One of last messages from doomed Titan submersible is revealed

Among the last words heard from the crew of an experimental submersible headed for the wreck of the Titanic were "all good here," according to a visual re-creation of the journey of the Titan before it imploded , killing all five on board. Meanwhile, the lead engineer for the submersible testified Monday that he felt pressured to get the vessel ready to dive and refused to pilot it for a journey several years earlier.

The U.S. Coast Guard presented an animation Monday on the first day of what is expected to be a two-week hearing on the causes of the implosion. Crew aboard the Titan were communicating via text messages with staff aboard the support ship Polar Prince, according to the presentation.

The crew lost contac t after an exchange of texts about the submersible's depth and weight as it descended. The Polar Prince then sent repeated messages asking if the Titan could still see the ship on its onboard display. One of Titan's final responses, which became spotty as it descended, was "all good here."

The Titan imploded on June 18, 2023, setting off a worldwide debate about the future of private undersea exploration.

The Titan was left exposed to the elements while in storage for seven months in 2022 and 2023, Coast Guard representatives said in their initial remarks Monday. The hull was also never reviewed by any third parties as is standard procedure, they said. That and the submersible's unconventional design subjected the Titan to scrutiny in the undersea exploration community.

The ongoing Marine Board of Investigation is the highest level of marine casualty investigation conducted by the Coast Guard. When the hearing concludes, recommendations will be submitted to the Coast Guard's commandant. The National Transportation Safety Board is also conducting an investigation.

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

Among those killed was Stockton Rush , co-founder of OceanGate, the Washington state company that owned the Titan. The company suspended operations after the implosion.

The hearing's first witness, OceanGate's former engineering director, Tony Nissen, testified Monday that he felt rushed to start operations during his time with the company. When asked if there was pressure to get the Titan into the water, he responded "100%."

The marine board also asked Nissen if he felt that the pressure compromised safety decisions and testing. After a long pause, he responded, "No. ... That's a difficult question to answer, because given infinite time and infinite budget, you could do infinite testing."

Nissen also noted that the Titan was struck by lightning during a test mission in 2018, and that might have compromised its hull. He said he was fired in 2019, the same year he wouldn't let the submersible go to the Titanic. He said he also told Rush the Titan was "not working like we thought it would."

The former engineering director said the submersible later went through other tests and adjustments before its subsequent dives to the Titanic. However, he said he didn't trust the operations staff and testified that when Stockton asked him to pilot the submersible, he replied: "I'm not getting in it."

Rush could be difficult to work for and was often very concerned with costs and project schedules, among other issues, Nissen testified. He said Rush would fight for what he wanted, which often changed day to day. He added that he tried to keep his clashes with Rush behind closed doors so that others in the company wouldn't be aware.

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

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

Some key OceanGate representatives are not scheduled to testify. They include Rush's widow, Wendy Rush, who was the company's communications director.

The Coast Guard does not comment on the reasons for not calling specific individuals to a particular hearing during ongoing investigations, said Melissa Leake, a spokesperson for the Coast Guard. She added that it's common for a Marine Board of Investigation to "hold multiple hearing sessions or conduct additional witness depositions for complex cases."

Scheduled to appear later in the hearing are OceanGate co-founder Guillermo Sohnlein; former operations director, David Lochridge; and former scientific director, Steven Ross, according to a list compiled by the Coast Guard. Numerous guard officials, scientists, and government and industry officials are also expected to testify. The U.S. Coast Guard subpoenaed witnesses who were not government employees, Leake said.

OceanGate has no full-time employees at this time but will be represented by an attorney during the hearing, the company said in a statement. The company has been fully cooperating with the Coast Guard and National Transportation Safety Board investigations since they began, the statement said.

The implosion also killed veteran Titanic explorer Paul-Henri Nargeolet; two members of a prominent Pakistani family, Shahzada Dawood and his 19-year-old son Suleman Dawood; and British adventurer Hamish Harding.

Last month, Nargeolet's family filed a $50 million wrongful death lawsuit against OceanGate. Known as "Mr. Titanic," Nargeolet participated in 37 dives to the Titanic site, the most of any diver in the world, according to the lawsuit.

Attorneys for his estate said in an emailed statement that the "doomed submersible" had a "troubled history," and that OceanGate failed to disclose key facts about the vessel and its durability.

The Titan lost contact with its support vessel about two hours after it made its final dive later. When it was reported overdue, rescuers rushed ships, planes and other equipment to an area 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 off the bow of the Titanic, Coast Guard officials said.

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 as well as compliance with regulations and crewmember qualifications.

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

Earlier this month, striking new images from a recent expedition to the Titanic wreckage show the decay on the iconic ship's bow with a large section of railing now on the sea floor, as well as the discovery of a bronze statue from the ship that was feared lost forever.

Tomasina Ray, director of collections at RMS Titanic Inc., told CBS News partner BBC that the discovery was a "reminder of the deterioration that's happening every day" at the wreck.

"People ask all the time: 'How long is Titanic going to be there?' We just don't know but we're watching it in real time," she added.

Editor's Note: This story has been edited to clarify that "all good here" was one of the last things heard from the submersible, not necessarily the very last thing heard.