Last year, a purported transcript of communications between the Titan submersible and its mother ship circulated widely on the internet. Viewed millions of times, the so-called log suggested that a series of alarms had turned a dive to the resting place of the Titanic into a heart-pounding crisis in which the five voyagers struggled in vain to return to the surface.

But the head of the U.S. federal government team investigating the disaster said the entire transcript is a fiction. After nearly a year of investigation, his group has found no signs that the five voyagers aboard the Titan had any warning of the catastrophic implosion that was to take their lives. Two miles down, where seawater exerts vast pressures, an implosion would have made the violent collapse of the vehicle’s hull instantaneous.

“I’m confident it’s a false transcript,” said Capt. Jason D. Neubauer, who retired from the U.S. Coast Guard and serves as chair of the Marine Board of Investigation, the agency’s highest level of inquiry. “It was made up.” Its authorship is not known.

Despite the log’s air of authenticity, the federal team saw through the pretense for a variety of reasons. Significantly, Neubauer’s team gained access to the records of the actual communications between the submersible and its mother ship, which remain an undisclosed part of the federal investigation.

He said that his team, aided by investigators from the National Transportation Safety Board, had “found no evidence” that Titan’s voyagers had any awareness of the imminent implosion or their fate.

His hope, Neubauer added, is that the truth will console relatives concerned that the five men inside the Titan may have suffered in their last moments.

The investigator’s disclosures are the first to emerge from a comprehensive inquiry begun last summer into the disaster and its causes. While there were expectations that the investigation would be concluded before the anniversary of the Titan’s destruction, a mix of technical and jurisdictional complexities mean that a final report could take years.

The five men aboard the submersible were Shahzada Dawood, 48, a British Pakistani businessperson; his son, Suleman, 19; Hamish Harding, 58, a British airline executive; Paul-Henri Nargeolet, 77, a French Titanic authority; and Stockton Rush, 61, a founder and CEO of OceanGate, the U.S. firm that built the submersible and ran its tourist dives. He was also the Titan’s pilot that day.

For years, starting in 2018, Rush brushed aside warnings that the sub’s maverick design was destined to fail. An OceanGate waiver for would-be passengers posted by the website Business Insider said that the “experimental” craft had plunged beneath the waves some 90 times and succeeded in reaching the depth of the Titanic on 13 dives.

The Titan calamity began June 18, 2023, when the craft was reported missing in the North Atlantic. On June 22, the Coast Guard, citing the discovery of debris from the Titan near the Titanic’s resting place, announced that the submersible had suffered a “catastrophic implosion.”

During the five tense days, a fleet of international vessels searched for the lost craft, raising hopes that the Titan voyagers were somehow alive but trapped in an increasingly grim crisis 2 miles down.

News reports asked how much oxygen might be left in the submersible’s life-support system. Underwater banging noises were also detected. Some analysts suggested that survivors in the lost submersible were desperately trying to signal their location in hopes of rescue.

The Coast Guard’s implosion announcement brought the survival narrative to an end. Public speculation in the following weeks turned to what might have gone wrong during Titan’s last minutes June 18.

The transcript apparently began circulating on the internet in late June and offered a minute-by-minute report rich in technical details. It recounted specialized Titan acronyms, the first name of a mother ship expert and credible depictions of the submersible’s descent. In short, the detailed report had an air of authenticity.

“Somebody did it well enough to make it look plausible,” Neubauer said. The log made the adventurers “look like they were panicking,” he added.

The maker of a YouTube video that has nearly 7 million views said in his line-by-line commentary on the fake log: “It’s just so scary to know that these guys spent 20 minutes in fear of their lives.”

The faux crisis centered on what the transcript called the RTM — short for Real Time Hull Health Monitoring system. OceanGate had hailed the proprietary system as “an unparalleled safety feature that assesses the integrity of the hull throughout every dive.” The network of sensors could — in theory — warn that the hull was failing and give the pilot enough time to escape the crushing pressures of the deep. Doubters of the system called it fake reassurance.

The bogus transcript told of Titan informing its mother ship of a series of hull alarms, as well as reports of crackling noises. Titan’s last purported message about the hull sensors read: “RTM alert active all red.”

The fake transcript ended on a troubling note of silence, as the mother ship sent seven terse messages inquiring about the submersible’s fate but received no replies. “Please respond if you’re able,” the purported last message read.

In an interview, Alfred S. McLaren, a retired Navy submariner, submersible pilot and president emeritus of the Explorers Club, said that he had found the transcript credible. “It makes sense,” he said. “It seems on the money” in terms of how Titan and its mother ship would have communicated.

Told in an subsequent interview of the Coast Guard refutation, McLaren speculated on the fraud’s motive. “It may have been done to embarrass OceanGate,” he said. “It certainly was guaranteed to stir up the relatives.”

In the interview, Neubauer told not only of his team’s dismissal of the transcript’s authenticity but how the investigation was one of the most complex he had ever encountered over the decades. Complicating factors, he said, included the lack of witnesses to the disaster, a wealth of novel vessel technologies, the need to test exotic materials and to extract data from electronic devices, and the disaster’s site off Canada in international waters, creating jurisdictional issues.

The dive itself illustrates the tangles. OceanGate was based in Everett, Washington, but its mother ship, the Polar Prince, was from Canada, and the five people aboard the submersible were citizens of England, Pakistan, France and the United States.

As a result, the Coast Guard investigation has many partners — not just the U.S. National Transportation Safety Board but also similar bodies in Canada, France and the United Kingdom. The agency relies on the U.S. Navy to recover debris from the accident site.

The multitude of angles and investigators, Neubauer said, has made some aspects of the inquiry more difficult than expected and pushed back its completion date.

The inquiry officially began June 23, the day after the implosion announcement, and its convening notice called for a finished report in a year. However, Neubauer said, a major report typically takes two or three years to complete. He suggested that the Titan inquiry would probably follow the same pattern.

Despite the time and effort, Neubauer said, he valued such investigations because the findings regularly get turned into new laws, rules and regulations that improve vessel safety.

Neubauer added that the friends and families of Titan’s victims might take comfort in knowing that such disasters have silver linings.

“It doesn’t make it any less painful,” he said. “But it can help.”

The New York Times News Service