Occupants inside the OceanGate Titan submersible before its demise experienced faulty communications with the crew above the surface of the Atlantic Ocean, with one of their last phrases being transmitted to the world above being, "all good here."

Nearly 15 months after U.K. billionaire Hamish Harding, OceanGate CEO Stockton Rush, father-son pair Shahzada Dawood and Suleman Dawood, and French mariner Paul-Henry Nargeolet, died when the OceanGate Titan submersible imploded on its way down the see the Titanic, the U.S. Coast Guard provided insight into those final moments, during the beginning of a multi-day hearing on the investigation.

The U.S. Coast Guard presented the animation on Monday on the first day of what is expected to be a two-week hearing on the causes of the implosion. 

The five people inside the Titan were communicating via text messages with crew aboard the Polar Prince, a support ship that hauled the submersible to the location of the ill-fated Titanic.

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An image of the Titan tail cone sitting at the bottom of the ocean, as seen in June 2023. (US Coast Guard / Pelagic Research Services)

The Polar Prince set sail on June 16, 2023, at about 9 a.m. local time from St. John’s in Newfoundland, Canada. With the Titan on board, the two vessels reached the location of the Titanic on the morning of June 18.

The submersible began its descent to the Titanic just before 9:20 a.m. that morning, with occupants on both vessels communicating through text messages.

At 9:53 a.m., the Polar Prince asked the crew of the Titan if they could see the Polar Prince on its display inside the submersible. The Titan crew did not respond, and after 15 minutes and six more messages, the crew texted back.

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Coast-Guard-Presentation

The Titan submersible imploded on its way down to see the Titanic, on June 18, 2023. (Coast Guard)

The Polar Prince told the crew of the Titan they needed better communications.

The person responding from the Titan identified himself as "PH," who the Coast Guard believes was Nargeolet.

At that time, the Titan had reached a depth of about 2,275 meters with a pressure of 3,337 psi.

Nargeolet responded to the Polar Prince, "all good here." when asked if they could see the Polar Prince on the display.

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The Titan submersible imploded on its way down to see the Titanic, on June 18, 2023. (Coast Guard)

Communications between the two vessels continued, with the Polar Prince asking about the Titan’s location to the Titanic and with a reminder to write down the location and time when deploying the "niskin bottle."

The crew on the Titan told the crew on the Polar Prince at 10:41 a.m. that they would not be deploying the bottle because it was not cleaned.

At 10:47 a.m., the Titan notified the crew of the Polar Prince that it had dropped two weights.

Moments later, the Titan imploded.

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This file image provided by OceanGate shows the Titan submersible descending into the ocean. (OceanGate Expeditions)

Just before 10:48 a.m., communications and tracking from the submersible to the Polar Prince were lost at a depth of 3,346 meters, the Coast Guard said.

The implosion that morning set off a worldwide debate about the future of private undersea exploration.

The Coast Guard’s report showed the submersible was left exposed to the elements while in storage for seven months in 2022 and 2023, adding that the hull was never reviewed by third parties, as is standard procedure.

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The Titan submersible in the Bahamas in May of 2018. The Titan imploded during a mission to view the Titanic on Monday, June 19, 2023.

The Titan submersible in the Bahamas in May of 2018. The Titan imploded during a mission to view the Titanic on Monday, June 19, 2023. (Becky Kagan Schott)

The unconventional design of the submersible also led to scrutiny from the undersea exploration community.

The first witness to testify during the hearing on Monday was OceanGate’s former engineering director, Tony Nissen, who said he felt rushed to start operations while he worked for the company. Nissen was asked if there was pressure to get the Titan into the water, and he responded, "100%."

The marine board also asked the former engineering director if the pressure compromised safety decisions and testing. After a long pause, Nissen said, "No. … That’s a difficult question to answer, because given infinite time and infinite budget, you could do infinite testing."

In 2018, Nissen testified, the Titan was struck by lightning during a test mission, which may have compromised the hull. Nissen said he was fired in 2019, the same year he refused to let the Titan go to the Titanic. He told Rush the Titan was "not working like we thought it would."

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The port bow railing of the Titanic

FILE PHOTO: The port bow railing of the Titanic lies in 12,600 feet of water about 400 miles east of Nova Scotia as photographed earlier this month as part of a joint scientific and recovery expedition sponsored by the Discovery Channel and RMS Titantic. Scientists plan to illuminate and then raise the hull section of this legendary ocean liner later this month.  (Reuters/File photo/File Photo)

The submersible would later go through additional tests and adjustments before making subsequent dives to the Titanic, Nissen testified. However, he told the panel Monday that he did not trust the operations staff and testified when Rush asked him to pilot the submersible, he said, "I’m not getting in it."

Nissen said Rush could be difficult to work for and was often very concerned with costs and project schedules. Nissen also said Rush would fight for what he wanted, which often changed daily.

"Most people would eventually just back down to Stockton," he said.

The ongoing Marine Board of Investigation is the highest level of marine casualty investigation conducted by the Coast Guard. After its conclusion, recommendations will be submitted to the Coast Guard’s commandant. The National Transportation Safety Board is conducting an investigation, too.

"There are no words to ease the loss endured by the families impacted by this tragic incident," Jason Neubauer of the Coast Guard Office of Investigations, who led the hearing, said. "But we hope that this hearing will help shed light on the cause of the tragedy and prevent anything like this from happening again."

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Stockton Rush OceanGate CEO

Stockton Rush, CEO of OceanGate exhibitions, poses at Times Square in New York, on April 12, 2017. (REUTERS/Shannon Stapleton)

Also scheduled to speak were the company’s former finance director, Bonnie Carl; and former contractor Tym Catterson.

After the Titan lost contact with its support vessel two hours after making its final descent, a massive search and rescue operation ensued, involving rescue ships, planes and other equipment. The search took place about 435 miles south of St. John’s, Newfoundland.

The search for the submersible attracted worldwide attention, as it became increasingly unlikely that anyone could have survived the implosion. Wreckage of the Titan was subsequently found on the ocean floor about 330 yards (300 meters) off the bow of the Titanic, Coast Guard officials said.

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The time frame for the investigation was initially a year, but the inquiry has taken longer. The Coast Guard said in July that the hearing would delve into "all aspects of the loss of the Titan," including both mechanical considerations and compliance with regulations and crewmember qualifications.

The Titan had been making voyages to the Titanic wreckage site going back to 2021.

The Associated Press contributed to this report.