Indonesian sub missing
 

A search job for Australian Poseidons ?
https://www.bbc.co.uk/news/world-asia-56829278

Hopefully the search area is quite limited - the Argentinian one was pretty big IIRC

Its gone down in 2,600ft. Everything crossed but I'm not hopeful. Its an aged Type 209 I think much like the Argentine one.

Indonesian rescuers searching for a submarine that went missing with 53 people on board found an oil spill on Wednesday near where the vessel dived, authorities said.

The 44-year-old submarine, KRI Nanggala-402, was conducting a torpedo drill in waters north of the island of Bali but failed to relay the results as expected, a navy spokesman said.

An aerial search found an oil spill near the submarine's dive location and two navy vessels with sonar capability have been deployed to assist in the search, the Defense Ministry said.

A ministry statement said requests for assistance had been sent and Australia, Singapore and India had responded......

Wreckage located on the bottom and, as feared, far far below crush depth.

When something goes wrong in a submarine it's often very bad news indeed - deepest commiserations to the families :(

Condolences, let’s hope it was quick for them.

An awful way to go ... RIP and condolences.

There has to be a design life for such a vulnerable craft as a submersible and 44 years must surely be beyond that.

The 209 is a coastal/littoral boat and normally would not go that deep that often. 25 years is a good age for a well maintained sub. Wake up tim,e for any navy still running these.

The USN "Ohio" is still in service after a major refit and she's 40 years old and has been worked HARD over the years

That reflects a relentless focus on daily maintenance, while under way as well as in port. Submarines are plumbing intensive, that stuff always has issues.
Nipping them in the bud is critical, but very difficult to implement. Somehow the USN has achieved that culture, maybe a legacy of Rickover's.

Think it was more to do with the aftermath of Thresher and Scorpion. They learnt the hard way and implemented subsafe.

According to this BBC article, the Nanggala underwent a major refit in Germany 2012. RIP to the crew - we all hoped for a better outcome.

You are surely spot on with that.
My very limited sub experience was decades plus after those disasters, but the maintenance routines were what stuck in my mind. They are relentless, which of course is what is needed to keep this contraption safe.
I do not know how to transfer that mindset to a different culture, but imho it is at least as critical as the technical training.

https://www.bbc.co.uk/news/world-asia-56879933

The 2012 refit was done in Korea.

Begs the question ,`are any subs fitted with `FDRs and CVRs` that can be recovered...?

I doubt it. Firstly, the wreckage normally seems to provide enough information to figure out what went wrong; secondly, any such device could be incredibly valuable to any adversary who gets to it first...

Seen that marine wreck salvage appears to be profitable, as evidenced by the looting of the Canberra and of some of the Java Sea combatants, it probably would be preferable to have such a device self deploy once enough below crush depth.
That would allow a more immediate alert and speed the location of the wreck.
s