Ku przestrodze, odkopuję odmęty internetu dosłownie sięgając dna 2000 r. #nurkowanie #sport #wakacyjnewypadki

Yuri Lipski, rosyjsko-izrealeski nurek, zginął 28 kwietnia 2000 roku podczas nurkowania w Blue Hole w Dahab, Egipt (zwanym również cmentarzyskiem nurków). Lipski, który miał tylko 22 lata, zanurkował na głębokość około 91 metrów, znacznie przekraczającą jego umiejętności, doświadczenie oraz możliwości jego wyposażenia.

Film rejestrujący całe zdarzenie.
https://www.youtube.com/watch?v=cRj0lymMMGs

Tarek Omar, po odratowaniu i znalezieniu kamery:

"Two days after we recovered his remains and gave [his mother] his belongings and equipment, she came to me asking that I help her disassemble them so she can pack them. The camera should have been damaged or even broken altogether because I had found it at a depth of 115 metres, and it is only designed to sustain 75 metres; but, to my surprise, the camera was still working. We played it and his mother was there. I regret that his mother will have this forever... If I had known the footage existed I’d have flooded it. I think the thing that really upset and saddened me about it was that his mom has it now – she has the footage of her own son drowning."

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Komentarz z yt - objaśniający dla nie-nurków pewne technikalia.

@SniffBackBetter 2 lata temu

"For those who are wondering what happened, I'll try to explain exactly what's going on with enough technical detail to make sense of it, but not so much that non-divers will be confused.

In this footage you're watching Yuri Lipski attempting what's known as a "bounce" dive, a fast descent to a given depth followed by an immediate ascent, almost always attempted by divers trying to break their own depth records. In diving circles they're known as being very dangerous, even with a lot of experience and careful planning. Without the necessary experience and planning, they're strictly frowned upon and regarded as extremeley reckless.

He'd apparently mentioned doing this bounce dive in the days before this footage was shot, and was repeatedly warned against it by fellow divers.

Recreational divers almost always dive using a single 12 or 15 litre cylinder of compressed air (the exact same air you're breathing right now, just compressed into the cylinder to get as much inside as possible) and they'll never go beyond 40 metres (131 feet) in depth.

There are several reasons for this depth limit, but the reasons most relevant to this video are as follows:

1. The deeper you go, the more the increasing pressure causes nitorgen to have a narcotic effect on the human body (and air is 78% nitrogen). Yeah it might sound crazy, but breathing air can actually be like taking a narcotic drug if you dive deep enough. This effect usually begins at around 18 metres (60 feet) and is known as nitrogen narcosis. It affects everybody differently but for most people it's safely manageable at 40 metres.

2. At a depth of around 57 metres (187 feet), oxygen as it occurs in normal breathing air actually becomes toxic to the human body, with rapidly increasing risk of seizures and death the deeper you go past that point.

3. The deeper you go, the faster you breathe your air due to the increased pressure (literally the result of all that weight of water above you pressing down). For example, on the surface, to fill your lungs with 1 litre of air takes (unsurprisingly) 1 litre of air, but at a depth of 40 metres that same breath would require 5 litres of air.

4. The deeper you go, the more the air inside your body and your buoyancy device (a piece of equipment divers use in order to control their ascent and descent) is compressed, which means the less buoyant you are and thus the more inclined your are to sink rather than to float.

5. The deeper you go, the more of the nitrogen contained within air that you're breathing is absorbed into your body. When you ascend again, this absorbed nitrogen has to leave your body and if you ascend too quickly, it can cause another extremeley serious illness called decompression sickness, so a relatively slow ascent is required. If enough time is spent at depth, what's known as decompression stops will have to be made, where the diver ascends a little, then stops and waits at a certain depth for a certain amount of time (usually calculated by the dive computer worn on the wrist), before then continuing up a little more and then stopping and waiting again, and so on (the deeper you go and/or the longer your dive, the more of these decompression stops you'll have to make as you ascend). This is known as decompression diving.

These last 3 factors combined mean that diving below 40 metres simply isn't practical for the amount of air being carried, as it'd result in a very short dive, most of which would be spent slowly ascending.

Diving deeper than 40 metres is known as technical diving. Technical divers breathe different mixes of gases that allow them to avoid the dangers of nitrogen narcosis and oxygen toxicity. They also take much more of it with them in multiple cylinders.

Now that you have this context, you'll understand how dangerous it would be to try to do a bounce dive to ~92 metres (300 feet) using a single 12 litre tank of compressed air, and this is exactly what you're watching Yuri do here.

From the start of the video to 2:42 he swims out until he's over the deepest water.

At 2:43 he goes into a slow descent.

At 3:20, still descending and still likely fairly shallow, you can hear him adjusting his buoyancy slightly using his buoyancy compensation device (BCD).

At 3:40 he's now venting air from his BCD, which will make him sink faster.

At 3:47 he goes into a rapid, head-first descent.

At 4:14 you can hear his breathing begins to make a strained, wheezing/squeaking sound as his regulator (the valve through which he's breathing the air) has to work harder to supply the much increased volume of air he's taking with each breath, each one using up a huge amount of air from his tank.

At 4:20 you can hear him briefly add some air to his BCD as he tries to slow his descent slightly.

At 5:09 you can hear some kind of alarm sounding on his dive computer, most likely a warning that he's now exceeded the maximum time possible before requiring decompression stops on his ascent.

At 5:37, he's approaching the bottom and begins to film his dive computer screen as proof of his depth to show to people later when he returns to the surface. Unfortunately, by now, he's already doomed and there's no possible way for him to return to the surface before he runs out of air.

At 5:55, after several seconds of trying to film his dive computer screen, we briefly see the maximum depth displayed on his diver computer screen- 91.6 metres, which is just over 300 feet!

The nitrogen narcosis he'll be experiencing at this point will be so extreme that it's a wonder he's even still conscious. It's also a miracle he's not already suffering severe seizures due to oxygen toxicity, although the rapid jerking, erratic movements that follow could be signs of his central nervous system being compromised.

By 6:04 he's almost delirious, staggering and thrashing around, beginning to panic.

At 6:07 he obviously has a moment of enough clarity to realise that he needs to ascend immediately, and you can hear the hiss of air as he tries to inflate his BCD which would ordinarily cause him to begin to float upwards towards the surface.

At 6:11 his BCD is likely fully inflated. At a recreational dive depth he'd now be rapidly ascending, but at this depth the pressure is so great and he's likely also overweighted, that he doesn't rise up at all. At this depth, it takes such a large volume of air to inflate his BCD that he's just used up almost all of the remaining air in his tank to do so.

By 6:13 he's probably totally confused by his lack of ascent, worsened by the severe nitrogen narcosis. He then begins to stagger and stumble around, likely now totally disoriented as he was expecting to be rising towards the surface.

At 6:32, the breath you hear is noticably shorter and quieter. His tank is almost empty.

At 6:37 we hear another short, strained breath. He now begins to panic as, even in his extremely debilitated mental state, he realises that his tank is about to run dry."