There were plenty of early warning signs. In a previous dive back in 2019 they had professional submersible designer Karl Stanley on board, who later wrote an email to OceanGate about the worrying cracking sounds he heard.
> "What we heard, in my opinion ... sounded like a flaw/defect in one area being acted on by the tremendous pressures and being crushed/damaged," Stanley wrote in the email, a copy of which has been obtained by CNN.
> "From the intensity of the sounds, the fact that they never totally stopped at depth, and the fact that there were sounds at about 300 feet that indicated a relaxing of stored energy /would indicate that there is an area of the hull that is breaking down/ getting spongy,"
It's more impressive that the sub continued to work while giving warning signs for 4 years.
https://abc7.com/titan-submersible-2023-incident-titanic-oce...