Decompression

[Mark Chase]

Originally Posted by Garf

quick Chasey, post some profiles, that'll sort everyone out

Piss off you

By the by M8 your avtar dosent need that name tag round its neck, we can reckognise you from the picture


ATB

Mark

[ianfirmin]

Originally Posted by Mark Chase

Decompresion theory required for PADI OW no deco diving is taught day 1.

Never ascend faster than your own bubbles and do a 3min safety stop at 6m.

Lets face it thats all you need to know for 25m dives with 20min bottom times.

I'm slightly surprised you said that. Which size of bubble do you get them to follow? I'd suggest they use a depth gauge and timer (or a computer).

Originally Posted by Mark Chase

I would take issue with this as i have seen a few and read about many incidance of people getting bent using computers who apear at first inspection to have been well within safety margins. Do a serch on YD and you will find a douzon or more incidance so mr Gilliams reserch is a tad questionable if you ask me.

People DO get "undeserved" DCI when using computers. This reinforces my main point. The Gilliam reseach was comparative. Of the many dives logged in a consistent environment the only DCI noted was with people not using computers. The point being that there is simply not the data to produce concrete results. If you killed a few thousand humans with DCI (instead of Goats and Pigs) it could tell you a good deal. 1000's of dives with no DCI actually tells you very little except, perhaps, it's a good idea to use one.

Originally Posted by Mark Chase

I may have misunderstood the meening of your point but I can asure you most computers offer a very very slow rout to the surface

I'm sure you are right. This is a GOOD thing. DCI is mainly (always?) caused by too fast an ascent. I'm a coward.

Cheers
Ian

[ianfirmin]

Nooooo! Don't take up Golf. The happiest day of my life was when I gave it up.

[NotDeadYet]

Originally Posted by ianfirmin

People DO get "undeserved" DCI when using computers. This reinforces my main point. The Gilliam reseach was comparative. Of the many dives logged in a consistent environment the only DCI noted was with people not using computers. The point being that there is simply not the data to produce concrete results. If you killed a few thousand humans with DCI (instead of Goats and Pigs) it could tell you a good deal. 1000's of dives with no DCI actually tells you very little except, perhaps, it's a good idea to use one.

Gilliam's survey was not scientific. One of the big flaws is that it didn't take into account experience. In a liveaboard environment (which is where it took place) that caters for US divers I would imagine that there would be a clear split between experienced divers owning computers and inexperienced who don't (and trying to monitor ascent rates on an analogue depth gauge). That will obviously skew figures. His survey as I read it depended on divers presenting themselves with symptoms, DCS denial in the early 90's (when this was done) was much more of a major issue (it was a real stigma) and sub-clinical DCI (niggles, fatigue, etc) was rarely spoken about as a serious situation. Bear in mind that as it was at least 15yrs ago, most US divers who were using tables were probably using old US Navy tables which I doubt many people today would touch.

Neither tables nor computers are inherently safe or unsafe, it depends on how they are used and who uses them. Give a muppet a screwdriver and a pair of safety goggles and he'll still have his eye out in half an hour.

Cheers,

Stuart

[ianfirmin]

Originally Posted by tootricky

I'd be interested to see your sources for this. It was my understanding that research had been inconclusive and that evidence in favour of nitrox being less narcotic than air is purely anecdotal.

Cheers/Nic

I did find this. But it's out of date and inconclusive.

Diving Doctor - Diver Magazine