A former Titan submersible passenger says there were issues onboard with thrusters, computers, and communications during his trip two years ago: It 'needed more time and more work'

• A former passenger on the Titan submersible says it had issues with thrusters, computers, and communications.
• "Expedition Unknown" host Josh Gates said parts of the vessel "needed more time or more work."

A former passenger on the Titan submersible — which went missing Sunday and is now believed to have suffered a "catastrophic implosion" that presumably killed everyone onboard — has detailed issues that the vessel ran into when he was onboard two years ago.

Josh Gates, the host of "Expedition Unknown" on the Discovery Channel, tweeted Wednesday that the Titan "did not perform well" on his dive.

"Ultimately, I walked away from a huge opportunity to film Titanic due to my safety concerns w/ the @OceanGate platform," he tweeted. "There's more to the history and design of Titan that has not been made public - much of it concerning."

OceanGate Expeditions, the company behind the vessel, declined to provide additional comment beyond its statement Thursday that it believes all five passengers "have sadly been lost." Gates did not immediately respond to Insider's requests for comment.

Gates also appeared on "The Today Show" to share more about his experience on the Titan.

"We had issues with thruster control," he said, referring to its propulsion devices. "We had issues with the computers aboard, we had issues with comms. I just felt as though the sub needed more time, and it needed more more testing, frankly."

Gates told "The Today Show" that he traveled with OceanGate for about two or three hours in 2021, while the company was still running tests and before their submersible made its first manned voyage to the wreck of the Titanic later that year.

"I have to say there are aspects of the sub's design that are incredibly impressive," he said on the show. "There were also aspects of it that frankly just seemed like they needed more time or more work."

On Thursday afternoon, the US Coast Guard said they'd found debris that was "consistent with a catastrophic implosion" of the Titan, which was carrying five passengers when it went missing Sunday while en route to the Titanic wreckage.