A pounding sound has been heard in the water at the wreck of the Titanic. It is unclear if it has anything to do with the missing submarine, but it is the only lead the Coast Guard has to go on.
The search operation has been ongoing since Monday and has been reinforced with several resources and international assistance.
Five men are on board the vessel, which was going down to the Titanic. Now time is running out to save them. The oxygen in the submarine is expected to run out at lunchtime on Thursday. However, they have not given up yet, according to the coast guard.