Rebreather or not?

[NAND]

when you have a dry suit as well, do you tap it off the DIL cylinder, or run another cylinder

Matter of redundancy and used CCR type. On CC you have 3 factors influencing your buoyancy- Drysuit, Wing and LoopVolume. In a perfect world the DIL would only act on the loop. Most CCR have integrated wings connected to the DIL circuit as you wrote and it is in fact the tool of choice for buoyancy control. Drysuits are commonly connected via either Argon bottle seperately or simply hooked to any offboard gas connection.
So far, I have not seen any drysuit directly on the DIL (which does not mean there may not be anybody out there doing it so).

If it comes to DIL usage, (and again a perfect world example) you would ideally only need the loop volume multiplied with the depth plus a bit of flushing- the overall demand is therefore rather low. But its as well a matter of training. In this regard OC differs a bit from CC but I believe general diving experience (no matter if CC or OC) is key to success.

Its perhaps an easier way to see any CCR rather to be some sort of on-the-fly-gasblender. Taking pure eCCR out of the equation it is again a requirement to plan your dive properly and add redundancy in orderly fashion. This of course involves the gas needed for buoyancy.

@JonnyC compared spelling words with knowing the alphabet. It makes sense in a way that critical tasks like stagehandling (Lean-to-Rich, Proper labels, Stuffing Regs etc.) is the alphabet. Breathing a rich bailout on bottom is equal to breathing deco gas down there. No difference. Same a potentially fatal mistake.

I have often been laughed at when pulling out my ducttape and additionally labelling the MOD on the regulators outflows. (Why would you do this? Noone needs that! You only paint your face...) True, I may not need it. But if in stress it may avoid an error. So everyone has additional strategies to create backups of his own brain malfunctioning. And this may happen definitely more likely on CC than on OC.

 

[Dave Bevan]

Hi Guys,

Thank you for all your responses I can see from this thread there is quite a lot of support for both sides of the argument. The poll was almost tied the whole time. I'm glad to have been able to facilitate some discussions even if they just made people think.

As for me I did a couple of nice dives on the beautiful red sea reef training this weekend and I felt really good. All my skills seem to be working well. Trim is good with Twinset and adding a stage. My equipment set up works and I can build my twinset with my eyes closed. Skills are firm in the muscle memory and I almost feel numb like a robot when carrying out Basic 5, S Drill, Back Up Deployment etc. I feel I have spare capacity and I mean that in a good way. I feel I can reach any piece of equipment on my rig without thinking about it. I'm a stable platform while I'm diving twinset and stage. Everyone else around me is doing normal Single profiles. I'm doing a normal single profile. I'm just carrying the equipment for training purposes. At this point I kinda realised that I should probably enjoy this! I really should go and get some diving done and really enjoy the fact that I'm comfortable. Why change everything now?

So I think my plan is going to remain the same. I will dive more and more OC until I'm feeling that its limiting me. Then I'll make the switch.

 

[JohnnyC]

Attempt at a metaphor:

"If someone wants to learn to shoot a gun we don't enroll them in a knife handling course first even though it's the backup tool to a gun depending on what you are hunting. The gun safety training program is much slower but all the training is focused on the intended tool."

I want to single this out because I think you're misunderstanding the comparison I made. Your metaphor would be akin to saying, "someone wants to hit a wreck at 200m, they should snorkel for a couple years." That's not the point I'm trying to make, and I think it's a gross oversimplification. To relate my explanation to your metaphor would be more along the lines of someone wanting to learn to shoot, so you hand them a .500 S&W Mag. There's a disparity in comparison that I think it's important to point out.

Again, not disagreeing with the right tool, just disagreeing that you should hand them the right tool before they're ready to handle it.

 

[northernone]

• I want to single this out because I think you're misunderstanding the comparison I made. Your metaphor would be akin to saying, "someone wants to hit a wreck at 200m, they should snorkel for a couple years." That's not the point I'm trying to make, and I think it's a gross oversimplification. To relate my explanation to your metaphor would be more along the lines of someone wanting to learn to shoot, so you hand them a .500 S&W Mag. There's a disparity in comparison that I think it's important to point out.
  
  Again, not disagreeing with the right tool, just disagreeing that you should hand them the right tool before they're ready to handle it.

Thanks for clarifying. That's an important distinction, didn't mean to misrepresent what your saying.

We may even fundamentally agree, terrifying thought to have current training standards and instructor methods applied to DSD classes of students all on rebreather for example.

I'm suggesting for sake of consideration a MUCH slower progression on rebreather (including rigorous OC bailout) is possibly a better learning path compared to extended OC training followed by the fairly fast CCR training progression.

To the OP. I'm glad you're going to take time to enjoy your diving, there is great joy in being underwater and when you 'need' to extend your bottom time, stealth, comfort or depth sounds like you'll make a fine CCR diver with your deliberate training mindset and drills.

Regards,
Cameron

 

[Dave Bevan]

I think one thing that can be agreed on is that throwing rebreathers into the recreational diving world as it stands now may not be the best idea.

 

[JohnnyC]

Thanks for clarifying. That's an important distinction, didn't mean to misrepresent what your saying.

We may even fundamentally agree, terrifying thought to have current training standards and instructor methods applied to DSD classes of students all on rebreather for example.

I'm suggesting for sake of consideration a MUCH slower progression on rebreather (including rigorous OC bailout) is possibly a better learning path compared to extended OC training followed by the fairly fast CCR training progression.

To the OP. I'm glad you're going to take time to enjoy your diving, there is great joy in being underwater and when you 'need' to extend your bottom time, stealth, comfort or depth sounds like you'll make a fine CCR diver with your deliberate training mindset and drills.

Regards,
Cameron

I think our difference of opinion probably stems from different ideas of mastery. Getting on a rebreather early in ones diving career isn't a bad thing, however I think I'm placing more emphasis on the mastery of OC skills prior is most important because ultimately it's those skills that will save your life.

Extended OC training followed by speedy CCR is dangerous. A slow CCR progression is more ideal. I absolutely agree with those statements. Even better, mastery of OC skills coupled with a slow CCR progression is probably the most conservative way of going about it.

 

[Gareth J]

Extended OC training followed by speedy CCR is dangerous. A slow CCR progression is more ideal. I absolutely agree with those statements. Even better, mastery of OC skills coupled with a slow CCR progression is probably the most conservative way of going about it.

I think this is worthy of serious reflection.

The inspiration classic, when it first cam on the market developed the nick name YBOD (Yellow Box Of Death).

This was no reflection on the quality, of the unit, or the safety of the unit. It was directly related to the users, I know a good few of them.
The initial purchasers of the inspiration where not 'new', 'newer', or 'inexperienced divers'. In fact they where the direct opposite. They where the very experienced, trimix qualified, deep diving groups. These where the group who where regularly diving the deeper UK wrecks, either as deep air, or trimix. This was the group that had embraced the newer developments in recreational diving over the preceding decade(s). This is the group had had embraced Nitrox, accelerated decompression, trimix etc before it had been accepted in the mainstream.
The availability of a 'sports' market, relatively inexpensive rebreather was seized on. Previously, rebreathers where very expensive, normally only available to the military. so very hard to acquire, and maintain.
This group did the course, and instead of allowing the new skill set to bed in, the drills and techniques to be practiced on the shallower dives. They took the new toy back to the diving they had been doing on OC. Where they had developed and mastered all the skills required to survive OC deep air and mixed gas diving. Unfortunately, whilst there are many directly comparable skills, CCR diving is not the same as OC diving. Some of the 'incident' management techniques are not compatible. The equipment failures are not equivalent, the emergency techniques are not the same.
The end result was a sudden spike in deaths and incidents.

A mixture of learning and improving CCR training, developing new techniques to solve old problems, adapting old techniques to suit CCR, and a survival of the fittest has resulted in rebreathers becoming 'safer'. (Actually the divers are safer the units haven't changed). In addition, people are moving to CCR's earlier, allowing time to learn to master the equipment on shallower dives and building techniques and experience as they progress to deeper diving.
Another factor is that we are more aware of the limitations of the units, the operating life and limitations of the consumables. People don't 'push the limits' of the sofnalime. We are more aware and conscious of the issues of ageing cells. As a community, we are aware its not clever to run 2 year old cells - your just an idiot. Our maintenance procedures have adapted to the CCR units, with a significantly improved understanding of how to look after them.

Once you are a competent OC diver there is no reason why you can't move to CCR. You do need to understand that the task loading will go up and you need to monitor the unit - even when it is behaving. Rebreathers seldom fail quickly - unlike OC, (which is normally giving gas and then not giving gas), most failures are slow, giving the informed user time to diagnose and resolve or manage the issue - as long as you pick the failure up early. Adapting to this, especially if you use a camera, or are doing other task loading dives is very important. CO2 is still the most feared issue for those of us using rebreathers.

Gareth

 

[MegDiver792]

I only had 50 dives before I went SCR, and maybe another 60 to CCR. My only regret was ever dealing with SCR, and not going straight to CCR.

Personally, unless you plan on staying the in GUE world, I'd skip tech 1, and go straight to mod 1 and then mod 2 CCR training. Skip the GUE/JJ CCR unless you plan to stay within that org and training. Look at a meg, revo, or unaltered JJ. All three are great rebreathers and you cant go wrong with any of them.

 

[JohnnyC]

Here's a fantastic example of what Gareth is talking about. It's a good demonstration of how our training, understanding, and adaptation has improved over the years, making us safer divers.

This guy was almost a victim of the YBOD. It demonstrates, quite well in fact, how it is inherently different, and must be treated in a completely different manner. They were inexperienced, made some seriously grave assumptions, and it almost cost one of them their life.

 

[PfcAJ]

Here's a fantastic example of what Gareth is talking about. It's a good demonstration of how our training, understanding, and adaptation has improved over the years, making us safer divers.

This guy was almost a victim of the YBOD. It demonstrates, quite well in fact, how it is inherently different, and must be treated in a completely different manner. They were inexperienced, made some seriously grave assumptions, and it almost cost one of them their life.

Excellent video.

Really makes a strong case for being good at OC diving so as much is "automatic" as possible, for diving in a team, and being able to easily donate gas from a large supply.