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

[Gareth J]

On the CCR, I still carry rich bailout on the right and lean bailout on the left. (So, recreational CCR I have the bailout on the left). This also matches the CCR, the DIL is on the left, the O2 on the right.

Cylinders are checked on the boat, and marked appropriately. So if you unhitch them in the water, you can easily identify them when you pick them up. But that should be standard practice. No one should get in the water without identifying what gas is in which cylinder and making sure that the cylinders are appropriately and clearly labeled.

On the very rare occasions I carry bailout strapped to the CCR itself Lean to left, and spare O2 to right.

It reminds of when we experimented with scooters. We where curious if the convention lean left, rich right caused issues with the scooter. Although we only had the 3 days, we didn't notice it causing a problem.
Because I dive with a break in the left of the harness, we also tried to break the harness when towing other divers.
In the end I had the buckle undone on the shoulder and could still tow 3 other divers. Granted the AquaZep was suffering a bit with the loading.
The only thing we managed to break was the casing of the CCR. But that was because I ended up with 3 divers hanging on to the CCR, rather than clipped into the rear D ring (butt D ring). We snapped the fixing point to the backplate. Now mine has a S.S. reinforcement where the casing interfaces with the backplate .

 

[rjack321]

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.

Hose routing from a right sided stage/deco bottle is almost always poopy. If it's a normal 40" hose it bows out all over the place, it can't go behind your neck, etc.

If you start doing custom hose and swivels and whatnot to mitigate this you now have different L/R regs and can't readily swap a leaky one out. Those changes also may make donating the stage/deco reg in your mouth to an OOA diver harder or unique compared to how the long hose and left sided 2nd stage is donated (especially if you use a shorter hose to reduce the big bow). Almost invariably deployed right sided stage regs are a mess.

 

[ND5342]

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.

How do you find suiting up with two large cylinders on a six pack size boat and no tuna door to step through to the swim platform in 2-3ft swells?

 

[flymolo]

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.

I can confirm that in sidemounted bailouts on a rebreather the light cable/canister is definitely more of a PITA than diving a canister light while having backmounted dil/bailout and bailout deco bottles all on the left.

As for complacency, anecdotally I do think LLRR tends to cause it, just based on the things I've heard divers who dive LLRR say. Similar to how some ppl use a green regulator hose/mouthpieces to indicate which is their o2 bottle instead of looking at the markings on the bottle itself.

Ultimately I guess I am just not a fan of the "whatever works" philosophy, because it makes it hard to standardize procedures in a buddy team, which is important to me when things go wrong.

 

[jlcnuke]

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.

Interesting perspectives. The access to the pockets seems to be almost more impactful for the dives I'm contemplating at the moment, but I can see your other points as valid potentially as well. Thanks for your input on the issue.

 

[rjack321]

How do you find suiting up with two large cylinders on a six pack size boat and no tuna door to step through to the swim platform in 2-3ft swells?

Easy?
Seriously this is a not a big deal.

 

[PfcAJ]

How do you find suiting up with two large cylinders on a six pack size boat and no tuna door to step through to the swim platform in 2-3ft swells?

Its not hard.

Sit on gunwale, clip scooter to crotch strap, place shroud on fins, mate hands you the 1st tank, clip it off, mate hands you tank 2, clip it off, backroll and enjoy your day. Hey look its me doin' just such a thing! Al40s in this pic, but I've done with with 80s.

I'd do it the same way w/ 3 bottles except put the third across my lap if the gunwale is low enough, clipped via a leash to the left hip d-ring. Or sitting on the gunwale to my left, still leashed.

 

[rjack321]

I can confirm that in sidemounted bailouts on a rebreather the light cable/canister is definitely more of a PITA than diving a canister light while having backmounted dil/bailout and bailout deco bottles all on the left.

Same, I sidemount my BOs with a backmounted CCR. LLRR even. It is quite a bit more annoying in every respect than OC doubles with 2 left mounted conventional stages which is a piece of cake. 100% agree that access to pockets is a special kind of pita.

 

[ND5342]

Easy?
Seriously this is a not a big deal.

I would not have asked if I have not have seen it.

 

[rjack321]

Its not hard.

Sit on gunwale, clip scooter to crotch strap, place shroud on fins, mate hands you the 1st tank, clip it off, mate hands you tank 2, clip it off, backroll and enjoy your day.

I'd do it the same way w/ 3 bottles except put the third across my lap, clipped via a leash to the left hip d-ring.

Same except my RIB is too small to support 3 bottle OC+scooter dives.

For a typical 2 bottle dive I would clip on the 50% on the left, backroll in, and pick up a 40 hanging on a tag line and attach it in the water. Or put the 40 on while sitting on the tube (on the left) roll in and grab the scooter off the tag line. Its possible to put all three things on while in the boat - just not usually ideal since there's only one person driving it and no mate.