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

[steinbil]

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?!

 

[Cthippo]

I was taught that in my OW class and I have many of the same comcerns you do with it. My take on it is similar to how we are trained to remove SCBAs for profile reduction, which is to say the hand on the regulator side never lets go of the shoulder strap.

I dive with a pony and a seperate weight harness, so losing my BCD would cost me some buoyency control and some air, but not all of either.

 

[steinbil]

I dive with a pony and a seperate weight harness, so losing my BCD would cost me some buoyency control and some air, but not all of either.

But isn't your pony attached to your rig somehow? If you take off your BC, how is your pony still attached to you?

PS.
This is the DIR forum, so I guess the pony talk is a little OT.

 

[PfcAJ]

Party trick.

No real reason to ever do this. In fact, the two that I’m aware of who tried to do this to pass a restriction both drowned.

Taking your gear off to get into a habitat or whatever is a different conversation. But if you’re doing that, you don’t need to ask questions about it on Scubaboard.

 

[rjack321]

Slow news day in DIR land. There is no reason to do this even in a wetsuit with an AL80, in a drysuit with a large steel tank its basically impossible.

 

[scubadada]

Party trick.

No real reason to ever do this. In fact, the two that I’m aware of who tried to do this to pass a restriction both drowned.

Taking your gear off to get into a habitat or whatever is a different conversation. But if you’re doing that, you don’t need to ask questions about it on Scubaboard.

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.

 

[steinbil]

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.

What kind of backplate? How was the weight distributed? Were you neutral in the water without your rig? What did you do with your slung tank when removing your back mounted rig?

 

[wetb4igetinthewater]

There's a very good reason why this is only a confined water skill and not an open water one. Students would be dying left and right if they were required to do this in cold water environments wearing 7 mills or dry suits.

I've done it with a weight belt for demonstration purposes, but no way am I going to upload those videos. I'll try to do it without a weight belt, but I'll have a second scuba kit set up to retrieve the one I just removed but was unable to replace!

 

[OrcasC205]

Hint: just because it involves a backplate and wing and long-hose doesn't mean it belongs in the DIR forum.

 

[NW Dive Dawg]

As a drysuit solo diver......the entanglement issue is my main concern for being prepared for this doff and don scenario. I'm a big guy and dive an integrated BC (Zeagle Ranger) with a back mount 19cf pony and a total of 28lbs of added lead in salt water. I know it sounds like a lot of lead but I dive a shell suit with a lofty undergarment and that's just what it takes and has worked for me for 30 years. I choose to split my weighting. I carry 10lbs on a standard weight belt, 5 on each hip. Then I have 14 lbs in the ditchable pockets of my BC..... 7 on each side. And finally the last 4 lbs goes into the non-ditchable BC trim pocket in back on my port side to offset my pony weight. If I ever needed to doff at depth in an entanglement scenario, and assuming that I would be either on a structure or on the bottom...... my plan is to first completely dump as much gas as possible from both my BC and drysuit before doffing. Then the 10 lbs on my belt keeps me negative enough to avoid an ascent without my system. I have never had to implement this in an actual emergency, but have performed it as a training exercise with a buddy close by and it's what works for me.