No stoic quote for this post.
Just a quick note here: The above Indonesian submarine appears to have sunk, taking 53 souls with her to the bottom. Fifty three more men on eternal patrol :(
The news report says that the ship went down in 600-700 meter deep water, which would be right at the crush depth of a very robust military submarine. Test depth is believed to be just 250 meters for this ship, and so it's unlikely that there are survivors. An oil slick has developed, which is likely propulsion lubricants or diesel fuel from ruptured tanks, indicating that the hull was likely breached.
Sad business, and a terrible way to exit this sorry world. Rest in peace, brothers.
https://www.abc.net.au/news/2021-04-22/australia-defence-help-rescue-mission-indonesian-submarine-crew/100087082
UPDATE 4-22-21
The approximate location of the missing submarine has been released. Maps are provided below.
Below: The red pin is Bali, Indonesia. The large island on the right is New Guinea, and the continent at the bottom is the Northern part of Australia. The string of islands going left to right and the large one up top belong to Indonesia
Below: The sub is believed to lie a short distance North of the island of Bali.
The news articles state that search teams have found a magnetic signature - possibly the submarine - in 100-150 meters of water, and also mention that air for the crew will run out in approximately 24 hours. This clashes with other reports that the sub went down in 600-700 meter deep water. There is nothing wrong with haste in attempting to locate and rescue any possible survivors, but I'm not optimistic about that at all. A realistic assessment would probably conclude that the entire crew passed. Sad tidings.
Update 7 May 2021
The wreckage of Nanggala-402 has been located, at the coordinates 7°48′56″S 114°51′20″E. You can find images of the wreckage elsewhere on the internet, but not on my blog. Out of respect for the crew and their families, I will not post those.
She was lost during a live-fire military practice exercise, similar to what the Russian submarine Kursk was doing when it was lost. Kursk was lost when a warhead is believed to have exploded in the torpedo room - but it is still unclear what caused Nanggala to be lost.
One current theory is that the submarine lost all electrical power. My problem with this theory is that even if a submarine loses electrical power, the crew can still blow the ballast tanks to gain buoyancy and emergency surface. Whatever the event was, it probably happened very quickly, or the crew would have been able to save the ship.
China has offered assistance to Indonesia, and perhaps even raise the wreckage. The ship has broken into three sections, and it is a small ship to begin with, so the process should not be too difficult. I will do further updates as more information is available.