Free Flow in reality!

[Diver0001]

I would not recommend your proposed method to any scuba diver.

I agree. I just wanted to re-quote that comment because I also believe that the OP is giving poor advice and I hope people understand that.

His proposed technique will only work for a exceedingly narrow range of equipment choices in ideal circumstances and executed by highly skilled divers. For the other 99.9 percent of divers, there are more logical responses.

R..

 

[peterbj7]

I agree with Devondiver and don't want to distract from what he's saying, but let me just clarify a point that two people are struggling with - I was postulating a FIRST stage failure, or more specifically failure of a hose where it comes out of the first stage. In those circumstances nothing you do to that hose downstream of the leak will help. As I said, I have seen this happen.

 

[MXGratefulDiver]

IMHO, if the What if ever happened the priority for any diver should be how to surface safely - NOT trying to figure out how to breathe from an already faulty scuba rig.

The exertion from shrugging off a scuba rig at depth to perform the actions you suggested are likely to exhaust the diver and waste his last lung of air.

I personally would just drop my weights and execute my CESA when this happens.

I also agree with Crowley. This is NOT a method for leisure divers / novices to practice, especially without a trained instructor to bring to their attention the risks involved.

Uh ... no.

The C in CESA stands for "controlled". Once you drop your weights, you are no longer in control of your ascent. You will NOT be doing a CESA ... you will be doing an emergency buoyant ascent, which is a last-ditch option when the only other choice is drowning.

You don't "drop your weights" and execute a CESA ... you swim yourself to the surface, and drop your weights once on the surface to assure that you stay there.

Maybe in the tropics, where you're wearing very little exposure gear and very little weight you can get away with it. But you try that in a cold water environment and you are in for one wild ride ... and the breach will be pretty impressive.

... Bob (Grateful Diver)

 

[ti325v]

While I understand peterbjs point I would like to add...

free flowing second stage,as a result of second stage failure.....pinch off the hose and go to your octopus.....alternately, pinch off and release the hose as you need to breathe the second stage. EASY !
First stage failure different story....I do not know the statistics on first versus second stage failures. But assuming non freezing conditions......50/50....so half the time have an easy solution. Open to other ideas on the first stage failing.....Then again I dive doubles so no worries.

 

[Thalassamania]

I think you might find that this was a huge breach of agency standards (any agency you care to choose) and served no purpose at all.

Putting aside the issues of releasing un-regulated high-pressure air into your mouth.... there really isn't a conceivable option where a simpler, quicker and more straightforward alternative would exist.

By teaching this, your instructor has overly complicated the decision making process needed in an OOA emergency by providing ineffective alternatives. Such hinderances would slow, or completely interupt, your reaction process during the demands of a real emergency.

It sounds like ego ("invented my 'own' method") won the battle against common sense and responsibility for this particular instructor.....

This was a fairly common exercise in recreational courses back in the sixties. In reality it is rather easy to accomplish, and as you observe, rather useless.

It is easy to breathe off a freeflowing regulator, the extra air will just vent out the exhaust diaphragm, there is no need to play half in your mouth / half out games.

A cut hose is a bit far fetched, I've know of IP hoses that failed due to manufacturing defects especially at the swedgings, but I don't remember hearing of an IP hose getting cut by a snag.

 

[DevonDiver]

This was a fairly common exercise in recreational courses back in the sixties. In reality it is rather easy to accomplish, and as you observe, rather useless.

Agreed. I am completely in support of using available pool time to conduct exercises aimed at developing dive related skills, dive fitness and general comfort and familiarity with being underwater, air depletion, problem solving etc. Even under the PADI system there is leeway for instructors to do this - provided they conduct an appropriate risk assessment and apply effective supervision and control.

However, teach non-standard and controversial skills exceeds the 'playing games' and taught as 'survival reactions' is irresponsible IMHO. The story illustrated by the OP is 'crossing that line'.

It is easy to breathe off a freeflowing regulator, the extra air will just vent out the exhaust diaphragm, there is no need to play half in your mouth / half out games.

I often wondered about this....as I've never experienced difficulty breathing directly from a free-flow reg without 'breaking the mouth seal'. I can only assume it is required to do that for a good reason that I don't know about....maybe too much stress/turbulance on the diagram or exhaust valve that could lead to failure? I speculate only....if anyone knows for sure, please let me know.

A cut hose is a bit far fetched, I've know of IP hoses that failed due to manufacturing defects especially at the swedgings, but I don't remember hearing of an IP hose getting cut by a snag.

I've seen plenty of perforated HP hoses....pinholes are common, given the wreck diving I do here daily. The gas loss is miniscule and never constitutes an 'emergency'...although I have had to abort dives on several occasions.

 

[Diver0001]

I often wondered about this....as I've never experienced difficulty breathing directly from a free-flow reg without 'breaking the mouth seal'. I can only assume it is required to do that for a good reason that I don't know about....maybe too much stress/turbulance on the diagram or exhaust valve that could lead to failure? I speculate only....if anyone knows for sure, please let me know.

I think in order to really see how this would go, you need to open up a 1st stage and remove the HP seat. I've recall a story from someone on scubaboard who had a 1st stage failure that caused HP air to be delivered directly to the 2nd stage. I remember that he said that the force blew the regulator right out of his mouth.

In any event I was left with the impression that it's not comparable to just pressing the purge button.

R..

 

[MXGratefulDiver]

I've seen plenty of perforated HP hoses....pinholes are common, given the wreck diving I do here daily. The gas loss is miniscule and never constitutes an 'emergency'...although I have had to abort dives on several occasions.

You DO realize those pinholes were manufactured into the hose, don't you?

High-pressure hoses are actually two sheaths of hose ... an inner sheath that is airtight and an outer sheath that is manufactured with pinholes in it. If something should happen to compromise the integrity of the inner sheath, the pinholes allow air to escape the outer one without causing a catastrophic rupture of the hose.

That's why when you have a leaking HP hose, you will almost always see it leaking from several places at once. As noted, the leaks will be small and they will typically allow you to complete your dive ... or at least make an orderly ascent ... without any real sense of emergency.

Most likely, the leaks in your hose were not caused by contact with a wreck ... but rather due to internal stresses on the hose ... or dry rot if the hose is old enough. Regulator hoses were never intended to last forever, after all ... like everything else made of rubber, they eventually break down and need to be replaced.

... Bob (Grateful Diver)

 

[wilde100]

Uh ... no.

The C in CESA stands for "controlled". Once you drop your weights, you are no longer in control of your ascent. You will NOT be doing a CESA ... you will be doing an emergency buoyant ascent, which is a last-ditch option when the only other choice is drowning.

You don't "drop your weights" and execute a CESA ... you swim yourself to the surface, and drop your weights once on the surface to assure that you stay there.

Maybe in the tropics, where you're wearing very little exposure gear and very little weight you can get away with it. But you try that in a cold water environment and you are in for one wild ride ... and the breach will be pretty impressive.

... Bob (Grateful Diver)

I apologise for adding to the confusion. Yes, I dive in the tropics without a wetsuit. I was referring to that situation.

 

[DevonDiver]

You DO realize those pinholes were manufactured into the hose, don't you?

Actually...I didn't

That makes perfect sense...as the pinhole leaks didn't seem to fit with damage from wrecks.

Thanks for sharing that...it's good info!