see:
>>19051681 PB
"At the meeting, Lochridge discovered why he had been denied access to the viewport information from the Engineering department – the viewport at the forward of the submersible was only built to a certified pressure of 1,300 meters, although OceanGate intended to take passengers down to depths of 4,000 meters," the lawsuit said. "The paying passengers would not be aware, and would not be informed, of this experimental design, the lack of non-destructive testing of the hull, or that hazardous flammable materials were being used within the submersible."
https://abcnews.go.com/US/lawsuit-alleged-flaws-titanic-submersible-now-missing/story?id=100251012>>19053290