Why the Titanic can't be taken out of the ocean floor?/Submarine and Submersible

The luxurious ship, Titanic, had met with her tragic end in 1912, on her maiden voyage, from Southampton (UK) to New York (USA). More than 1500 people died in this giant ship disaster.

• Where is the Titanic now?

It is in the "midnight zone" of the North Atlantic Ocean, about 740km away from the coast of Newfoundland, Canada. The wreckage of the ship is 3.8 km below the surface.

It was first located by the oceanographer Dr. Robert Ballard in 1985 and in 2012,(on the 100th year of the tragedy) UNESCO declared it as World Heritage Site.

• Why can't it be taken out?

The deep ocean is too dark since sunlight is fast absorbed by seawater. Beyond 1000 meters, it is pitch dark and the area is rightly nicknamed as the midnight zone.

It is a herculean task even to reach there. Then, how can the jumbo-sized ship parts to be pulled out? Imagine that an expert team reached the seabed with enough lights and equipment- even then, it is not possible. Because underwater currents are too treacherous. 

Another factor is that the pressure felt on the ocean floor is 390 times higher than the surface! It is really difficult to overcome such pressure and bring up the parts without damage. Moreover, the Western Boundary Undercurrent surrounds the Titanic parts, it causes extra coldness and ripples.

But overcoming all these challenges, a 20 ton, 300sq.ft part of the ship was brought back in 1998.

• Why was the ship not decayed yet?

It is decaying and is predicted to dissolve and disappear completely by 2030. The saline water of the ocean has been gradually eating up the ship. Though underwater currents and microbes have also been attacking the ship constantly, the process was rather slow. But in 2016, scientists discovered that extremophile bacteria have begun to attack the ship and they are notorious for dissolving pounds of iron per day.  

Q. What is the difference between a Submarine and a Submersible?

Ans: Submarines are 'independent' underwater vessels. But Submersibles are 'dependent' watercrafts of a mother ship.

Submersibles are launched underwater from the mother ship for a fixed duration, and they should come back to the vessel in time to re-energize or re-equip themselves. The Submarines, on the other hand, are full-fledged and have a more effective propellant system.