Former Titan submersible passenger who took 4 dives in it, including to the Titanic, said communication with the surface ship was lost 'every single time'

• Mike Reiss said there were communication issues on all four dives he took in OceanGate's Titan.
• "I don't blame the submarine as much as I blame deep water," Reiss said.

A former passenger of the Titan submersible said he took four dives in it, including to the Titanic shipwreck, and that there were communication issues on every one of them.

The five people who were on the Titan submersible when it went missing on Sunday are believed to be dead, the Coast Guard said Thursday. Debris found near the Titanic wreck site appeared to be from the vessel, which officials believe experienced a catastrophic implosion.

The Titan went missing Sunday morning after losing communication with its surface vessel less than two hours into the dive. As a submersible, the Titan could not launch and return to port the way a submarine can and instead relied on a surface vessel to carry it to and from the dive spot.

The submersible also relied on the surface ship for navigation, as GPS is not an option 13,000 feet below sea level. The surface vessel sent text messages to people in the submersible, who then used a video-game controller to navigate according to the instructions.

Mike Reiss, a writer and producer for "The Simpsons," took the same voyage to the Titanic with OceanGate Expeditions last year.

"I took four different dives with the company, one to the Titanic and three off of New York City, and communication was lost, at least briefly, every single time," Reiss told CNN on Tuesday. "It just seems baked into the system. I don't blame the submarine as much as I blame deep water, but you would always lose it and come back."

When the 23,000-pound Titan submersible left for its dive to the Titanic on Sunday morning, OceanGate CEO Stockton Rush was one of the five people on board.

The US Coast Guard began its search Monday, at which point officials estimated the submersible, if it was still intact, had around 70 to 96 hours of oxygen left, enough to last until Thursday at the latest.

No signs of the submersible had turned up again until Thursday morning, when debris was discovered by a remotely operated vehicle on the ocean floor.

OceanGate and the Titan have come under scrutiny over safety concerns. Reiss said he knew there was a possibility he would die on his dive to the Titanic and that the waiver he signed beforehand mentioned the possibility of death several times. But he told CNN he did not feel the company acted recklessly.

"There was one dive we took — as soon as communication went out, we went right back to the surface," Reiss said. "We had gone to see a U-boat just off the shore of New York. We saw it for one second, and they said, 'We're going back up. We shouldn't be down here.'

"So they're not hot dogs. They're not daredevils here. They take this very seriously."

Editor's note: This story has been updated.