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safety: equipment/methods

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Well-Known Member
Aug 19, 2001

I'd scaned the forum for different equipment/methods to take care of the diver in danger (counter-weight etc.)
But I didn't find what I have in mind for ages.

My idea is to use the monitor device, such as those used in hospital(mounted on fingers), to monitor the hart beat.
In case of danger(blackout) the device will ignite tank/baloon an drag the diver up to the surface. Such system, but without the danger monitor, we saw in BigBlue (tank and vest).

I see some problems:
1) what is the best indication of blackout. on this the design of danger monitor will depend.

2)how big should be the tank to uplift the 3diver from ~40m

I don't think this system may be suitable for alone diving. I see situation : 2 divers, one get problems, system lift him up to the surface, second diver asist in ascending.

Please, share your opinions!
Those devices measure heartbeats don't they? Waiting for the heart to stop beating before starting to transport the diver to the surface is a little late I would think! :)

Although I have never had a blackout I'm pretty sure the heart keeps beating, doesn't it? Perhaps the heartrate drops as a result of a blackout which could be detected, but I'm not sure how reliable this would be since it is normal for the heartrate to drop during dives.

Originally posted by Beaky
I'm not sure how reliable this would be since it is normal for the heartrate to drop during dives.


Of course I mentioned heart beat but it could be differ indication (muscle stretch, neural activity-the same device as in brain study)

I think if there is strong (realiable) indication of blackout in human body, then the device to measure that, will be available.
Of course we should consider the costs and technology.

From my side this is only deliberations and I'd like to know your opinions.
It’s a very difficult thing to do. First, any kind of electronic monitoring device of vital signs is difficult and expensive to do underwater. Heart rate monitors are the only ones I know that are somewhat practical to use underwater, but they are expensive. Also, like Beaky said, there is no clear indication of the heart rate that the person has blacked out until it stops and that is way beyond a safe recovery state. An automatic timer makes the most sense in cost efficiency and reliability.

Second, when recovering from depth, the safety lanyards and rescue inflatable floats used in competitive freediving are attached to the wrist so that hopefully the divers head will lean forward with closed mouth, and water will not be forced down into the lungs. The inflatable life vests are designed to float a diver face up, which is what you want at the surface, but not on the way to the surface.

The size of the tank is easily computed. At 40 meters the volume of air is ¼ of the surface volume and thus has ¼ the amount of lift. Determine the amount of air you want at the surface than multiply it by four and add a pressure relief valve to the system to let air out on its way up so that it does not blow up.
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