ARA San Juan (S-42)

The search and rescue operation was carried out under the auspices of the International Submarine Escape and Rescue Liaison Office, an organisation of over 40 countries set up in 2003[26] following the Kursk submarine disaster.[27] The search area was 482,507 square kilometres (186,297 sq mi) in size[28] and weather conditions throughout the search and rescue period changed, making the task far more difficult on days with large waves and high winds.[29][30] Search efforts continued several days, without success.

The Argentine ambassador in Austria Rafael Grossi, an expert in security, disarmament and nuclear non-proliferation issues, had the idea to use an international hydrophones network, owned by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, to search for clues about what could have happened with the vessel. He convinced Lassina Zerbo, CTBTO executive director, to order investigations in past records the organization has, looking for anomalies that could help. On 23 November the Argentine Navy said an event consistent with an implosion had been detected[31] at 46.12°S 59.69°W / -46.12; -59.69[32] by the CTBTO listening posts on Ascension Island (HA10) and Crozet Islands (HA04), and records did match with the day the submarine stopped communicating.[33][31][34][35]

By 24 November, the search and rescue operation involved more than 30 aircraft and ships from Argentina, the United Kingdom, Brazil, the United States, Chile and other countries. In all, more than 4,000 personnel from 13 countries assisted the search, scouring an area the size of Spain.[36]

On 27 November, it was revealed to the press that according to the submarine's last report from 15 November, San Juan's snorkel had leaked water into the forward storage batteries the day before, which ignited a fire. After quenching the fire, the crew disconnected the forward batteries. The submarine continued to move powered by the aft batteries.[37]

On 30 November, 15 days after San Juan went missing, the Navy declared that the rescue phase of the operation was over, but the search for the submarine on the seabed would be continuing.[1] The loss of 44 crewmen constitutes the largest loss of life aboard a submarine since the Chinese submarine 361 malfunctioned in April 2003,[38] surpassing the K-152 Nerpa accident of 2008. A criminal investigation was launched into the disappearance.[3]

On 16 November 2018, the remains of ARA San Juan were found at a depth of 907 metres (2,976 ft), at 45°56′59″S 59°46′22″W[18] (20 km or 12 mi NNW from the seismic anomaly previously reported by the CTBTO) and nearly 270 nautical miles (500 km; 310 mi) from Comodoro Rivadavia, by a remote submersible operated by the Norwegian ship Seabed Constructor of the company Ocean Infinity, a private maritime company hired by the Argentine government.[39][40]

It had been considered that the probability of locating the wreck in the area where it was eventually found was 90%, but previous searches failed to find it due to insufficient technology and presence of numerous submarine canyons.[41] A "hydro-acoustic anomaly" consistent with an implosion had been detected 30 nautical miles (56 km; 35 mi) north of the submarine's last known position at 10:31 ART (13:31 UTC) on 15 November 2017. Photographs were released showing the shattered remains of the submarine broken up on the seabed. Ocean Infinity will receive a reward of US$7.5 million for finding the missing vessel.[3][4] Argentine Navy spokesman Captain Jorge Balbi presented close-up photos of the wreck in a press briefing. The pictures show the imploded pressure hull, with the bow section, sail and propellers scattered in an area of 8,000 square metres (86,000 sq ft).[42][43]