Status of Left Lean and Right Rich Philosophy in B/M Open Circuit Technical Diving

[rjack321]

Interesting there's no dil MAV, relying upon the ADV. How are dil flushes managed (or is the ADV manually operable, a-la Inspo)?

Having the dual 7's for diluent seems a good idea for shallower dives - say 30m/100' - where you won't need another bailout cylinder.

The JJ ADV is basically a second stage diaphragm in one of the T pieces. You can reach up to your shoulder and push the membrane with your finger like a second stage purge button.

 

[ND5342]

Well no it isn't because that's not what I'm saying.

If someone was taught to use deco stages on each side then I don't have a problem with that.

I understand the choice is a little tongue in cheek.

I was going to have that as a choice but that could have added two more choices. I wanted to try to keep the survey simple. Just choose the selection that you currently use and your comment is noted.

 

[helodriver87]

Interesting there's no dil MAV, relying upon the ADV. How are dil flushes managed (or is the ADV manually operable, a-la Inspo)?

Having the dual 7's for diluent seems a good idea for shallower dives - say 30m/100' - where you won't need another bailout cylinder.

Beyond that it's stage city, just like every other rebreather diver

You can push a button on your left T piece to fire the ADV while holding the cl dump open with your right hand. Works the same for dewatering. If you can jack the 50s up to 3600, it's fine for 250-300ft open water dives without another bottom gas cylinder. That assumes proper deco gas progression and a similarly equipped team (not team bailout, but realistically, it's all shareable and multiple bailouts are unlikely).

 

[flymolo]

Helps to reduce likelihood of switching to the wrong deco cylinder at the wrong time, makes it easier for buddies to confirm that you're on the right cylinder, and helps standardize procedures across team members (not sure I can find a rationale to agree with that, but it says it).

I'm not quite sure LLRR really helps mitigate those problems. What's to say you (or a boat crew member) didn't accidentally clip your tanks onto the wrong side? Or say you drop your bottles somewhere and pick them back up later, but you're in a hurry, or stressed, so you switch sides accidentally? It seems with LLRR you'd still need to visually confirm the your gas before switching, so in the end you're just left with a configuration that is more likely to interfere with your light canister or long hose for no other real benefit.

 

[Wibble]

I'm not quite sure LLRR really helps mitigate those problems. What's to say you (or a boat crew member) didn't accidentally clip your tanks onto the wrong side? Or say you drop your bottles somewhere and pick them back up later, but you're in a hurry, or stressed, so you switch sides accidentally? It seems with LLRR you'd still need to visually confirm the your gas before switching, so in the end you're just left with a configuration that is more likely to interfere with your light canister or long hose for no other real benefit.

Which is why it's without question best practice to properly check your stages during the switch process. LLRR in reality means stashing stage cylinders either side, but no guarantee that they're in the right place.

The one exception should be for the bailout cylinder on CCR: you should know where that is at all times and most (all?) agencies will have the bottom gas bailout on the left hand side. (You need to be careful when touching left-hanging stageS to ensure your bottom bailout's definitely not moved from where you expect it to be)

 

[shurite7]

I am looking for peoples' current view on the subject so that is why I did not have the choice of "what you learned on". Are you currently diving using both methods or what the "team decides"? I could make that a choice if it is that popular. Again remember this BM Doubles.

Currently, with BM doubles the bottles on left. I don’t dive with a team so their is no dictation by others. Nonetheless, I’m not a fan of referring to lean-left and right-rich as antiquated, inappropriate, or out of date. Your poll selections are too rigid and limited, which is why I am unable to vote.

 

[ND5342]

Currently, with BM doubles the bottles on left. I don’t dive with a team so their is no dictation by others. Nonetheless, I’m not a fan of referring to lean-left and right-rich as antiquated, inappropriate, or out of date. Your poll selections are too rigid and limited, which is why I am unable to vote.

Ok thanks for stopping by.

 

[jlcnuke]

I'm not quite sure LLRR really helps mitigate those problems. What's to say you (or a boat crew member) didn't accidentally clip your tanks onto the wrong side? Or say you drop your bottles somewhere and pick them back up later, but you're in a hurry, or stressed, so you switch sides accidentally? It seems with LLRR you'd still need to visually confirm the your gas before switching, so in the end you're just left with a configuration that is more likely to interfere with your light canister or long hose for no other real benefit.

Which is why it's without question best practice to properly check your stages during the switch process. LLRR in reality means stashing stage cylinders either side, but no guarantee that they're in the right place.

The one exception should be for the bailout cylinder on CCR: you should know where that is at all times and most (all?) agencies will have the bottom gas bailout on the left hand side. (You need to be careful when touching left-hanging stageS to ensure your bottom bailout's definitely not moved from where you expect it to be)

Now, I'm still learning, but it seems to me that there's no guarantee any bottle is the right bottle until you've verified it, regardless of where you stowed the bottle so that would be a "problem" that exists everywhere. I don't think I've heard of an agency that suggests you should just breath a bottle without checking it regardless of where you stow it, so you should be doing proper gas switches and verification of a gas before breathing it regardless of how you choose to store the bottles on your rig, right?

It also seems to me that it could be entirely situational as to whether it would be easier or more of a hassle/problem to do all on the left, all on the right, or on both sides. Rebreather divers seem to have managed to find a way to not trap their light with it on the right as it is, as presumably the people diving LLRR probably have found a method to not trap their light or long-hose. My dive buddy learned to dive sidemount with his long hose on the left due to dexterity and strength issues from previous surgery that make the normal configuration not work for him (and BM doubles wouldn't work for him either for the same reason). For AN/DP, however, we trained deco on the left and I/we check his hose not trapped/still deployable before starting the dive, and that's how he's been diving since then. However, we were surfacing on deco gas so trying to stow it on the tank underwater wasn't an issue in that case. It still hasn't been hard to avoid trapping his long-hose so far in our diving thus far (whether the long hose tank had an AL40 or AL80 attached on the same side). When we do our trimix course I'm 100% sure there will be discussion about how best to stage his deco cylinders and what that means for us as a team.

I've seen 3 arguments against LLRR as far as I can tell:
1. You'll trap your long hose and not be able to donate it.
2. You'll trap your light cord.
3. You'll get complacent and not check your gasses before switching to them.

The first two seem pretty straightforward to avoid - do proper staging of your gear and verify it isn't trapped with an S-drill (or whatever similar method you use). The last once is as simple as do your gas switches following proper procedure. From my perspective, it seems like you can pick any method you like of staging that works for you as long as you take the time to do it right and there shouldn't be a problem. I may be missing something though.

 

[Wibble]

Currently, with BM doubles the bottles on left. I don’t dive with a team so their is no dictation by others. Nonetheless, I’m not a fan of referring to lean-left and right-rich as antiquated, inappropriate, or out of date. Your poll selections are too rigid and limited, which is why I am unable to vote.

LLRR is an older system or certainly an older nomenclature. LLRR is inaccurate as you cannot just assume it'll always be correct without adding in checking protocols: reading labels before sucking on the gas.

So it's not being that nasty to refer to it as antiquated and inappropriate.

 

[stuartv]

I've seen 3 arguments against LLRR as far as I can tell:
1. You'll trap your long hose and not be able to donate it.
2. You'll trap your light cord.
3. You'll get complacent and not check your gasses before switching to them.

Regarding the first 2 - I think it's worth noting that those are concern every time you manipulate the right side bottle. It's not as simple as "get it right once, when you're gearing up". If you unclip the bottom to move it out of the way, so you can reach into your pocket, if you unclip and stage the whole bottle somewhere, etc.. Every time you mess with it, you need to make sure you haven't trapped a hose or cord.

Also, I would add:

4. The right side bottle is in the way of reaching into your right thigh pocket.
5. The right side bottle is in the way of clipping anything else to your right side - like a camera, a scooter, a tool bag, a reel, or whatever.

Of course, those are predicated on agreeing that you are going to have a cylinder clipped on the left, regardless. I think that is a reasonable presumption.

Also, the difference between having 1 or 2 cylinders clipped on the same side is small. The difference between having 0 or 1 cylinders clipped in a place is large. I.e. if I have 1 cylinder clipped to my left and I'm deciding where to clip a second cylinder, (to ME) the overall difference to me is smaller if I add it to the left than if I put it on the right.

I have never found it difficult to maintain level trim (side to side) with 2 bottles (even 2 x AL80) on the left. Maybe it's a skill, but I think it's a pretty easy skill.