The disaster that occurred in April 2021 with the Indonesian submarine Nanggala-402 in the Bali Sea reminded experts again of the possible role of internal waves in such tragedies. The hypothesis that internal waves could have caused the destruction of the American nuclear submarine, USS Thresher, in April 1963 has been discussed in scientific and popular literature many times.
In an article published by Stepanyants, Y. (2021) on arXiv, the author expresses his own point of view regarding this event, and describes the loss of another American nuclear submarine, USS Scorpion, in the Atlantic in May 1968. There are no convincing explanations for either of the tragic accidents in the official reports. The author explains the physics of internal waves (similar to turbulence in aeroplanes), presents satellite images and instrumental recordings of internal waves, describes their parameters in shallow and deep ocean regions, and show that in many cases, they can manifest as solitary waves of depression.
These solitary waves can attain amplitudes (height of the wave from crest to trough) of 150m or more, and their speed can be two to three m/s [2]. When a submarine enters such a large-amplitude solitary wave, it experiences a deficit of buoyancy and can start sinking. Delay in submarine control can lead to disastrous consequences, especially if the submarine is already near a critical depth. The hydrostatic pressure in water increases at one atmosphere for every 10m descended, reaching 30 atmospheres at 300m depth.
Analysis of the hydrological conditions where the submarines Thresher, Scorpion, and Nanggala-402 perished shows that large-amplitude, solitary internal waves could have been responsible for their destruction. Officially, the Indonesian Navy has admitted this hypothesis. The details on the catastrophic events occurred with the American nuclear submarines and Indonesian diesel submarine can be found in the article by Stepanyants[1].
- Stepanyants, Y. (2021) How internal waves could lead to wreck of American and Indonesian submarines? [online] www.arXiv.org Available at: ArXiv:2107.00828v2 [physics.geo-ph] [Accessed 6 July 2021]
- Apel J., Ostrovsky L.A., Stepanyants Y.A., Lynch J.F. Internal solitons in the ocean and their effect on underwater sound. J. Acoust. Soc. Am., 2007, 121(2) 695–722.