Search for Argentine Sub Enters Critical Phase

U.S. Air Force cargo aircraft prepares to deploy undersea rescue equipment to Argentina (USN)

Published Nov 20, 2017 9:44 PM by The Maritime Executive

On Monday, the Argentine Navy reported that search vessels have picked up what may be a distress signal from the missing submarine ARA San Juan. Two ships identified a sonar signature that could be the sound of tools banging on the submarine's hull.

While it is "intermittent and weak," the signature allowed the Argentine Navy to narrow the search area to a 35-square mile region located about 300 nm off the coast of Patagonia. As many as 20 vessels from the UK, Chile and Argentina are braving 20-foot waves to look for the missing submarine. 

Conditions on scene (Argentine Navy)

However, they may not have much time: spokesman Enrique Balbi told media on Monday that the sub only had about seven days' worth of oxygen on board, and even if it were still functional and traveling below the surface, it would not be able to come up for air because the sea state is too rough. “This phase [of the search] is critical,” said Balbi.

On Monday, the Argentine Navy also provided new information about the last radio contact with the San Juan, which occurred in two calls on November 15. The sub's commanding officer had reported a "failure" or "short circuit" in his vessel's battery system, spokesman Gabriel Galeazzi told media on Monday. Galeazzi said that at the time of contact, the problem was not considered an emergency, and all crewmembers were reported safe. Shoreside commanders instructed the San Juan to head for its home base at Mar del Plata for repairs; however, the vessel lost contact the same day and has not been heard from since. 

In a blow to rescuers’ hopes, a series of seven satellite communication attempts that the Argentine Navy reported on Saturday turned out to be a false alarm. Officials now believe that the calls originated from a ship that was broadcasting on the frequency normally used by the San Juan. 

The U.S. Navy has dispatched two complete sets of submarine rescue equipment to the scene in case the vessel is found. Its San Diego-based Undersea Rescue Command is dispatching two independent rescue systems that are suitable for the variable ocean depths found near South America's southeastern coast. Four cargo planes full of gear for the first system were scheduled to arrive in Argentina on Sunday. 

The first system, the Submarine Rescue Chamber, is a McCann rescue chamber designed during World War II and still used today. It can rescue up to six persons at a time and reach a bottomed submarine at depths of 850 feet. 

The second rescue system, the Pressurized Rescue Module, will be transported by additional flights and is scheduled to arrive in Argentina early next week. It can submerge up to 2,000 feet for docking and mating, with a submarine settled on the ocean floor up to 45-degree angle in both pitch and roll. It can rescue up to 16 personnel at a time. 

Both systems are operated by two crewmembers and mate with the submarine by sealing over the submarine's hatch, allowing sailors to safely transfer to the rescue chamber.