If they all escaped, and are in the water in the South Atlantic, there is a finite time before the cold has it lethal effects. That might answer why, for the moment, the crew might be biding their time in escaping?


@Marcantilian: are you aware of whether or not there is a buoy-borne ELT system equipped on the subs in Argentina for emergencies like this? (The idea being release the buoy, it goes to the surface and then transmits distress signals periodically using salt water battery, sending "last known location" and an alert ... etc ...)

Uh, the crew died because an oxygen generator fell in the water, probably an accident by the crew. So that's not really a reason to delay the rescue.

updated.....

Yes, the submarine has two EPIRB buoys.

Regards,

No it wouldn't. The crew in a submarine are breathing air at 1 atmosphere. The water pressure outside the submarine is 1+(x/10) atm where x is depth in m. So if donning escape breathing gear, an escapee has to be pressurised in a water-lock in a short period of time to outside pressure, then be released to swim free. That is already quite a challenge, even just down to shallow depths. Then there is then the question of what gas they would breathe. Air is only good down to about 40-50m. Most people get gas narcosis (like being drunk) at deeper than 40m, and below 60m the risk of CNS poisoning due to high oxygen partial pressure becomes impossible to manage. Hence the RN SETT tank is only 30m deep because that is the maximum depth escape is realistically possible using air as a breathing gas. From that depth you don't need the bulk and complication of scuba gear - just swim free with the submarine escape apparatus.

Worth pointing out also that SETT training in RN is carried out in warm (above 30 degree) water with good visibility - not conditions which would normally be encountered.

Then it is more than a little worrying that no emergency signal has been detected.

YS

https://www.youtube.com/watch?v=XKNhg7PNBvc

The present system does not use compressed air but works at 1 atmosphere with a suit, tested to 170 mtrs. Compressed air even one breath leaves the victim with a serious risk of decompression sickness (DCS)and unless a chamber is very close potentially killing the survivour. A DCS medical treatment chart asks if the injured party has taken a breath of compressed gas, if not then they do not have a risk of DCS. Decompression chambers are used for diving incidents where the rate of assent is far too quick as in medical emergency or equipment failure. Maximum ascent rate for a recreational scuba diver is 18m/min with a stop of 3 min at 5m or until the air supply is nearly exhausted. Muli gas diving using various combinations of 02 and He is a totally different sport, the same as using rebreather systems.

Think of free divers down to a couple of hundred metres, present record is 214 on one breath. They enter the chamber sealed in a 1 ATM environment and end up on the surface in a 1ATM environment. Free divers descend on a sled attached to a cable and release a balloon to return to the surface. In their case the main daanger is shallow water blackout and hypoxic fitting as the remaining oxygen in the blood is consumed. In this case there is plenty of air in the suit to breathe.

https://www.youtube.com/watch?v=0voNailcOg0

This is the first part of the QED documentary about free diving and the research done at DDRC (Diving Diseases Research Centre) on people who are free divers.

SETT allows training in being able to use the escape systems, suits, lockout etc and as we learnt doing NBC drills to give confidence in the equipment.

As this continues, the hope for survival is growing less. If the worst comes to the worst, in I believe in the submariners world the crew would be forever 'On Patrol'.

In the 'good old days' shipping used 500KHz as a calling frequency but at h+15 and h+45 there was a 'Silence Period' for 3 minutes to ensure any distress traffic could be passed without hindrance and guaranteed(?) reception. Somewhere in the recesses of my mind is mention of another frequency on the lower end of 4MHz which was reserved for 'Sub Sunk' and 'Sub Smash' auto distress (I think - rather vague now).

https://www.theguardian.com/world/20...upply-runs-low

A massive search and rescue operation has intensified to find the Argentinian navy submarine ARA San Juan that went missing six days ago in the South Atlantic.

If the crew are still alive the submarine would only have one day’s worth of oxygen reserves left. If the vessel is found, a submarine rescue chamber (SCR) will be lowered to couple with the vessel’s hatch and bring the crew up to the surface six members at a time.

US rescue equipment and personnel left the Argentinian port of Comodoro Rivadavia on Tuesday heading for the last known location of the San Juan.

The SCR and other equipment left aboard the Skandi Patagonia, an oil exploration vessel hired by the US Navy for the rescue mission, heading for the spot 432km (268 miles) east of the Argentinian coast from where the submarine made its last transmission.

If the vessel is found, the SCR will be lowered down a cable to try to couple up for the rescue.


A total of 49 ships and aircraft from Argentina, the US, the UK, Brazil, Chile and other countries were taking advantage of improved weather conditions to search an area larger than the state of California. More than 100 personnel were participating in the rescue operation, including US and Argentinian navy operatives.

The US navy said it was deploying four unmanned undersea vehicles in the search
.

A large liferaft found in the search area on Monday night, and flares sighted by rescue ships, turned out not to be from the San Juan, the Argentinian navy said on Tuesday. Underwater sounds detected earlier on Monday and seven satellite phone calls that failed to connect on Saturday were not from the missing submarine either, it has been confirmed.

Play Video 1:11
Argentinian navy releases video of search for missing submarine – video
Relatives of the 44 crew members have gathered at the Mar del Plata naval base where the submarine had originally been scheduled to arrive on Monday.

Argentinian flags and signs bearing messages of hope for their loved ones had been attached to the wire fence around the base. “We trust in God,” said one sign.

The families were receiving psychological support from naval doctors at the base.

“We’re grateful for the support,” María Victoria García, the mother of Luis Esteban García, told the TN news station. “I have my sights placed on God and the Virgin Mary asking them to bring him back. I am shouting to the sea to send back my son.”

This is the latest graphic from Argentine MOD depicting search assets, including UK:

http://bucket1.glanacion.com/anexos/...574233h765.jpg

4340 Kilohertz : NATO Combined Submarine Distress frequency

The following request is being shared on radio forums.

https://www.facebook.com/aguaseguras...type=3&theater

That probably explains why the Grauniad was reporting a Royal Navy C-130 being involved.

A truly international search effort. I wish them the best, but the clock is ticking.

Trim Stab,

Thanks for posting the picture of that chart, showing the assets involved in the search. A staggering effort.

I'm interested to know how the search is co-ordinated. Who is the controlling agency - an Argentinian SAR organization or an on-scene commander?

I also couldn't help noticing that a certain group of islands to the south has been extruded from the map and coloured green, to match the treatment of mainland Argentina!

The map's produced by Argentina; since their government maintains a claim on the islands, they could hardly do anything else.

I'm quite confident it won't be a distraction for anyone involved in the SAR operation...

I hope so !

Fingers crossed....

On reading the Daily Mail report that the submarine is only in 230ft (well within the range of competent divers) I became more optimistic that a rescue could be effected, because there would not need to be a long delay getting the USN's specialist ROVs in situ, and because rescue could be effected by divers even if the submarine is lying on it's side.

La Nación is reporting now that of the 44 on board, 6 are "Buzeos tacticos" who are the Argentine equivalent of SBS and who are all highly trained divers, and would be trained in underwater egress from a submarine. I would have thought there would be an escape attempt by them by now, if oxygen levels were critically low, and if the boat really is in 230ft. So maybe oxygen is not yet critical, or else the scenario is bad.

The Argentine Navy are also reporting that the oxygen situation is only an estimate, and that they could have sufficient for ten days (ie another 3). Also, the original electrical fault was caused by a water ingress while operating at snorkel depth.

El problema eléctrico se originó a raíz de una entrada de agua - 22.11.2017 - LA NACION

I see that an RAF A330 is currently (1215Z 22nd) routing over Argentina (passed overhead Buenos Aires about 15 mins ago) at FL400 having left Brize last night at around 2215Z

A very unusual occurence in itself, I suspect must be related to the rescue effort?

Before anyone asks/comments, this is clearly visible in the public domain on FR24!

Meanwhile El Clarín is reporting that the "heat stain" detected by USN could be an old wreck that is not charted, so are expressing caution.

I am not sure what is meant by a "mancha caloricá" as I can't believe that it would be possible to detect a heat source 230ft under the sea, given that water absorbs and diffuses very strongly infra-red radiation. I guess it may mean a magnetic anomaly but has been lost in journalistic translation. Any kipper fleet who might be able to clarify?

https://www.clarin.com/sociedad/ara-...Sk-LlwzeM.html