Cronkite school of journalism at Arizona state university. Amna: The international effort to find and rescue a missing summer civil is continuing tonight -- submersible is continuing tonight. The U.S. Navy is sending special equipment to help if the craft is found. The challenge is is enormous. Rescuers are racing against the clock and a dwindling oxygen supply to find the submersible lost at sea. U.S. Coast guard officials in Boston updated the public on what they called an incredibly complex operation. >> The coast guard is coordinating search efforts with the u.s.-canadian coast guard, and have searched a combined 7600 square miles, an area larger than the state of Connecticut. Those search efforts have not yielded any results. Amna:amna: For the five passengers on board, time is of the essence. >> We know there are about 40 hours of breathable air left. Amna: Owned by Washington state-based ocean gate expeditions, the vessel, known as the titan, takes passengers into the sea to see wreckage of the titanic. The submersible began its dissent near where the titanic went down around Newfoundland, and all contact was lost about an hour and 45 minutes after it began its dive. No one on the surface knows why. One of the passengers said this year brought "The worst winter in Newfoundland in 20 years, but a weather window just opened up to attempt a dive." Rescuers report that the water in the area is fairly calm, but their search covers a vast expanse of ocean on the surface and below. The titanic upon wreckage rests more than two miles underwater, the equivalent to 10 empire state buildings stacked on top of each other, more than twice the depth of the grand canyon. Those on board include the ocean gate founder and CEO Stockton rush, a british-pakistani executive at one of Pakistan's largest conglomerates, and his son the. Along with a French explorer, director of the company that owns the rights to the titanic's wreckage. If found, it is unclear how or if they could retrieve the vessel. >> We have a group of our nations best experts, and if we get to that point, those experts will look at what the next course of action is. Amna: I am joined by retired U.S. Navy submarine captain David mark eight. You heard what the rescuers are up against. If the vessel has not surfaced somehow, still underwater, how are they carrying out a search like this? >> There are two components to the search. First, the search on the surface of the water. You can cover wide areas with airplanes that fly relatively quickly and have radar. During the daytime, you can use your eyeballs. I am pretty confident if the ship were at the surface, it would've been found by now. Underwater at the depths of the titanic, it is a different story. First of all, you hope that if they were in there and capable, they would be making noises, using piggy owners or underwater telephone or banging on the whole of the summary. We are not hearing that. I am fearful that something catastrophic has happened. When there is an abrupt termination of communication, it would signal multiple systems going down at the same time. Amna: Captain, if they located the vessel, what then? Is there a way to rescue people underwater? >> There is no way to rescue people underwater on this type of ship. What you need to do that is have two ships with the same type of surface that would come together, and the ship, the hatch is bolted on from the outside. The rescue ships that have those kinds of surfaces don't go that deep. We need to get that ship up to the surface. We either glued to use lifting equipment that comes under, like a sled, then inflate and go up, or, we drop a two mile cable with a hook on it. Then we can real it up to the surface. We need to get that equipment to Newfoundland and then on a ship and out to the rack of the titanic, which is 400 miles away. Amna: You can see there is news that leaders in the submersible sent a letter to the CEO expressing concerns that he wasn't sticking to their guidelines, warning of the catastrophic potential ahead. Does it surprise you? >> That was reported in the "New York Times," a remarkable letter. We see this tug with innovation where innovation might get ahead of regulation and the ability of the governing laws, as to how those vessels and how that area should operate, and then it goes back and forth. I admire the spirit of innovation and pushing the boundaries and not wanting to be fettered by rules written in the industrial age, but at the same time, it is people's lives here. We take great care of our submarines. They are designed with multiple redundancies. We will test everything at the dock, and then we go to sea in shallow water, it's a very deliberate process, and it is hard for me to see how a commercial company will have as many resources. It is a very harsh environment. The pressure is 380 times atmospheric pressure down at that depth. Amna: David, captain, thank you for your time.
