ARA San Juan

2017

South Atlantic, hydrogen flash, forty-four Location: South Atlantic, ~270 nmi off San Jorge Gulf · Coordinates: 45.95°S 59.78°W · Casualties: 44 · Survivors: 0 · Depth: 907 m · Cause: battery compartment flood · implosion — Reported a seawater leak into her forward battery compartment on the morning of 15 November 2017. Hours later an acoustic event consistent with a hydrogen explosion or implosion was detected. She was located nearly a year later by Ocean Infinity at 907 metres. · Fate: located 2018 · protected war grave · Type: submarine · TR-1700 class · Tonnage: 2,264 tons · Crew: 44 · Flag: Argentina · Launched: 1983 Argentine TR-1700-class diesel-electric submarine, on patrol off the Patagonian coast. Reported a seawater leak into her forward battery compartment at 07:30 on 15 November 2017; an acoustic event consistent with hydrogen explosion or implosion followed hours later. 44 dead. Located 907 metres down by Ocean Infinity on 17 November 2018, a year to the day after her loss, after a crowdfunded family campaign forced the Argentine Navy's hand. The Vessel The ARA San Juan (S-42) was an Argentine Navy diesel-electric submarine of the TR-1700 class, built at the Thyssen-Nordseewerke yard at Emden, West Germany between 1983 and 1985 and commissioned on 19 November 1985. She was 66 metres long, 2,264 tons surfaced displacement (2,336 tons submerged), and armed with six 21-inch torpedo tubes. Her propulsion was diesel-electric: four diesel engines for surface operation and one main electric motor for submerged operation. The TR-1700 class was a specific German-designed submarine intended for the Argentine Navy's medium-range coastal patrol and territorial-waters mission. Her specific design was sophisticated for a 1980s submarine; her specific operational capability was comparable to contemporary German Type 209 submarines. By 2017, San Juan was 32 years old. The specific maintenance condition of the submarine had been substantially variable; she had completed a major overhaul at the Argentine Navy's Tandanor shipyard in 2013-2014, which had substantially updated her systems but had also been the subject of various specific technical concerns. Her master on her final voyage was Captain Pedro Martín Fernández, 40, a career Argentine Navy submariner. Her complement on 15 November 2017 was 44 officers and enlisted personnel. The Disaster At approximately 11:15 on 15 November 2017, an unexplained acoustic event was recorded by multiple international hydrophone installations in the South Atlantic. The specific acoustic event was located at approximately 46 degrees south, 59 degrees west, approximately 432 kilometres east of Comodoro Rivadavia, Argentina. The specific event was consistent with a catastrophic structural failure or explosion. The ARA San Juan was subsequently established to have sunk at approximately 11:15 on 15 November 2017 at the location of the acoustic event. The specific mechanism of the sinking was subsequently identified as a catastrophic implosion of the submarine's pressure hull at a depth substantially below her operational depth limit. The specific causal chain leading to the implosion was: (i) the initial seawater ingestion through the snorkel system; (ii) the subsequent battery fire in the flooded battery compartment; (iii) the subsequent loss of electric propulsion and buoyancy control; (iv) the progressive uncontrolled descent of the submarine to depths exceeding her design operational limits; (v) the eventual implosion at approximately 900 metres depth. The specific search operation for San Juan was one of the largest international submarine search operations in history. Multiple countries (Argentina, the United States, the United Kingdom, Brazil, Russia, Germany, and others) deployed submarine rescue equipment and search vessels over approximately 2 weeks (15 November through 30