> The sub has already survived multiple dives to 4000 meters, and so far nobody has come out with reports of any apparent problems The goal is to have extremel

> The sub has already survived multiple dives to 4000 meters, and so far nobody has come out with reports of any apparent problems The goal is to have extremely high reliability at the given rating. Not failing for a half dozen trips is nearly meaningless. Safety critical equipment is expected to meet the rated load thousands of times without issue. Using equipment well outside its rated working load, in situation where failures kill people, is highly irresponsible.