Should I switch to BP/W?

[JeffG]

Unfortunately, the concept of 'balanced rig' makes the optimistic assumption that a loss of buoyancy failure will happen with no other complicating factors (such as a coldwater leg cramp, or OOA) being present that could in any way impair the diver's physical swimming abilities.

and it doesn't account for the change in the gravitational force when the aliens attack our solar system, but nice try in adding in some new additional failure points to justify your lack of knowledge on balanced rigs

 

[GreenDiverDown]

When all of your ballast is integrated into your rig, if worse comes to worse and you have to ditch ballast, it means that your tanks have to be left behind with your ballast.
-hh

Like I said... not a good idea. IMHO, leaving your rig behind is never a wise choice... aside from some wierd alien abduction-type event.

I agree with Jeff... I think that you are missing the big picture when speaking of a balanced rig.

 

[GreenDiverDown]

and it doesn't account for the change in the gravitational force when the aliens attack our solar system, but nice try in adding in some new additional failure points to justify your lack of knowledge on balanced rigs

Wow! That's freaky that we both came up with the alien thing, eh?

 

[Dive-aholic]

Perhaps I'm not following you, but... I don't think that cutting off your harness and leaving your rig on the bottom is a good idea.

Better than staying down there with it.

I don't ever foresee this as being an action I take. But I also won't have any problem doing it if the situation ever arises. I can't give you an example because I don't know what that situation would be. When it happens, though, I'll know.

 

[JeffG]

Wow! That's freaky that we both came up with the alien thing, eh?

Great minds think alike

 

[MXGratefulDiver]

Great minds think alike

So do strange ones, apparently ... :browsmile

... Bob (Grateful Diver)

 

[JeffG]

So do strange ones, apparently ... :browsmile

... Bob (Grateful Diver)

Yuk it up why don't ya

 

[MXGratefulDiver]

Yuk it up why don't ya

Uh oh ... (keepin' a wary eye out for an armed cat) ... :11:

... Bob (Grateful Diver)

 

[-hh]

A lot has changed in 20 years ...

...and some things haven't changed.

Divers still die and are later found on the bottom still wearing their weightbelts.

Specifically, in this case, diving protocols changed with the invention of the BCD.

Not quite. The protocols changed with the advent of the Jacket BCD's popularity, because the training doctrine of "weightbelt last" was no longer important because the Jacket's lack of a crotch strap.

It is now two decades later, and the BP/W is enjoying a resurgence in popularity, so those elements that had become obsolete with the Jacket are no longer irrelevant.

As to an earlier comment you made about releasing the weighbelt from under the crotch strap being too complicated ... it's not.

No, its not that it is "too complicated", Bob. It is that what was an "N" step task sequence is under your training an "N+1" task sequence, which from a work taskloading perspective is a step backwards.

Keeping in mind that the most common cause of a catastrophic dive accident is because the task workload capacity of the diver was exceeded, what is your justification for INCREASING a stressed diver's work taskload?

It simply doesn't matter how easy/hard the task is when it can be completely eliminated. Logically, such an increase in work taskloading can only be justified if results in some real, tangible benefit afforded by your protocol that in balance justifies its existance.

Call it Hogarthian or whatever you want, but when there's no benefit to the increase in complexity, then it should be eliminated.

If you want to dive as you were taught 20 years ago, feel free...

You missed my point: there were things that were known 20+ years ago that have become "lost art" as the dive equipment technology moved on. You try to whitewash over this by the feel-good mantra...

"A good diver is always learning" ...

...but you've forgotten:

"Those who cannot remember the past are condemned to repeat it."
- George Santayana (1905)


Now from what you've said, NAUI's training policies on this have apparently done a complete and full reversal. Fine - what was their rationale for precisely why?

Let's hope that there really is a good, concrete reason and that its not simply that they've forgotten the lessons of the past.


-hh

 

[-hh]

Like I said... not a good idea. IMHO, leaving your rig behind is never a wise choice... aside from some wierd alien abduction-type event.

I agree with Jeff... I think that you are missing the big picture when speaking of a balanced rig.

Leaving the rig behind scenario's occur primarily because the diver's ditchable vs non-ditchable ballast percentages were poorly planned, or not planned at all.

The basic premise of 'balanced rig' is the belief that you're going to be able to swim up from max operating depth if you have a catastrophic BC failure and no redundency, usually because you've minimized your weighting. Its also sometimes claimed to describe trim, but that's pragmatically irrelevant here.

Yes, minimizing your weighting is generally a good thing, but consider a diver in a coldwater FJ wetsuit: he's going to have around at least 10lbs worth of wetsuit compression by 100fsw, plus he will have at least 6lbs (AL80 or larger) worth of air virtually regardless of any other factors regarding the dive.

As such, if he were to have a BC failure immediately upon reaching the bottom, he's at least 16lbs negative, and if he can't generate at least 16lbs thrust for, say, two minutes, if he doesn't have lift redundency, then he's stuck on the bottom until some form of aid arrives (buddy, etc)...

...or...

...he ditches ballast. Either enough such that he's either now buoyant (not particularly desirable) or enough such that his remaining negative buoyancy can now be overcome by the amount of thrust he can deliver for the required time period.

There is no doubt that a controlled ascent is always better than an uncontrolled one, but what is being overlooked is that an uncontrolled ascent isn't the worst possibility here: what is worse than an uncontrolled ascent is NO ascent.

AFIAC, Jeff can go worship his 'balanced rig' if he wants. My question would be how did he quantitatively determine how much thrust he can deliver under what conditions for what period of time? Afterall, if we've not tested ourselves to determine for sure what level of physical performance we can deliver in a time of need for how long, then all of this contingency planning has just become sabotagued by a single "Trust Me".

The accident reports also include instances of negatively buoyant divers making it up as far as their stop(s), then sinking to their deaths because they couldn't maintain thrust to maintain depth or surface. Happens not quite every year, but seems that way.

However, not all is lost, for one thing that a good 'balanced rig' evalation process can do is to determine your worst-case max negative condition on the bottom at the beginning of a dive, which would also represent the most amount that you would need to have as ditchable weights to effect an immediate non-swimming (buoyant) ascent. Again, its not the first choice ... it is one short of the last choice.


-hh