Titanic submersible missing: How is it different from a submarine?

Submersibles have a smaller crew or be operated remotely and are usually meant for scientific purposes.

The tourist Titan submersible, that is missing since Sunday after it had gone to explore the Titanic wreck, can explore deep sea like submarines but still has limited features. Submarine are generally military vessels and are highly equipped compared to the submersibles, which are more limited in their movement. (Missing Submersible Titanic LIVE Updates)

The submersible vanished in the North Atlantic while taking five people down to the wreck of the Titanic. ((OceanGate Expeditions via AP))

Submersibles have a smaller crew or be operated remotely and are usually meant for scientific research. The United States' government agency ‘National Oceanic and Atmospheric Administration’ explains that “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.”

The craft in question is a submersible – 'Titan', that is missing since four days triggering a frantic search operation in deep sea waters off the Canada coast by a collaborative effort between the US and Canada. Operated by US company OceanGate, the submersible had five people onboard, including a pilot. It has enough oxygen to last the five people on board for 96 hours but currently, the situation is critical as authorities are racing against time to relocate the submersible before the oxygen supply runs out.

How deep can the Titan submersible go?

The white tube (like in the picture) is 2.8 metres wide and 6.7 metres (21 feet) long. It has a porthole in the front. Its maximum velocity is three knots, equivalent to 5.5 kilometers per hour and can take the passengers to a depth of 4,000 metres, according to OceanGate.

The Titanic wreck, which the crew went to explore, is located in the North Atlantic at a depth of 3,800 metres which means the submersible can just reach it.

Earlier, popular for scientific purposes, submersibles are in increasing demand for tourism these days, Stefan Williams, an underwater robotics expert at the University of Sydney, told AFP.

Who are onboard?

Pakistan-based businessman Shahzada Dawood -- the vice-chairman of Karachi headquartered conglomerate Engro -- and his son Suleman; British billionaire Hamish Hardings, and founder of operating company OceanGate Stockton Rush, along with the 77-year-old French explorer Paul-Henri Nargeolet are said to be onboard the craft.