The KRI Nanggala (402), also known as Nanggala II, was a Cakra-class Type 209/1300 diesel-electric attack submarine operated by the Indonesian Navy. Built as part of a $625 million deal financed by a West German loan, it was designed by Ingenieurkontor Lübeck and constructed by Howaldtswerke-Deutsche Werft in Kiel, with Ferrostaal handling the sale. Laid down on March 14, 1978, and launched on September 10, 1980, the vessel was commissioned on July 6, 1981, after being tested in West German waters. The submarine measured approximately 59 meters in length, with a beam of about 6.2 meters, and a displacement of around 1,300 tons submerged. Nanggala underwent major refits, notably in 2012 by Daewoo Shipbuilding & Marine Engineering (DSME), which cost over $63 million. The refit modernized its systems, increased its maximum diving depth to 257 meters, and enhanced its weaponry, sonar, and propulsion, boosting its top speed from 21.5 to 25 knots. It was capable of firing four torpedoes simultaneously and launching anti-ship missiles like Exocet or Harpoon. The vessel had a crew capacity of approximately 34, but at the time of sinking, there were 53 personnel onboard, including 49 crew members and 3 weapon specialists. Throughout its service, Nanggala participated in numerous naval exercises and intelligence operations around Indonesia, including in the Indian Ocean, East Timor, and near Ambalat. It also engaged in training and joint drills, such as Passing Exercises with the USS Oklahoma City and Cooperation Afloat Readiness and Training exercises. The submarine's operational history included sinking decommissioned vessels and tracking strategic targets. Tragically, Nanggala sank in April 2021 during a routine torpedo drill in the Bali Sea after losing contact. Debris and oil slicks were found near the last known location, and subsequent underwater scans confirmed the vessel had imploded at a depth of approximately 850 meters, well beyond its crush depth. All 53 personnel onboard perished, and the incident marked a significant loss for Indonesia's naval capabilities. The sinking underscored concerns over aging submarines and maintenance issues, with investigations suggesting possible causes including a power outage or structural failure. The vessel's loss prompted national mourning and posthumous promotions for the crew, highlighting its maritime significance and the ongoing challenges faced by Indonesia's submarine fleet.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.