Stockton Rush, the OceanGate co-founder and CEO behind the doomed Titan submersible, knew it would eventually kill him but kept his venture moving forward because he knew he wouldn't be held accountable, his friend told authorities this week. 

Karl Stanley, of the Honduras-based Roatan Institute of Deepsea Exploration, testified Tuesday before a U.S. Coast Guard panel conducting an inquiry into the June 2023 vessel implosion. 

The disaster happened as the vessel was on its way to the Titanic site. Five people were killed, including Rush.

The Titan imploded less than two hours after beginning its descent toward the wreck site on June 18, 2023.

EERIE VIDEO SHOWS TITAN SUBMERSIBLE TAIL CONE ON OCEAN FLOOR

The Titan submersible is seen underwater

General view of 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)

"He knew that eventually it was going to end like this, and he wasn’t going to be held accountable," Stanley, Rush’s longtime friend, testified Tuesday during the Coast Guard's inquiry into the catastrophe.

"But he was going to be the most famous of all his famous relatives," Stanley said of Rush, a descendant of a pair of Declaration of Independence signers.

Stanley, a submersible expert who knew Rush for 10 years, said he heard cracking sounds during a April 2019 test sea dive on a Titan prototype, as well as other issues like drop weights, in the Bahamas. 

OHIO BILLIONAIRE PLANNING ‘RETURN TO THE TITANIC’ DESPITE DOOMED TITAN SUBMERSIBLE VOYAGE

Stockton Rush’s longtime friend Karl Stanley testified during the hearing.

Rush’s longtime friend Karl Stanley testified during the hearing. (U.S. Coast Guard)

Stanley emailed Rush about his concerns but was brushed off, he said. 

"I felt also, this exchange of emails strained our relationship from what it had been previously," he said. "I felt like I pushed things as far as I could without him telling me to shut up and never talk to him again."

He added that Rush wanted to "leave his mark on history," which prompted him to possibly ignore key problems with the submersible. 

"The definition of an accident is something that happened unexpectedly and by sheer chance," he said at the end of Tuesday's inquiry. "There was nothing unexpected about this. This was expected by everybody that had access to a little bit of information."

Coast Guard members in Titan hearing

Coast Guard members of the investigative board for the Titan marine board formal hearing take an oath inside the Charleston County Council Chambers Monday, Sept. 16, 2024, in North Charleston, S.C. (AP Photo/Mic Smith)

"And I think that if it wasn’t an accident, it then has to be some degree of crime. And if it’s a crime, I think to truly understand it, you need to understand the criminal’s motive. The entire reason this whole operation started was Stockton had a desire to leave his mark on history," Stanley said.

Stanley also said he viewed OceanGate's characterization of paid passengers as "mission specialists" to be an attempt to avoid accountability.

"It's clearly a dodge with trying to get around U.S. regulations with passengers," he said.

Additionally, the company’s "entire business plan made zero sense," Stanley said. He also said he felt the implosion ultimately stemmed from Rush's desire to leave his mark on history.

OCEANGATE CEO CRASHED SUBMERSIBLE INTO SHIPWRECK IN 2016, THREW CONTROLLER AT CREW: EX-EMPLOYEE

Titan-Wreckage-1

The Coast Guard Marine Board of Investigation (MBI) released remotely operated vehicle footage of the Titan submersible’s aft dome, aft ring, hull remnants and carbon fiber debris on the seafloor before upcoming technical testimony for the Titan MBI hearing in North Charleston, South Carolina. (U.S. Coast Guard video courtesy of Pelagic Research Services)

Amber Bay, director of administration for OceanGate, said that the company would not "conduct dives that would be risky just to meet a need."

However, she agreed that the company wanted to deliver for those who paid $250,000 and were encouraged to participate as "mission specialists."

"There definitely was an urgency to deliver on what we had offered and a dedication and perseverance towards that goal," she told the Coast Guard panel.

Titan-Wreckage-2

The Coast Guard Marine Board of Investigation (MBI) releases remotely operated vehicle footage of the Titan submersible’s aft dome, aft ring, hull remnants. (U.S. Coast Guard video courtesy of Pelagic Research Services)

CLICK HERE TO GET THE FOX NEWS APP

Last week, the Coast Guard released video footage of Titan wreckage spread on the ocean floor. Remotely operated vehicle footage shows the submersible’s aft dome, aft ring, hull remnants and carbon fiber debris resting on the bottom of the ocean off Newfoundland, Canada.

Fox News Digital's Greg Wehner as well as The Associated Press contributed to this report.