Catastrophic Implosion of a submersible explained:
When a submarine hull collapses, it moves inward at about 1,500 miles per hour - that’s 2,200 feet per second.
The time required for complete collapse is 20 / 2,200 seconds = about 1 millisecond.
A human brain responds instinctually to stimulus at about 25 milliseconds. Human rational response (sense→reason→act) is at best 150 milliseconds.
The air inside a sub has a fairly high concentration of hydrocarbon vapors.
When the hull collapses it behaves like a very large piston on a very large Diesel engine.
The air auto-ignites and an explosion follows the initial rapid implosion. Large blobs of fat (that would be humans) incinerate and are turned to ash and dust quicker than you can blink your eye.
Info Source: Dave Corley, former Nuke sub officer

https://twitter.com/olilondontv/status/1671951053753909255?s=61&t=tYcx9K8IT1b1jHEqELZ4Vg

[–] Entropywins@kbin.social 1 points 1 year ago

Glad they didn't have to suffer

[–] Lantech@kbin.social 1 points 1 year ago (2 children)

unless of course there was some creaking and cracking noises first, then maybe a little spray of water.

[–] phi1997@kbin.social 1 points 1 year ago

That deep? I doubt it

[–] ryknow@sh.itjust.works 0 points 1 year ago (1 children)

At that depth, I feel like creaking and cracking is probably common. However, I don't think there would be any spraying as an indicator. Based on this tweet I saw earlier.

[–] Antik@lemmy.ml 1 points 1 year ago

Yeah but they had to get to that depth. With the pressure gradually increasing, I don't see why it's not possible for them to hear creaking and groaning as the pressure increased, until they eventually reached fatal depth.