The normalization of dives to 100 meters and beyond

[silent running]

I can think of five publicized fatalities in dives to around 100m in the last few years. If there are indeed only a few hundred people making these dives, they must indeed be hazardous. I think they were predominantly just shy of 100m rather than just more than 100m, perhaps that's why.

That was my seat of the pants impression from 20+ years of RB diving. If I’m off, it’s by one order of magnitude, so let’s say a few thousand. And I would agree, it means hypoxic trimix diving is still a risky proposition. BUT, the reasons why it’s risky are and should be a matter of continuing debate. Is it because we don’t know enough about physiology and helium based mixtures and high PO2 diving? Or are the skill sets/procedures for hypoxic trimix still in need of refinement? One is much more manageable as risk than the other, and it needs to be further sorted out to whatever degree possible. It is imperative that we do so if we want the sport to continue, IMHO...

 

[rjack321]

I don't do these sorts of dives and I do recognize that you have firsthand expertise. Yet there have been fatal accidents that do not involve a high level of support -- no habitat, no dive team placing stages before or cleaning them up after. I would hold up as examples the double fatality at Eagles Nest about a year ago, and the recent double fatality in Lake Michigan. In each case, there was surface support in the form of other divers with emergency gas on hand, but nothing beyond that---no chamber aboard, no habitat, no bailout placed at depth beyond what the divers took with them, no communications. I think the track record of the WKPP and some other exploration oriented groups shows that it is possible to conduct dives to these depths safely. What I find troubling is that a buddy team -- whether husband and wife or two friends -- would undertake such dives with no more outside support than, say, a dive on the Spiegel Grove.

Part of the attraction of a rebreather is that it allows dives that were previously team dives (due to gas logistics) to be conducted by buddy pairs or solo divers.

Well in this recent MI event and Eagle's nest double fatality we dont actually know if support divers would have made any difference at all. At Eagle's it seems that at least one diver had to remove his functioning CCR to get out of Revelation Space. So not sure what supporting divers at <200ft would have done unless they just waited and waited for two emerging divers exiting on one diver's BO and one being extremely light from ditching his JJ. Which honestly nobody plans for anyway (lead to hold him down?)

 

[Schwob]

Which honestly nobody plans for anyway (lead to hold him down?)

I believe that to be true from mere, but limited observation. Not diving RB or even OC teh diving, mind if I ask:
Wouldn't the ideal way of diving a balanced rig involve having the rig and yourself balanced so as you still are balanced w/o rig (I do realize that posdibly multiple BO tanks additiobalky complicate that)?
What, in a practical world speaks agains planning and executing that way?
I am asking more to learn than to question... don't take it the wrong way...

 

[rjack321]

I believe that to be true from mere, but limited observation. Not diving RB or even OC teh diving, mind if I ask:
Wouldn't the ideal way of diving a balanced rig involve having the rig and yourself balanced so as you still are balanced w/o rig (I do realize that posdibly multiple BO tanks additiobalky complicate that)?
What, in a practical world speaks agains planning and executing that way?
I am asking more to learn than to question... don't take it the wrong way...

There's no way to not have your body be positive in a drysuit - unless you want to wear a weight belt and risk losing it. Which is way worse

 

[2airishuman]

Well in this recent MI event and Eagle's nest double fatality we dont actually know if support divers would have made any difference at all. At Eagle's it seems that at least one diver had to remove his functioning CCR to get out of Revelation Space. So not sure what supporting divers at <200ft would have done unless they just waited and waited for two emerging divers exiting on one diver's BO and one being extremely light from ditching his JJ. Which honestly nobody plans for anyway (lead to hold him down?)

I'm just pointing out that in neither case was there any support team in the water.

I don't have an opinion one way or another on whether the presence of a support team in the water would have improved the odds in these two particular cases.

 

[AfterDark]

Physiological conditioning might happen if the older diver went diving 2-3 times a week all year round, but I doubt that’s what most recreational divers do. Insert running, swimming, cycling, or any other physical activity, and it makes more sense. And even then, most of the gains in performance are lost after a layoff of several weeks.

We are discussing 300+FSW dives, most tech divers don't do such dives routinely. So we're discussing the few, the exceptions, to the most. I do agree an exercise program tailored to scuba diving is a must in the equation, as well as a moderate life style. As far as gains lost in performance, that is not the same as the body adapting to a repeated stress. Expressed another way, IMO decades of diving creates a familiarization that the body retains. A 55 year old gets OW @56 AOW @ 59 gets into tech @ 65 makes extreme type dives. That is not the same as someone that goes thru the same time line starting at 20 or even 30 and continues to dive into their 60's and starts making extreme dives.

Anyone conditioned to physical activity will, after a long layoff recover to their former condition sooner than someone trying to get to the same level conditioning for the 1st time. That is the type conditioning I'm trying to express.

Albert Falco was diving into his 80's. Not the extreme dives we're discussing but who's to say what's extreme for an 80+year old?

 

[TrimixToo]

There's no way to not have your body be positive in a drysuit - unless you want to wear a weight belt and risk losing it. Which is way worse

Weight harness. Hard to lose.

 

[rjack321]

Weight harness. Hard to lose.

are you ditching CCRs at like 280-290ft?

 

[TrimixToo]

are you ditching CCRs at like 280-290ft?

No. However, it's an alternative to a weight belt.

 

[Superlyte27]

Eagles Nest was a Cascade of mistakes that started before they entered the water. Support wouldn't have changed anything.