> Clearly the sub wasn’t safe enough, but I’m not seeing anything that makes it obviously badly built. A lot of this is bewilderment at the choice of carbon fi

> Clearly the sub wasn’t safe enough, but I’m not seeing anything that makes it obviously badly built. A lot of this is bewilderment at the choice of carbon fibre for the pressure vessel, which is sensitive to impact damage and wear from repeated load cycles, damage is hard to diagnose, and as it's very brittle, prone to catastrophic failure. It's not commonly used for this sort of application, and there may not be good data on (1) when it would eventually fail and (2) whether you'd be able to tell before use. As I understand, the choice was motivated by wanting the sub to have the large interior space necessary to bring along that many passengers. Deepsea subs usually don't attempt that either.