For those who have been following this tragic event the following article may be of some interest. As an ex submariner myself - hence the forum handle - my deepest sympathies go out to the family and friends of the crew of that 'boat' who have now crossed the bar. RIP, your duty is now done and may you find safe anchorage.

ANALYSIS OF ACOUSTIC DETECTION OF THE
LOSS OF THE ARGENTINE SUBMARINE SAN JUAN By Bruce Rule

An analytical review of all information released by the Comprehensive Nuclear-Test-Ban Treaty Organization on the acoustic signal associated with the loss of the Argentina Submarine ARA SAN JUAN confirms the following:
That acoustic signal originated near 46-10S, 59-42W at 1358Z (GMT) on 15 November 2017. It was produced by the collapse (implosion) of the ARA SAN JUAN pressure-hull at a depth of 1275-feet. Sea pressure at the collapse depth was 570 PSI. The frequency of the collapse event signal (bubble-pulse) was about 4.4 Hz.
The energy released by the collapse was equal to the explosion of 12,500 pounds of TNT at the depth of 1275-feet. That energy was produced by the nearly instantaneous conversion of potential energy (sea-pressure) to kinetic energy, the motion of the intruding water-ram which entered the SAN JUAN pressure-hull at a speed of about 1800 mph.
The entire pressure-hull was completely destroyed (fragmented/compacted) in about 40 milliseconds (0.040s or 1/25th of a second), the duration of the compression phase of the collapse event which is half the minimum time required for cognitive recognition of an event.
Although the crew may have known collapse was imminent, they never knew it was occurring. They did not drown or experience pain. Death was instantaneous.
The SAN JUAN wreckage sank vertically at an estimated speed between 10 and 13 knots. Bottom impact would not have produced an acoustic event detectable at long range.
The open question is: why was no corrective action - such as blowing ballast - taken by the SAN JUAN crew before the submarine sank to collapse depth? According to Argentine Navy spokesman Gabriel Galeazzi, the Commanding Officer of the SAN JUAN reported a "failure" in the submarine's "battery system," The time of that report was 0730 on 15 November, assumed to have been GMT. Subsequently, the problem was reported to have been "fixed." The SAN JUAN intended to submerged and continued its transit north. The SAN JUAN pressure-hull collapsed at 1358 GMT on 15 November.

In the case of the loss of the US nuclear submarine SCORPION (SSN 589), hydrogen out-gassed by the main battery exploded at 18:20:44 GMT on 22 May 1968 incapacitating/killing the crew with an atmospheric over-pressure in the battery well estimated to have been 7-10 times the fatal value. The pressure-hull was not breached. This assessment was based on analysis of acoustic detections of the event and damage observed in pieces of the fragmented battery recovered from the wreckage at a depth of 11,100 feet by the US submersible TRIESTE, e.g., microscopic, spectrographic and x-ray diffraction analyses. (There was no flooding of the pressure-hull before the battery exploded.)
SCORPION lost power and sank slowly over nearly 22 minutes to collapse at a depth of 1530-feet at 18:42:34 GMT on 22 May 1968.
There is the possibility that a similar sequence of events occurred aboard the SAN JUAN. If the wreck is located and efforts are made to recover components, emphasis should be placed on the battery system.
The author of this assessment was the lead acoustic analyst at the US Office of Naval Intelligence for 42 years, analyzed acoustic detectors of the loss of the USS THRESHER (SSN 593) on 10 April 1963 and testified before that Court of Inquiry. The author expresses his appreciation to those who supported this assessment with research and calculations

So sad.

Fascinating analysis and very tragic. Good to hear they didn't suffer. Thanks for the post.