Who says this? Total nonsense.
Deep dive and user adjustment knob
- Thread starter dandecraene
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Probably someone who once was told that water is at its highest density around that temperature, and later mixed up things royally.
Freezing freshwater is pretty exactly 0 degrees C. Freezing saltwater is a few degrees colder. And the proper mixture of ice, water and salt is between 15 and 20 degrees C below zero. In all cases, the water is at the same temperature as the ice, i.e. below 39F/4C
NOTE: This post is about slow paced drysuit diving in very cold water with no current and with helium on deeper dives. My thoughts do no apply to fast paced high workload wetsuit dives on air to 130 feet. I am also not qualified to give medical advice...
Everyone I know dives with the venturi lever on minus and the adjustment knob at least somewhat tightened and with less than 10bar of IP and nobody I know has ever been treated for IPE.
I have never found a slightly higher cracking pressure to be a real problem (except once and then I had my regs serviced). Slightly higher could mean different things to different people, as I have no actual numbers to present.
It is worth mentioning though that when diving deeper than 115 feet we typically use 35% helium in the breathing mix (because of the environtment). It's easier to breathe than nitrogen. Also, there are no currents here and we typically dive quite slowly (it makes the gas last longer - gas consumption is relative to speed squared - twice the speed, half the distance (ignoring base consumption)). The workload on our dives is thus low, irrespective of depth. Hence, carbon dioxide retention is not a major problem.
I do not know why people suffer IPE, but as far as I know it is not caused by breathing effort only. It also depends on how much water you drink and in which position you are in the water. I tend to dive in fairly decent trim. Hence there is no pressure gradient acting on my body and pushing body liquids up. I also tend to drink too little (drysuit, no pee valve) but I compensate for that with conservative decompression. Hence, there is less water to flood the lungs. Other divers drink more and they still do not get IPE.
I am aware of two unexplained deaths while diving, though (in ten years). Could be anything. Medical reports are not public. In the same time there have been several deaths caused by free flow and the stress caused by the situation.
Everyone I know dives with the venturi lever on minus and the adjustment knob at least somewhat tightened and with less than 10bar of IP and nobody I know has ever been treated for IPE.
I have never found a slightly higher cracking pressure to be a real problem (except once and then I had my regs serviced). Slightly higher could mean different things to different people, as I have no actual numbers to present.
It is worth mentioning though that when diving deeper than 115 feet we typically use 35% helium in the breathing mix (because of the environtment). It's easier to breathe than nitrogen. Also, there are no currents here and we typically dive quite slowly (it makes the gas last longer - gas consumption is relative to speed squared - twice the speed, half the distance (ignoring base consumption)). The workload on our dives is thus low, irrespective of depth. Hence, carbon dioxide retention is not a major problem.
I do not know why people suffer IPE, but as far as I know it is not caused by breathing effort only. It also depends on how much water you drink and in which position you are in the water. I tend to dive in fairly decent trim. Hence there is no pressure gradient acting on my body and pushing body liquids up. I also tend to drink too little (drysuit, no pee valve) but I compensate for that with conservative decompression. Hence, there is less water to flood the lungs. Other divers drink more and they still do not get IPE.
I am aware of two unexplained deaths while diving, though (in ten years). Could be anything. Medical reports are not public. In the same time there have been several deaths caused by free flow and the stress caused by the situation.
What is the formula you are using to reach this conclusion??
Do you mean one quarter the distance?
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