Underwater rescue - diver cam footage!
Discussion
Amazing. Felt a rising tide of panic watching that.
I presume the problems bringing him up would be due to being down there for 3 days. He was breathing the air that he sunk in, so not pressurised out of a tank, or the weird mixture of gases the divers used.
Can anyone explain.
Love how cool the Saffer in command was, eh!
I presume the problems bringing him up would be due to being down there for 3 days. He was breathing the air that he sunk in, so not pressurised out of a tank, or the weird mixture of gases the divers used.
Can anyone explain.
Love how cool the Saffer in command was, eh!
WOW, I have a mate who'se done this for many years both in the military and privatly. I sent it on to him, thanks for the link, i know the whole situation is a bit grizzly but i couldnt help laughing when the sat diver s
ts himself when the hand appears and waves at him, totally unexpected!
ts himself when the hand appears and waves at him, totally unexpected!croyde said:
Amazing. Felt a rising tide of panic watching that.
I presume the problems bringing him up would be due to being down there for 3 days. He was breathing the air that he sunk in, so not pressurised out of a tank, or the weird mixture of gases the divers used.
Can anyone explain.
Love how cool the Saffer in command was, eh!
At 30m he would suffer from the bends (nitrogen trapped in blood) if they brought him up too quick.I presume the problems bringing him up would be due to being down there for 3 days. He was breathing the air that he sunk in, so not pressurised out of a tank, or the weird mixture of gases the divers used.
Can anyone explain.
Love how cool the Saffer in command was, eh!
They will have to decompress bringing him up slowly on tri mix (http://www.techdiver.ws/trimix_eng.shtml) a process which I'd imagine would take hours being down for that long.
croyde said:
Amazing. Felt a rising tide of panic watching that.
I presume the problems bringing him up would be due to being down there for 3 days. He was breathing the air that he sunk in, so not pressurised out of a tank, or the weird mixture of gases the divers used.
Can anyone explain.
Love how cool the Saffer in command was, eh!
A normal scuba regulator delivers gas at around 10 bar above ambient pressure to a demand valve in the diver's mouth. The diver breathes as normal and the gas going into is lungs will be equal to the ambient pressure. Every 10 metres sees pressure increase by 1 bar, so 1 bar at sea level plus 3 for 30 metres means the diver is breathing gas at a pressure of 4 bar.I presume the problems bringing him up would be due to being down there for 3 days. He was breathing the air that he sunk in, so not pressurised out of a tank, or the weird mixture of gases the divers used.
Can anyone explain.
Love how cool the Saffer in command was, eh!
The air pocket the survivor was in is still pressurised due to the ambient pressure of the water, so he is absorbing nitrogen the same as a diver would. I understand in this case, they took him back to the diving bell (which is at the same ambient pressure). This would then be brought up to the support vessel (maintaining the pressure at the working depth) where it would dock with a larger chamber, which is pressurised to the same depth. In here, the survivor and the divers could be brought back to ambient pressure at sea level in a controlled manner.
If you look at the PADI dive tables, a recreational diver is allowed to do a no stop dive to 30 metres for 20 minutes (there are other deco models but most divers will know that one). If you stay any longer, you are racking up deco, and at that depth for 3 days, it will take a long time to off-gas. It is most likely he would have been given a gas mix with a higher oxygen content to speed up decompression and reduce the risk of decompression sickness, but it would still take a long time.
I just run a calculation through the deco software I have on my phone and it come out with around 22 hours total deco, using 50% O2 at 21 metres and 100% at 6 metres, however, I am using it beyond its design parameters and the methods hyperbaric medical staff use will differ. I can say the time spent decompressing him would have been a long one, with close monitoring and further treatment afterwards.
Pixel-Snapper said:
At 30m he would suffer from the bends (nitrogen trapped in blood) if they brought him up too quick.
They will have to decompress bringing him up slowly on tri mix (http://www.techdiver.ws/trimix_eng.shtml) a process which I'd imagine would take hours being down for that long.
The bends, or 'decompression injury' is caused by inert gasses in the tissues - not in the blood. It is a result of compressed gas expanding and forming bubbles (although they can get amongst the blood stream and cause more problems). There is always nitrogen in our blood as the air we breath is roughly 79% nitrogen.They will have to decompress bringing him up slowly on tri mix (http://www.techdiver.ws/trimix_eng.shtml) a process which I'd imagine would take hours being down for that long.
Trimix is a blend of oxygen, nitrogen and helium. The helium is in the mix to reduce nitrogen narcosis. It does not aid decompression (helium is a 'fast gas' meaning your tissues absorb it quickly, so you have to account for helium absorption in your deco plan). The key to off-gassing efficiently is to get the oxygen content as high as possible - trimix would offer no benefit as a deco gas.
Edited by Ganglandboss on Wednesday 27th November 12:32
I believe this rescue was done divers in Saturation, as such they did no decompression in-water and simple took the poor chap back to the bell and would have deco'ed him out on the support vessel.
FWIW You can use Trimix as a decompression gas, that's if you're sufficiently deep to justify swapping off your bottom gas to a mix richer in O2 and lighter in Helium to reduce your deco obligation but its usually referred to as a travel gas, its more common to come shallow enough to jump straight to Nitrox. In saturation you can get away with deeper use of O2 as you're in a dry bell to speed the process up as there is less risk of and danger in a tox.
I would assume his major problem was CO2, in a confined space there would have been a considerable build up and it's a nasty gas when you have no access to a "fresh" breathing gas.
FWIW You can use Trimix as a decompression gas, that's if you're sufficiently deep to justify swapping off your bottom gas to a mix richer in O2 and lighter in Helium to reduce your deco obligation but its usually referred to as a travel gas, its more common to come shallow enough to jump straight to Nitrox. In saturation you can get away with deeper use of O2 as you're in a dry bell to speed the process up as there is less risk of and danger in a tox.
I would assume his major problem was CO2, in a confined space there would have been a considerable build up and it's a nasty gas when you have no access to a "fresh" breathing gas.
I could not imagine going through that. He must of presumed that he was done for and that no one was going to get him. Surprised that he didn't try to get out. Can that be done at 30m if done immediately?
I suppose you'd have to be a free diver to stand a chance. Then you would be in the middle of the sea waiting for rescue, if it ever came.
That is one lucky Cookie.
I suppose you'd have to be a free diver to stand a chance. Then you would be in the middle of the sea waiting for rescue, if it ever came.
That is one lucky Cookie.
croyde said:
I could not imagine going through that. He must of presumed that he was done for and that no one was going to get him. Surprised that he didn't try to get out. Can that be done at 30m if done immediately?
I suppose you'd have to be a free diver to stand a chance. Then you would be in the middle of the sea waiting for rescue, if it ever came.
That is one lucky Cookie.
He hardly looks like an athlete, he wouldnt know which way to get out and it would be pitch black, who'se to say he could even swim?...You could do an emergency ascent from 30m straight after the boat settled but you have to knowif you were deep enough to try, you'd have to what you're doing and even then it would be very dangerous as you have to release the air in your lungs at the same rate it expands to stop yourself getting a lung embolism...basically even someone who knows all that like myself would think twice about it.I suppose you'd have to be a free diver to stand a chance. Then you would be in the middle of the sea waiting for rescue, if it ever came.
That is one lucky Cookie.
Interestingly I sent it to my friend who has done this kind of work for a good few years and I told him before he watched it that the diver shat himself when someone tapped him on the head unexpectedly when searching a wreck, his response to it was "lol - been there". Can't wait to hear that story next time I see him!
croyde said:
I could not imagine going through that. He must of presumed that he was done for and that no one was going to get him. Surprised that he didn't try to get out. Can that be done at 30m if done immediately?
Possibly if you know what you're doing. Don't forget the chap was breathing air which was pressurised to 30m due to the water pressure. For every 10m depth you get another 1 bar pressure (so it's 4 bar at 30m because its 1 bar at the surface). Hold your breath on the ascent and the decreasing pressure will expand the gas in your lungs causing burst lungs.You would need to constantly breathe out and it's meant to be almost impossible to run out of air on the ascent due to the expansion. PADI teach 12m as a safe maximum for a controlled emergency ascent.
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