back to article World's largest private submarine in mystery sink accident

One of the world's only privately built submarines has reportedly sunk under mysterious circumstances on the Danish coast. The 33-ton diesel-electric boat, UC3 Nautilus, is said to have foundered after getting into difficulty in Køge Bay, around 25 miles southwest of Copenhagen. Prominent Swedish newspaper Aftonbladet wrote …

Anonymous Coward

A crowdfunded vessel sinking.

What are the odds?

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Joke

"A crowdfunded vessel sinking.

What are the odds?"

Well if Retro Computers Ltd were in charge of building the submarine, it'd never get the chance to sink.

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It's a powerful metaphor to be sure.

I do feel a little bad for them though. I'm the type of person to want to buy a submarine (I'd be in massive debt) and I can't imagine how gutted I'd be if it sunk... in a bad way.

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Ironically the Danish navy got rid of its submarines a few years ago so this would have been the most powerful one there even without weapons.

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even without weapons.

What's Danish for "Conn, ramming speed!"?

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According to Google Translate...

"Conn, stampeblanding fart"

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What's Danish for "Conn, ramming speed!"?

I speak Danish.

Ramming speed = Vædder fart

Also the concept of a ramming includes a ram with a big dick in Danish and English.

So we have a Big Dick Fart.

The captains name is Peter. That name is derived from the noun Stone (in English). Perhaps the captain was stoned on something that produces gas....

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"Ironically the Danish navy got rid of its submarines a few years ago "

Who are they hoping will come and rescue them if russia starts getting belligerent in the Baltic Sea?

Sweden?

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Re: What's Danish for "Conn, ramming speed!"?

"I speak Danish."

Clearly, Google doesn't :/

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Re: What's Danish for "Conn, ramming speed!"?

Clearly, Google doesn't

Google doesn't understand the military concepts or they try to censor them. A good example is Cock Pit

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Anonymous Coward

Re: Vædder fart

Good thing it wasn't a Darth Vædder fart!

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Pirate

Overland journey?

"One of the world's only privately built submarines has reportedly sunk under mysterious circumstances on the Danish coast."

Good trick if you can do it.

See title.

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Coat

So...

There is something rotten in Denmark?

And as for the iconic shape of a submarine... I've flushed better shaped things.

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Facepalm

If this was crab shaped (aka a scientific sub) would it have scuttled itself?

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Pirate

Crab shaped or spheroidal don't go anywhere - just up, down and scuttle about seabed.

So while this typical sub-shaped submarine is currently scuttling about the seabed on the ebb and flow of the tides, it should be more capable than a crab-shaped submersible at going from A to B without a surface ship to lug it about while clear of the water.

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I sea what you did there

/I'll grab my wetsuit

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There are worse ways to sink a submarine

The old story was much funnier. Sometimes there is a downside to checking wakipedia before posting, as there is some evidence that the internet has been unfair to Captain Schlitt.

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Unhappy

Re: There are worse ways to sink a submarine

The old story, in British Submarines was known as 'getting your own back', as you had to lean over the bowl in order to flush.

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Coffee/keyboard

Re: There are worse ways to sink a submarine

There's a reason submariners I've known call it the freckle locker.

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Devil

Re: There are worse ways to sink a submarine

"you had to lean over the bowl in order to flush."

U.S. subs have a 3 foot lever (with green handle) to operate a 3 inch (or so) ball valve. Instructions for operating the toilet are on the wall. And you could operate it standing up, more or less, without sticking your nose in the bowl.

instructions were something like:

a) ensure ball valve is shut.

b) use the commode

c) open ball valve

d) flush with sea water using sea water valve

e) shut ball valve

f) leave approximately one inch of water covering valve

it was implied that if your crap stuck to the side of the bowl, you were supposed to get some TP and wipe it so it went down the hole. Maybe that's when you'd get a bit of poo-gass in your face.

the toilets were made of a kind of stainless steel that tolerates sea water. but during 'field day' people cleaning the heads would use a bit of coolaid (aka 'bug juice') from the galley to shine 'em up a bit. It actually works pretty well.

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Meh

Cruashed

Well at least if the hatches were left open when it went down, it wouldn't be crushed. Might even be salvageable.

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Alert

Nice Linkey

Interesting picture of a very grotty place showing no submarine. Is this offered by the Danes as proof that the sub's sunk?

Reminds me of a picture I once saw entitled "Cow eaten grass" ...

Via Google mangle:

"According to TV 2 News, Peter Madsen has been flown away in a helicopter wrapped in carpets."

Madsen or the helicopter? Enquiring minds etc ...

Any sign of a bag of quicklime, a submarine backhoe digger or a PFY??

So many icons to choose from and so little time ...

>> Mine's the one with the blow up rubber ring in the pocketses.

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Anonymous Coward

now there's an idea ...

Nonetheless, the submarine hull form is now iconic, in the same way as Concorde will forever represent supersonic passenger aircraft. ®

crowd-funding for a private supersonic passenger aircraft, anyone ?

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Re: now there's an idea ...

I'm in.

We should be able to get it to go supersonic by dropping it from a great height.

Just an outline thought.

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Mushroom

Re: now there's an idea ...

I'm in for a tenner. When should I expect my first free flight?

All's well that doesn't end in rapid unscheduled disassembly.

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What's sixze got to do with it?

Article reads that the crushing depth is somehow less of a problem for a bigger vessel. I'd have thought that if anything, the relationship would be inverse. And the Trieste seems to back my case....

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Re: What's sixze got to do with it?

The Trieste was not a true submarine, it was a bathyscaphe:

https://en.wikipedia.org/wiki/Bathyscaphe.

Essentially a sphere for us humans (= best shape to withstand pressure) suspended below a large tank of gasoline (= less dense than water and incompressible). It got back to the surface by releasing it's iron shot ballast.

What I noted about the article's submarine was that it had portholes! I would of thought that was a major weak spot.

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Boffin

Re: What's sixze got to do with it?

actually, a larger sized vessel would have a better positive bouyancy on the surface. You can run the calculations, but basically the displacement of the hull, combined with the volume of air inside the boat plus empty ballast tanks, and the total mass and shape of the boat itself (with empty tanks), determines how much of the boat must be submerged at all times. The larger the boat, the more likely this is to be a higher value for positive bouyancy. Typically that might be something like 85% of the hull submerged at all times, and the other 15% is controlled/compensated by ballast and trim tanks.

in this case...

It's a fair bet that there was a major seawater leak, and too much water went into the people tank, forcing the boat to sink. Blowing ballast and pumping trim wouldn't have been enough to get positive bouyancy.

I suspect that some low-price low-quality component failed (the U.S. Navy has a program called 'sub safe' to prevent the $5 part from sinking the billion dollar boat). It could have been a port hole, a valve, a weld, a pipe fitting, a ballast tank vent, or anything that couldn't be properly isolated, nor have the drain pump [assuming it had one] pump the water overboard fast enough.

All of those kinds of safety systems would have to be designed with surviving a flooding casualty.

So one possibility is that one of the portholes blew out because it was made of substandard materials. Again, $50 part sinking the million dollar boat. Oops.

They should have had some means of RAPIDLY isolating the cause of the leak [assuming there was not]. They should have a means to get the water off the boat assuming "worst case leak". The 'drain pump' would have to be reliable enough to run with the power out (let's say on separate battery power), and run submerged if needed. A backup pump would also be a good idea. Being able to isolate compartments would be even better, especially if you can pressurize a compartment that is being flooded. [watch any old sub movie, and they'll talk about that, pressurizing a compartment to keep the water out, and run on the surface so the water pressure is lower, use the drain pump to get water out, etc.]

So yeah making a _SAFE_ boat that can go underwater to 500 meters is NOT something to be taken lightly. You have to consider the behavior of materials under cyclic compressive stress, the ability to recover from a reasonable flooding casualty, safety systems that can be remotely activated, 'emergency blow' on the ballast tanks guaranteed to work every time, and operating procedures that go along with all of this stuff [as well as maintenance]. And if one of the ballast vents fails, can you recover from that? How about 2 vents? Compartmented ballast tanks with multiple vents helps make that possible. I think the old WW2 boats had 6 or 8 ballast tanks, each with its own vent valve, that was shut as soon as they submerged so they could emergency blow on a moment's notice.

And all of the welds on the hull should be x-rayed for cracks and other defects on a regular basis. The fracture toughness of the hull material should be well known, and all design margins calculated based on the minimum detectable flaw sizes, like would be done for a bridge, or a cargo ship, or anything else made of steel that's likely to undergo heavy stresses during normal operation.

And the maximum allowed depth should be based on the worst case design margin in the worst possible place, for safety. The claims of 400 to 500 meters is pretty optimistic, yeah.

/me points out that at 500 meters, water pressure would be about 800psi... imaging getting hit with a stream of water at 800psi because something broke. Even a half-inch hole at 800psi could slice you in half. It's no joke dealing with this kind of thing.

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Headmaster

Re: What's sixze got to do with it?

"I would of thought that was a major weak spot."

Second only to the grammar that has been crushed...

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Re: What's sixze got to do with it?

Yeah, I assumed crushing would be a bigger problem the bigger the vessel. Or at least the bigger vessel would require proportionately thicker bulkheads to operate at the same depth.

No doubt somebody who actually understands these things will pop up sooner or later to give the correct answer.

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Re: What's sixze got to do with it?

"While her theoretical crush depth is given as "400m-500m", this seems a tad optimistic. Proper naval submarines tend to operate at these levels, and the 18-metre Nautilus is far smaller than those."

A DSRV is much smaller than any sub with a combat role, but can dive much, much deeper.

And I'd go as far as calling it a proper naval submarine.

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Re: What's sixze got to do with it?

I was going to comment on this, but you've got it essentially correct. It's to do with the curvature of the pressure hull; like an arch, the tighter the curve, the stronger it can withstand pressure. A smaller sub will withstand a greater pressure than a larger sub with the same thickness of hull.

On the other hand, the cube-square law applies: the bigger the sub, the more material it can have in the hull for the same buoyancy. That's assuming that they have the same arrangement of ballast tanks, of course, but then it's relatively easy to add more tankage in the design.

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Anonymous Coward

Crush depth optimism?

The article states:

"While her theoretical crush depth is given as "400m-500m", this seems a tad optimistic. Proper naval submarines tend to operate at these levels, and the 18-metre Nautilus is far smaller than those."

I agree that the claimed crush depth does seem optimistic on the face of it, but from an engineering point of view the bigger a submarine, the greater the challenge of designing it to withstand pressure.

The "crush depth" is derived from the pressure calculated to cause the pressure hull to fail catastrophically. The design depth of a submarine is calculated as the nominal maximum depth the sub can cope with before pressure hull failure, allowing for a certain margin of error in addition to the raw crush depth calculation; the pressure at which failure will actually occur is hopefully greater than the specified design depth.

Now consider that military submarines are operated in peacetime at much less than their crush depth: in peacetime, the maximum operating depth aka "test depth" is (according to the Wikipedia article on submarine depth ratings): 2/3 design depth for US subs, 4/7 for RN subs, 1/2 for German subs.

That article also states this:

"Modern nuclear attack submarines like the American Seawolf class are estimated to have a test depth of 490 m (1,600 ft), which would imply (see above) a collapse depth of 730 m (2,400 ft)."

Taking all that into account, perhaps UC3 Nautilus was indeed designed with the claimed crush depth.

How much faith the people behind UC3 Nautilus had in their crush depth calculations and construction quality can perhaps be gauged by the fact that the Wikipedia article on the sub states that they operated UC3 Nautilus at depths of no more than a nominal 100m (1/4 to 1/5 of the crush depth) - or maybe they were just being super-cautious.

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Re: Crush depth optimism?

Precisely. There's a reason why crush depth isn't operational depth. Consider a tube 2 meters in diameter with a 25 mm wall, a back of the envelope calculation at 50 atmospheres pressure, which is approximately 500 m depth, only produces stress of 180 MPa which is only about 70%-80% yield for mild steel and your high strength steels can potentially be 3 times stronger if not more. If you could make a perfect vessel it shouldn't have many issues. The problems are going to be in the slight defects introduced in welding and other things like seals for the hatches, shafts, and other miscellaneous but necessary holes which tend to make very nice stress risers.

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Re: Crush depth optimism?

Well, you don't run your car just below redline all the time either or use a capacitor with a working voltage of 20V in a circuit with 19.9 volts. At least not if you want some longevity. And running a sub at close to its theoretical crush depth would tend to make me fear for its occupants' longevity.

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Re: Crush depth optimism?

It also had portholes, presumably for seeing things outside.

Not a lot to see 100m down. Not much point going deeper unless you are hiding from other vessels, collecting surface (sea-bed) samples, or simply want to brag that you went that deep.

Safer and just as fun to cruise at a more confortable depth.

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Anonymous Coward

But, but, but ..

.. aren's submarines supposed to sink? AFAIK, a submarine that floats is called a ship.

I'm all confused now, it's too close for the weekend for this..

:)

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Anonymous Coward

Re: But, but, but ..

No, functional submarines 'dive', sinking is as bad for a sub as a surface vessel.

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Re: But, but, but ..

Hence the traditional submarine Captain's cry:

"Sink! Sink! Sink!"

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Headmaster

Re: But, but, but ..

actually it's "Dive, Dive" and "Surface, Surface, Surface". if you hear anything else, in a movie or anywhere else for that matter, they're doing it wrong. heh. [there's an equal number of blasts on the diving alarm, 2 for dive, 3 for surface]. So no "Dive, Dive, Dive" nor "Surface, Surface". I snicker a bit when they do that. Hollywood... heh

not being too pedantic, because even submarine movies get it wrong sometimes, and they're supposed to have ex-Navy consultants to keep them on track...

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Happy

Re: But, but, but ..

It's 'whoosh whoosh whoosh'...

Sarcastic propellers overhead.

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Anonymous Coward

Re: But, but, but ..

It's 'whoosh whoosh whoosh'...

Sarcastic propellers overhead.

Oh, it's OK, it amuses me greatly when people go in all seriousness into a piss take while the joke innocently flies over their head. It's part of the fun of making the joke in the first place, and this wasn't even a particularly good one :).

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Headmaster

Re: But, but, but ..

if you hear anything else, in a movie or anywhere else for that matter,

I doubt they'd be using 'Dive, dive' on vessels where English is not the native language. Such as, for instance, in Denmark.

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submarines owner is charged with murder now

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Coat

"Real submarines are rare"

No doubt.

How big a vessel is needed to carry 2 tonnes of "cargo" from Columbia to say Miami quietly enough to avoid Coast Guard sonar?

It's life jacket.

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Devil

Re: "Real submarines are rare"

"quietly enough to avoid Coast Guard sonar?"

it's not likely they'd evade U.S. Navy sonar, but the Navy subs and anti-sub aircraft would kinda have to be looking for them...

The Coast Guard probably doesn't have as good of equipment as the Navy. But they'd coordinate if things got bad enough. During the cold war the military put listening devices all over the ocean. That's going to make it very hard for anyone to get a submarine into U.S. coastal waters without detection.

this tech is really old:

https://en.wikipedia.org/wiki/SOSUS

http://www.public.navy.mil/subfor/underseawarfaremagazine/Issues/Archives/issue_25/sosus.htm

I suspect it's a lot better, now.

Even the tech that I know about [which shouldn't be discussed here] is over 30 years old and I suspect that things are a LOT more sophisticated nowadays. The threat of a diesel/electric boat sneaking into a harbor to perform a terrorist attack has been on a lot of military minds since 2001.

on a lighter note, the movie 'Down Periscope" with Kelsey Grammer

https://en.wikipedia.org/wiki/Down_Periscope

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Ogi
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Re: "Real submarines are rare"

Private submarines have been possible for a while, but the only people with the cashflow and a real need are the mafia, who don't really advertise their capabilities. The only knowledge is from submarines scuttled or captured by authorities while in dock, like this one:

On 3 July 2010 the Ecuadorian authorities seized a fully functional, completely submersible diesel electric submarine in the jungles bordering Ecuador and Colombia.[3] It had a cylindrical fiberglass and Kevlar hull 31 m long, a 3 m conning tower with periscope, and air conditioning. The vessel had the capacity for about 10 tonnes of cargo, a crew of five or six people, the ability to fully submerge down to 20 m, and capable of long-range underwater operation.

Excerpt from https://en.wikipedia.org/wiki/Narco-submarine, which is a really interesting read in of itself. Seems drug runners have been at it for a long time, as reports and rumors abounded in the 1980s of scuttled submersibles being discovered.

Sure they don't dive as deep as this one, but it was captured in 2010, so 7 years have passed. It could be that the ones capable of submersing deeper just haven't been captured yet. Just like the government, you can never be sure what the current state of the art is with the mafia.

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Anonymous Coward

Re: "Real submarines are rare"

"The threat of a diesel/electric boat sneaking into a harbor to perform a terrorist attack has been on a lot of military minds since 2001"

Why car bombers dont use Prius'

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Pictures

Here are much better pictures of the UC3 Nautilus.

UC3 Nautilus

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Re: Pictures

Why does it seem to have outer doors for torpedo tubes, though?

(Paging Skip Tyler.)

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