Missing Titanic sub: Submersible vs submarine - what is the difference as 5 missing on OceanGate’s Titan

It is thought that a British businessman is on board the vessel as a frantic search is underway

A rescue operation has been launched after a submersible which was set to explore the wreck of the Titanic has gone missing with five people on board. The expedition, organised by OceanGate set out on Sunday (June 18) but now, those above ground have lost contact with the crew.

The submersible, named Titan, was taking part in its third annual voyage by OceanGate Expeditions to monitor the decay of the ship’s wreckage, following previous trips in 2021 and 2022. British businessman Hamish Harding who is on board, posted before the trip that bad weather conditions meant this was likely to be the first and only manned mission to the Titanic in 2023.

However, a frantic search is now underway after the US Coast Guard said contact with the small sub was lost about an hour and 45 minutes into its dive. Meanwhile, it is thought that only 96 hours of “life support” is available on board.

According to the OceanGate website, Titan is a Cyclops-class manned submersible designed to take five people to depths of 4,000 metres (13,123 feet) for site survey and inspection, research and data collection, film and media production, and deep sea testing of hardware and software. It adds that through the innovative use of modern materials, Titan is lighter in weight and more cost-efficient to mobilise than any other deep-diving submersible.

But, for those who are not familiar with deep-diving terminologies, you might be wondering what the difference is between a submersible  and submarine. We have broken down what the differences are - and some could be crucial to why the vessel has gone missing.

Submersible vs Submarine - what’s the difference?

According to the Ocean Explorer website, the difference between a submarine and a submersible is a submarine has enough power to leave port and come back to port under its own power. A submersible has very limited power reserves so it needs a mother ship that can launch it and recover it.

Submersibles are launched from support ships which take the submersible to the site where the vessel will deep dive - similar to how a boat deposits a scuba diver into an area of the ocean to explore. Titan’s location is unknown because it lost contact with its support ship, Polar Prince, as CNN reported.

OceanGate told the BBC, Titan’s dive began on Sunday after Polar Prince escorted the submersible to the site of the Titanic wreckage, which is near Newfoundland, Canada.

However, according to the OceanGate website Titan is paired with a patented, integrated launch and recovery platform making it ‘easy to operate in varying sea states’ using a local appropriately sized ship for the project.

It adds that in coastal waters this means they do not need a large support ship with a crane or A-frame.

Submarine

In comparison, submarines can propel themselves forward through the water using propellers or jets that shoot out water. These can be powered by diesel engines, or even nuclear reactors, and do not need a support ship to launch.