I’ve got my vote for the guy who thought carbon fiber would do great under pressure after being told “no” by tons of experts in the field.
This is a great example of why “It was fine last time.” is not an excepted safety standard in (most) engineering.
The Titan sub was a private vessel hosting visits to the Titanic wreck at $250k per ticket.
Its main cylinder was composed of carbon fiber, which goes against naval engineers’ recommendations that submarines have bodies made of steel (or any material known for its compression strength).
Not only generally, but the owner of the sub was repeatedly warned by engineers that the vessel would not sustain the pressure of the depth they were diving to.