Diving incident at Eagles Nest Sink

[oya]

Warming up another liter (2%) water on the skin shouldn't be that much of a dent in lowering the core body temperature. We are not flushing the warm water out anyway. We are letting the cold water in, warming it up, keeping that warm water inside the suit & letting the air out.

To sound a bit less glib and more constructive (because this is one of those things that makes my eye twitch when I hear instructors imparting this "wisdom" on their students, who will then go out into the wild to repeat this)...

All systems go from a state of order to a state of disorder. This is an eternal truth. Eggs don't unbreak. Logs don't un-burn in a fire. And heat dissipates, it never, ever concentrates without expending energy to make it do so.

You are not "warming" the water in your wetsuit (or, in this example, the drysuit). You are losing heat to it. That water will, in turn, also start to lose heat to any surrounding media. In the case of a wetsuit, that media is a layer of lycra, then air-filled neoprene, then another layer of lycra, then the surrounding water. The air-bubbles of the neoprene are providing a layer of insulation against the surrounding water. This happens less effectively at depth considering the air-bubbles get smaller at depth (ever notice how water at depth seems colder, even when there's no thermocline?).

Given enough time a 98.6 degree, live person in a 7mm wetsuit in 70 degree water will be a dead 70 degree body in a wetsuit where every tiny airspace is 70 degrees in 70 degree water.

If you flood a drysuit there is no insulating layer at all. You are, effectively, naked in 70 degree water. And going to freeze to death. Soon.

S = k log W

 

[Dan]

To sound a bit less glib and more constructive (because this is one of those things that makes my eye twitch when I hear instructors imparting this "wisdom" on their students, who will then go out into the wild to repeat this)...

All systems go from a state of order to a state of disorder. This is an eternal truth. Eggs don't unbreak. Logs don't un-burn in a fire. And heat dissipates, it never, ever concentrates without expending energy to make it do so.

You are not "warming" the water in your wetsuit (or, in this example, the drysuit). You are losing heat to it. That water will, in turn, also start to lose heat to any surrounding media. In the case of a wetsuit, that media is a layer of lycra, then air-filled neoprene, then another layer of lycra, then the surrounding water. The air-bubbles of the neoprene are providing a layer of insulation against the surrounding water. This happens less effectively at depth considering the air-bubbles get smaller at depth (ever notice how water at depth seems colder, even when there's no thermocline?).

Given enough time a 98.6 degree, live person in a 7mm wetsuit in 70 degree water will be a dead 70 degree body in a wetsuit where every tiny airspace is 70 degrees in 70 degree water.

If you flood a drysuit there is no insulating layer at all. You are, effectively, naked in 70 degree water. And going to freeze to death. Soon.

I'm referring to a life or death emergency situation of being positively buoyant due to drysuit full of air, when you doff your gear. Besides, don't you put some layers of warm clothing underneath your dry suit?

 

[Steve_C]

Water is a much better conductor of heat than air. So stuff+water will conduct better than stuff + air where stuff is drysuit, garments, etc. Not saying stuff + water will not give some insulation. Just that it will be less. It's physics.

 

[Jack Hammer]

I think flooding the drysuit to reduce the positive buoyancy is a good idea. I think the cold water entering inside the suit will soon be warmed by the body temperature & becoming part of the dry suit, a wet-drysuit, so to speak.

Our body contains 65% of water, about 50 liters of water for a 160lb guy. Warming up another liter (2%) water on the skin shouldn't be that much of a dent in lowering the core body temperature. We are not flushing the warm water out anyway. We are letting the cold water in, warming it up, keeping that warm water inside the suit & letting the air out.

No personal offense intended, Wild speculation mixed with reading Wikipedia only muddy getting at the truth of what happened and confuse others.

ps: It doesn't sound like you are familiar with how a drysuit provides insulation.

 

[PfcAJ]

I'm referring to a life or death emergency situation of being positively buoyant due to drysuit full of air, when you doff your gear. Besides, don't you put some layers of warm clothing underneath your dry suit?

They won't be warm when soaked with water.

Good grief.

 

[Dan]

Water is a much better conductor of heat than air. So stuff+water will conduct better than stuff + air where stuff is drysuit, garments, etc. Not saying stuff + water will not give some insulation. Just that it will be less. It's physics.

True. Given this Diver2 situation, what would you do? Would you let the air out of the dry suit which may also trickle some water, as it displaces the air, to manageable buoyancy to get down & search for the CCR & a full 95 BO or stay up plastered on the ceiling? We know the outcome of the latter.

 

[cerich]

Great post but good undergarments do slow heat loss even when wet. It is far from optimal, also far from having no insulation at all.

I probably shouldn't say this as I only sell shell suits, but I have always recommended that when doing long exposure deco dives in cold water that a neoprene drysuit offers a better safety hedge.

To sound a bit less glib and more constructive (because this is one of those things that makes my eye twitch when I hear instructors imparting this "wisdom" on their students, who will then go out into the wild to repeat this)...

All systems go from a state of order to a state of disorder. This is an eternal truth. Eggs don't unbreak. Logs don't un-burn in a fire. And heat dissipates, it never, ever concentrates without expending energy to make it do so.

You are not "warming" the water in your wetsuit (or, in this example, the drysuit). You are losing heat to it. That water will, in turn, also start to lose heat to any surrounding media. In the case of a wetsuit, that media is a layer of lycra, then air-filled neoprene, then another layer of lycra, then the surrounding water. The air-bubbles of the neoprene are providing a layer of insulation against the surrounding water. This happens less effectively at depth considering the air-bubbles get smaller at depth (ever notice how water at depth seems colder, even when there's no thermocline?).

Given enough time a 98.6 degree, live person in a 7mm wetsuit in 70 degree water will be a dead 70 degree body in a wetsuit where every tiny airspace is 70 degrees in 70 degree water.

If you flood a drysuit there is no insulating layer at all. You are, effectively, naked in 70 degree water. And going to freeze to death. Soon.

S = k log W

 

[Dan]

No personal offense intended, Wild speculation mixed with reading Wikipedia only muddy getting at the truth of what happened and confuse others.

ps: It doesn't sound like you are familiar with how a drysuit provides insulation.

My wild guess is air is the insulation. But we are discussing life / death situation decision to make.

 

[cerich]

My wild guess is air is the insulation. But we are discussing life / death situation decision to make.

Air and the materials used, they work together. Using a drysuit you have to be aware of how air provides loft in the undergarments which increases heat retention over a compressed undergarment that allows much faster heat transfer (to the water from you-bad).

 

[Dan]

They won't be warm when soaked with water.

Good grief.

They won't. However, it might be surviveable and a trade-off with a better buoyancy to search for the gear.