Question about “balanced rigs” and having all ballast unditchable

[REVAN]

So far, I've only read the first page of this thread.

On the terminology: I think the term "balanced rig" is confusing in it's meaning as diver's tend to use it. If the rig and the diver are each weighted to be close to neutral when the diver is separated from the rig underwater, this would be better described as a "neutral rig". When someone says "balanced rig", I think of a kit that is properly trimmed to stabilize the diver horizontally in the water; not nose heavy, not tail heavy, but balanced.

If folks want to adopt the "neutral rig" terminology, I think it would be self explanatory language that will make communications between divers clearer. Probably not going to happen, but thought I'd throw it out there anyway.

 

[MichaelMc]

So far, I've only read the first page of this thread.

On the terminology: I think the term "balanced rig" is confusing in it's meaning as diver's tend to use it. If the rig and the diver are each weighted to be close to neutral when the diver is separated from the rig underwater, this would be better described as a "neutral rig". When someone says "balanced rig", I think of a kit that is properly trimmed to stabilize the diver horizontally in the water; not nose heavy, not tail heavy, but balanced.

If folks want to adopt the "neutral rig" terminology, I think it would be self explanatory language that will make communications between divers clearer. Probably not going to happen, but thought I'd throw it out there anyway.

You mostly just missed how blown o-rings flood and sink tanks, and pony sizes relate to the question.

What about 'neutral diver' as the 'able to hover separate from rig' term? The rig comes with a wide ranging air bladder, while the divers lungs have other demands.

Edit: though when you took it off the rig did need to be neutral for you to be as well.... Slow, sorry. And boulderjohn telling us to stick to single tank no-deco as this is in basic. But the first few pages are good.

 

[lowviz]

...//... Spare air is for recreational, so assuming 40m max depth, it would have effective volume of 1.0 cu ft based on an average depth of 20m.

This is buddy think. It won't work IRL but my bud will be there for me. I got wrapped around a piling on an outgoing tide. How stupidly simple is that? It turned out to be a damn good thing that I always dive with a buddy. My constant buddy is AL Faber, 19 cuft.

You need to personally test your assumptions before you encourage someone to kill themselves. No, I'm not overstating this. IRL.

 

[CWK]

This is buddy think. It won't work IRL but my bud will be there for me. I got wrapped around a piling on an outgoing tide. How stupidly simple is that? It turned out to be a damn good thing that I always dive with a buddy. My constant buddy is AL Faber, 19 cuft.

You need to personally test your assumptions before you encourage someone to kill themselves. No, I'm not overstating this. IRL.

There is video evidence of a diver who correctly calculated that his contingency OOA gas reserve requirement would be satisfied by 13cu ft pony for a dive to 60m. This is by no means the only answer. Your SAC and the contingencies that you plan for dictates the gas that you will want to carry. If you wish to plan for the contingency of being wrapped around a piling on an outgoing tide and carry a 19 cu ft pony, so be it.

FWIW, I was discussing doing the SDI Solo course with my last tech instructor who was adamant that nothing short of a 7.5 liter tank (53 cu ft) would suffice as a pony for the course. I also discussed the possibility of doing a solo dive to the house reef where I had seen some false pipefish as well as a peacock razorfish. For this dive to less than 10m, my tech instructor was also insistent that the minimum pony size was a 7.5 liter tank. There may be other divers who view your 19 cu ft pony as being inadequate. It is certainly not the case of one size fits all.

I don't see how I've said anything that would encourage anyone to kill themselves. I do encourage everyone to learn to calculate their own contingency gas reserves requirements.

 

[CT-Rich]

There is video evidence of a diver who correctly calculated that his contingency OOA gas reserve requirement would be satisfied by 13cu ft pony for a dive to 60m. This is by no means the only answer. Your SAC and the contingencies that you plan for dictates the gas that you will want to carry. If you wish to plan for the contingency of being wrapped around a piling on an outgoing tide and carry a 19 cu ft pony, so be it.

FWIW, I was discussing doing the SDI Solo course with my last tech instructor who was adamant that nothing short of a 7.5 liter tank (53 cu ft) would suffice as a pony for the course. I also discussed the possibility of doing a solo dive to the house reef where I had seen some false pipefish as well as a peacock razorfish. For this dive to less than 10m, my tech instructor was also insistent that the minimum pony size was a 7.5 liter tank. There may be other divers who view your 19 cu ft pony as being inadequate. It is certainly not the case of one size fits all.

I don't see how I've said anything that would encourage anyone to kill themselves. I do encourage everyone to learn to calculate their own contingency gas reserves requirements.

I think referring to a spare air as scuba equipment in some quarters is encouraging killing yourself. You are equating getting away with something with it being appropriate. I think an AL80 to 180’ and having a 13 pony is cutting margins extremely tight. The prop on his boat was fouled in what looked like a ghost net. How much time do you have to de-f*ckerize your situation at 180 fsw before you run into a deco obligation that exceeds your gas capacity?

I realize that this person (DD?) May have been doing bounce dives like this for years but at those depths margins are very tight and saying he planned it well and got lucky are very different things. And this is a basic forum.

 

[seeker242]

I’m seeing many people buy into the no ditchable weight balanced rig idea, and I wonder if they really understand what they are getting into, and if they understand the original purpose.
What is the original theory behind it?

A "balanced rig" does not mean you have no ditchable weight. It means you can comfortably swim it up with wing failure and still hold a deco stop if necessary.

 

[Eric Sedletzky]

A "balanced rig" does not mean you have no ditchable weight. It means you can comfortably swim it up with wing failure and still hold a deco stop if necessary.

That’s just properly weighted.
“Balanced rig” IMO is a mismomer,
“Balanced ballast” would be more accurate.

 

[Eric Sedletzky]

With the reg blowout at 180’,
It looked to me like the diaphragm blew out possibly because of an instant seat failure causing the IP to go through the roof. The diaphragm was exposed to full tank pressure. When he got back on the boat and they pressurized the reg air was blowing out through the IP adjustment nut. The only thing vulnerable behind that is the diaphragm. If the retainer nut was loose there would have been a slow build up of bubbles.
This could be one reason why some consider piston regs to be better, they’re not prone to this problem.

A dive to 180’ on a single with only a 13 as a backup and solo, Wow! OK.

 

[richmonddiver]

I think referring to a spare air as scuba equipment in some quarters is encouraging killing yourself. You are equating getting away with something with it being appropriate. I think an AL80 to 180’ and having a 13 pony is cutting margins extremely tight. The prop on his boat was fouled in what looked like a ghost net. How much time do you have to de-f*ckerize your situation at 180 fsw before you run into a deco obligation that exceeds your gas capacity?

I realize that this person (DD?) May have been doing bounce dives like this for years but at those depths margins are very tight and saying he planned it well and got lucky are very different things. And this is a basic forum.

The diver was Dumpster Diver. I believe he was using a diaphragm 1st stage and the diaphragm blew.
Here is the link to the thread.

DumpsterDiver emergency ascent from 180'

 

[Lorenzoid]

That’s just properly weighted.
“Balanced rig” IMO is a mismomer,
“Balanced ballast” would be more accurate.

Okay, it's a misnomer. I agreed in post #4 above, and I suspect most others might agree. Someone posted the link to the GUE gear configuration, where it says:

The diver should be able to drop unnecessary weight and swim up without a functioning BC. As with all diving, the key component to proper buoyancy is diving with a properly balanced rig.