Nanggala was declared missing on 21 April 2021, hours after losing contact with surface personnel while it was underwater. It was in the middle of a torpedo drill in waters north of Bali and had fired a live SUT torpedo before it went missing. The navy estimated that the submarine's oxygen supply would last for about three days, and multiple domestic and international vessels were sent to search for Nanggala.
Three days later, on 24 April, debris from the submarine was found on the surface, and the Indonesian Navy declared Nanggala sunk. The next day, scans positively identified the remains of Nanggala, and the loss of all 53 crew members on board was confirmed. The death of 53 sailors constitutes the largest reported loss of life aboard a submarine since the Chinese submarine Changcheng 361 malfunctioned in April 2003.
The submarine was named after the Nanggala, a powerful, divine short spear wielded by Prabhu Baladewa, a Hindu god mentioned in the Mahabharata and a character in wayang puppet theatre. Legend states that the spear is capable of melting mountains and splitting oceans. The weapon is depicted on the submarine's badge.
The vessel was also known as Nanggala II in order to differentiate it from RI Nanggala (S-02), an older Whiskey-class submarine sharing the same name.
Nanggala was laid down on 14 March 1978 and launched on 10 September 1980. It was tested in West German waters before it was handed over to Indonesia on 6 July 1981.Nanggala left West Germany in early August 1981 with 38 crew members under the command of Lieutenant Colonel Armand Aksyah. The submarine was first presented to the public on the 36th anniversary of the Indonesian National Armed Forces on 5 October 1981. Sixteen days later, it was commissioned by Minister of Defense and Security General M.Jusuf.
During the 1960s, Indonesia was known as one of the largest Asian naval powers, with 12 Soviet-made Whiskey-class submarines in its fleet. However, by 1981, during the Indonesian New Order, when Cakra and Nanggala arrived in Indonesia to reinforce the country's naval defenses, only one of the 12 Whiskey-class submarines had still retained the ability to dive. The Indonesian government had planned to purchase a Type 206A submarine from Germany in the late 1990s, but was unable to do so due to funding issues.
During the beginning of the Reform Era, an embargo on military equipment imposed by the U.S., as well as continuing financial problems experienced as a result of the Asian financial crisis, meant that the Indonesian Navy was unable to procure any additional submarines until 2017. As a result, Cakra and Nanggala were the only active submarines in the Indonesian Navy between the decommissioning of KRI Pasopati in 1994 and the commissioning of KRI Nagapasa in 2017.
By 2020, Indonesia had made plans to own and operate eight submarines by 2024.
The submarine conducted a number of intelligence gathering operations in the waters around Indonesia, including one in the Indian Ocean from April to May 1992, and another around East Timor from August to October 1999, in which the boat tracked the movements of the International Force East Timor as it landed in the region. During May 2005, the submarine was tasked with scouting, infiltrating, and hunting down strategic targets around Ambalat, after Indonesian KRI Tedong Naga [id] and Malaysian KD Rencong were involved in a minor collision near the area.
Nanggala underwent a refit at Howaldtswerke that was completed in 1989. Roughly two decades later, the boat underwent a full refit for two years in South Korea by Daewoo Shipbuilding & Marine Engineering (DSME) that was completed in January 2012.[a] The refit cost US$ 63.7 million, replaced much of the submarine's upper structure, and upgraded its weaponry, sonar, radar, combat control and propulsion systems. After the refit, Nanggala became capable of firing four torpedoes simultaneously at four different targets and launching anti-ship missiles such as Exocet or Harpoon. Its safe diving depth was increased to 257 metres (843 ft), and its top speed was increased from 21.5 knots (39.8 km/h) to 25 knots (46 km/h). Roughly five years later in November 2016, the submarine was equipped with an ASELSAN KULAÇ echosounder system.
The navy announced in a written statement that Nanggala had requested permission to dive to fire a SUT torpedo at 03:00 WIB (20:00 UTC, 20 April). About an hour after being given clearance, the boat lost contact with surface personnel.
According to the navy, at around 04:00, Nanggala should have been flooding its torpedo tubes in preparation for the firing of the torpedo. Indonesian military spokesperson Major GeneralAchmad Riad [id] reported that the last communication with Nanggala was at 04:25, when the commanding officer of the training task force would have authorized the firing of torpedo number 8.Chief of Staff of the Indonesian NavyYudo Margono reported that Nanggala had fired a live torpedo and a practice torpedo before contact was lost.
The navy subsequently sent a distress call to the International Submarine Escape and Rescue Liaison Office at around 09:37 to report the boat as missing and presumably sunk. The navy stated that it was possible that Nanggala experienced a power outage before falling to a depth of 600–700 m (2,000–2,300 ft). Widjojono stated that Nanggala was able to dive to a depth of 500 m (1,600 ft). The deepest areas of the Bali Sea are over 1,500 m (4,900 ft) below sea level.
At the time it went missing, Nanggala had 53 people on board, including 49 crew members, 1 commander, and 3 weapons specialists. The highest-ranking naval officer in the submarine was ColonelHarry Setyawan, the commander of the submarine unit of the 2nd Fleet Command. Subordinates with him were Lieutenant Colonel Heri Oktavian, the commander of the submarine, and Lieutenant Colonel Irfan Suri, an officer from the Weapons Materials and Electronics Service.
At noon on 22 April, Yudo Margono stated that the oxygen reserves on Nanggala would be sufficient for the entire crew and passengers for three days after it had submerged, noting that the oxygen would run out on Saturday, 24 April, at 03:00 (20:00 UTC, 23 April). Submarine experts stated that submarines have backup systems that may provide sufficient oxygen for some time depending on the state of the equipment. Sources in the Indonesian Navy reported that the underwater telephone (UWT) of the submarine was defective during the drill, hampering communications between the boat and rescue vessels in the area.
Around 07:00 on 21 April, an aerial search revealed traces of an oil spill on the surface of the water near the location where the submarine was believed to have dived. Achmad Riad later reported that an oil spill had been observed at multiple locations. He added that Raden Eddy Martadinata had detected movement underwater at a speed of 2.5 knots (4.6 km/h), but was unable to obtain enough information to identify the contact before it disappeared. Yudo Margono also reported on Thursday that an Indonesian naval vessel had detected an object that was magnetic at a depth of 50 to 100 metres (160 to 330 feet).[c]
The location where Nanggala was found
On 24 April 2021, the Indonesian Navy announced the finding of debris, including a part associated with torpedo tubes, a coolant pipe insulator, a bottle of periscope grease, and prayer rugs. Because the debris was found within 10 nmi (19 km; 12 mi) of the point of last contact and no other vessels were believed to be in the area, the debris was believed to have come from the submarine, and Nanggala was declared sunk.[d] Yudo Margono stated that a sonar scan had shown the submarine at a depth of 850 m (2,800 ft), while its crush depth was presumed to be 500 m (1,600 ft).
The navy stated that Nanggala may have experienced a power outage. After the finding of debris from Nanggala, Yudo Margono stated that the submarine may have cracked instead of exploded, as an explosion would have been detected by sonar.
Indonesian People's Representative Council member and retired major general of the Indonesian ArmyTubagus Hasanuddin suspected that the refit, performed by a South Korean firm in 2012, may not have been performed properly. He stated that after the refit, the submarine had failed a torpedo firing test, which resulted in three deaths. Hasanuddin also stated that Nanggala had exceeded its design capacity of 38 with 53 people on board when it sank. Yudo Margono said the boat was combat ready, had received a letter of acceptance, and had a history of successful firing exercises.
Hankook Ilbo reported that submarines must undergo maintenance at least every six years, and that a DSME official had stated that they had not been involved with the submarine since the 2012 refit.
Parliamentarian Utut Adianto stated that Indonesia's defences required modernization, while military analyst Connie Rahakundini Bakrie [id] shared similar concerns.Frans Wuwung, former head of the engine room of Nanggala, stated that despite the submarine's age, its equipment was still in good condition due to proper maintenance, and did not consider such a modernization necessary.
After the navy declared Nanggala lost with all hands, the People's Consultative Assembly recommended a posthumous promotion for all personnel on board. Hadi Tjahjanto stated that he would propose the promotions to Joko Widodo. A day later, on 26 April, Joko Widodo announced that the government would award a posthumous promotion and confer posthumously the Bintang Jalasena 'Navy Meritorious Service Star' to everyone on board Nanggala.
Tubagus Hasanuddin recommended that the Indonesian Navy's remaining Cakra-class submarine be taken out of service.
During the search, use of the hashtag #PrayForKRINanggala402 and #KRINanggala402 became popular on Twitter. After Nanggala had been declared sunk, the phrases "On Eternal Patrol" and "Rest In Peace", and the motto Wira Ananta Rudira 'Steadfast to the End', used by the submarine unit to which Nanggala belonged, saw increased usage.
Lt. Col Heri Oktavian (left) and Colonel Harry Setyawan, commanders aboard Nanggala when it sank in 2021