Diving to 200' and Beyond

[dumpsterDiver]

No, the OP descibed 200' dives on a single, no gas specified, and 250-270' dives on trimix, with a single and a pony. It's not unreasonable to assume that the 200' are on air.


I can of course only speak for myself, but since I don't think baiting sharks is partiiclarly smart either, I'd say you're building a pretty large strawman there.


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Try reading what the op wrote. You continue to take the thread off topic . y.

 

[Bennno]

What do I mean by this: As a CCR diver, along with you Jim and Pete have accepted a much higher risk by using a CCR. The current rate of death is still around 1 in 70 units sold will kill someone. It is equivalent to BASE jumping or wing suit jumping. This is not about skill either. Many very accomplished divers have died using CCRs including Wes Skiles. What is the difference between us accepting the elevated risk of using a CCR and the OP accepting an elevated risk for their dive? Are we not all setting a personal level of accepted risk that is different from others? How can I, as a CCR diver, judge another's accepted risk level and call them a dinosaur? I think it is hypocritical at the least!

This is an excellent point.

I would bet that most dives being done on CCR these days could be done on OC.
Can't wait to hear from the people that called air diving stupid.

Pete, didn't you just buy a SF2? Those are pretty dangerous...

@DevonDiver
Don't you teach deep air?

 

[Bennno]

I think both are basicaly stupid...

I just don't agree with that, I believe that the general max air depth of 40m was introduced to suit the PADI/SSI mass and vacation/resort market. I believe, if diving was still a niche, at least 50m would still be OK with most 'advanced' divers. I just don't see the danger and nobody has really had a good example what the dangers is. In your example, I don't think the depth was the core issue but the all over conditions... and I did say earlier, for deep diving on air, the conditions need to be good, experience and you need enough bail out gas.

 

[DevonDiver]

@DevonDiver
Don't you teach deep air?

I teach the full TecRec program; which includes air at 40, 45 and 50m increments, then (normoxic) trimix to 65m and full / hypoxic trimix at 90m (training depth, no limit therafter).

However, Tec45 and Tec50 can now be taught with a normoxic trimix addition. A good move.

That's in line with most of the community nowadays. However, it's also important to note that technical diving training also puts a high emphasis on narcosis management... and every diver is taught to consider that factor as a formal component in dive planning.

Practises change. That's a big issue in this thread. When I started tech diving it was normal to conduct deep air dives, as helium and trimix training was much less available... especially in the tropics. I used to do some quite serious air diving back then. If I remember correctly, my deepest was circa 90m. I also dove solo, at night, to depths around 75m...also on air.

There's no way I'd do that now. Not for a long time. Practices get re-evaluated as time changes. If they didn't, I might end up as some old crone doing horrific dives like 'back in the day'.... and that's the difference.

 

[Bennno]

@DevonDiver
So what is the max on air when you teach? 50m?

 

[DevonDiver]

@DevonDiver
So what is the max on air when you teach? 50m?

Yep, 50m with TecRec. TDI and some others use 55m.

But, as a caveat, that's based on the diver, the conditions and the mission. The Tec50 course is a relatively straight-forward 4-tank dive. I teach in tropical warm water (albeit very variable viz) and little current on the sites used. I wouldn't do 50m for penetration, or in any conditions that I felt were unreasonably taxing.

With the new Tec45-tmx and Tec50-tmx options, I can suggest that students use trimix to gain their qualification. This means a process of evaluation can be conducted on the course build-up dives. If there are noticeable, hazardous, performance-degrading narcosis issues then an additional 2 dives qualifies and allows graduates to set prudent ENDs.

The deepest air dive I've planned in recent years was circa 60m. It was supposed to be a double body recovery from a crashed air force jet. There was no helium available. Sadly (for the families concerned) the wreckage was never located and the dives didn't happen.

Personally, I don't have big issues with narcosis. I put that down to experience, muscle memory, very ingrained protocols and having dived enough that very few unique problems arise. .That said, I'm intimately aware of narcosis issues from my old deep air diving days - it only takes one unforeseen and relatively novel issue to arise to cause confusion. Problems amplify rapidly once that happens.

My personal choice would always be to dive at a max END of 30m; but the reality of living in the Philippines is that helium is very expensive and stocks can be unreliable. Deep air OC diving between 30m and 50m is just a reality, when cost and availability are considered as factors. Relative to the cost of living and income here... I can live for a month for the cost of helium on a full trimix OC dive...

 

[MXGratefulDiver]

The only part of the OP I have an issue with is the "baby dives" comment ... suggests to me a mindset that's trying to prove something, and that's how people get in trouble on scuba gear.

I've personally done solo dives down to about 250 feet, but not on a single cylinder, and not considering doing deco on back gas. I wonder if that's a pony she's carrying or a deco bottle ... given she's diving a single cylinder, it'd be foolish to be the latter but given the depth profile it's foolish to be relying on back gas deco as well.

Old school divers did a lot of things that modern divers would (or should) consider foolish. I once met a couple out in Neah Bay who routinely dived will one of them ran out of air ... then they would both surface while buddy-breathing off the other person's tank. It's how they learned to dive in the '70's, and they'd done it that way ever since. Not my idea of best practices, but it's worked for them for a lot of years.

... Bob (Grateful Diver)

 

[Bob DBF]

The only part of the OP I have an issue with is the "baby dives" comment ... suggests to me a mindset that's trying to prove something, and that's how people get in trouble on scuba gear.

And at the end of the dive she discussed the OP's extended safety stops and commented "you can never be too careful". Sounds like a real interesting character, and I would have liked to been in the OP's situation.

It is too bad the thread turned into a bash of single tank deep air of someone using trimix with a bail out bottle, instead of discussing the facts in the original post. Probably why the thread has lasted this long.


Bob

 

[beester]

What do I mean by this: As a CCR diver, along with you Jim and Pete have accepted a much higher risk by using a CCR. The current rate of death is still around 1 in 70 units sold will kill someone. It is equivalent to BASE jumping or wing suit jumping. This is not about skill either. Many very accomplished divers have died using CCRs including Wes Skiles. What is the difference between us accepting the elevated risk of using a CCR and the OP accepting an elevated risk for their dive? Are we not all setting a personal level of accepted risk that is different from others? How can I, as a CCR diver, judge another's accepted risk level and call them a dinosaur? I think it is hypocritical at the least!

I have no experience with CCR diving (outside trying some mccr and eccrs in a pool). However I do personally feel that CCR is a magnificent tool in certain circumstances were TX is available in limited quantities or where diving OC just becomes impractical. I'm not sure I'll ever reach that level... but I digress.

Point is, if it's a tool used for particular dives, then it's part of that dives risk management. Obviously this means doing learning to dive with that equipment shallow (babysteps)... but I would buy the tool only when I would have reached "end-game" in OC. However I do see to many people starting CCR diving, without any specific need. (ie the dives they do can easily be done in OC). But of course just my opinion.

 

[beester]

I just don't agree with that, I believe that the general max air depth of 40m was introduced to suit the PADI/SSI mass and vacation/resort market. I believe, if diving was still a niche, at least 50m would still be OK with most 'advanced' divers. I just don't see the danger and nobody has really had a good example what the dangers is. In your example, I don't think the depth was the core issue but the all over conditions... and I did say earlier, for deep diving on air, the conditions need to be good, experience and you need enough bail out gas.

Bennno I believe that diving deep(er) on air vs trimix is a very very personal decision, based on your own airdiving experience, your experience with narcosis, how you perceive risk , etc. I've just checked my logbook and I've done in the past about 90 45-65m air dives. This going from tropical dives, to dark deep quarries to north sea wrecks, to wrecks on the French Riviera.

For me personally I've had a couple of experiences with narcosis which convinced me of the nefarious effect of it... Not the being totally out of your mind episodes which are mentioned in dive lectures, but the slowly creeping up on you kind... Dark narcs in a quarry, Having seen somebody go totally outside of plan on a 55m French riviera wreck, doing myself a 42m dive where my buddy asks me to become no 1 (take the lead), me not getting that is dc had crashed (depth was fixed at 28m), having gone into current and overbreathing myself (CO² being very very narcotic), etc etc etc... but these are all very personal. Maybe I'm very susceptive to the narcotic effects... but I've had enough, and that's why I'm limiting myself to an END of 40m in good non technical circumstances, and an END of 30m for everything else.

But as I said... YMMV, and I'm cool with that... I have some personal friends who still regularly do 50m air dives... but no longer with me