Yeah, I had exactly the same thought! If it’s a single hull and not a double hull or something, and that’s the actual inside of the hull we are seeing, how the fuck is that safe? Someone uses too long of a screw and bow you have what, 400 atmospheres of pressure pushing against the presumably sharp point of the screw?

Strain monitoring built into the hull only helps you if you can surface in time once you notice a problem, and not at all if it is a catastrophic failure.