGate, told The Associated Press on Monday that the Titan had a 96-hour oxygen supply.

The submersible’s dives to the Titanic wreckage usually last about 10 to 11 hours.

One pilot and four tourists are trapped on board, including a British billionaire and one of Pakistan’s wealthiest men and his 19-year-old son.

Submersible on voyage to Titanic — So-called “Titaniacs” pay $250,000 to ride aboard the submersible to the iconic wreck 12,500 feet below the surface.

Hamish Harding, a successful British businessman, was confirmed to be one of the trapped tourists, according to Action Aviation, a company for which Harding serves as chairman.

Harding is also an adventurer who holds three Guinness World Records, including the longest duration at full ocean depth by a crewed vessel.

Shahzada Dawood and his son Suleman, members of one of Pakistan’s most prominent families, were also on board, according to a family statement sent to the Associated Press.

This was OceanGate Expeditions’ third annual voyage to chronicle the deterioration of Titanic since 2021.