The KRI Nanggala 402 Tragedy Indonesia Submarine Warfare Leave a Comment on The KRI Nanggala 402 Tragedy The tragic tale of the Indonesian submarine KRI Nanggala 402. Lost on April 21, 2021, during a torpedo exercise in the Bali Sea. How human error and mechanical failure lead to the loss of 53 souls. (Visited 14 times, 1 visits today)