Decompression in very cold water

[Amphiprion]

I fully admit to being pretty much a warm water diver and just got a drysuit so I can practice my skills in the cold Texas winter. However, the whole concept of very cold water diving and decompression diving got me thinking - always a bad idea - I know.

What would someone do if there was a significant deco obligation and a drysuit failure say for example during a dive in antarctica? I suppose if the failure was at the wrist or foot area, one could use line or something to cut off airflow out of the suit, but what about a neck seal failure? I would think that you wouldn't have a long time before you pass out.

I've never done ice diving and most of my diving has been in the gulf, the caribbean or hawaii if not in Texas waters, so this topic has never come up among my more experienced buddies or in class.

 

[Blackwood]

If it comes to bent or die, I'll go with bent.

 

[DevonDiver]

It's one of the reasons why wrist mounted gauges are useful. Blow wrist seal.... cinch the computer strap up tight.

There's not much you can do about a puncture in any other area, other than trim your position so that the least amount of air migrates out of it. In the case of the neck seal, that would mean raising the feet up slightly from horizontal, so that the head/neck was the lowest point.

Effective undergarment insulation would be critical. It needs to be a material that still insulates efficiently even when wet.

Other than that, you're facing a typical tech diving dilema... caught between the devil and the deep blue sea.

 

[TSandM]

This is one of the reasons why we spend so much money on expensive, purpose-made undergarments. They have to keep you warm when you're dry, but more importantly, they have to continue to provide significant insulation when you are wet.

It's also one of the reasons why long deco obligations in cold water are not to be treated lightly. Hypothermia can kill, and so can DCS -- you can be faced with some ugly choices.

 

[DevonDiver]

All I have left to say is..... I just love tech diving in a rash guard

 

[Kevin Carlisle]

All I have left to say is..... I just love tech diving in a rash guard

All I have to say about that is :mooner:

 

[Doppler]

All I have left to say is..... I just love tech diving in a rash guard

I agree with Kevin... see above.


However, in answer to the OP's original question, planning for cold water decompression DOES require some special considerations as well as very particular choices for kit. Also worth noting that knowing contingency tables (either on the fly or printed and carried in a pocket) is a boon. If something does go totally pear shaped, it is a comfort to have some framework to build an absolute minimum stop time around.

 

[evil_xander]

+1 on proper undergarment. They cannot do miracles, but can do wonders comparing to something you pickup at your local sports store.

 

[rjack321]

If it comes to bent or die, I'll go with bent.

I'll go with not racking up significant deco in the first place. "significant" in 28F antarctic water would be none. 40F probably 35-40mins. 50F about 60mins. 60F about 90mins.

This is loosely based on time before exhaustion/unconciousness in case of major suit flooding.
Hypothermia Prevention: Survial in Cold Water | Minnesota Sea Grant

 

[cfenton]

This really is the one failure that we can't do a hell of a lot about. We can dive purpose-made undergarments, and cinch up gauges, but in my experience with flooded suits I still get cold, and fast.

I see this as the major limitation in cold water deco diving. At the end of the day I think it's wise to have a plan for cutting time. Coupling that with trying to figure out what you think you will be able to get away with in terms of time in the water with a flooded suit. This would give a picture of what to plan for in terms of max deco obligation.

For the most part I agree with rjack123's numbers. I might stay a little longer, but not much.