O-Ring Failure

[BobbyWombat]

Anyone have 1st hand experience or a trustworthy source on what happens when you have a tank o-ring failure at depth?

Is it typically:
1. An annoying leak that you should get fixed when you finish the dive
2. Losing air fast, but plenty of time to get make a controlled ascent (let's use 100' for arguement)
3. Time to find your buddy because you are going to be out of air very soon


More to the point: Do I need to worry about this?

 

[Michael Schlink]

Somewhere there are posted times of different failures, but you should be able to make a normal ascent and possibly all or part of your safety stop. Your buddy should, already, be next to you and "standing by" to help, if needed.
It will typically be more than a hiss and a few bubbles and you shouldn't try to finish a dive with a leak in progress, it can always get worse, much worse.
Thumb the dive, signal your buddy and start up, textbook and simple. Be ready to share air. If your ascent was normal, you could repair the problem and finish the dive.

 

[redacted]

Anyone have 1st hand experience or a trustworthy source on what happens when you have a tank o-ring failure at depth?

Is it typically:
1. An annoying leak that you should get fixed when you finish the dive
2. Losing air fast, but plenty of time to get make a controlled ascent (let's use 100' for arguement)
3. Time to find your buddy because you are going to be out of air very soon


More to the point: Do I need to worry about this?

you should worry if you do not have a backup. But the chance of both your primary gas supply and your backup gas supply failing simultaneously is negligable.

 

[CrawfishDiver]

had one happen a 30 ffw normal ascent replaced it and still had 2000 lbs

 

[lazyturtle]

All the total o-ring failures (as in loud pop and air begins gushing out) that I've seen have occured when the tank is first turned on or the tank is onboard (and still full) and sitting in the sun. It's unlikely that as the pressure in the tank decreases (from you breathing the air) that a failure will occur. If it doesn't happen when before you get in the water, it's unlikely to happen on the bottom.
When we bleed takns to do a VIP (for which the tank must be empty) it takes between 10-20 mins for the tank to drain down to empty.
A mild hissing (as in you need to be next to the tank to hear it) is merely annoying, don't stress about it.
If it stresses you out, just replace the o-ring (they're dirt cheap) and it's not worth any ammount of stress.

 

[Diver Dennis]

I've only seen, or heard actually, two and as turtle posted these were topside. I have never seen one or met anyone who has had one underwater.

 

[herman]

The severity of the failure can range widely, from a simple stream of bubbles to a fairly noisy shower of bubbles. Reguardless of the severity of the failure, with a reasonably full tank you have a good bit of time to do a safe accent. The worst problem you have is panic. A full O-ring rupture is going to be pretty noisy, a lot like a freeflow on a reg. You have plenty of time to react as long as you keep calm. Get your buddies attention.....likely he has already been looking around wondering what the noise is and do a slow, safe accent. It is a fairly uncommon occurance at depth. Next time you have a 1/2 full tank after a dive, spin the valve open and see how long it takes to drain it down most of the way, I think you will be surprized.

Welcome to the board.

 

[NC myerssl]

Speaking from experience, I had an O Ring blow on my contingency bottle 5 minutes into a dive at 120'. Lots of bubbles and it gets everyones attention:11doh:

The bottle was a 30 cft and the O Ring had a slice in it on the side (similar to a bagel that is pre-sliced). It did not show up on the surface when the air was turned on but at depth and five minutes into the dive.

I was able to turn the bottle off and come up because I only had my primary tank working correctly (one is none philosophy). But the amount of gas lost was significant (lost around 10 cft in about 45 seconds). Would I have enough gas to perform a normal ascent to the surface with a blown O Ring on the primary? Probably. But I would not dally around, I would call the dive and start up.

 

[BobbyWombat]

Good advice. Thanks all.

I feel better knowing that likely if I keep my head on straight and ascend with my buddy ready to help, it's all good.

SpareAir makes a big deal about this on their website. The consensus of ScubaBoard, to paraphrase, is something like "good for getting out of a helicopter crash, not good for SCUBA divers".

A pony bottle is not always available for rent, and a PITA to travel with.

So, I think for now I've settled on reinforcing good SPG checking habits, not stressing about O-ring failure and passing on buying/traveling with a secondary air supply.

 

[captain]

If you own your own tanks and properly maintain them I feel this is a non issue. In 40+ years of diving the only time I have had an issue with an O ring is when I failed to get the regulator squarely mounted on the tank and when I turned it on the O ring popped out. I have never had a valve to tank O ring leak much less a failure while in the water. I think this is mostly either a rental tank issue or bad assembly or maintenance.