What we know about the internal waves that may have sunk Indonesia’s submarine

Last week an Indonesian submarine cruised through the Lombok Strait between the islands of Bali and Lombok to carry out routine testing. 

But in the early hours of April 21, the 44 year-old KRI Nanggala 402 submarine dropped out of contact and plummeted 838 metres to the ocean floor, taking 53 crew members with it.

Indonesian military officials found the sunken vessel broken into three parts on the bottom of the Bali Sea. 

While some speculated that the submarine was hit by a foreign missile or a power blackout, Indonesian authorities now suspect the submarine was pulled under by a powerful underwater current called an internal solitary wave.

Hold on … an internal solitary what?

The ocean is in a constant state of motion with the…