Thank you, I will have to check that out

As you correctly stated, the internal pressure of a military sub would be 'normalised' (at 1 atm) to allow it to surface quickly without any adverse physiologic effects on the crew. The whole point being that the air-pressure has to be very precisely controlled, and would need to remain effective against a whole spectrum of external forces. This could be anything from relatively low pressure near the surface, to the crushing forces found as we approach depths of around 800ft.

Now imagine if you could effectively take this principle and turn it 'inside-out'. That is how I think vault 111 has been designed.

Yes, the Vault is kept at a higher pressure than the outside. This could be a overpressure system to keep contaminants out of the Vault, to aid in the cryo process as others have speculated, or possibly to simulate spaceflight conditions. I really can't wait until we get to dig through terminals and find out what's going on...this is going to be such fun.

I actually have some fairly solid ideas as to how the cryo-tech could work within this setup. And I know what you mean - November can't come round fast enough! Will post the cryo/vault info with some other news about the possible timeline used in the game

Just realised that when our protagonist goes into the vault, he will literally be a sub-marine

Spaceflight conditions, once IN space, cabin pressure is significantly LESS than 1atm, so the structure doesn't have to be quite so robust to contain it, leaks aren't nearly as catastrophic, etc.

I can see the logic in this line of thought, I think it might be a case of being of primary use for one side (i.e the Cryo works better or only under pressure) and give them a beneficial side effect if you will of keeping almost everything out of the vault. Wonder if that means we are going to have to endure a decompression chamber? After all 200 years in a high pressure air environment is way off my dive tables....

Interesting point about the decompression. This could tie in with our guy being a little 'out of breath' when he emerges (once it is safe for him to do so).

For the record, I have just added some more info to the OP, also shown below. It is an update on the possible 'submarine'/cryogenics connection.

I've just had another thought to do with the design of the vault.

Remember in FO3 when we go back to vault 101 during "trouble on the homefront"? The schematic behind the previously locked picture frame is now made available to us, depending of course on our stats. In vault 111, we know that at least one scientist didn't make it, due to the skeleton next to the vault door controls in the gameplay footage, and there is a fair chance that he was the only one. We also know that this was one of the last vaults to be built. Given the possible 'submarine' based design as I have suggested, what if there was not one but two ways out of the vault. The main one, as well as an escape route for the scientists in case the lift-shaft were to become blocked or damaged. This is how I would picture it:

We leave the vault after completing the tutorial, but somewhere on the lowest level is a securely locked hatch. Some time later, when we've levelled up a bit, we return to the vault, and kill a group of raiders that have since moved in. We then unlock the hatch, and it leads down to a hidden area containing a number of cool items, as well as a submersible. We enter the submersible, and via a large submerged tunnel we end up in the lake north-east of the vault as seen in http://i.imgur.com/tFek3MP.jpg image. The submersible could then be air-lifted out of the lake by vertibird, which would open up a whole possible new area of underwater exploration. Incidentally, the real world lake is actually known as 'Fresh Pond', and is located fairly close to a research facility as seen http://www.freshpond.org, who seem to specialize in evolution and genetics!

To back up this theory, I have posted two new links to the concept art in http://www.gamesas.com/topic/1524192-more-clues-in-the-concept-art thread, showing what would appear to be a small submersible, and also what looks like a giant squid...

EDIT: the hatch leading below the vault could even explain how the Institute gained access in the first place in order to remove our spouse and child.

You also need the vault (and all vaults) to have positive pressure in order to keep air from the outside from entering the vault through minuscule holes in the walls/etc.

Pressurization is almost certainly part of every vault. I really think the OP is stretching it with his assumptions/theories.

Also, the interior of a submarine is similar to a very cramped surface ship - there is very little inside of one to indicate that it's pressurized. The hatches between sections of a submarine look identical to the ones on surface ships.

(also, the hatch looks nothing like a submarine hatch)

If we look at the design of previous vaults, they are all relatively similar. With vault 111 however, we see a drastic shift not just aesthetically, but in ways that also seem to be functional. For example, the warnings on the outer door, as well as the enormous purge valve, actually suggest not just positive pressure, but very high levels of positive pressure. This would also tie in with whatever cryogenic technology is being used inside the vault. Note that there is a direct relationship between extreme low temperatures and extreme high pressure (which explains why the sea bed is not just a huge block of ice).

Also note that I have suggested further on in the thread that vault 111 would likely be built using the concept of a submarine as a basis, not that it would be built to be exactly like one. The key difference would be the 'normal' air pressure on the outside, rather than the crushing water pressure we find beneath very deep water. The whole idea would be to keep pressure in, not to keep it out. And the progressive nature of increasing pressure levels once the cryo is fully active would also make sense, because you have the lowest pressure in the lift-shaft, which is right next to surface level, so that the whole thing doesn't end up exploding outwards.

Interestingly, http://www.uncleodiescollectibles.com/img_lib/01%20Captain%20Nemo%20Submarine%20Hatch%2001%209-6-4.jpg showing a prop from a 'Captain Nemo submarine' as featured in a 70's TV show, looks surprisingly similar to the 'red valve' we see above the vault in post-war shots from the trailer and also the E3 showcase. If my memory serves me correctly, didn't Captain Nemo also feature a submersible and a giant squid...

Far less than 1.1 bar (0.1 over pressure) will keep anything out. even if far from airtight far less pressure is needed if you also try to make it airtight. You need more than 2 bar for any chance of bend, this equal 10 meter deep.

Now as the vault has to be airtight and also survive over-pressure from the blast is will be build a lot like an submarine. it also make sense to have air thigh partitions inside in cause of breach or fire.

This generate the sub feeling.

https://www.youtube.com/watch?v=D5esyZPt5Jo&feature=youtu.be&t=4m21s from concept art @ 4:27 top middle (don't think it's a flying machine, but could be wrong) and yes it would make sense to have a vault sealed like a sub with oxygen scrubbers and all the other necessities to maintain life without outside interaction. Only when/if the vault is opened might that integrity be broken if a double seal airlock was not in place or functioning properly. Enjoy the theories and it will be interesting to see the real deal in November and see just how close you've come!

This looks like it could end up being be a very big sub, and I'm guessing it might be something we find whilst exploring underwater.

I agree with the 1.1 bar as just a measure of isolation from the outside contamination, but if they are using pressure to inhibit ice crystal formation in cryogenics, then the pressures that even depress the freezing point appear to be in the 100s bar/Kbar range, and thats enough to outright kill, and deposit some Nitrogen on your tissue.... Maybe they used helium.... sorry just thinking of the voice acting in a high pressure helium environment. (lowest point of water/ i.e. the liquid component of blood and tissue, is 251.165K @ 209.9 MPa then it goes directly into Ice II III IV or IX depending on temperature, though I think that you would shoot for ice III since its the most dense form of ice, its denser then liquid water at 1 bar, However ice II has a slice all the way to 0K ) Just had to break out a little look on ice to find the phase diagram for ice its on wiki)

That whole 'using pressure to inhibit ice crystal formation' stuff is just stuff the OP made up to explain his submarine thesis, not something that has any evidence behind it for the game. Cryonics have already been shown in the Fallout universe, and without any kind of high-pressure environment around the sleep pods (see the Sierra Army Depot in Fallout 2).

Yes, you'll probably be a marine and you'll probably be frozen - but the OP is jumping at the scant information we have and making wild conjectures from it simply because theorizing is fun, not because he has much of a chance of being right.

And I agree that theorizing is fun, and something to do while we all wait.

If you wanted to preserve somebody for that long without damaging their body in any way, then you would probably be looking at a very careful balance of extreme high pressure and low temperature. Looking at real world examples, the pressure outside of a submarine at 800 feet is around 347 psi, or 24 bar. With regards to temperature, the most commonly utilised coolant in cryogenics is liquid nitrogen, which will be at around 77 kelvin, or close to -200 degrees celsius. Now lets just say that instead of submerging your subject in the liquid nitrogen, you designed your pod so that they would be surrounded by a layer of coolant in the outer shell of the pod. Increasing the pressure to such a high level whist rapidly introducing the coolant would effectively stop cell progression without freezing or damaging their blood, tissues, and organs. It would also stop the outer shell of the pod from expanding due to the incredibly low temperature.

Now I know that this is still speculation at this stage, but I'm just trying to picture how you would achieve such a feat using what would essentially be relatively low technology compared to anything we see post-war, and that includes all of the other games in the fallout series. I'm also trying to tie all of this in with the idea of vault 111 being built around the concept of a sub. And as you quite rightly said, this gives us something to do whilst we wait for the game to be released!

*reserved*

This reminds me of the movie Pandorum.

I'm definitely curious to find out what the experiment in Vault 111 is all about, however, I really hope they don't go overboard with the whole marine theme as that would get old really quick.

Anyway, Vaults would have to be 100% pressurized and sealed due to the radiation, so it's not unlikely that different levels could have different pressures in order to observe how human live and develop over long periods of time under various pressures, but that would be unlikely since they were all frozen, wouldn't it?

"In the town where I was born,

lived a man who ran to see

if a vault would save his life,

shaped like a submarine..

Then he raised up to the sun

to a scene of withered green

and the radioactive waves

from his vault-like submarine.

We all live in a yellow submarine

Yellow submarine, yellow submarine

We all live in a yellow submarine

Yellow submarine, yellow submarine"

Hahahaha, awesome =)

Very creative, I like it

*whistles tune to submarine song

Hmmm, Beatles radio mod confirmed...