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Anderson Cooper 360 Degrees

Search And Rescue Ships Return To Port; Sub Expert Raised Questions About Possible Defect In Area Of Titan Sub In 2019 E-mail; While OceanGate Touted Safety, Experts Say Some Design Materials Were "Already Large Red Flags"; Russian Generals Accuse Wagner Leader Of Attempting Coup; Wagner's Prigozhin Vows Retaliation After Accusing Russian Military Of Bombing His Forces; Survivors Of Shipwreck With Hundreds Missing Raise Questions About Greek Coast Guard's Account Of Tragedy. Aired 8-9p ET

Aired June 23, 2023 - 20:00   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

ERIN BURNETT, CNN HOST: Where do you still want to go next and dream of going?

VICTOR VESCOVO, SUBMERSIBLE TEST PILOT, FRIEND OF TITAN SUB IMPLOSION VICTIMS: There's still other deep ocean trenches I've not visited, so I'd like to one day visit those as well and there is also going into space. I've done it once and it was an extraordinary experience.

So going into orbit would be a fantastic experience.

BURNETT: As I said, it is amazing even sit here next to someone like you and just imagine how you see the world.

Thank you so much. I appreciate it, Victor.

VESCOVO: Thank you for your time.

BURNETT: And thanks so much to all of you for being with us. AC 360 starts now.

[20:00:27 ]

ANDERSON COOPER, CNN HOST: Good evening from St. John's, Newfoundland.

A lot has occurred since we broadcast from here last night at this time. In fact, right behind me, two of the ships involved in the search for OceanGate's Titan submersible, the Canadian Coast Guard vessel, Terry Fox and another ship, the Skandi Vinland have just now returned here to port. This is them coming in just moments ago.

The Canadian Coast Guard ship, Ann Harvey is expected here within the next hour or so and Titan's support ship, the Polar Prince is due back in here sometime in the overnight or early morning hours.

Polar Prince left here, as you know, a week ago, just today, a week ago today traveling the more than 400 miles to the site of the Titanic disaster. It was to be Titan's first trip of the season down to the Titanic. Polar Prince sails under the Canadian flag and this afternoon, Canada's Transportation Safety Board announced it is launching a probe into the doomed expedition, which resulted to the death of all five people on board.

Also today, the Odysseus 6 remotely operated vehicle which located the wreckage yesterday made another trip to the ocean floor to map out debris fields. The company spokesman saying they expect similar missions to continue searching and mapping out the field, that that's going to continue for at least another week.

However, he said that any attempt to actually recover or bring up anything from the bottom would be a larger operation involving different equipment that's better suited to lifting bigger and heavier objects.

Meantime, a Pentagon official tells CNN's Oren Liebermann that the Navy's deep ocean salvage system, which only got here, Wednesday is being pulled out of the area, as are other navy vessels and equipment. Naval personnel, however, will continue to assist the salvage operation we're told.

Also today, we learned far more about what "Titanic" director and deep sea explorer, James Cameron talked to us about last night on the program, namely, the concerns surrounding Titan's carbon fiber hull, concerns that were raised directly and repeatedly by a number of people to OceanGate's CEO, Stockton Rush who died on the Titan.

We knew last night about a 2018 letter that was drafted by several sub experts, which warned of possible catastrophic outcomes. But tonight, you're going to hear from a man called Karl Stanley, who operates submersibles out of Honduras. He emailed Rush in April of 2019 after diving aboard Titan with Rush and hearing cracking noises that got louder the deeper they went.

In the e-mail, he warned Rush not to give into pressures from investors or others to start taking paying passengers on board. And I'm quoting now from his e-mail that rush received: Imagine this project he said, was self-funded and on your own schedule, would you consider taking dozens of other people to the Titanic before you truly knew the source of those sounds?

Again, he was not alone in his concerns. Joining me tonight, CNN's Miguel Marquez who has been reporting from here all week.

First of all, let's talk a little bit more about the investigation now into the tragedy, what do we know about it?

MIGUEL MARQUEZ, CNN SENIOR NATIONAL CORRESPONDENT: They are scanning the seafloor, and by that, I mean trying to get a very good sense of the debris field. There are five pieces, two debris fields.

They want to take pictures and understand that carbon fiber hull, the titanium, the window, the shape of the vessel, because it blew apart, so it imploded and blew apart, two different debris fields, and they are hoping through pictures to understand in scanning that to understand exactly what the dynamic of that was and if they can learn any from anything from it.

COOPER: Also just the number of warnings that we are now hearing about this sub, and I think we're going to be hearing more about the concerns that were raised and whether or not modifications were made or changes were made.

MARQUEZ: So the 2018 letter -- the sub that that letter was written about was a different sub that went down in the Titan that we know now.

COOPER: And the 2019 letter e-mail as well that we just talked about from Mr. Stanley, that was also now a different sub because he made modifications based on what Stanley said.

MARQUEZ: He made modification. So, we're still learning more. What is not clear, because there are a lot of concerns about the design, about the materials, what is not clear as what OceanGate.

PH Nargeolet, who is a very experienced deep sea diver, he clearly had believed in it. Many people have talked about they believed it was safe and it was sound, but we don't know everything he did to meet those standards in this very serious, very technical community.

COOPER: And not just the initial testing on the design concept, but also just checkup testing after dives and with each season how much -- how rigorous was that, if at all?

MARQUEZ: I think that is the real Achilles heel here, because carbon fiber, because these other materials, they don't know as much about them, dive after dive after dive, what is the stress on that vehicle.

[20:05:04]

COOPER: Yes, Miguel Marquez, appreciate it.

In addition to many questions raised both in retrospect and about -- at the time, about Titan's design and construction, we are also learning about claims that Stockton Rush made about prestigious partners like Boeing, which he said he had.

CNN's Gabe Cohen reports, some of those claims are now coming up short.

(BEGIN VIDEO CLIP)

STOCKTON RUSH, CEO, OCEANGATE EXPEDITION: There are certain things that you want to be buttoned down, so the pressure vessel is not MacGyvered at all, because that's where we work with Boeing and NASA and the University of Washington.

GABE COHEN, CNN CORRESPONDENT (voice over): Stockton Rush defending his design to the Titan, touting impressive partnerships over and over again.

RUSH: We partnered with aerospace experts at the University of Washington, NASA, and Boeing on the design of our hull. COHEN (voice over): And in the 2021 news release, OceanGate credited at least a dozen partners with helping them design, build, and test the structure of the Titan, including its now controversial carbon fiber hull.

But CNN has learned Boeing and the University of Washington are denying partnering on Titan. In a statement UW tells CNN: "The School of Oceanography testing tanks were used by OceanGate, but no UW researchers were involved in any of those tests. And UW personnel did not provide any verification or validation of any OceanGate equipment as a result of those tests."

And the school's Applied Physics lab told CNN, its staff only worked with OceanGate on a different shallow diving steel hulled submersible.

Boeing firmly told CNN the company was not a partner on the Titan and did not design or build it, declining to comment further.

NASA whose collaboration Rush raised frequently told CNN it "consulted on materials and manufacturing processes for the submersible," but "did not conduct testing and manufacturing or any approvals."

Titan was not certified by an independent firm, and in 2019, the company put up a blog post defending that decision. But two months later, after a test dive in the Bahamas, OceanGate publicly raised the name of one of those certification companies saying the dive was validated by a representative from Lloyd's Register.

In a statement, a spokesperson for Lloyds tells me it declined a request to certify Titan after observing the dive and did not go on to class the installation. The spokesperson wouldn't elaborate.

WILL KOHNEN, PRESIDENT AND CEO, HYDROSPACE: A five-passenger submarine with new materials going down to 4,000 meters is extremely challenging, and when I mean extremely challenging, I'm not trying to be hyperbolic over here.

COHEN (voice over): Will Kohnen heads the Submarine Committee at the Marine Technology Society and penned a letter to Stockton Rush in 2018 warning that an experimental approach to Titan could have serious consequences.

COHEN (on camera): Do you feel that it has validated the concerns that you raised in 2018?

KOHNEN: Look, everybody is saying the same thing. Anybody that has gray hair and you're interviewing is going to tell you the same thing. This was preventable.

(END VIDEOTAPE)

COOPER: Gabe Cohen joins us now.

Based on your reporting, I mean, were the passengers on Titan, who were paying a lot of money for this. I mean, were they misled about the safety of the vessel? Did they have all this information? Because the verbiage that was used in partnering with NASA, partnering with Boeing, it certainly leaves the impression that those organizations were deeply involved.

COHEN: Well, Anderson, they certainly didn't have all of this information. Whether or not they were misled, ultimately, that's for others to decide. And in fact, all of these companies and institutions had some connection with OceanGate, but the ones we have spoken with are clearly saying the relationship was different than how OceanGate was characterizing it.

And we have reached out to OceanGate several times about these claims. So far, Anderson, the company just hasn't commented.

COOPER: Gabe Cohen, I appreciate the reporting. Thank you.

We mentioned Karl Stanley and his 2019 e-mail warning to Stockton Rush at the top of the program. I spoke to Mr. Stanley just before air.

(BEGIN VIDEOTAPE)

COOPER: Karl, if you can describe for us what it was like when you were on Titan and the noises that you heard when you went down in it?

KARL STANLEY, SUBMERSIBLE EXPERT: Yes, so Stockton, warned us ahead of time to prepare us. He told us that when he was down there that the submarine had made many loud noises, and that this was to be expected and it was not anywhere close to catastrophic.

He had also tested models at this point and he had -- he knew exactly where the models failed and so I didn't feel that our life was really in grave danger at that point.

I feel the real failure came with cracking over time and also with the joint and water getting in there, and another thing that happened was electrolysis because even though carbon fiber is not a metal, in some ways, it behaves like a metal that it is conductive, so the saltwater in between there and the titanium flange over time would have corroded things and caused even more delamination with the carbon fiber.

[20:10:14]

Unfortunately, I doubt there is enough pieces --

COOPER: You don't think it's a coincidence that this implosion happened on the first dive of the season because of the issue that you just raised. You think it's possible saltwater could have gotten in even from a previous season or a previous dive and just been sitting there the year before.

STANLEY: The year before, it had been working. Yes. Yes.

COOPER: So you heard these noises when you went down with him. You waited a day, you wrote out an e-mail to Stockton Rush and I want to read some of what you wrote in this e-mail once you are back on land.

STANLEY: Okay. COOPER: You said: What we heard in my opinion sounded like a flaw a defect in one area being acted on by the tremendous pressures and being crushed/damage. From the intensity of the sounds, the fact that they never totally stopped at depth, and the fact that there were sounds at about 300 feet that indicated a relaxing of stored energy would indicate that there is an area of the hull that is breaking down, getting spongy.

Can you explain just what do you mean by getting spongy? And also what Stockton Rush's response was to that e-mail?

STANLEY: Well, so I mean, we were actually staying in the same house in Marsh Harbor in the Bahamas during this whole trip and I took a lot of time to kind of digest the whole experience and send him an e-mail specifically, because I didn't want there to be any kind of like heated exchange between us.

I mean, he's not the kind of character that would take criticism very well -- or I wanted to, you know, have him have something that he could refer back to, and that he couldn't just start an argument that he would have to read it, and he didn't respond in writing. We spoke about it. But we didn't speak about it at length, but he did take measures.

He extended -- he pushed -- he canceled that year's dives, and took that carbon fiber tube and cut it up, found the defects and made a new one at the cost, I believe of well over a million dollars. He was making these tubes out of the exact same material that Boeing is making airplanes out of.

I think he actually got the material from Boeing or the same supplier. I mean, he had an over 20-year background in aviation. He was a pilot at 19. He made his own composite airplane, and I feel that's also as a mitigating circumstance in this all is that his background in aviation caused him to have -- he was thinking about it from an aviation standpoint, not -- he switched horses in midstream and continued --

COOPER: You also wrote to him -- the other thing you wrote to him in that e-mail, you said, imagine the project is self-funded and on your own schedule, would you consider taking dozens of other people to the Titanic before you truly knew the source of those sounds?

You knew that he was under, certainly at that time, under pressure, from investors from people, high net worth individuals who wanted to go out and see Titanic.

STANLEY: Yes. He was under a lot of pressure. There were -- I met a lot of the people that were waiting to go, and he kind of brought them out there. So that I mean, they had already given large deposits, and he wanted them to be able to see.

I mean, it was also for them, I think part of the experience and seeing -- you know, they are not just tourists, they are mission specialists, so they are involved in the whole process and they were chomping at the bit. They were just like, when is this going to be ready? When is this going to be ready? And if memory serves me correctly, there was even one person who was terminally ill, and I mean, if he kept delaying it, this person might have died before they even got their chance to go.

COOPER: Mr. Rush told you after -- later on, he told you that there had been a manufacturing defect with the Titan's hull, the Titan that you had been on, and that he made adjustments and made a new hull.

Did you ever find out? Did you have confidence? I mean, did you believe it was the appropriate to be taking passengers down in this vessel?

STANLEY: I felt that -- I saw one interview with James Cameron and he said that, you know, I assumed that somebody here was smarter than me. I assumed that Stockton with his engineering degree, with his large amount of funding from my perspective, and he never got into the nitty-gritty with me about exactly how many model tests he had done, exactly where they failed exactly, but my impression was that he had done enough diligence that lives were not at risk.

[20:15:08]

And the if you tested a couple models and made 30, 40, 50 percent deeper, and you saw over and over exactly how they failed, you already know enough to not dive.

I don't know exactly how -- I don't know the numbers. I never went over all the data and I hope OceanGate -- I hope this doesn't turn into a huge litigation mess. I hope it turns into a learning experience.

COOPER: Karl Stanley, I really appreciate you being with us tonight. Thank you.

STANLEY: Okay, thank you.

(END VIDEOTAPE)

COOPER: CNN reached out to OceanGate about Karl Stanley's claims they said: "We are unable to provide any additional information at this time."

We mentioned that some search and rescue vehicles are returning right now, but there remains activity out of the disaster site.

More on that now with CNN Tom Foreman.

Tom, we talked about the remote -- the underwater remote vehicle earlier. Talk a little bit more about what we know about it.

TOM FOREMAN, CNN CORRESPONDENT: I think, Anderson this may be the most important craft out there over the next week. The Odysseus 6 is operated by Pelagic. This is a real state of the art piece of equipment. It is about the size of a car, it weighs close to 4,000 pounds, seven feet by eight feet by five feet, roughly. It has got seven thrusters on it and this is what it's going to descend all the way down to go to that debris field and start mapping everything out there.

It has got a couple of robotic arms. So, it could pick up things along the way if it wanted to. But mainly, it'll be there to take photographs and video and record where everything is.

There are two debris fields in this area and the Coast Guard made the point of saying they're not in the area of any other Titanic debris, like you have over here near the stern. So they'll have a clean area in which to work.

And they're going to try to record not merely the things that are on the ground, but ultimately, investigators want to be able to get things that might also be floating before they float away, because some of this will be slightly buoyant. So that's the first task. That's why I say this rover, very likely has it work for the next week, as you noted earlier, could be the most important vessel out there.

COOPER: And we saw two ships already coming back. What do we know about other vessels brought in for the search. Are any going to be staying in the search area?

FOREMAN: Well, as you note, Anderson, this really is sort of the great departure. After all of these assets were out there. Earlier on, you saw the mothership for the Titan, the Polar Prince. You mentioned it was coming back in. There is an image of it coming back.

There will be some support that will stay out there to support this mapping, this gathering of evidence out there. It will be very limited compared to what we saw during the search.

COOPER: How do investigators go about piecing together what exactly happened at the sub now? How important is it for them to actually get fragments of the craft back up?

FOREMAN: Well, everything you said so far, Anderson, leads us to why it is important. What they're going to do basically is try as much as they can to gather different parts here. The Coast Guard, NTSB involved now, these agencies are going to say, look, we want to gather all the pieces we can, put it together as best we can so we can see if there are any clues as to what happened here.

And I will tell you, I was talking to two Georgia tech engineers, professors down there, some of the best in the world about this today; one in materials, one in aerospace and both of them said this carbon fiber thing, that may not be the issue, but they say the way this -- all the reports about this are troubling to them for all the reasons you talked about.

Repeated stress, being in the water, possibly becoming delaminated, the glue, it is not the carbon fiber itself, it is the glue, the epoxy that holds a carbon fiber together, that's what gets into trouble and they are looking very hard at that and their own observation of it from afar, I'm sure investigators will look at all of that as they put this together from all these pieces.

COOPER: Tom Foreman, I appreciate it. Thank you.

Coming up next, the former commander of the US submarine fleet on the network of sensors that apparently detected the sounds of Titan imploding.

Also new information about a far greater ocean disaster, the sinking of a fishing trawler in the Mediterranean packed with migrants. The loss of hundreds of lives. The CNN investigation ahead.

(COMMERCIAL BREAK)

[20:22:55]

COOPER: Looking there at the Ann Harvey, the third of three vessels to return within the last hour or so from the search for the Titan submersible which sadly ended with the loss of the sub and all five on board.

The Titan's mothership, Polar Prince is expected back here in the overnight morning hours.

When we first learned that a Navy undersea surveillance network likely picked up sounds of the OceanGate Titan's destruction, it turned a spotlight on a system dating back to the Cold War and the early days with submarine launched ballistic missiles.

In a moment, the former commander of American Submarine Forces joins us, but first, CNN's Oren Liebermann at The Pentagon.

Oren, what do we know about this underwater listening system?

OREN LIEBERMANN, CNN PENTAGON CORRESPONDENT: Well, this is a system the Navy has had in place for decades. It was designed as you pointed out to move and pick up on the movement of enemy submarines.

If you could hear where they are going and sort of triangulate that position, you know, where one of the enemy's key assets is.

Basically, how it works is that sound travels incredibly well underwater, and because of that, if a few of these sensors pick up on a noise, they can triangulate exactly where it is.

For example, if all three picked up on noise at the exact same time, it must be equidistant from the sensors and you'd know where that spot is.

But if it's not, it will take the difference in time to zero in on a location, and that's effectively what happened in this case. They used it to narrow down on the search location. The reason it didn't end the search immediately or to move it from a search and rescue to a recovery is because it was not definitive that audio of the implosion that was picked up by the Navy. They didn't know it was an implosion, though they pass the information on to the Coast Guard.

It was only several days later when an ROV got down there and they got eyes on the debris that they put those two pieces of data together and realized that noise that they'd heard was the implosion of the submersible.

COOPER: How long -- has it ever been used to locate a missing submersible before?

LIEBERMANN: Absolutely, several times in the past, including in some fairly famous cases. Obviously, the implosion of a submarine makes a tremendous noise. So in a very famous example, back in 1968 going back decades here, the Soviets lost a ballistic missile submarine in the Northern Pacific.

[20:25:06]

The US realized this because they saw increased Soviet naval activity and understood that they must be looking for a missing submarine. They went back and looked at the data collected by the system and the different sensors and were able to pinpoint a location and realized that the Soviets were looking in the completely wrong location and that allowed them several years later to actually recover part of a Soviet ballistic missile submarine.

It was considered an intelligence coup, even though the operation itself was only partially successful. But crucially, it started with this same system or an older version of it, I should say, picking up on the sound of the implosion and allowing it to help the Americans zero in on a specific location, just as they did in this case -- Anderson.

COOPER: Oren Liebermann, I appreciate it. Thank you.

Former commander of US Submarine Forces and before that, submarine forces in the Atlantic, retired Vice Admiral Michael Connor certainly knows all about American undersea detection capabilities around the Titanic and though he likely can't go into all the details, we are certainly glad he could join us tonight.

Admiral, thank you so much for being with us. I'm not going to ask you for a lot of details, because I know you won't be able to give them to us, but can you just talk in general about these listening devices?

VICE ADMIRAL MICHAEL CONNOR (RET), US NAVY: Sure, I'm happy to help, Anderson.

I think Oren has it about right. There are systems. They're located in various places around the world that are of interest to the country and they do passively detect noises in the ocean, usually used to classify what's out there and can help in situations like this.

COOPER: We are told that this was determined to be not determinative. And, you know, they didn't know for sure what it was, but that the information was passed on to an incident commander. Do you know who makes the decision of whether or not to release that information in an operation like this?

Because obviously, questions are raised about why they released information about days later about, you know, sounds being heard that raised hopes of that the people were still alive and not release information about, well, there was this other sound, we don't know exactly what it means, but just putting the information out there. Who makes that call?

CONNOR: So there are many parties involved in a search. In a situation like this, they tried to typically flow the information through the incident commander, so the incident commander has best information.

The incident commander, probably made some decisions about how much of the information they had to reveal. In this case, I think, I would suspect, and again, I don't know this for a fact that he found out fairly early in the process that the probability of a catastrophic event was pretty good.

But there's an active search going on and what they probably did with that information was focused the people closest to the Titanic looking on the bottom, and then cover the other situation where maybe the vessel came to the surface and started to drift and they used other assets to continue that search to make a premature and possibly wrong announcement that the sub was lost before you knew that for a fact would only disincentivize a proper search.

And I know that if one of my family members was on there, I would want all efforts exhausted until there was no hope, and I think they achieved basically that result. So I give them credit for the way they did it.

COOPER: As someone who spent their life under the water, I'm wondering what you make of, of this whole sort of, I don't know if tourism industry is the right word, but you know, they called them mission specialists, but people who are able to pay a lot of money to go down and, you know, take this risk.

It seems clearly at this point, a very unregulated as professionals, you know, underwater, former Admiral, what do you make of it?

CONNOR: What's going on here is a very different thing than the way the Navy and most navies would operate. First of all, the depths they are going to are an order of magnitude deeper than what we typically go to and the cost of operating deep are exponentially expensive, exotic materials as you've been being briefed on all evening.

It's a very difficult thing. I think it's a very difficult thing if you're attempting to do it for a profit, and it really probably warrant some pause on what you do, how you do it. What you tell your customers, whether you call them passengers or mission specialists, the net result is about the same.

COOPER: Yes, Vice Admiral Mike Connor, I really appreciate your expertise. Thank you.

CONNOR: You're welcome. Thank you. COOPER: Up next, more on what one expert has called large red flags that she says were apparent in the design materials of the Titan submersible.

There is also breaking news out of Russia, accusations Wagner Group leader, Yevgeny Prigozhin is launching a coup. The FSB is launching a criminal investigation of Prigozhin and there are reports of military vehicles now on the streets of Moscow. The very latest and what we know ahead on the program.

(COMMERCIAL BREAK)

[20:30:00]

COOPER: Looking now live picture of some of the vessels just back from the search area, about 400 miles from the port here in St. John's where the OceanGate Titan imploded and settled. Just short of the wreck of the Titanic, the Titan support ship Polar Prince is expected back in port, in the hours ahead overnight.

Earlier, we spoke with a submersible expert who tried to flag CEO Stockton Rush back in 2019 about what he believed was a potentially dangerous. What he called a flaw in the Titan, that was a different version of the Titan than the one that was now used. He said there were warning signs.

Joining me now is Rachel Lance, who, we talked to earlier in the day. She's an assistant professor at Duke University for hyperbaric medicine and environmental physiology. She's also a biomedical engineer and has said that the vessel's design materials were already known as what she called the large red flags to people.

[20:35:09]

Rachel, I really appreciate you being back with us. Can you just talk about the concerns you had about Titan, particularly what it was made of, not just the carbon, but the epoxy between the layers of it and the attempt to go down to the ruins of the Titanic in a vehicle like this?

RACHEL LANCE, ASSISTANT PROFESSOR, DUKE UNIVERSITY: Yes, of course. So there were two red flags that I had when I first looked at the design of this vessel. And the first one is exactly what you mentioned. It's the fact that a lot of the strength of this pressure hole relied on the material carbon fiber. We know carbon fiber as a lightweight and incredibly strong material that is used for many applications today.

However, once you start putting it into saltwater, it changes its properties. The reason for that is because that saltwater can create and augment what we call galvanic currents, which is basically the traveling of electrons between different types of materials. The carbon fiber gets its strength because these sheets of interwoven threads of long strands of carbon are then alternated with layers of epoxy, and it's this sort of layer cake effect that gives it its Total strength, right? A croissant is neither bread nor butter. It's both. Carbon fiber is neither carbon strings nor just epoxy. It's both. And so when these galvanic currents start to affect the epoxy in between the layers, it starts to break down that layer of glue and those multiple layers of glue in between them, which dramatically reduces its strength.

It is possible to use carbon fiber underwater --

COOPER: And is that --

LANCE: -- people do it for other applications and there are other ways it can go. But when you're dealing with not only repeated pressurization, that will, first of all, weaken the hull over over time, but also at the same time repeated pressurizations in saltwater, you've created kind of a difficult scenario for this material to hold its strength long term.

The fact that it passed the pressure test on the first day is not indicative of the length of time that it would work overall.

COOPER: And if it had been, if it had been rigorously tested over a long period of time, which would be both perhaps prohibitively expensive for for a business application, and also would mean that passengers wouldn't be able to go on for a longer length of time.

But if it had gone through, you know, what others in the industry wanted it to go through in terms of studies testing, stress testing, would the risk of multiple uses over many seasons, that would've been greatly reduced.

LANCE: It would have been reduced by having intermittent testing. It was never a great material choice for a submersible in the first place. Just because this material has been tested before, it has been used before, it has been known to have this property of weakening over time with these repeated immersions.

COOPER: I understand you were also skeptical of the idea that Titan had 96 hours of oxygen on board. Why is that?

LANCE: Well, when we're breathing in an enclosed space, and this is one of the major problems when you have a disabled submarine scenario, you're not only consuming the oxygen in there, but you're also producing carbon dioxide. And it's the carbon dioxide that becomes the problem much more quickly.

As much as we like to think that technology has advanced, and it has in many ways, when it comes to removing carbon dioxide from an area -- from an enclosed area, we actually haven't made that much progress in the past 100 years, and our methods are still the same.

We need a material that looks a lot like kitty litter and there are a couple more advanced methods. But they don't take up a much smaller volume. And in the case of Titan, in order to keep those five passengers alive for 96 hours, they would have needed enough material to fill about half of a standard bathtub. This material then gets insulated, heavily insulated, and needs to also be coordinated with the airflow inside the submarine. And based at least on the publicly available photos, there were no structures attached to this vessel that meet those volume requirements to give those 96 hours.

I would be interested in seeing the internal diagrams for the breathing system by the company, but those have not been released.

COOPER: Yes. Listen, I really appreciate your expertise. Again, thank you so much.

A quick programming note, we'll be doing a special hour on the underwater tragedy, the recovery effort, and the dangers of deep sea exploration. The whole story airs Sunday night at 8:00 p.m. on CNN.

Up next, breaking news tonight to tell you about Russian generals are accusing the volatile leader of the mercenary group, Wagner, of an attempted coup. Yevgeny Prigozhin has vowed retaliation after he says military leaders, Russian military leaders, bombed his forces. Security measures have been stepped up in Moscow itself. We'll have details next.

(COMMERCIAL BREAK)

[20:43:18]

COOPER: Tonight, Russian generals are accusing mercenary leader, Yevgeny Prigozhin of trying to launch a coup. Russia's internal security agency has started a criminal investigation of Yevgeny Prigozhin. Military vehicles have now been reported on the streets of Moscow itself.

All of this in the wake of an alleged Russian attack on Prigozhin's Wagner fighters, in a video, Prigozhin calling for retribution. Now, bear in mind, the two sides of this clash, Prigozhin and many of the Kremlin generals, are supposed to be on the same side and there's no clear indication of where this may be heading.

CNN's Matthew Chance joins us now with the very latest. He's in Kyiv for us tonight. Matthew, this is extraordinary. First of all -- and we've been watching Yevgeny Prigozhin mouth off against Russia's generals and the Kremlin policies in Ukraine for quite some time now. What is he saying now?

MATTHEW CHANCE, CNN SENIOR INTERNATIONAL CORRESPONDENT: Well, I mean, it's been more of the same in the sense that, you know, we've been watching this simmering dispute between Yevgeny Prigozhin, the leader of Wagner and Russia's high command, its defense minister, and its military chief who Prigozhin has, for months, been accusing of incompetence of mishandling the war.

And that's led to various sort of very angry tirades that he's been posting on social media. There was one actually earlier today in which he took a step further and he said, look, you know, the Russian Defense Ministry misled President Putin. And they, you know, sort of lied about the threat that Ukraine posed back in February, 2022, which led to what was essentially an unnecessary invasion.

So he basically challenged the premise of the invasion of Ukraine by Russia, which is, of course, a big no-no as far as the Kremlin's concerned.

[20:45:07]

Within hours of that -- and it's not clear whether it's related -- but within hours of that, Prigozhin was back on social media, absolutely furious and distraught really, because, you know, this camp that he said was run by his mercenary fighters had been struck with artillery or an airstrike, and many people inside, many of his fighters had been killed.

And he was accusing the Russian Defense Ministry of doing that. He's furious, as I say, and he's vowed to kill Russian troops in retaliation for that strike against his own paramilitary forces. That's led to these extraordinary developments of him being accused of launching a coup.

The Russian security services, the FSB and other prosecutors have launched criminal proceedings against him. And so, this incredible tension that we've all been witnessing over the course of the past several months is now coming to ahead, plunging Russia into a very high degree of uncertainty, Anderson.

COOPER: So Matthew, I mean, what are his options? What are -- what power? I mean, obviously, he has Wagner forces, who, I guess, are under his control. I mean, not sure if in the showdown with the Kremlin, who they would side with, but I know he's talked about marching on Moscow. What can he actually do?

CHANCE: I mean, it's -- well, I mean, we're in uncharted waters at this point, but you're right. Yevgeny Prigozhin has about 25,000 men who are, you know, at this point are very battle hardened as well, who apparently, still under his command. Although, of course, when it comes to an order to march against the Russian Defense Ministry, it's not clear how many of them, if any at all, would actually comply with that kind of command.

Certainly, Russian Generals have come out on state media, launching statements on social media as well, sort of demanding that Wagner fighters step back and don't sort of make good on that threat. They've obviously, said they're going to take appropriate action, and I think we all know what that means, if they see there's a threat posed against them.

The latest that we've heard is from Yevgeny Prigozhin himself, who's posted on social media in an audio message, saying that his forces have now begun entering the Southern Russian region of Rostov. Not the city itself yet, but the region. It's the region that one of the regions that borders Ukraine. So they've, obviously, started coming out of Ukraine and heading properly into Russian territory. So the next few hours could really be very crucial.

COOPER: I mean, this is extraordinary. I want to bring in -- stick around Matthew, I want to bring in CNN Military Analyst and Retired Army Lieutenant General Mark Hertling. General Hertling, I don't even know what to ask. What do you make of this? I mean, do -- how serious should Russian generals take Prigozhin? What's to stop them from just taking him out and seeing what the Wagner forces do?

LT. GEN. MARK HERTLING, CNN MILITARY ANALYST: Well, a couple things, Anderson. What I'd say is I've been tracking this for the last couple hours and it's certainly fascinating and it's going to get a little bit sporty here, I think, in the near future because part of Wagner's forces under Prigozhin have allegedly been marching and there seems to be indicators on film of them marching, as Matthew just said, into the southern oblast of Rostov-on-Don.

What's fascinating about that is they are coming off of the front lines in the Donbas and in the southern areas of Kherson and Zaporizhzhia. What is more important is the number of Russian generals to include General Surovikin (ph) who have been on telegram channels, talking about -- telling the Russian, or excuse me, telling the Wagner group soldiers to put down their weapons, get back to the front.

They are at the zero line as Russia likes to call their final defenses, prepared to defend against the Ukrainian attacks, and they're giving them that kind of speech while at the same time, sending these messages on telegram channels. And one of the generals, I'll mention Surovikin (ph) was part of the coup attempt in Moscow as a young officer in 1993.

So he was one of the guys that was put in jail by Yeltsin after the coup attempt or by Gorbachev, when he actually fired on the Russian, Moscow White House, the location of the Parliament. So this is another just kind of the craziness of personalities inside of the Kremlin, inside of the Russian military with these private military organizations that are doing the bidding of Putin and sometime get out of his control.

But it all comes at a very fascinating time when Ukrainian forces are just beginning to gain momentum in their offensive operations in the same locations where Russian troops are needed.

[20:50:10]

So this whole Prigozhin action tonight, and the reaction by the Russian generals are probably -- it's probably causing huge morale problems within the Russian senior military hierarchy, while also confusing the bejesus out of the Russian soldiers on the front lines. Couldn't have happened at a more inopportune time for Russia, but a very opportune time for Ukraine.

One last thing I'll mention, just to throw another wrinkle into this, and Matthew can comment on this. Every military operation that Russia does has an element of what they call maskirovka, our deception. And it's -- you know, the fact that there's so many people on telegram channels and on the internet proclaiming this, could all be a demonstration or a ruse. I doubt it.

I would think that the U.S. White House, and it's been said that they know what's going on and I would almost bet they know more than what the Russians know going on in the southern oblast. They're watching this very closely to see exactly what is imploding and what may not be imploding on the Russian side of the lines tonight.

COOPER: Matthew Chance, what are Ukraine officials saying?

CHANCE: Well, I mean, there, as you can imagine watching this with relish, their official statement is they're watching it closely, but, you know, other Ukrainian officials who have been saying this is, you know, basically Russia imploding.

The best information we have, though, I think that comes from the Russian Defense Ministry itself, who are saying that the Ukrainian forces around Bakhmut, which has been of course, a meat grinder of a battle over the past several months. Ukrainian forces are now, they say, trying to take advantage of the confusion and have launched new offensive in that -- offensives, in that area of the frontline.

And so, yes, it's not an opportune moment for the Russians, but it may be an opportunity for Ukrainian forces to gain some sort of advantage. And there's certainly looking for opportunities like that in this counteroffensive.

COOPER: Yes, Matthew Chance, General Hertling, thank you so much. We'll continue to follow this.

Just ahead also, a CNN investigation about another tragedy of sea, this time off the coast of Greece. Hundreds of migrants are missing after their vessel capsized and sank last week. Survivors who spoke with CNN question the official account of the shipwreck, raising the question of whether the Greek coast guard is actually to blame. Details next.

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[20:55:03]

COOPER: I want to tell you about a CNN investigation as we try to understand how this tragedy on the Titan submersible occurred. Questions are being raised half a world away about how a vessel crammed with more than 700 migrants, capsized and sank in the Mediterranean off the coast of Greece last week.

Now, hundreds of people are still missing. Survivors and their relatives spoke with CNN, say, the fault lies with errors made by the Greek Coast Guard, whose officials deny the charges. Jomana Karadsheh has been investigating the story. Here's her report.

(BEGIN VIDEOTAPE)

JOMANA KARADSHEH, CNN CORRESPONDENT (voice-over): The desperate, exhausting weight for the promise of a new life in Europe. These Pakistanis crammed into a small room by smugglers in Libya. Some of them believed to be among the hundreds presumed dead. These last images before they embarked on their ill-fated journey. About 750 refugees and migrants were packed into this fishing vessel bound for Italy before it capsized off the coast of Greece. Only 104 survived. And with them, the harrowing accounts of what they'd been through.

UNIDENTIFIED MALE (through translator): I can still hear the voice of a woman calling out for help. You would swim and move the floating bodies out of your way.

KARADSHEH (voice-over): The Syrian survivor spoke to us from Greece. He asked for his identity to be concealed for security reasons. His another accounts obtained by CNN not only contradict the official Greek version of events, but point to fault on the part of the Greek Coast Guard.

(on-camera): Greek authorities who watched and were in communication with the boat for an entire day insist that it was not in distress and refused assistance. Our investigation tells a very different story.

(voice-over): Just before 1:00 p.m. on June 13th, the boat was first spotted by the E.U.'s Border Patrol Agency, Frontex, which says it notified Greek authorities of a heavily overcrowded fishing vessel. Those on board were in distress, lost at sea with no food or water for days, according to survivors and activists in touch with the boat throughout the day.

At about 7:00 p.m., an activist in Italy recorded one of the calls, capturing the horror on board.

UNIDENTIFIED FEMALE (through translator): Can I notify the coast guard that six people died.

KARADSHEH (voice-over): As activist repeatedly relayed calls for rescue to authorities, two merchant vessels approached the boat instructed by the Greek Coast Guard to provide the boat with food and water. But as darkness fell at 10:40 p.m., a Greek Coast Guard vessel moves in. Now the only ship on the scene. Three hours later, the haunting last words from the boat to the activist group alarm phone.

"Hello my friend, the ship you send is..." and the line cuts out. What happened next is likely to raise more questions as the investigations continue. Survivors tell us it was a botched attempt by the Greek Coast Guard to tow their boat that caused it to capsize.

UNIDENTIFIED MALE (through translator): They decided to throw us a rope, so the guys at the front tied it. They towed us, the boat tilted to the right, and everyone was screaming. People began falling into the sea and the boat capsized. People couldn't get out from under the boat.

KARADSHEH (voice-over): The Greek Coast Guard have declined our request for an interview, but in previous comments, they've denied towing the troller saying when the boat capsized, "We were not even next to it, how could we be towing it?" Instead, they blamed a, quote, "A shift in weight, probably caused by panic". For years, Greek authorities have been accused of systematically and violently pushing back migrants and refugees. Video like this one released by the Turkish government captured the now well-documented practice. Grace denies.

This deadly incident is not just about what they may have done, it's also about what they didn't do.

VINCENT COCHETEL, UNHCR SPECIAL ENVOY FOR THE CENTRAL MEDITERRANEAN: It was clear it is part of a trafficking movement from Libya to Europe. So the authorities had the responsibility to intervene to save life.

KARADSHEH (voice-over): As Fortress Europe hardens its immigration policies to deter some of the world's most vulnerable, this disaster will almost certainly not be the last.

(END VIDEOTAPE)

COOPER: Jomana Karadsheh joins us now. You mentioned that the Greek authorities have been accused of pushing back migrants and refugees at sea. We saw those videos, how has that impacted other Mediterranean countries?

KARADSHEH: Well, Anderson, for years they've been accused of this practice that they continue to deny despite all the evidence, including this, video and others. But what we are hearing right now over the past few months is this new practice, this pattern that not only Greece but other Mediterranean countries are also accused of.

And it is not just pushing back these boats with migrants and refugees back to international waters or back to Libya, where they had come from, but pushing them forward towards Italy, facilitating their movements by providing them with food, water, and sometimes, fuel and pushing them onwards to Italy. That is dealing with a serious increase in arrivals this year because these countries don't want to deal with rescues and arrivals.

And, of course, the concern is, that this is also putting these vulnerable people, putting their lives at even more risk at sea. Anderson?

COOPER: Yes. Jomana Karadsheh, I appreciate it. Thank you.

Before we go from here in St. John's, I just want to thank the people of St. John's who have welcomed us here and helped us in our work the last few days and all week. I've traveled all over the world, but I've rarely ever met such kind and decent and concerned people as I have in just the last few days here in St. John's.

The news continues. "CNN PRIMETIME" with Kaitlan Collins starts now. Kaitlan?