November 29, 2017

Water Enters Snorkel, Reaches Batteries, Hydrogen Gas Explodes

Due to the breakdown in the Argentine Navy's public relations process, evidence or rumours (depending on your inclinations) now point to this scenario.

Sea water entered San Juan through its snorkel. see of 28 November 2017

Comment - It is not unusual that a small amount of sea water through its snorkel can enter a submarine. But San Juan's snorkel pumping equipment may have been too old and faulty to remove the seawater before its volume became too much to handle. This has happened before with San Juan, but on 15 November 2015 became catastrophic.

On 15 November 2017 a San Juan crewman reported: "Entry of seawater by ventilation system to battery tank No. 3 caused a short circuit and the beginning of a fire in the balcony of battery bars, bow batteries out of service, at the time of immersion, propelling with a split circuit. I will keep staff informed," of 28 November 2017.

Comment - Seawater in the snorkel system then entered San Juan's ventilation system, then gushed  down to San Juan's batteries level. This seawater-battery contact produced hydrogen gas. Hydrogen gas (once seawater caused electrical sparks ignite it) can then catch fire and explode.



Josh said...


The loss sounds much like the loss of USS Cochino from everything I've heard so far, except with much more tragic results (Cochino benefited from having USS Tusk in attendance).


Anonymous said...

Luckiest sailors in the Argentine Navy:

"Sailor who should have been on doomed Argentinian submarine got off with just seconds to spare - because he needed to do admin for his house purchase"

"News of the miracle escape of one of the San Juan crew comes after it emerged another sailor who was supposed to be on the sub was also spared the fate of his colleagues after getting off the vessel to tend to his ill mother."


Anonymous said...

If the San Juan was lost due to a snorkel failure, it wouldn't be the first time a
Sub had Snorkel issues. The French Daphne class had such problems as well:

"The MINERVE was lost by accident in the Western Mediterranean on 27 January 1968.
The EURYDICE went down in the same area on the 4 March 1970. A third boat was
reputed to nearly been lost through flooding through the snort head valve. This was
caused by the snort head valve being jammed open on lowering by a piece of debris
stuck in it. Subsequently all snort masts of the DAPHNEs were redesigned with a grid
opening around the snort head valve."


Peter Coates said...

Hi Josh

Yes USS Cochino seems a likely precedent. I also looked at

"Her group ran through a violent polar gale off Norway, and the joltings received by Cochino played their part on August 25 [1949] in causing an electrical fire and battery explosion, followed by the generation of both hydrogen and chlorine gases.[9]

Defying the most unfavorable possible weather conditions, Commander (later Rear Admiral) Rafael Celestino Benítez (1917–1999), commanding officer of Cochino, and his men fought for 14 hours to save the submarine, displaying seamanship and courage. But a second battery explosion on August 26 made "Abandon Ship" the only possible order, and Cochino sank. Tusk's crew rescued all of Cochino's men except for Robert Wellington Philo, a civilian engineer. Six sailors from Tusk were lost during the rescue.[10]"

Too bad such help didn't come to ARA San Juan.



vinayk said...

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

Unknelled uncoffined in that watery grave SAN JUAN on eternal patrol. RIP

Peter Coates said...

Thanks vinayk

I see more detail on Bruce Rule's analysis posted a 3rd way down at by "BlackBat242". This is noting "Bruce Rule is a real Sonar analyst, and is in fact a well known expert in the world of sonar analysis".

Links to detail supporting Bruce Rule's account would be handy.