DIR- Generic Removing kit (BP/W) underwater - risk/reward & weighting

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I found this video on Youtube, showing a tech instructor doffing and donning a single tank BP/W underwater, and it made me question a couple of things regarding this skill:


Questions:
- Has anyone here been taught and/or practiced this skill? Does it have any real world application?
I guess entanglement of a part of the tank you can't reach while solo diving is a possible application, but other than that I can't think of many scenarios that would justify the risk of removing the rig (and gas supply) underwater. Am I underestimating the value of this skill?

- Is it possible to weight yourself in a way that makes this skill possible to execute in a safe way (read: balanced rig and neutral diver)?
If yes, what configuration would that require? As you can see in the video, the diver is positive, and the rig is negative. If he were to drop the rig, I'm guessing he would rocket to the surface (and lose his gas supply) unless he was able to swim down against his buoyancy. If the diver was neutral, he could inflate the wing to make the rig neutral, but I'm guessing he didn't because he wasn't neutral himself without the rig - which makes sense considering he has a wetsuit and no weight belt. In my steel doubles and drysuit with heavy undergarments, I'm pretty sure it's impossible to make it work, as I would need a lot of weight on my belt to make me neutral, which would make the whole rig very overweighted. In any case, I have never seen this (being neutral without rig) being discussed on the topic of making sure your rig is balanced.

- How do you mitigate the risk of being separated from your gas supply?
I guess if you're entangled, it's probably close to the bottom, which would at least stop the rig from falling too far away from you. But if you're positive and you lose your grip, I hope you can swim down against your buoyancy to reach the rig.

- Am I overestimating the importance of being neutral without the rig?
I mean, even with a balanced rig you have to be prepared to swim up a few kilos if you have a catastrophic loss of buoyancy at the start of the dive with full tanks, but you have a lot of gas to deal with it, and it would get easier the more you breathe it down. I don't know how I feel about having to swim down against a few kilos to chase your gas supply. Actually, I know how I feel about that: it's frigging scary!

PS.
I also just realized:
If a single tank is a requirement for being able to perform this skill safely, and solo diving is the only reason you would need to take off your tank underwater - what about redundancy?!
When I see the amount of gear people carry today I doubt they could realistically get out and back in safely. With a simple rig and the weight split between the rig and a weight belt it’s no problem. I routinely put on and take off my rig in the water. Steel twins and wing or steel single and bcd. Both used with a weight belt. I’ve taken off both underwater, the rig and diver can be neutral in a drysuit. But the diver is slightly heavy deep in a wetsuit, in either case there’s no reason to lose control. There’s something badly wrong if you can’t control the rig.
 
So, I'll provide my perspective from a DIR standpoint. I won't discuss Solo diving since it's not a type of diving I engage in or plan to, although that's debatable for some, but I won't delve into that.

When should you remove your equipment? The simple answer is only when you encounter entanglement or a narrow passage that you believe you can't navigate through without removing your gear. Let's break down these two scenarios.

Entanglement:

In such situations, it's advisable not to remove your equipment because there are various ways to address this issue without resorting to gear removal. Here's why:

1. You can try untangling yourself, if possible. As DIR divers, or at least in GUE (which is the training I've received), we typically carry a knife that can be used in such situations.

2. Since we engage in team diving, if you're unable to solve the entanglement on your own, you can always seek assistance from your team or buddy. In 99% of cases, the problem can be resolved this way, eliminating the need to remove your equipment. (That's why GUE doesn't emphasize training for this skill.)

3. If the situation is extreme and you find yourself entangled in a net, for example, you can use the knife to cut the BP webbing and free yourself. This brings up the concern of losing buoyancy and your gas supply. So, what do you do? Well, you have your buddy's gas supply, which should be more than enough to ascend both of you to the surface (which is our minimum gas requirement). Additionally, you can rely on your buddy for buoyancy assistance.

Narrow passages:

Usually, you're aware of a narrow passage before diving into it. During the dive briefing, you'll likely be informed about any narrow passages you'll need to navigate. Therefore, it's a good idea to prepare the appropriate equipment setup for this dive, such as a sidemount OC/CCR setup.
 
As this is part of IANDT Rec-Trimix course, I've done it in a drysuit, 8°C waters with corresponding lofty undergarments, no weight on weight belt or similiar.

As much as I'd say it's useless in the real world, it was a way smaller issue than at least I thought it would be - simply make sure the rig remains on top of yourself for the entire process.

Course requirement (states deeper than 6 meters!)
 
I've seen this twice in my life outside of training. Both instructors.

First case: I was joining the local dive shops in one of their recreational outings. The leader of the dive was the shop owner (Nikos - @wetb4igetinthewater knows him). One of his double tanks was leaking some gas from the neck. Not a big deal but as I was relatively new diver I considered it right to let him know, so I signaled to him small leak and pointed to his manifold. He remained very calm and withing seconds he had his BPW with doubles straight in front of him, saw the leak replied to me that it's ok and put it back! All this while maintaining perfect horizontal trim and keep (slowly) fining/moving with the group!!!
The way he did it was to unstrap his weist strap and then pull with both hands the manifold on top of his head to bring his rig in front of him. To don it, he put his hands through the shoulder straps with his rig in front of him and then pushed his BPW/tanks back on top of his head.
Both him and his BPW/tanks seemed to be perfectly trimmed and neutral even when separated so he could effortlessly hold his rig in front of him. It looked like he could comfortably do the whole dive like that.

Second case. Towards the end of a dive during an Egyptian LOB we were slowly fining at SS depth to reach our boat. Out of the blue the dive leader removed her BCD/tank, had a look at the back/side of it for something (no idea what she was looking for) and put it back like nothing happened. Again she remained trimmed and neutral throughtout.
The way she did it was to remove on hand from the shoulder strap and rotate her rig around her other hand in front of her, saw what she wanted to see, and reverse to put it back.

Both dives were in calm. clear, warm water.

Since I dive solo frequently I have tried to practice this a couple of times. Yes I can do it, but not nicely.
 
This is wrong. I had to doff and done my single back mount with slung redundant gas both on the bottom and in mid-water to pass my SDI solo diving course. I do a lot of solo drift diving in SE Florida. Twice, in minimal current, I have caught up my drift flag line on my regulator post. Once was while following a great hammerhead swim up on my right side, cross in front of me. and then swim away. Both times I simpley doffed my BC, freed the line, and dived on.

I guess if you have a buddy, like the DIR divers, this would never happen. However, this is the real world.
You are in the DIR forum.

Also lol if it’s a struggle to move a line off your tank valve… reach back there and move it?

Needless complication.
 
I've seen this twice in my life outside of training. Both instructors.

First case: I was joining the local dive shops in one of their recreational outings. The leader of the dive was the shop owner (Nikos - @wetb4igetinthewater knows him). One of his double tanks was leaking some gas from the neck. Not a big deal but as I was relatively new diver I considered it right to let him know, so I signaled to him small leak and pointed to his manifold. He remained very calm and withing seconds he had his BPW with doubles straight in front of him, saw the leak replied to me that it's ok and put it back! All this while maintaining perfect horizontal trim and keep (slowly) fining/moving with the group!!!
The way he did it was to unstrap his weist strap and then pull with both hands the manifold on top of his head to bring his rig in front of him. To don it, he put his hands through the shoulder straps with his rig in front of him and then pushed his BPW/tanks back on top of his head.
Both him and his BPW/tanks seemed to be perfectly trimmed and neutral even when separated so he could effortlessly hold his rig in front of him. It looked like he could comfortably do the whole dive like that.

Second case. Towards the end of a dive during an Egyptian LOB we were slowly fining at SS depth to reach our boat. Out of the blue the dive leader removed her BCD/tank, had a look at the back/side of it for something (no idea what she was looking for) and put it back like nothing happened. Again she remained trimmed and neutral throughtout.
The way she did it was to remove on hand from the shoulder strap and rotate her rig around her other hand in front of her, saw what she wanted to see, and reverse to put it back.

Both dives were in calm. clear, warm water.

Since I dive solo frequently I have tried to practice this a couple of times. Yes I can do it, but not nicely.
Must have been, aluminum doubles?
I would like to see that with 104s
 
What’s a good way to practice this particular party trick? Besides being easily able to get in and out of your gear in the first place. And importantly not letting go of it
 
Must have been, aluminum doubles?
I would like to see that with 104s
Aluminum cylinders are not common in Greece.

But throw in wearing a dry suit with no weight belt. While the diver in question far more skilled than me, wearing a dry suit with thick undergarments with a steel 100's on my back and an addition 10 lb v-weight results in significant torque when taking off the twinset from one's back. You have to keep it close to your body or you're going up to the surface and your twinset is going down to the bottom.
 
Aluminum cylinders are not common in Greece.

But throw in wearing a dry suit with no weight belt. While the diver in question far more skilled than me, wearing a dry suit with thick undergarments with a steel 100's on my back and an addition 10 lb v-weight results in significant torque when taking off the twinset from one's back. You have to keep it close to your body or you're going up to the surface and your twinset is going down to the bottom.
Exactly,,,

To derail this thead further,,,
It's very similar with sidemount,
Aluminum versus big steels

Big steels tend to become part of you, and you can't just hand them off.
 
https://www.shearwater.com/products/teric/
http://cavediveflorida.com/Rum_House.htm

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