The co-founder of the company that owned the experimental submersible that imploded en route to the wreckage of the Titanic is scheduled to testify before the US Coast Guard on Monday as part of its investigation of the maritime disaster.

Businessman Guillermo Sohnlein founded Titan owner OceanGate with Stockton Rush, who was among the five people who died when the submersible imploded in June 2023.

The Coast Guard opened a public hearing earlier this month that is part of a high-level investigation into the cause of the implosion.

Mr Sohnlein left the Washington company years ago, but in the aftermath of the submersible’s implosion, he spoke in defence of its efforts.

Titanic Tourist Sub
A June 2023 United States Coast Guard still frame from video provided by Pelagic Research Services of the sub at the bottom of the ocean (US Coast Guard Video courtesy Pelagic Research Services via AP)

In his testimony, he is expected to provide perspective into the company’s inner workings. The public hearing began on September 16 and some of the testimony has focused on the troubled nature of the company.

Earlier in the hearing, former OceanGate operations director David Lochridge said he frequently clashed with Mr Rush and felt the company was committed only to making money.

“The whole idea behind the company was to make money,” Mr Lochridge testified.

“There was very little in the way of science.”

Other witnesses expected to testify on Monday include former OceanGate engineering director Phil Brooks and Roy Thomas of the American Bureau of Shipping.

The hearing is expected to run through Friday and include more witnesses.

During the submersible’s final dive on June 18, 2023, the crew lost contact after an exchange of texts about Titan’s depth and weight as it descended.

The support ship Polar Prince then sent repeated messages asking if Titan could still see the ship on its onboard display.

Titanic Tourist Sub
An illustration of the June 18, 2023 communications between the submersible and the support vessel Polar Prince, not shown, is represented at left (US Coast Guard via AP)

One of the last messages from Titan’s crew to Polar Prince before the submersible imploded stated, “All good here,” according to a visual re-creation presented earlier in the hearing. When the submersible was reported overdue, rescuers rushed ships, planes and other equipment to an area about 435 miles south of St John’s, Newfoundland.

Wreckage of the Titan was subsequently found on the ocean floor about 300 metres off the bow of the Titanic, Coast Guard officials said.

No one on board survived.

OceanGate said it has been fully co-operating with the Coast Guard and all other investigations since they began.

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