Lost Argentinean submarine found

[Hawkmoon]

The Argentinean submarine that disappeared a year ago has been found, partially imploded, at a depth of almost 3,000 feet (907 meters).

https://www.reuters.com/article/us-argentina-submarine/argentine-sub-found-partially-imploded-after-yearlong-search-idUSKCN1NM08B

This was a German-built, diesel-electric submarine. Does our resident squid know if that class of boat is designed for that kind of depth? According to Wikipedia, that class of boat was designed for a test depth of 300 meters, so where it was found is  three times as deep as it was designed for. Not good.

[HeroHog]

While I was stationed on a Sub base, I bobbed on top of the water and we didn't mingle much with the bubble-heads so I'm not as up on subs as all that. I would only know what Google tells me!

[dogmush]

Not a bubble head but:

The sub almost certainly sank from some other issue, and imploded on the way down, rather than exceeding crush depth.  The phrase "partially imploded" would imply to me that part of the sub had air and pressure,  and part of it was flooded (so at water pressure) when it hit crush depth.  Whatever caused that flooding is probably the "cause" of the sinking.

[Scout26]

It was still in use well beyond it's "Discard after" date.   I think RKL will confirm that the hull is compressed by water pressure every time it dives, and decompresses every time it surfaces.   You can only do that so many times, before metal fatigue sets in, then once more is too many.   32 years is a long time on a sub hull. 

[RoadKingLarry]

I've been following this pretty close since it happened. The Facebook submariner community has been very supportive of the families and last year we collected several thousand dollars that was donated to the families and children of the crew to ensure they had some tiny bright spot at Christmas time.
44 men, brothers of the 'phin were lost that day. I hope the families can find some closure now.

As to the technicalities of the tragedy...
32 years in service is a hell of a long time for a sub. Of course op tempo would have a lot to do with how much wear and tear a boat would get.
As Amy pointed out metal fatigue is a real issue with submarine hulls. When you dive deep the walls really are closing in on you. A string stretched tight across inside between frames of the hull will slack an alarming amount. the neat thing to do is stretch a length of para-cord while at test depth and take bets on what depth it parts at on the way back up.
The boats I was on had a "test depth" of 1200' I do not know what the current boats are rated for.

One small consolation for those of us that prowled beneath the waves was that in the event of a catastrophic failure we didn't have to worry about a long, lingering death, once the ship implodes death would be as close to instantaneous as one could imagine.

[TommyGunn]

RKL;  As well as the pressure hull compressing at depth:

   After my father returned stateside from the Korean War, in which he served in U. D. T. Team #3,  he transfered into the submarine service.   He served on a W.W. 2  diesel-electric  called the U. S. S. Cavalla.  It was a "thin skin" Gato class that had once been taken below it's theoretical crush depth.

Every time it submerged it had a leak.   A small one that apparently wasn't locatable or fixable.  That must have been .... interesting.
I've been aboard that sub back when I was a kid in the 1960s.  I would NOT like being there submerged.   Geeeesh ...."sardine can"  indeed.

[BlueStarLizzard]

RKL;  As well as the pressure hull compressing at depth:

   After my father returned stateside from the Korean War, in which he served in U. D. T. Team #3,  he transfered into the submarine service.   He served on a W.W. 2  diesel-electric  called the U. S. S. Cavalla.  It was a "thin skin" Gato class that had once been taken below it's theoretical crush depth.

Every time it submerged it had a leak.   A small one that apparently wasn't locatable or fixable.  That must have been .... interesting.
I've been aboard that sub back when I was a kid in the 1960s.  I would NOT like being there submerged.   Geeeesh ...."sardine can"  indeed.

Total aside: My mother refused to go on a day cruise with my real father, largely due to the fact that they would not be submerging. Almost everyone who did go out got horribly seasick. According to Mumma (which I assume she learned from being married to a bubble head) those things are not meant to float on top of the ocean and the ride is much smoother underwater.

[TommyGunn]

Total aside: My mother refused to go on a day cruise with my real father, largely due to the fact that they would not be submerging. Almost everyone who did go out got horribly seasick. According to Mumma (which I assume she learned from being married to a bubble head) those things are not meant to float on top of the ocean and the ride is much smoother underwater.

That's true of modern subs.  Those WW2  fleet subs were faster on the surface ..... the way they usually operated was as surface boats with the capacity to submerge when needed. Submerged, they ran on batteries which needed recharging after so much use .   That required surfacing and running on diesel.

Modern nuclear subs are a very different critter.

[BlueStarLizzard]

That's true of modern subs.  Those WW2  fleet subs were faster on the surface ..... the way they usually operated was as surface boats with the capacity to submerge when needed. Submerged, they ran on batteries which needed recharging after so much use .   That required surfacing and running on diesel.

Modern nuclear subs are a very different critter.

Yes, that would be different. 

[HeroHog]

All of the above is spot on from what little I know/have heard/read. Any sub, new or old is a BITCH on the surface, in rough seas, because they lack any real keel.
Our ship had a shallow draft "canoe" hull and it was bad in almost ANY sea of note. I was sick as hell MANY times on that ship!

[Hawkmoon]

Our ship had a shallow draft "canoe" hull and it was bad in almost ANY sea of note. I was sick as hell MANY times on that ship!

I sometimes wonder if that isn't a problem on our newest littoral combat ships. They're shallow-draft, to enable them to operate closer to shore in shoal-draft conditions.

[RoadKingLarry]

All of the above is spot on from what little I know/have heard/read. Any sub, new or old is a BITCH on the surface, in rough seas, because they lack any real keel.
Our ship had a shallow draft "canoe" hull and it was bad in almost ANY sea of note. I was sick as hell MANY times on that ship!

Surface transits in rough weather could be a royal bitch.
A couple of memorable surface transits include the Straights of Juan De Fuca in early Spring and crossing the North Sea from Den Helder to Edinburgh. I wasn't particularly susceptible to "Mal de Mer". Mostly the worst I got was a little queezey. I did get a few dry heaves induced when a ship mate barfed down my leg once.

In 1991 we were on NATO ops in the Atlantic working mostly with the Canadians. We had the distinct pleasure of experiencing "The Perfect Storm*" up close and personal. Running submerged at 400' we were still taking 10° rolls and 100' depth excursion due to surface wave action.

*https://www.history.com/this-day-in-history/perfect-storm-hits-north-atlantic

[French G.]

I sometimes wonder if that isn't a problem on our newest littoral combat ships. They're shallow-draft, to enable them to operate closer to shore in shoal-draft conditions.

I was on a big amphib. Relatively shallow draft, dumb hull shape and a huge amount of sail area and top heavy out of the water. It moved a ton for an 800ft ship. I was fine with it in my normal places, but go somewhere else and I'd feel I'll. Every place moved differently. The thing would kind of skid a little in heavy seas so high up front where I slept always travelled the waves in a circle. Up, skid across, slam down in a trough, skid some more, up again....

I went in a sub tied up to a pier. Good enough for me, let's go find the sun. I had a chance to tour an Ohio class and stupidly didn't. My amphib was bad enough at well deck operations, a couple of times we nearly became a submarine.

[HeroHog]

Nice thing about being a snipe is working amidship and right at the waterline. Go up in the conn, aft or in the bow and HANG ON FOR DEAR LIFE in rough seas!

[dogmush]

My LCU can get lively in seas. You get used to it, and a few trips will weed out the folks that don't want to be Mariners.

I have been known to occasionally call a snipes to the bridge to chat in bad weather.  I'll stand there swaying and eating and see how long they can chat.

[RoadKingLarry]

We had a Corpsman* (HM1) that couldn't handle much motion at all.
The guy would start getting queasy when the command to "single up all lines" went down.
He'd hang out outside the head till we submerged.
Neat thing about that class of submarine. The san tanks (poop tanks) were blown to see with high pressure air. Well, obviously after the tanks were blown the pressurized air in the tanks had to go somewhere. Couldn't vent it overboard as the bubbles would give away the position of the boat so they were vented inboard through charcoal filters. Now that sort of worked to take the edge off the stank it wasn't just real effective.
 
Now remember our hapless Corpsman hanging out near the head in case he got to barfing.

We would "blow shitters" as soon as we crossed the 12 mile limit while still on the surface just prior to diving.
The charcoal filters were located under a step on the aft side of the forward watertight bulkhead, just outside the head.
So, here had our Corpsman sitting on the step outside the head because he was seasick and the san tanks were vented inboard and BAM, Corpsman gets a face full of poorly filtered pressurized sewage air coming right out of the filters he is effectively sitting on.
Yup, power heaving commenced almost immediately.
This wouldn't have been such a memorable thing except it happened every *expletive deleted*ing time we went to sea while he was onboard.

* I don't refer to him as "Doc" because he never earned that honorific. He left the boat less than a year after reporting aboard, not Qualified in Submarines and minus a stripe.

[HeroHog]

I have been known to occasionally call a snipes to the bridge to chat in bad weather.  I'll stand there swaying and eating and see how long they can chat.

You are an Evil EVIL man! 

[French G.]

I had a 15 year choef that had been force converted to my rating because his ceased to exist. His whole career had been on sub tenders that are often moored with steel cables they leave port so seldom. He was nervous as a cat in six foot seas on a carrier. Hadn't even cleared the bridge tunnel yet. I loved rough seas, cut the chow line down. I puked once, hung over on liberty, breakfast was a quart of chocolate milk and an Italian sub, get on a dive boat in some pretty choppy water. Chum!

[230RN]

Pressure hulls and beer cans.

(For those having interest or curiosity.)

The strength required to prevent collapsing  a vessel under outside pressure is far greater than to prevent bursting from inside pressure.

With inside pressure, the walls of the vessel are under tension, and forces tend to spread out over a weak spot.

With outside pressure, the walls of the vessel are under compression and any weak spot tends to create catastrophic collapse.

That is why cans of vacuum-packed food have ribbed walls for reinforcement.  If they were (ha-ha) "pressure packed," the ribbing would not be needed.

Note how thin the walls of beer cans are, by contrast.

Terry