The search for the Titanic sub has to happen so fast that its 'very much like the original sinking of the Titanic where the rescuers just couldn't get to it in time,' ocean explorer says

• Rescuers have struggled to find the lost Titan submersible before it runs out of oxygen.
• An ocean explorer says the race against time is just like the original sinking of the Titanic.

The race against time to search for the lost Titanic submersible is "very much like the original sinking of the Titanic where the rescuers just couldn't get to it in time," an ocean explorer who helped find the wreck says.

Tom Dettweiler — an explorer and engineering consultant whose crew first discovered the Titanic wreckage in 1985 — told CNN that the submersible needs to be found "quite quickly" before its passengers run out of oxygen.

"It's just we are dealing with a long distance and difficult conditions," he explained to CNN. "If you think about it, it is very much like the original sinking of the Titanic where the rescuers just couldn't get to it in time."

The Carpathia, the first ship to come to the Titanic's rescue in 1912, arrived more than 3 hours after the Titanic first hit the iceberg, and more than an hour after the ship's stern finally slipped underwater.

And just like the original sinking 111 years ago, time is of the essence for the rescue of OceanGate's Titan submersible.

Dettweiler told CNN that even if the submersible is found, it would still take hours to bring it to the surface.

"The thing to do would be to bring it up as quickly as possible and open the hatch and get to the people," Dettweiler told CNN. "Unfortunately, it cannot be brought up all that quickly when it is on the end of a cable and dependent on the speed of a winch to bring it up. You're still talking about hours, potentially, to get it up."

Experts believe that the Titan sub may have already run out of oxygen early this morning.