This is not true either. As the submarine commander interviewed lays out, the testing is done by actual dives, and there is a certification body for it. Almost

This is not true either. As the submarine commander interviewed lays out, the testing is done by actual dives, and there is a certification body for it. Almost every other deep sea exploration submarine is certified. However, getting certified is voluntary. Of course, certifying it just means that independent experts take a look at the design and use sensors during dives. All of these vehicles are experimental. But not even trying is negligent.