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A friend of mine also nearly drowned in a pool. He described it as a light switch being turned off the instant he inhaled water and then laying poolside coughing it up. No memory of the time in between. Sounded to me like the experience someone has as they're sedated for surgery. One moment you're looking up at a nurse or doctor in their mask and then, with no sense that hours have passed, you're groggily coming to in Recovery.

The idea that it's a frightening but quick and painless end will be no comfort to families of the sailors. But in a situation like this hard decisions such as sealing off water tight compartments must be made. Whoever made that call will have to live with it the rest of his life.

katana said: "A friend of mine also nearly drowned in a pool. He described it as a light switch being turned off the instant he inhaled water ..."

I think there may be some very interesting physics involved.

Let's start by thinking about what happens when an aircraft at high altitude loses cabin pressure.

Just prior to decompression, the passengers are all breathing normally. They inhale a mixture of relatively inert nitrogen and about 21 percent oxygen. When exhaled, the air still contains about 16 percent oxygen.

Each breath only exchanges a small fraction of the total lung volume during breathing at rest. There is quite a bit of air with perhaps 18 or 19 percent oxygen available in the lungs.

Imagine now that a person intentionally holds their breath. The amount of oxygen in the lungs slowly falls as it is carried away by the blood and is replaced by carbon dioxide. For perhaps several minutes, the amount of oxygen in the blood is relatively unaffected because of that available oxygen already in the lungs.

Now lets imagine that person on an airplane has just experienced an unexpected decompression. The environment is suddenly at one-third atmospheric pressure, which means that there would be only one-third as much oxygen available. The greater pressure in the lungs would force a person to exhale forcefully about two-thirds of the air in their lungs. The oxygen content in the lungs would fall to one third of what it was due to the pressure change.

With so little oxygen now in the lungs, any oxygen in the blood that reaches the lungs is going to diffuse into the lungs instead of in the normal direction. Unconsciousness would quickly follow in just seconds instead of minutes. Getting to an oxygen mask quickly becomes a matter of life and death.

Now let's imagine what happens to a drowning person. They exhale air and inhale water. After just a couple of breaths, the lungs contain water instead of air. The passage of oxygen into the blood ceases immediately and unconsciousness occurs quickly.

If anyone has a better explanation I'd be delighted to hear it. I thought this through once because I was curious as to why one can't simply hold their breath during an airplane decompression event. The force of the air pressure in their lungs doesn't allow them to hold onto the life preserving oxygen.

But in a situation like this hard decisions such as sealing off water tight compartments must be made. Whoever made that call will have to live with it the rest of his life.

In my submarine training, the sounding of the collision alarm was enough to get the ship sealed, whether we were on the surface or submerged. Saving the ship is much more important than saving a few in the leaking compartment(s). It's what you did, not what you thought about like in the movies.