What's with the UTD haters?

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In fairness, he's diving in relatively warm, shallow spots like Truk. It's not as though he's pushing any boundaries or doing anything noteworthy from an exploration perspective. I'd expect ratio to be just fine in those circumstances.
There's nothing shallow about diving two weeks continuously on the wrecks of the Fourth Fleet Anchorage (San Francisco Maru, Aikoku Maru, Nagano Maru, Shotan Maru et al) all ranging 45m to 57m; and the Oite Destroyer or the Katsuragisan Maru both near the North Pass at 63m and 66m deep respectively.
Except that it apparently doesn't, hence the addition of IWR to the decompression strategy. I don't know, it just seems to me that if the plan includes pretty much expecting to get bent, it might be an idea to take another look at the plan...

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---------- Post added June 26th, 2014 at 08:45 AM ----------

Kev, what does NEDU research regarding possible problems with deep stops have to do with strategies for managing decompression over multiple dives/multiple days of diving? I'm not seeing the logic. On-gassing of slow tissues during deep stops has nothing to do with long-term build-up of inert gas in those tissues over extended periods of decompression diving, other than to suggest that you should be using an old-fashioned neo-haldanian model (raw Buhlmann, anyone?) so as to avoid compounding the problem by hanging around deeper during your ascents.

Apart from anything else, Ratio Deco was originally intended to mimic the output from algorithms modified to start decompression deeper - precisely the model that NEDU are suggesting might be flawed. Trying to 'fix' that with IWR rather than going back and re-examining the decompression strategy seems, at best, stubborn.

And I'm genuinely curious to know whether this approach to decompression - "probably bend and hope to mend", perhaps - is something you were trained to use, or you've arrived at it in the course of your own experience.

Edit: For some reason, Tapatalk wasn't showing me the pale grey bit until after I posted. So you're not actually using RD at all, then, but running your dives with either VPM-B or ZH16 on the Petrel?


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Absolutely agree that IWR is a potentially valuable tool - I'm six hours from a chamber if everything slots into place and the timings work out, anything up to a couple of days if there's a problem.

What I don't get is the implicit 'I don't expect my chosen decompression strategy to get me through my planned dives unbent, so I'm ready to rock with IWR' approach. As you say, it's all a matter of probabilities, but I'd be looking for ways to shift the odds in my favour in preference to starting every dive with a FFM hooked up to a G-cylinder of O2.


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Paradoxically, that's what the NEDU study seems to be implying with regards to deep air decompression diving (I would still like to see an additional NEDU lab study testing deep stops, but with the use of trimix standard gases with intermediate Eanx50 deco mixes and pure oxygen). I still use RD similar to 30/85 GF's, with S-curve deco profile sequences on Eanx50 starting at 21m, but now extending the O2 profile at 6m out 10 to 20min on top of what RD prescribes, and with shorter deep stops --especially if using high fractional N2 content bottom mixes like 20/20 trimix or Deep Air. The Petrel is there to track CNS O2 exposure and inert gas loading real time during the dive and residual inert gas retention over as many continuous days or weeks that I'm deep diving with deco.

Another factor IMO/IME is inflammation due to muscularskeletal/joint injury --both of my DCS I incidents coincided with just prior shoulder-upper arm muscle/joint strains due to manipulating stage bottles (left shoulder Truk 2007); and fatigue/strain from cruising & grand touring on scooter (right upper arm Bikini Atoll 2013 --the USS Saratoga aircraft carrier being 888'/270m long, depth range 18m to 57m), see this link:
http://www.pvv.org/~olafb/dir-no/library/deco/bubble_immune_response.pdf
 
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MODPOST

Many posts have been removed from this thread, as they only represent personal back-and-forth, and add nothing at all to the topic. I believe the topic has been exhausted; if anyone has specific questions which were not covered, please feel free to start another thread to ask them.
 
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