Missing Indonesian submarine declared sunk, human error ruled out

KRI Nanggala, an Indonesian Navy (TNI-AL) Cakra-class diesel-electric submarine (SSK) that was reported missing in the Bali Sea on 21 April, has been found destroyed into three main parts at a depth of about 830 m, with the service declaring all 53 personnel on board deceased.

TNI-AL chief Admiral Yudo Margono said in a press conference on 25 April that visual confirmation of the boat’s final resting location was obtained using a remotely operated vehicle (ROV) deployed from the Republic of Singapore Navy (RSN) submarine rescue ship M/V Swift Rescue.

Admiral Yudo also told reporters that human error has been ruled out as a contributing factor.

“Based on our initial evaluations, this is not because of human error, but is due to natural factors,” he said, suggesting that the likely cause is due to environmental hazards such as internal solitary waves that have often been recorded in the Bali Sea and Lombok Strait.

The TNI-AL had confirmed the submarine’s status as sunk as early as 24 April, following the recovery of items that evidently originated from within the SSK. These include a bottle of periscope lubricant and escape suit, insulation material from the air-conditioning system, as well as torpedo tube components.

The SSK was first reported missing after it failed to report its status on 21 April.

KRI Nanggala, which entered service in 1981, was originally one of two German-built Type 209/1300-class SSKs operated by the TNI-AL, and. It underwent a major refit by South Korean company Daewoo Shipbuilding and Marine Engineering (DSME) around 2009 to 2012. The improvements included a refurbishment of the boat’s propulsion system, hull scantlings, and combat management system.

It is understood that the TNI-AL plans to eventually recover the boat and the crew’s remains, although the depth of the wreckage site poses a significant challenge and can only be accessed by specialised and expensive salvage equipment.

by Jr Ng