A former employee of the company behind the doomed Titan submersible has told a public hearing he believed a safety incident was "inevitable" as the firm "bypassed" all standard rules.

OceanGate's former operations director David Lochridge testified to US Coast Guard investigators that he had warned of potential safety problems before he was fired in 2018, but was ignored.

Five people on board the Titan sub died when the experimental deep-sea craft imploded in June 2023 as it began a planned descent to the wreck of the Titanic.

The public hearings began on Monday as part of a two-week inquiry by the US Coast Guard into the disaster. The investigation has been going on for 15 months.

Mr Lochridge's highly anticipated testimony on Tuesday marked his first time speaking out publicly since raising concerns with his former employer.

He was fired from OceanGate and sued by the company for revealing confidential information. He countersued for wrongful dismissal.

A key former employee of the company, he had been asked by the CEO, Stockton Rush, to assemble a quality inspection report in 2018 of the Titan.

US court documents show Mr Lochridge had major concerns with the Titan's design, including the fact it was made from carbon fibre, warning that the material would damage further with every dive.

On Tuesday, he told US Coast Guard investigators the "whole idea" of OceanGate was "to make money".

"There was very little in the way of science," he said.

Mr Lochridge also accused the company and its CEO of "arrogance", saying they refused to work with experts at the University of Washington to develop the Titan submersible and opted to do all the engineering in house.

"They think they could do this on their own without proper engineering support," he said.

He testified his relationship with the company began breaking down in 2016 because he raised concerns about safety, saying he was probably labelled "the troublemaker" for being outspoken.

Mr Lockridge was one of as many as 10 former OceanGate employees, including co-founder Guillermo Sohnlein, and experts in marine safety and undersea exploration expected to speak to the Coast Guard's Marine Board of Investigations (MBI).

On Monday, officials detailed communications between the Titan and its mother ship, the Polar Prince.

It was revealed "all good here" was one of the final messages from the submersible before it imploded.

OceanGate’s former engineering director Tony Nissen told the hearing that he once refused to get into the sub several years before Titan’s last trip.

“‘I’m not getting in it,’” Mr Nissen said he told the company CEO, Rush, also testifying that he had felt pressured to get the vessel ready to dive.

While offering a historical look at the Titan, officials noted it was never subject to third-party testing and had been left exposed to weather and other elements while in storage.

They noted that during 13 dives to the Titanic in 2021 and 2022, the submersible had 118 equipment issues.

Officials also offered a handful of specific examples of submersible failures including its batteries dying and leaving passengers stuck inside for 27 hours.

As well as OceanGate's CEO, British explorer Hamish Harding, veteran French diver Paul Henri Nargeolet, the British-Pakistani businessman Shahzada Dawood and his 19-year-old son Suleman were on board the ship.

OceanGate suspended all exploration and commercial operations following the incident.