KRI Nanggala (402)

KRI Nanggala (402), also known as Nanggala II, was one of two Cakra-class Type 209/1300 diesel-electric attack submarines of the Indonesian Navy.

Ordered in 1977, Nanggala was launched in 1980 and commissioned in 1981. It conducted intelligence gathering operations in the Indian Ocean and around East Timor and North Kalimantan. It was a participant of the international Cooperation Afloat Readiness and Training naval exercise and conducted a passing exercise with USS Oklahoma City. The vessel underwent major refits by Daewoo Shipbuilding & Marine Engineering (DSME) in 2012 and Indonesian state-owned shipyard PT PAL in 2020.

On 21 April 2021, the ship went missing during a routine exercise in the Bali Sea. It was commanded by Colonel Harry Setyawan, and had 49 crewmembers and 3 weapon specialists on board. The Indonesian Navy, assisted by other countries, conducted a search, and three days later debris was discovered 19 kilometres (12 mi) from the point of last contact, and Nanggala was declared sunk. There were no survivors; all 53 people on board the ship died. On 26 April, the Indonesian government awarded posthumous promotions to everyone aboard the ship.

The cause of the sinking is presumed to be a power outage. Nanggala had experienced outages before but recovered successfully. Lt. Col. Heri Oktavian, who was killed in the incident, had previously voiced his frustrations about the maintenance of the ship; he claimed that the workmanship quality and maintenance services performed by state-owned naval dockyard PT PAL were unsatisfactory.