The U.S. Navy deployed several naval and undersea rescue assets over the weekend to help Argentina search for its naval submarine, the A.R.A San Juan  (S-42), in South Atlantic waters.

The U.S. is supporting a request from Argentina’s government for international assistance in the search for the missing submarine and possible rescue of the vessel and crew, if located.

The U.S. Navy’s Undersea Rescue Command (URC) musters the Pressurized Rescue Module (PRM) to support search and rescue efforts for the Argentine Navy submarine ARA San Juan in the south Atlantic Ocean on Nov. 19. (Photo: U.S. Navy)
The U.S. Navy’s Undersea Rescue Command (URC) musters the Pressurized Rescue Module (PRM) to support search and rescue efforts for the Argentine Navy submarine ARA San Juan in the south Atlantic Ocean on Nov. 19. (Photo: U.S. Navy)

The Argentina Navy lost contact with the diesel-electric San Juan last week, with its last confirmed location as 268 miles off Argentina’s south Atlantic Ocean coast on Nov. 15 as it headed to Mar del Plata on the country’s northeastern coast. Since then, the Argentina’s government has requested help from other Navies to find the 44-person vessel.

Deployed U.S. assets thus far include two Undersea Rescue Command (URC) systems, one Bluefin 12D (Deep) unmanned underwater vehicle (UUV), three Iver 580 UUVs, two P-8A Poseidon aircraft, and a NASA P-3 Orion research aircraft.

Three Air Force C-17 Globemaster II and one Air Force C-5 Galaxy cargo aircraft transported the URC’s Submarine Rescue Chamber (SRC) and underwater intervention Remotely Operated Vehicle (ROV) from Miramar to Comodo Rivadavia, Argentina over the weekend.

The second URC system is the Pressurized Rescue Module (PRM), which was expected to arrive in Argentina early this week.

The Navy explained that the SRC is a McCann rescue chamber designed during World War II and can rescue up to six people at a time while reaching submarines at a depth of 850 feet. The PRM can rescue up to 16 people at a time while submerging down to 2,000 feet for docking and mating with a submarine settled on the ocean floor at up to a 45-degree angle in pitch and roll.

Each system is operated by two crew members and makes a seal over a submarine hatch to mate with a submarine and allow sailors to exit the damaged vessel.

Both kinds of deployed UUVs use Side Scan Sonar to search wide areas by creating an image of the sea floor. The Bluefin 12D can travel at 3 knots and a maximum depth of nearly 5,000 feet for 30 hours. The Iver 580s can travel at 2.5 knots down to 325 feet for up to 14 hours.

The San Juan is a TR-1700-class submarine, one of three total submarines in the Argentine Navy. It was built by Germany’s Thyssen Nordseewerke, now a business of ThyssenKrupp AG, and has been in service since 1985. It is over 216 feet long and almost 25 feet wide.

According to Télam, the Argentine government news service, in 2008 the submarine entered into its mid-life repair period for two years of engineering work at the Argentine Industrial Naval Complex (CINAR). The repair work included cutting the San Juan’s hull in half to replace the engines.

On Monday the Argentine Navy said the San Juan reported a short circuit or breakdown in the submarine’s power battery. The submarine’s captain was then ordered to change course and return immediately to Mar del Plata. The search for the ship and its crew was still ongoing as of publication.