November 19, 2017

Radio Satellite Messages NOT Likely From Submarine San Juan

I indicated  (on 18 November 2017) that submarine ( submarino ) ARA San Juan on 15 November 2017 “Likely Sunk With All Hands”. Despite some announcements from the Argentine Defense Ministry (providing some hope or comfort) it is still likely all or most of the crew have been lost.

The Argentine Defense Ministry reported “We received seven signals from satellite calls that originated from the San Juan submarine... The Defense working with an American company that specializes in satellite communication to determine the exact location of the signals."

The [signals] lasted between four and 36 seconds in the late morning and early afternoon on Saturday ([18 November 2017] local time). Apparently, and so far, these signals failed to establish San Juan’s location.

The US has sent one or two small deep submergence rescue submarine systems (see Photo 2 and Artwork below) to Argentina. These systems must be deployed from specially fitted-out ships to operate in the search area.


As indicated in COMMENTS-1 yesterday Emergency Position Indicator Radio Beacons EPIRBs form one means of search and rescue communication that San Juan likely has/had. San Juan may also have even more effective naval floating rescue buoys which may be attached by thin cable to San Juan and automatically released in the event of a serious accident or sinking. No crewman need be alive to release the buoy that then transmits messages/calls/signals automatically.

An EPIRB (see Photo 1 below) is a type of transmitter which can float. An EPIRB's signals, through satellite triangulation, can provide an approximate or exact location of the people or the craft, who manually or automatically turned on the EPIRB.

However, unfortunately an EPIRB/rescue buoy can float and transmit independently of the fate of San Juan:

-  an EPIRB/rescue buoy may have been automatically released by San Juan as San Juan fatally sunk
-  an EPIRB/rescue buoy would normally be programmed to send out regular distress signals, even if there are no human operators present
maybe it is possible some crew may be floating, maybe with an EPIRB
hopefully there is a thin cable (see Photo 1 below) connecting San Juan to an EPIRB/rescue buoy.
-  Such a thin cable may permit exact location of San Juan even if San Juan is on the seafloor
-  if there is no thin cable an EPIRB/rescue buoy may have floated many miles away from San Juan’s, likely seafloor, location
-  as EPIRBs only cost a few hundred dollars they are very commonly carried by ships and even small fishing boats. So their transmissions may not be related to the fate of San Juan.

[Regarding the final point above, The [UK] Guardian subsequently reported on 21 November, 2017: "None of the communications on Saturday [18 November 2017] were from the San Juan,” [Argentine Navy spokesman Enrique Balbi] told reporters. News of the attempted calls were disclosed on Sunday, but they turned out to be from another ship broadcasting on the same frequency employed by the San Juan, Balbi said."] 

Photo 1 - A floating Emergency Position Indicator Radio Beacon EPIRB used to indicate location of a sailor in a raft. Note the thin cable connecting EPIRB to raft. If an EPIRB (or similar naval floating rescue buoy) is connected to San Juan there may be some hope. (Photo courtesy .

Photo 2 - Heavy US transport aircraft are reportedly delivering submarine rescue systems to Argentina. A remotely operated, deep diving, pressurized rescue module (PRM) may form part of a the San Juan rescue mission (Photo courtesy US Navy via USNI)
Artwork - It is also likely the US Navy has flown Bluefin-21 or similar autonomous underwater vehicles (AUVs) to Argentina to aid in the search for San Juan. AUVs can “see” submarines on the seafloor using side-scan sonar and other sensors. (Image courtesy General Dynamics Marine Systems).

Submarine ARA San Juan was travelling north from Ushuaia to the main submarine base at Mar Del Plata when it vanished (Map courtesy the Daily Mail (Australia Edition).


1 comment:

Anonymous said...

I agree with you that any chance of survival in the very cold and hostile Southern Ocean would be miraculous.