It was one of two Cakra-class Type 209/1300 diesel-electric attack submarines of the Indonesian Navy. Nanggala was made by the Howaldtswerke shipyard in Kiel, West Germany in 1979, and entered active service in 1981. The submarine conducted operations in the Indian Ocean.
The propulsion system of the KRI Nanggala-402 consists of a low-speed Siemens diesel-electric motor whose labor is directly channeled to the propeller at the stern. The thrust strength is 5,000 ship (shaft horsepower), while the electric batteries weighing about 25 percent of the gross weight of the ship store electric power. Four supercharged MTU diesel engines are responsible for supplying the ship’s electric power.
Nanggala was declared missing on 21 April 2021, hours after losing contact with surface personnel while it was underwater. 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 at a depth of 840 meters in the Bali Sea, into three parts, the hull of the ship, the stern of the ship, and the main parts are all separated, and the loss of all 53 crew members on board was confirmed.