S80 buoyancy aid for multi-stage dives

[7b7]

Hello everyone, (long-time lurker, first-time poster).

Background: I am a diver from Czech Republic, OC, highest qualification would be Cave. Mostly diving dams or freshwater lakes nearby. I usually switch between SM and BM, but the question is only for open water "deep" (40-50m) dives utilizing BM twins and multiple stages.

I have not been able to find an answer, and would love imput on the following:
When diving with 2 stages, I carry both of them on my left and there are no problems.
However, when utilizing a 3rd stage as follows: (usually this would mean the backmounted twins 2x12 @300 bar + bottom stage S80 with bottom gas + EAn50% + Oxygen)
I carry the oxygen stage on a leash on the left D-ring and is swinging behind me. Nothing out of the ordinary I believe, but it is extremely umcomfortable to have a heavy stage hanging on my thigh this way. I hope this makes sence...

I am usually OK with a S40 for oxygen, but to make the stage more buoyant, it was reccomended to me to use an larger S80 only filled to cca 70-80 bar.
What would be the "correct" approach to this? I was thinking of using some lift-aid, something like crushed polystyrol insulation, to attach to the S40 to make it neutral when full (once I am breahting the OXY, the buoyancy doesnt matter as it is clipped on the left now).

Looking forward to any and all ideas, examples or tips

 

[inquis]

I have heard that the length of the leash has much to do with comfort. When I've carried an AL40 on a leash, it didn't seem overly heavy to me. I sized my leash as described in this video.

That said, it is a fact that a half-full AL80 of O2 is 1 kg less negatively buoyant than a full AL40. (-0.5 kg vs -1.5 kg for Luxfer cylinders in salt water with 1 kg regulator).

 

[treasurehunter]

I dive mostly in river with a decent amount of current ,and the leash method for my travel gas is a pain in the a** for the same reason you mentioned. Also Once the tank is breathed down and becomes buoyant ,the leash method becomes useless, it can start floating and swinging around you like a metal smb.
I clip my travel tank straight to my butt D ring, this way it is still between your thighs ,but much more comfortable ,and manageable. When clipped straight on my butt D ring I know it is not going anywhere I don’t want it to go.

Hope this helps.

 

[7b7]

When I breathe down a bottle, I usually nose-clip it to my left D-ring and it sits very comfortably there, so thats not an issue, but thanks I understand.
Makes sence, should be more comfortable on the butt.
Cannot imagine with the current... must be fun.


Thanks for the vid.

 

[treasurehunter]

When I breathe down a bottle, I usually nose-clip it to my left D-ring and it sits very comfortably there, so thats not an issue, but thanks I understand.

Sure that’s fine, but for me I’d rather not over populate the left D ring or left side of my configuration if I don’t have to.

When I want to check my gauge from time to time, I like only having to fiddle with three clips to find my gauge clip.

Once the tank is buoyant it will no longer be between your thighs. It like it’s not even there.
If there is a tank or other gear that I want to get out of my way ,it will usually go to my butt D ring.

Also if you give the butt D ring a try , you will probably have to do a few dives and reposition it to find the best position for your comfort of reaching it.

 

[PfcAJ]

Hello everyone, (long-time lurker, first-time poster).

Background: I am a diver from Czech Republic, OC, highest qualification would be Cave. Mostly diving dams or freshwater lakes nearby. I usually switch between SM and BM, but the question is only for open water "deep" (40-50m) dives utilizing BM twins and multiple stages.

I have not been able to find an answer, and would love imput on the following:
When diving with 2 stages, I carry both of them on my left and there are no problems.
However, when utilizing a 3rd stage as follows: (usually this would mean the backmounted twins 2x12 @300 bar + bottom stage S80 with bottom gas + EAn50% + Oxygen)
I carry the oxygen stage on a leash on the left D-ring and is swinging behind me. Nothing out of the ordinary I believe, but it is extremely umcomfortable to have a heavy stage hanging on my thigh this way. I hope this makes sence...

I am usually OK with a S40 for oxygen, but to make the stage more buoyant, it was reccomended to me to use an larger S80 only filled to cca 70-80 bar.
What would be the "correct" approach to this? I was thinking of using some lift-aid, something like crushed polystyrol insulation, to attach to the S40 to make it neutral when full (once I am breahting the OXY, the buoyancy doesnt matter as it is clipped on the left now).

Looking forward to any and all ideas, examples or tips

I’d make sure your leash is the right length. The leash should drape over your thigh kind of in your butt/leg-crease and the bottle should kind of sit between the backgas tanks.

As for having the o2 not completely full, sure, so long as you have enough reserve gas.

 

[tbone1004]

I’d make sure your leash is the right length. The leash should drape over your thigh kind of in your butt/leg-crease and the bottle should kind of sit between the backgas tanks.

As for having the o2 not completely full, sure, so long as you have enough reserve gas.

ditto. Make sure the leash is the right length, most peoples are too long in my experience.
For things like O2 and EAN50 I typically prefer an 80 filled "light" vs a full 40. Gets you the added benefit of less pressure in the bottles with high O2 and a 3/4 full AL80 is still more gas than a full AL40....