Titanic Sub Searchers: Breathable Air Dwindling Fast

If the five people on board the missing Titan submersible are still alive, they have around 40 hours of breathable air left, Coast Guard officials said Tuesday afternoon. US Coast Guard Capt. Jamie Frederick made the estimate at a news conference at 1pm Eastern, saying searches of an area larger than Connecticut "have not yielded any results," the New York Times reports. He said more ships are headed to the area to join the "incredibly complex operation." Asked if the passengers could be rescued, Frederick said next steps would be assessed if the sub is found. "Our nation's best experts" are involved in the operation, he told reporters.

The vessel had a supply of around 96 hours of oxygen when it went missing on a dive to the wreckage of the Titanic Sunday morning. Frederick said he was confident the sub would be found if it is at the ocean surface. If it is on the seabed, there is currently no equipment at the site that could rescue the crew even if they are found alive, the CBC reports. Asked if he believes help will arrive in time, Frederick said: "I don't know the answer to that question. What I will tell you is that we will do everything in our power to effect a rescue." The US and Canadian coast guards are using sonar to try to detect sounds below the surface.

Experts say it's possible the sub became tangled in the wreckage of the Titanic. Alistair Greig, a professor of marine engineering at University College London, says another possibility is a leak in the pressure hull, the Guardian reports. "If it has gone down to the seabed and can’t get back up under its own power, options are very limited,” Greig says. "While the submersible might still be intact, if it is beyond the continental shelf, there are very few vessels that can get that deep, and certainly not divers." Retired US Navy submarine captain David Marquet gives NPR this comparison: "It's basically imagining a spacecraft disappeared on the far side of the moon. A, you have to find it. B, you have to get to it." (More Titanic stories.)