- A former OceanGate consultant said its engineering was "ad-hoc" and "ultimately inappropriate."
- Rob McCallum said it's "incredibly sad" the sub industry was being compared with OceanGate's Titan.
OceanGate's approach to engineering was "ad hoc" and "ultimately inappropriate," a former consultant to the company said.
$4 told Insider that the Titan submersible was an "outlier" as it had been the only non-certified vehicle operating commercially.
"Comparing Titan to the commercial fleet is the same as comparing a home-built go-kart with a Formula 1 car," he said. "The differences in engineering standards are profound."
The $4, who consulted for the company after it was founded in 2009, said it's "incredibly sad" that a sector with an "impeccable" safety record was being tainted by a "home-built" sub.
"This disaster validates the approach the industry has always taken," he said. "It's become evident that OceanGate's approach to ocean engineering was ad hoc and ultimately inappropriate. The people that enabled that culture and now are faced with some need for serious self-reflection."
He said the industry's record "validates" the safety of commercial submersible expeditions as there hadn't been any other fatal incidents in the past 70 years.
McCallum, who founded tour operator $4, previously $4 in 2018 that he was putting passengers in danger because the sub hadn't been independently assessed.
"Until a sub is classed, tested and proven it should not be used for commercial deep dive operations," he told Rush, according to emails seen by BBC News. "I implore you to take every care in your testing and sea trials and to be very, very conservative."
Rush appeared to dismiss his fears and suggested experts were attempting to use $4 to block innovation.
"The Titan disaster verifies and validates the industry's approach to only using classed vehicles," McCallum said Sunday.
The Titan sub was reported missing on June 18. The US Coast Guard said the $4 after a search found debris from the sub on the ocean floor.
US Coast Guard Rear Admiral John Mauger, who led the search, said the debris found was "consistent with the $4 and an implosion.
OceanGate didn't immediately respond to a request for comment from Insider, made outside normal working hours.