Can a submarine turn upside down?

[Really_Not_All_That_Bright]

Yeah, but the submarine would still need to be moving very quickly to overcome gravity.

[doorhinge]

@Really_Not_All_That_Bright

Yeah, but the submarine would still need to be moving very quickly to overcome gravity.

Submarines need not be moving forward (underway under power) to change it’s position vertically in a water column. That’s what the buoyancy tanks are for.

[muldoonthief]

I think RNATB meant that in order to have the apparent force in the submarine be towards the keel during a loop, so that you could go upside down without suffering all the horrible effects of everything falling towards the top of the sub, you’d have to go a lot faster than a sub is capable of.

So, using the standard A=v[sup]2[/sup]/R, and assuming a 500 m loop radius (I have no idea if that’s valid, but given that USN attack subs are about 100 m long, it seems reasonable), and A=2g= 19.6 m/s[sup]2[/sup], so at the top of the loop the apparent force is still 1g towards the keel, I get v=99 m/s or 192 knots. Even if we drop the radius to 200 m, and A=1.5 g so you’ve only got 1/2 g towards the keel, it needs to be travelling 54 m/s or 104 knots.

[doorhinge]

@muldoonthief

…So, using the standard A=v[sup]2[/sup]/R, and assuming a 500 m loop radius (I have no idea if that’s valid, but given that USN attack subs are about 100 m long, it seems reasonable), and A=2g= 19.6 m/s[sup]2[/sup], so at the top of the loop the apparent force is still 1g towards the keel, I get v=99 m/s or 192 knots. Even if we drop the radius to 200 m, and A=1.5 g so you’ve only got 1/2 g towards the keel, it needs to be travelling 54 m/s or 104 knots.

Thank for the info. In an Immelman turn, the keel would change from the outside of the loop to the inside of the loop but the seamen on the floor would still end up on the walls and ceiling and the plumbing wouldn’t work.

[Elendil_s_Heir]

I love the mental image (“That’s not the deck, that’s the overhead!”), but I can’t imagine it working. The hull might even break, which Would Be Bad.

[muldoonthief]

@doorhinge

Thank for the info. In an Immelman turn, the keel would change from the outside of the loop to the inside of the loop but the seamen on the floor would still end up on the walls and ceiling and the plumbing wouldn’t work.

I looked at the Immelman page on wikipedia, which described it as a half loop followed by a half roll, not them happening simultaneously. Of course, the actual super-secret top speed of a Seawolf could be 200 kts - if the actual former submariners on the board stop posting on this thread, I’ll take that as confirmation.

[Really_Not_All_That_Bright]

@muldoonthief

I think RNATB meant that in order to have the apparent force in the submarine be towards the keel during a loop, so that you could go upside down without suffering all the horrible effects of everything falling towards the top of the sub, you’d have to go a lot faster than a sub is capable of.

So, using the standard A=v[sup]2[/sup]/R, and assuming a 500 m loop radius (I have no idea if that’s valid, but given that USN attack subs are about 100 m long, it seems reasonable), and A=2g= 19.6 m/s[sup]2[/sup], so at the top of the loop the apparent force is still 1g towards the keel, I get v=99 m/s or 192 knots. Even if we drop the radius to 200 m, and A=1.5 g so you’ve only got 1/2 g towards the keel, it needs to be travelling 54 m/s or 104 knots.

That. Except all the math stuff I’m not smart enough to have supplemented my own post with.

[obbn]

@doorhinge

Thank for the info. In an Immelman turn, the keel would change from the outside of the loop to the inside of the loop but the seamen on the floor would still end up on the walls and ceiling and the plumbing wouldn’t work.

We call that Tuesday around here! Sorry for the juvenile comment, but your post made me spew diet coke all over my keyboard. Thanks for the laugh, it came at the perfect time!

[Atomic_Alex]

@Mr_Quatro

I was on a round bottom diesel submarine that did a 57 degree roll one time and I thought I was going to die being as how I was the lookout in the bridge and reached out touching the lull of the wave.

We did have one captain that would get the sub going as fast as he could and then roll off like a fighter jet going port and then starboard. He wanted to do a 360 but couldn’t figure out how to keep the batteries all in one place.

We had one captain that use to run around the Med at periscope depth without the periscope up with those big oil tankers coming out of the Suez Canal having a 60’ draft … now that’s what I call crazy.

He went on to be in the commander in charge of all submarines on patrol out of Colorado.

I have no idea why I find those examples so amusing. Its kind of reassuring in an odd way!

@muldoonthief

I looked at the Immelman page on wikipedia, which described it as a half loop followed by a half roll, not them happening simultaneously. Of course, the actual super-secret top speed of a Seawolf could be 200 kts - if the actual former submariners on the board stop posting on this thread, I’ll take that as confirmation.

While conducting research on this topic (OK ‘research’ is a bit over the top given the nature of what I was reading about) I came across one person who, although he naturally couldn’t go into details about it, informed us that the B2 Stealth Bomber is kitted out with super-secret wave-gravity generators and is capable of low-earth orbit.

Now there’s an interesting image.

Forgot to say, thanks for the answers everyone!

[zoid]

So to be clear, it sounds like a sub can turn upside down, it’s just that it’s a very bad idea - correct?

[Blue_Blistering_Barnacle]

@Kevbo

Some of the responses seem to assume sub=nuclear power. Many navies still operate diesel electric subs. It would be considerably easier to modify one of these for inverted operation, since electric motors don’t care and batteries can be sealed and secured…but still no good reason to do so.

I would never perform a “Philadelphia experiment” style manouver in anything LESS than nuclear!

[minor7flat5]

@zoid

So to be clear, it sounds like a sub can turn upside down, it’s just that it’s a very bad idea - correct?

In a nuclear sub, I think the engine room would not survive and some people would die—not because of the reactor, but because nuclear power plants are also steam plants.

I initially was just considering the steam generators having water going into the steam piping, but that’s not the worst of it.

That would be nothing compared to all of the condensate collecting below the main condenser suddenly pouring back into the furiously spinning turbine blades as the main engines are inverted. The main engines would likely explode. Here is a very basic schematic of a steam plant; the condenser is below the main engines and has lots of condensate in the “hot well” at the bottom.

Diesel engines might fare better: any oil filled sumps would of course empty and the oil would bathe the cylinders, but that might not kill the engines. Fuel would also stop flowing the way it is supposed to flow, but again that is likely not a death sentence.

[Earl_Snake-Hips_Tucker]

@zoid

So to be clear, it sounds like a sub can turn upside down, it’s just that it’s a very bad idea - correct?

Does indeed sound like you could possibly do it. Once.

[dba_Fred]

More precisely, part of once.

[GIGObuster]

@Disposable Hero

A very long time ago I read about the story in the below link concerning a Soviet Philidelphia Experiment style…experiment…utilising a submarine. Supposedly the submarine followed a magnetic moebius strip path turning upside down once in every revolution.

Leaving aside the patent implausibility of the story I always wondered could a submarine even do that, turn upside down like that and still function safely?

Somehow I doubt it.

67 Not Out: A Moebius Strip Which Made A Ship Disappear

I think the tale is fiction, like the one I was planing of writing 10 years ago.

Submarine ends upside down, how will it go up?

I asked the same question, and a former submariner replied:

@wolf189

Bouyancy for modern submarines requires that the ballast tanks be trimmed as necessary with air and the tanks have valves at the tops to keep that air in, however the bottoms of the ballast tanks are open to the sea (consider that the water which displaces that air does have to come from somewhere, ya know?)

A submarine which (for whatever bizarre reason) should happen to become fully inverted would have the air in the ballast tanks empty out almost instantly and any attempts to pump more air to replace the lost bouyancy would simply allow that additional air to escape as well. Without the support of this air the submarine would descend to the bottom (or more likely, would sink to crush depth and the hull would collapse under the intense pressure).

And before anyone comes up with any bright ideas about using the engines to bring the sub rightside up i would point out that a nuclear reactor subjected to these sort of gymnastics would have scrammed rather promptly leaving the sub powerless and sinking into the darkness (not that the sub’s control surfaces are made for the challenge of flipping a submarine back over from an inverted position anyways). Regardless, an upside down submarine is effectively a doomed one.
wolf189 (former submariner)

After ten years I have figured out how to get my fictional characters out of that predicament, but I’m not telling until I publish.

[Atomic_Alex]

@GIGObuster

I think the tale is fiction, like the one I was planing of writing 10 years ago.
Submarine ends upside down, how will it go up? - Factual Questions - Straight Dope Message Board

I asked the same question, and a former submariner replied:

After ten years I have figured out how to get my fictional characters out of that predicament, but I’m not telling until I publish.

Oh sure, its definitely fiction, which is confirmed by the knowledgable people in this thread. But I find those kind of science urban legends interesting.

Whats the name and basic outline of your book, again it sounds interesting!

[Mr.Goob]

Thank Og I served on an aircraft carrier. Nobody would ever ask the question if the flight deck would still work upside down.

[Really_Not_All_That_Bright]

You must be new here. What if the flight deck had a treadmill built into it…?

[Mr_Quatro]

@Heracles

Please disambiguate:

[ul]
[li]He went on to be commander, out of Colorado, in charge of all submarines on patrol (everywhere).[/li][/ul]
or
[ul]
[li]He went on to be commander in charge of all submarines on patrol out of Colorado (probably none).[/li][/ul]
?

@chorpler

I was going to ask this same thing. Is it just a humorously-phrased description of a promotion (#1 on your list), or a euphemism for “They stopped putting him in charge of things because he was nuts” (#2 on your list)?

@VunderBob

Promoted into a desk job from which the only way out is retirement.

@gnoitall

Sure. A naval officer assigned to a staff billet in the mountains has received the unambiguous message “You’re done, kthxbye”.

(Maybe. In my stint at USSTRATCOM, I did see several gold dolphins on Lieutenant Commanders who looked (and were rumored) to still be on the track to their star. I guess it depends on the specific assignment… leadership or paper-pushing.)

@BubbaDog

Except for the fact that NORAD is in Colorado which leaves open the possibility that the comment was in regards to the possibility that the captain was deemed appropriate for top level work.

That was my initial reaction. Is the guy sidelined or frontlined?

I should’ve made myself more clear, sorry. Yes he was assigned to be Commander of all submarine forces out of Norad … the ones on patrol that is.

He was a young Lt Commander when he surfaced under his first ship and they promoted him to Commander after that inquiry. He was a full Commander when he surfaced underneath his second ship off the coast of San Francisco and they promoted him to full captain with four stripes and assigned him to our FBM USS Ethan Allen SSBN 608 and after he gave the orders to the OOD to run around the Mediterranean at periscope depth without the scope up …

we figured he was bucking for admiral lol

[Ranger_Jeff]

What I’ve gathered from this thread is that “Yes, it’s possible to half roll a modern submarine if you really want to”. From other readings about modern submarines, I do believe there are many less complicated methods for self-destruction of the boat and killing of all it’s crew. Like going to the Marianas Trench, set the attitude to a 10 degree down bubble, and just waiting for the hull to implode? Setting off a warhead in the torpedo room? Leaving a window open?