Submarine KRI Nanggala 402 Low-poly 3D model

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. During the exercise, the ship was commanded by Colonel Harry Setyawan, with 49 crewmembers and 3 weapon specialists on board. The Indonesian Navy, assisted by other countries, began to search for the missing ship. On 24 April 2021, three days after the ship lost contact, debris from the ship was discovered 19 kilometres (12 mi) from the point of last contact, and the ship was declared sunk. There were no survivors; all 53 people on board the ship perished. 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. The ship had experienced power outages before but recovered successfully. Lt. Col. Heri Oktavian, who was also killed in the incident, had previously voiced his frustrations about the maintenance status of the ship. Oktavian claimed that the workmanship quality and maintenance services performed by PT PAL are unsatisfactory.