[anamexis]

Submarines used for commercial use must be certified by DNV according to their safety standards.

It’s not that hard, and in any case complexity does not imply authoritarianism.

[brutusborn]

Then how did this vessel operate without?

To my knowledge DNV certification is part of insurance processes. The crew could have asked for such a certification if they wanted to reduce risk (they definitely had the cash).

[anamexis]

Because it’s not a regulation.