The Indonesian Navy submarine Nanggala has been reported missing some 50 miles off Bali. Nanggala was engaged in support of an Indonesian Navy drill when it failed to report yesterday morning. The submarine, a 40-year-old German-built Type 209 boat, was carrying a crew of 53 when it went missing. An Indonesia Navy task force has begun to search for the submarine, and Indonesia has called for assistance from both Singapore and Australia. Unfortunately, the submarine went missing in an area of seafloor depth up to 700 meters, well below the rated crush depth of the boat.
Nanggala is a Cakra-class submarine, a variant of the ubiquitous German Type 209 boats. It was ordered in 1977 and delivered in 1981. Nanggala received refits in Germany in 1989 and in South Korea in 2012, the latter resulting in a substantial upgrade to its combat systems. Type 209 submarines have been exported extensively around the world, with a series of modifications and upgrades allowing them to keep pace with contemporary submarine developments. Sixty-one boats of various generations have been built in Germany and elsewhere, with more than 50 submarines remaining in service. If not successfully recovered, Nanggala would be the first Type 209 submarine to be lost in operational service.
There are as of yet no details regarding any mechanical problems reported by Nanggala. The last major submarine accident involved the loss of the Argentinian navy boat ARA San Juan in November 2017. The San Juan was also constructed in Germany, and was a rough contemporary to the Nanggala, albeit to a modified design. The San Juan was lost with its crew of 44 because of a battery failure compounded by an onboard fire. A major international rescue effort failed to find the submarine, which had imploded after sinking beneath its rated crush depth.
The Indonesian Navy has embarked on a significant effort to upgrade its submarine force in recent years, including the acquisition of three Nagapasa-class boats from South Korea since 2017. The Nagapasa class is itself an upgraded version of the Type 209, license built in Korean yards with the integration of Korean technologies, part of a broader pattern of military cooperation between Indonesia and the Republic of Korea. South Korea is expected to deliver three more Nagapasa-class boats in the next few years. It is uncertain at this point what effect the loss of Nanggala, if it is not recovered, might have on these upgrade plans.