Planned deco on a recreational dive?

[Patoux01]

It most certainly is. In a club diving environment (my club is CMAS affiliated, but I'd be surprised if BSAC clubs were very different), you're not just assumed, but even expected to plan your dive within your limits, and then do the dive with your buddy - be it a regular one, or your buddy of the day. We don't have guides or DMs in the water, no-one is babysitting us

That's not true for all of CMAS.

FFESSM (France), but in France, the law says (N1,N2,N3,N4 are divers levels, where N4 is basically a dive leader and N1 is like a nothing):
-N1, not allowed to dive by themselves, can go up to 20m with a N4.
-N2, allowed by themselves up to 20m, require a N4 (or more) and is then allowed to 40m.
-N3, allowed byx themselves up to 60m.
-N4, same as N3 but can also guide.

CMAS.ch doesn't seem to have a very different system to this one.

And yes, N2 are allowed to do deco.
Only N4 has requirements on his equipement, which is mainly "you need 2 separate first stages".
None of these levels requires v-drills, Nitrox or anything like that.


Basically: I'm not shocked by some slight deco, it's done all the time in a lot of Europe, and also in some more remote countries, eg Vanuatu.

 

[Edward3c]

Ok, and I hope I'm not taking this out of context: said accident happened, is the troubled diver not responsible for knowing his limit and aborting ? I would hope the idea that you are able to make decisions to turn back or proceed is upon yourself, and I hope that it's taught that way.

It seems that everyone wants to instill liability on someone other than themselves, imho. If your leader takes you into a risky and untrained depth, you should be obliged to surface and never use him again! The leader should not be scott free, so I understand that it's contradictory of me to say, he should be reprimanded.

There is legislation in some countries, like Belize and Malta, where taking a BSAC OD or PADI OW on the dive prescribed would be illegal.

 

[KenGordon]

Ok, and I hope I'm not taking this out of context: said accident happened, is the troubled diver not responsible for knowing his limit and aborting ? I would hope the idea that you are able to make decisions to turn back or proceed is upon yourself, and I hope that it's taught that way.

It seems that everyone wants to instill liability on someone other than themselves, imho. If your leader takes you into a risky and untrained depth, you should be obliged to surface and never use him again! The leader should not be scott free, so I understand that it's contradictory of me to say, he should be reprimanded.

Yes and no. An entry level diver can easily be persuaded to do a dive too far with an appropriate application of pressure or BS. They don't know what they are getting into and the responsibility lies with the pushers.

 

[David Mayle]

The dive is always the responsibility of the diver which is why everyone is told you can always call a dive at any time. People are persuaded to do all sorts of things but that does not releave them of being responsible for the action. If you cant say no then you are a safety hazard everywhere and not just diving.

 

[KenGordon]

The dive is always the responsibility of the diver which is why everyone is told you can always call a dive at any time. People are persuaded to do all sorts of things but that does not releave them of being responsible for the action. If you cant say no then you are a safety hazard everywhere and not just diving.

So if I persuade some new diver to do the 45m 10minute deco dive above with a load of persuasion about the warm water, good via and so forth it is entirely their fault if it goes wrong?

What if a diver is on a course and the instructor misses signs that they are nervous, or decides the time table is more important?

Or if the risks are more subtle, but apparent to an experienced diver - maybe poor exit conditions and weather getting worse?

 

[211ratsbud]

The dive is always the responsibility of the diver which is why everyone is told you can always call a dive at any time. People are persuaded to do all sorts of things but that does not releave them of being responsible for the action. If you cant say no then you are a safety hazard everywhere and not just diving.

I always operated under this assumption. As a diver, and student. That's why I asked, and even conceded that the leader is still the leader and probably imho should be shared in SOME responsibility for overall safety. Yet persuasion should not be an excuse to why you did wrong yourself. I think self consciousness,, confidience, awareness, firm rationale and other decisive traits are a must for someone taking education in an activity which shares death as a possible outcome.

That's just my thoughts.. I think anyone determined and focused should have the ability to be come proficient at sport diving easily, and move to training with significant higher expectations incl technical diving. I'm sad I waited to long to embrace the community as it is lol

 

[admikar]

Let's just remember that in France you'll be allowed to do deco under supervision and it'll hardly require any kind of redundancy (as a matter of fact, there's no required equipment) and the guide is only required to have 2 separate 1st stages.

Furthermore, let's add that BSAC and virtually all of CMAS do deco diving straight from their 2nd level of diving, without any of them at any point calling their diving "technical diving".

Would be cool if we could let it that way, because stuff like is kind of annoying:

I just put in bold the things that do not matter and added some comment...

Unfortunately no, CMAS ** is not allowed to do deco.Two Star Diver Training Programme
We do have theory about Haldane, half times, on and off gassing, deco tables in course, but not allowed to do deco.
Under CMAS level 3 is stage deco capable (I think non accelerated).
It might be worthy to note that to reach level 3 you need 50 dives, including night and deep, so it is not exactly regular AOW doing deco diving.
I did some deco diving in tech configuration, but only after getting more deco theory. Was it legal? No. Was it safe? I think it was, more importantly my instructor/buddy think it was.

 

[Patoux01]

FFESSM does, CMAS.ch does, ... They're probably among the biggest members of CMAS I believe.

 

[Miyaru]

Planning a bit of deco on a rec dive.... after reading the thread it still feels strange. I choose another approach.

The recommended limits of OW make it pretty hard to exceed your NDL. 18m/60ft gives you a NDL of 51 minutes on a Suunto computer. Even if you dive a bucket profile, I'd be totally impressed if a novice diver actually manages to last that long on a single 80cuft or 12l tank.
After some diving experience, doing the deep dive of the AOW course puts that NDL within reach. Exceeding it means slowly ascending from 30m/100ft where your gas consumption is a lot higher. Wanna take that risk with a single tank being a novice diver? I ask my students and get various answers. Most just back off and say no, other come up with valid arguments like a wreck at that depth - the goal of their dive. One approach is to discuss deco, another is to look for ways to prevent it, e.g. use of nitrox.

One of my students (OW/AOW/EAN certified) showed me his 40m/130ft achievement, I watched his video and saw the dive profile on his computer. It was his 50th dive, warm water, good vis. He enthusiastically told his story how he signalled the DM that he was gonna go to 40m, after a third of the dive. The DM signalled no (which I saw in the video) but followed him anyway. Touch 40m and ascend. His AI computer showed the dive profile with remaining gas, gas consumption and TTS. He was ascending the minimum speed required to stay just within the NDL. His gas consumption was so high that he surfaced with roughly 20bar/300psi.

I told him I wasn't impressed. To me, this dive was unplanned borderline stupidity and I didn't teach him that. Of course all the what-if's didn't happen, but if they did, he didn't have an answer on what to do in those cases. His wife then smacked him on the head and cursed (I recall reading somewhere that this is excluded in the teaching standards).

Next dive, I'm taking him to 40m/130ft. This time, he has calculated how much gas he needs, which nitrox mix is the best choice and how much time he has to complete that dive without any deco. And if deco is required for some reason, there will be ample reserve.
No planned deco. All within recreational boundaries. Deco stops are still an experience level away....

If you plan a littlebit of deco, do you also plan contingencies for that littlebit of deco? Since you're diving at depths where deco is almost certain, does a recreational planning provide for all contingencies? Ascending in case of problems is no longer an option. If nobody teaches you which contingencies to plan, how and why, you might have to deal with an unforeseen issue for the first time down below. However if you take the training you'll also understand why there's a recreational limit at 40m/130ft.

But then again, it only ends bad on your last dive....

 

[KenGordon]

Your student is a good example of doing a dangerous no stop dive. Not properly planned or executed. That is true whether it is an AOW diver, a AN/DP diver or a a Sports Diver. Dives need planning.

Recreational planning ought to account for gas at the safety stop. Deco planning has to account for gas at actual stops. This is the same.

The contingencies need to be planned for and understood. Training is required.

Why is there a limit at 40m?