Really Cold Water and Max Obligation Time

[rjack321]

Back to the question.... I think that DAN (or an equivilent MD) could provide some good insight to this. The time spent exposed to cold water will become fatal, but so will DCS. I think that some time tables for exposer to water temps probably exist somewhere. Beyond those limits, you would have to surface and try to get to a chamber ASAP.

At some point, well before your dead, your extremities will be so constricted and with so little blood flow that they won't be off-gassing anyway.

I suppose your spine and core with have off-gassed, but as soon as you warm up all that super-saturated blood and peripheral tissue will flood into your core. Not good.

A suit failure is really deep doo doo, one of the few things you can't train and practice for either.

 

[rjack321]

In terms of the drysuit flood, it would take a slice across the entire front of the suit for example to cause a "major" failure. The above summary of the flood experience is right on. I once dove in 33 degree water with a hole in my suit. I realized it the moment I submerged, surfaced to inspect, then dove for as long as I was reasonably comfortable. The right thermals will do a good job to 'wic' the water away from your skin until it become saturated. I lasted for 15 minutes with water coming in my arm until I needed to surface.

Locally, I don't know all the details, a diver sliced open a DUI TLS 350 on a wreck. This was beyond 150ft and he had a serious deco obligation. OMG time. He completed as much deco as possible getting quite hypothermic in the process. I don't think there were any chamber rides involved or if was winter (49F) or summer (53F)

 

[limeyx]

...

A suit failure is really deep doo doo, one of the few things you can't train and practice for either.

Be careful what you say or some morons (er, training agency) might take you up!

 

[limeyx]

As someone who has done an hour dive in Puget Sound (55 max temp) in a 3 mil wetsuit and 1mil gloves, I can assure you -- your body can take more than you think. I did stop shivering about 40 minutes in, and did come up mildly hypothermic, and yes it was stupid, but if I was in mandatory deco I'd do it again. What can I say -- I really wanted to dive

Re: wetsuit as undergarment. It sucks. You have no flexibility, and although it's better than nothing, the thermal properties really don't help much. I bought an el-cheapo seasoft undergarment and it works substantially better (now I have a Weezle and it's amazing).

Keep in mind that even a wet drysuit will also provide thermal protection -- especially in an undergarment like a Weezle, which remains an insulator even when wet. A fully soaked drysuit with a good undergarment will always be better than a thin wetsuit or nothing at all.

I'd say "I really wanted to do the dive" is something of a poor reason, however, a no deco dive, you can (by definition) essentially ascend when you get cold and be OK.

I belive deco research shows that you deco really poorly when cold, so a 30 min deco obligation could become an hour to make up for it. Of course, in those 30 mins you get even colder ...

I would say really really seriously consider a drysuit for any serious kind of a dive in those temps, or at the very least a thick wetsuit.

 

[Tassie_Rohan]

Hhmmm - another advantage of a neoprene drysuit: keeps you warmer in case of a flood.

 

[fire_diver]

At some point, well before your dead, your extremities will be so constricted and with so little blood flow that they won't be off-gassing anyway.

I suppose your spine and core with have off-gassed, but as soon as you warm up all that super-saturated blood and peripheral tissue will flood into your core. Not good.

A suit failure is really deep doo doo, one of the few things you can't train and practice for either.

That's my feeling on the subject also. Better to end the deco early (after standing as much frigid water as possible) and pray you get a quick ride to the chamber.

 

[rjack321]

Be careful what you say or some morons (er, training agency) might take you up!

Anything's possible, but I doubt this will be added to any course soon!

 

[Daryl Morse]

Superwarm wet hood. Hands and feet are the first to go, but on Saturday's 80min dive I never got cold (did swim around a bit on the 20' to keep the blood flowing).

What do you wear to keep warm on an 80 minute dive (e.g., gloves, hood, undergarments)? My dives in Vancouver are typically 40-50 minutes depending on profile and I'm getting pretty cold by the time I get out of the water. The reason I ask is because I'm getting fitted for a new drysuit next week and I'm thinking about what undergarments to get. I've been wearing fleece, but I'm considering a Weezle. I will probably switch to dry gloves as well.

 

[TSandM]

I've done 80 minutes a couple of times, and a dozen or so 70 minute dives in the Sound. I use a Diving Concepts 200g Thinsulate jumpsuit, with a 200g Thinsulate vest over it; under that, I wear a layer of nylon/fleece skiing undergarments. A good hood and dry gloves complete the picture. As long as I keep moving, I get a little cold but don't shiver.

 

[Rick Inman]

Under my Diving Concepts trilam custom suit, I'm wearing some Whites undies (200g I think), a layer of polertec fleece and a fleece skin. Also, dry gloves and 7mm hood. On my feet, fleece socks under Weezel Extreme socks.

And argon.

Last night I got a little cold after an hour, but we were going really slow. Actually, I was with a guy who just wated to practice holding still, so we did a lot of that.

Also, I feel like I get colder in fresh water than salt.