The sub went missing while carrying five people to the wreckage of the Titanic.
3 points
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There are some videos online of Delta P and it’s affects. Most are not NSFL, but it illustrate this better below is a video of a railroad tanker car that was drained of liquid but not vented:
https://www.youtube.com/watch?v=Zz95_VvTxZM
That’s at 1ATM maximum. At 13,000ft there 500ATM. A large delta P has no problem pulping just about anything given the chance for catastrophic failure.