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 thecollapse 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 questionis: ... *Why was no corrective action - such as blowing ballast - taken by the *SS SAN JUAN* *crew before the submarine sank to collapse depth?*
According to Argentine Navyspokesman Gabriel Galeazzi, the Commanding Officer of the *SS SAN JUAN* reported a *"failure"* in thesubmarine'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 *SS SAN JUAN* intended to submerged and continued its transit north. The*SS 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.)
*USS SCORPION (SSN)* 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 *SS SAN JUAN*. If the wreck is located and efforts are made to recover components, emphasis should be placed on the battery system.
Lead acoustic analyst at the US Office of Naval Intelligence