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ETpro's avatar

How come he didn't run out of oxygen? See details.

Asked by ETpro (34425points) December 5th, 2013

A Nigerian man survived over 3 full days in a sunken tugboat he was a crewman on. He was fortunate enough, when a rouge wave capsized the tug, to find an inner compartment with an air pocket in it. He survived breathing that air, and staying hydrated by sparingly using a single bottle of Coca Cola he found there.

But why didn’t he soon breathe up all the oxygen in the space. As the CO2 content of the air rose, did the water naturally absorb it and give back new, fresh oxygen to sustain his respiration? There’s an interesting physics debate about this underway here. One thing we can’t argue with it the fact this man did survive in a relatively small air pocket for 3 days. How was it possible?

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17 Answers

CWOTUS's avatar

For one thing, the air was highly compressed, because of the depth of the wreck. So his breathing would have been much “shallower” in terms of oxygen usage, than it would have been at sea level. Credit the builder of the tug he was on, which fine construction enabled a relatively large bubble of compressed air to remain in what was never intended to be “a pressure vessel”.

I don’t know the depth of the wreck, but judging by the squeaky voices of the divers on the audio track, and the fact that a decompression stage was required for the divers and the survivor, it had to have been fairly deep. So that air that he was breathing was quite highly compressed.

Smitha's avatar

It’s truly a miracle. He is alive just because of his strong will power and determination to live. His physical strength, capacity to bear cold and survive on limited supply of oxygen all gave him the chance to live again.
Scientifically speaking there was obviously enough compressed oxygen in the space to support his biological requirements for survival, but there couldn’t have been much to spare. His ability to keep calm kept him from burning through his limited oxygen supply.

Coloma's avatar

Maybe he just has a really small brain that doesn’t require a lot of oxygen, or, that bottle of Coke, ya know, the gods must be crazy. lol

Pandora's avatar

Or maybe it was really just a misprint and it was 3 hours or 30 hours and not 3 days.

Lightlyseared's avatar

I take it we’re not going to accept because there was enough for him to survive for 3 days as an answer?

YARNLADY's avatar

@Lightlyseared That was my answer when my grandson bought it up. I just figured there must have been enough air in there to last.

Maybe it was like the Haunakkah oil and God made it last long enough.

JLeslie's avatar

I thought of Chanukah also. :)

The story is remarkable. I wonder if the details are really correct?

Seek's avatar

From reading the source story, it seems he was in a fairly large cabin. Large enough that he had to “wade across the room” to bang on the wall trying to get their attention. It’s not like he spent three days in a coffin-sized space.

gasman's avatar

A typical resting oxygen (O2) consumption is 250 ml per minute.
There are 60*24 = 1440 minutes per day.
There are 28.32 liters per cubic foot.

So oxygen consumption is (0.250)*(1440) / (28.32) = 12.8 cubic feet of pure oxygen per day. In air, however, oxygen is diluted to 21%. So O2 consumption, expressed as a volume of air, is 12.8/0.21 = 61 cubic feet per day. 3 days would require 183 cubic feet of air.

The story I read said the guy was trapped in a toilet 4 feet square, with an air bubble about 4 feet tall. Taken at face value, this makes his air supply 4*4*4 = 64 cubic feet—seems like just enough for one day.

But wait—the sunken boat was found in 30 meters (about 100 feet) of water, corresponding to a pressure of roughly 3 atmospheres. Thus the air had been compressed by a factor of 3, so every cubic foot of this air contained the same number of molecules as 3 cubic feet of air at sea level. So the air bubble was effectively 192 cubic feet of air—just enough to survive 3 days.

He could not have survived another day!

JLeslie's avatar

Figures @gasman knows the math for O2 consumption.

Would his bubble be all O2 though? Part of the air is other gases isn’t it?

snowberry's avatar

@gasman You’re forgetting this regarding the diving bell spider: “Frequent replenishment at the surface is unnecessary in well-oxygenated water, because the structure of the bell permits gas exchange with the surrounding water: oxygen is replenished and carbon dioxide expelled by diffusion…as oxygen in the bubble is used up, more can diffuse in, whereas as carbon dioxide accumulates, it dissolves in the water and is lost. This system has been referred to as “the water spider’s aqua-lung of air bubbles,” but it is actually more advanced than the real Aqualung, which needs to be refilled frequently with compressed air, not having the option of continuous exchange of oxygen and carbon dioxide with the gases dissolved in the water.”

A certain amount of air in his little room had to have been replenished with oxygen.

gasman's avatar

@JLeslie The bubble starts off 78% nitrogen regardless of pressure. Little by little, however, the oxygen gets replaced by a roughly equal volume of carbon dioxide. By the time your oxygen runs out, you’re probably already sick with CO2 toxicity (acidosis, narcosis, etc).

@snowberry The comparison between spiders and people fails because of scaling factors. Both the spider and its air bubble are something like 100 times smaller than the man and his bubble. The surface area to volume ratio is much greater for the spider, which means that diffusion of oxygen & CO2 at the gas-liquid interface is also greatly enhanced for the spider compared to the the man.

Also he’s in a bathroom where the only air-seawater interface, to allow even a meager amount of gas diffusion, is around his waist—the rest of his bubble’s surface consists of impermeable walls.

filmfann's avatar

It was a remarkable story. He had a large enough oxygen pocket to last, but just barely.
The rescuers were just trying to gather the bodies. They didn’t expect anyone to be alive.

ETpro's avatar

@CWOTUS The ship was about 30 meters, or roughly 100 feet down.

@Pandora The story was widely reported by numerous reputable news agencies. All gave the details of dept, construction of the vessel, etc. the same. He was down there for three days.

@gasman I believe that even though scaling factors might not be equal, @snowberry is at least partly correct. As the O2 and CO2 levels of the air bubble changed, the diffusion of CO2 into the water and O2 from the water to the air would increase at the gas-liquid interface, thus extending the time a given volume of air would be sufficient to sustain life. Now, the bonus question. How does this diffusion rate differ at 30 meters depth?

Judi's avatar

@ETpro, I learned some of that in my scuba classes but I don’t remember. I better stay I. Pretty shallow water when I go again.

ETpro's avatar

@Judi You definitely don’t want to be making SCUBA dives to 30 meters if you don’t remember all the lessons.

gondwanalon's avatar

I’m not sure if anyone has mentioned that the cold Atlantic water would slow down the man’s metabolism which of course would slow his O2 consumption.

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