How much time do I have with a stuck inflator

[dumpsterDiver]

Now that makes sense-general wear n tear causing a slow leak--Kinda like a worn tap washer.Of the failures you have seen how many were of this nature and how many were emergencies?



Wouldn't first stage freezeup cause the oposite effect.Ie no air? or your second stage to suddenly freeflow?
The danger refered to is a sudden return to the surface but don't all BC's have an emergency dump to prevent overinflation? so it can only fill to max.

Doesn't propper washing of your gear prevent crystal formation?
Doesn't regular maintainence prevent the o ring failure?
Hey again guys please this isn't some "smartalec kid" trying to prove you guys wrong or anything idiotic like that This is a genuine desire to understand.

NO NO NO. Regular maintenance REDUCES but never prevents gear failures. You need to move away from the idea of "prevention" and more toward "trying to make it less likely that stuff fails".

Put a brand new hose on your regulator... It is probably more likely to blow on the first dive than a one year old hose that has done 100 dives...

 

[Saudi-Diver]

Dumpster Diver has very eloquently summed up every equipment failure I have ever had. The spectacular failures have all been with recently serviced or new equipment. Usually you get loads of warning of an issue, a reg starts to Free flow a little in current or an inflator starts to sneakily inflate your BCD. Familiarity with your equipment is a good thing. Also if it feels wrong but you cannot put your finger on whats wrong trust your instincts, its wrong.

 

[Frosty]

well thar you go -I learned something today. Thanks guys

 

[haumana ronin]

If my BCD inflator were to get stuck open, how much time to I have to disconnect/vent before it could lead to injury?

**cut**

What is your ascent rate with a BC fully inflating? How much does flaring reduce your ascent speed? Obviously, I don't want to test this on myself just for the heck of it.

To the OP
Here at my school we practice BC disconnects and emergency flares for such an event. For the latter we have all our students lie 13ft on the pool bottom facing up. Once they give us an OK, DM's and instructors then mash down on the students inflator until their BC auto-dumps, then we let go. We usually have to hold them down for a few seconds before this happens. For me this is fairly easy to do.
With an Air 2 it happens a lot quicker, I only have to hold the student for a brief second before I can let them go.

Sounds like a neat exercise. How fast were they rising with a full BC? Do all of them successfully disconnect? What about lung over expansion for new student divers who might be holding their breath in the excitement of it all?

************************************************
OK, so practice on land, then in the shallows, then with a prewarned buddy or instructor in the deep. Practice until it becomes easy without looking. Part of my original question remains though: how fast? Tenth, quarter, half, one, or how many seconds? I did it in OW, though at chest level, but there was never a target time and I was futzing with it a while.

And stabilize depth either by venting while finning down and by venting while disconnecting the power inflator. At all times keep venting to maintain depth, which is easy since dump valves are faster than inflators. A dump-fill-dump might be enough to work the valve shut if it is not a rapid emergency. OK

And truthfully, if it happened and I caught it soon enough, I would probably leave it disconnected and continue the dive.:cool2: After inflating to level out my initial descent and venting a couple times during the dive, the BCD just seems like a handy place to hang weight pouches....

:zen:

 

[windapp]

If it is as common as you say then what causes that kind of failure and what should be done to prevent it?

Any valve that is pushed back by a spring or air-return can fail when the friction of the valve exceeds the force of the spring. This is usually caused by contamination like sand or silt. I had air-pilot return valves fail on my in a manufacturing situation when the synthetic compressor oil over-expanded the buna rubber o-rings. Of course, if this happenes in your scuba equipment, your air is really really bad.

Wouldn't first stage freezeup cause the oposite effect.Ie no air? or your second stage to suddenly freeflow?

A regulator (in its simplest form) is essentially a valve that has a preloaded spring pushing it open against air pressure coming from the downstream flow. If the valve froze, it could freeze in any position, open or closed, or somewhere in between.

 

[TSandM]

When my buddy and I did our first dive with Andrew Georgitsis, we got about five feet underwater when Andrew grabbed my buddy's inflator and mashed on it. He went head down, kicked down, and opened his butt dump. He was able to remain underwater until I was able to help him with a more permanent solution to the problem (and no, it was not removing Andrew ). So, if you respond promptly to an autoinflating BC, you probably have a lot of time to solve the problem. If you do not recognize what the issue IS, not so much.

You are correct that a BC can only inflate to the pressure that pops the OPV -- but that's a tremendous amount more air than you need, even at deep depths, so a full BC is going to be a powerful force to lift you to the surface.

Freezing in a first stage may cause the piston not to seat smoothly, which means the first stage will continue to allow high pressure gas out of the tank, even when the second stage valve is closed. That excess pressure will blow out somewhere . . . usually as a freeflow, but on occasion, it may blow through the BC or drysuit inflator.

 

[vladimir]

I have seen the other thread with the Hat, so don't post that.:tongue2: And yes, proper BC maintenance and not holding your breath on the way up are two important things too...

:zen:

You've seen the hat, but have you seen Deep Sea Supply's valve flusher? It looks like a good idea to me, and I would have one if I had a garden hose. They also make a handy little tool for disassembling inflators, which I do have, and which works well.

 

[BluewaterSail]

This thread is timely for me, as I have been mulling it over in my mind.

This past Friday, the night dive from my AOW was ended early because this happened to another participant. The diver had an unusual Aqualung bcd, which has a lever mounted on bcd itself to inflate, rather than a button on a hose. Her computer somehow got wedged in, and the lever was jammed to the open position. Having accidentally dropped her flashlight while trying to unjam the lever, she had no option but to surface and swim back to the shore. With the rest of us following once we figured out what happened.

Ever since that, I have been going over scenarios in my mind.

Also, as I observed in my offshore sailing in the past, its usually not one thing going wrong that gets you, its that it starts a series of unfortunate events that further complicate the situation.

 

[dumpsterDiver]

.

Also, as I observed in my offshore sailing in the past, its usually not one thing going wrong that gets you, its that it starts a series of unfortunate events that further complicate the situation.

Definitely true in diving as well.

 

[Frosty]

Definitely true in diving as well.

It applies in other "worlds" too. =The day you forget your dive knife is gonna be the day you need it.