# Can a submarine turn upside down?

**URL:** <https://boards.straightdope.com/t/can-a-submarine-turn-upside-down/680123>\
**Category:** Factual Questions\
**Created:** [January 30, 2014, 11:50am UTC](https://boards.straightdope.com/t/can-a-submarine-turn-upside-down/680123 "2014-01-30T11:50:07Z")\
**Posts on this page:** 1\
**Showing post:** 35

<div class="post-metadata">

**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\
**Post date:** [January 31, 2014, 9:50am UTC](https://boards.straightdope.com/t/can-a-submarine-turn-upside-down/680123/35 "2014-01-31T09:50:44Z")

</div>

> [@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](http://www.67notout.com/2011/10/moebius-strip-which-made-ship-disappear.html)

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?](https://boards.straightdope.com/sdmb/showthread.php?t=159352)**
>
> If a submarine suddenly ends upside down at sea, what would happen? Besides the mess, does the sub will right itself like a rubber ducky or do submariners have to maneuver the sub to a straight position? What are the dangers on the engine room on a...

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

> [@Submarine ends upside down, how will it go up?](https://boards.straightdope.com/t/submarine-ends-upside-down-how-will-it-go-up/151431/5):
>
> 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. 🙂

---

_[View the full topic](https://boards.straightdope.com/t/can-a-submarine-turn-upside-down/680123)._