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I’ve attached an image here, to further illustrate the scenario. Imagine that the wreck is at the bottom of the Marianas trench, 10km underwater.
Would jumping into the water kill you from the pressure? Or would it only kill you if you swam to where there is no cover on the right side of the wreckage?
In: Physics
The air will be at the same pressure as the surrounding water, as everyone has pointed out. To make the problem worse, the air is compressible. The bubble will shrink proportionally with the pressure. At the bottom of the Trench, the pressure is about 1000x that of sea level. If you started with a decent sized room full of air, you’re down to about a cubic foot of air at depth.
As others have noted, in this situation the air pressure matches the water presure. Research suggests that the maximum survivable air pressure for humans is 100 atmospheres, at about a depth of 1000 meters. However, there are additional issues with breathing air at those pressures – oxygen toxicity and nitrogen narcosis. Unless you are in an air-bubble of heliox (helium oxygen blend for deep sea diving), those things will probably kill you first.
The good news is that your lungs will contain 100 lungs worth of air as you start your ascent. The bad news is that you have to let it out as you float up, otherwise your lungs will explode. Any other air-filled spaces in your body that were not crushed as the pressure increased will now try to expand as you ascend – this may pop your eardrums, and will make you burp and fart as you ascend.
If you were not in heliox, then massive amounts of nitrogen forced into your bloodstream and tissues will start to foam out like Guinness. This is decompression sickness, or the bends. Incredibly painful before it kills you by blocking and tearing blood vessels in your brain.
And, of course, even at 1km below the surface, you cannot reach the surface before you die from asphyxiation. Even if you have an air-tank, you can’t breathe in because of the pressure of the air coming out of your lungs.
And one other problem – below about 20m, humans have negative buoyancy. You won’t float up, you will sink down. Unlucky.
If you ever find an air pocket in a shipwreck (which has happened to me several times while scuba diving), **do not breathe the air!** The air is likely to be hypoxic and may contain toxic gases too. It’s still ok to poke your head up and take a selfie. Just be sure to breathe only through your regulator.
You are perfectly fine to jump into that water pressure is not going to kill.
The pressure in the air pocket is already at the same pressure as the water.
This is actually something called a moon pool that t saturation divers use. They don’t have an airlock on the bottom of the ocean. Just a hole in the floor. The air pressure of the capsule keeps the water out.
What will kill you at depth is:
– wrong air mix. You can’t just compress regular air. Eventually the absolute amount of O2 becomes toxic. You can only add N2 to a point as that eventually also becomes toxic. You can then add an inert gas such as helium but that also has issues that need to be adjusted for.
– temperature, it is damn cold down there.
– the bends, when you go to ascend to the surface you have to do it slowly. As you have a bone of dissolved gasses in all your tissues, come up too quickly and it bubbles out. Think about cracking a 2L of Pepsi. Similar to that. So you have to slowly lower the pressure and let the gasses out slowly.
Thank you for all the answers! Does that mean that regardless of whether there’s an air pocket or not, there would be no conceivable way of being alive in the air pocket without some sort of depressurized suit protecting you?
And as an extension, if you took a submarine, and slowly went down to the bottom of the ocean, if the submarine was theoretically able to withstand infinite pressure, would you die the instant you got out of the submarine into the air pocket, due to the air in the air pocket already being so pressurized? Would it make a difference if you very slowly opened the hatch, or would you die either way?
Would not the AIR pressure in the ‘bubble’ be compressed to the same as the water Pressure?
The air would compress to the same relative pressure as the ocean, so no. That’s why any crack or failure in a submarine causes it to implode.
The start of your premise, in which you are at the bottom of the ocean in an air pocket, is already a flawed premise. How would you get down there, by floating down with the wreckage? As the wreckage sinks, with you inside that bubble, the air pressure would increase inside, eventually causing you to implode. So forget about jumping in the water at that depth; there’s no way I can think of that you could even get in that bubble in the first place.
Someone correct me if I am wrong here.
The air bubble would not hold under that pressure so this scenario isn’t possible. The air would compress and ultimately disperse into the water, filling the chamber with water.
The air pocket will feel the pressure of the water. The water surface is pushing up on the air pocket and the air pocket will compress until it reaches a volume where the air pressure is equal to the water pressure.
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