Blown o-ring at depth :o

[Kevrumbo]

Im posting this in this section as ive seen it come up in other threads on the board.

August 2009 - Sharm El Sheikh, Egypt (~40c/105f air temp)
Were jumping in for some manta ray action for our third dive of the day. We actually spotted one from the boat so we jumped in and followed it for a few minutes, ending up at around 20m/65 ft.
When I look back at my buddy I think shes having a way big exhale, but it last too long and she turns around looking for the weird sound coming from behind her and I realize theres a REAL major leak from her tank valve. I get closer to her and offer my octo, but she dont realize whats going on as she cant see the bubbles and think its a speedboat or something she explains to me later.
I signaled for her to stop, look at her pressure gague and take my octo before I shut down her tank valve and we start to get closer to the reef and ascend as we where pretty far away from the reef out in the blue.
We never got noticeably stressed or anything, so from that point of view it was just a perfect air-share ascend drill.

My buddy was a small woman that usually use about half the air I currently do.
I came up with 30 bar/435 psi less than I jumped in with while she had used 80 bar/1160 psi. Probably 70 bar/1015 psi of that was lost in a matter of a couple of minutes.
Total dive time was 10 minutes.
This WAS a badly blown o-ring, but it was a matter of a minute or two to take out almost half of her air.

What I learned from this was pretty much that I will do the EXACT same thing if It happens again, especially if its as bad a leak as this one was;
1. Donate an alternate air source
2. Shut down the freeflowing tank
3. Abort the dive safely.

If theres doubles or multiple tanks in other configurations it may be different, but for single tank dives, Ill just get an alternate air source to the person in need and abort the dive ASAP.

I had kept an eye on my buddy (as I think everyone should with theirs) for the duration of the dive so I know for a fact that this was not already leaking as we got in.

Raja Ampat 2007, my DM/Guide has his tank valve O-ring extrude resulting in a major leak on initial descent to 12m depth; I donated my long hose, shut-down his tank valve, showed my SPG reading 190 bar (like you should always do during a S-drill), and we elected to continue the dive gas-sharing at 9m for 30min touring an absolutely gorgeous reef.

http://www.scubaboard.com/forums/near-misses-lessons-learned/304301-blew-o-ring.html

 

[viakovlev]

These are good examples of buddy system, but.... the most common cause of accidents is still out-of-air situations (whatever reason). Even a good responsible buddy is not always within a reach (against current, around a corner, taking photo..) Therefore, a redundant air bottle, pony or doubles, side- or backmounted, MUST be a standard on any dive where you cannot surface safely on pretty much one exhalation.

 

[windapp]

Raja Ampat 2007, my DM/Guide has his tank valve O-ring extrude resulting in a major leak on initial descent to 12m depth; I donated my long hose, shut-down his tank valve, showed my SPG reading 190 bar (like you should always do during a S-drill), and we elected to continue the dive gas-sharing at 9m for 30min touring an absolutely gorgeous reef.

On a single air source for two people with no redundancy?

 

[Tigerman]

These are good examples of buddy system, but.... the most common cause of accidents is still out-of-air situations (whatever reason). Even a good responsible buddy is not always within a reach (against current, around a corner, taking photo..) Therefore, a redundant air bottle, pony or doubles, side- or backmounted, MUST be a standard on any dive where you cannot surface safely on pretty much one exhalation.

However, this thread was never about the buddy system or overhead enviroments to begin with, it was about what will actually happen to your air if you blow your o-ring and how fast youre screwed..

 

[finnks]

On a single air source for two people with no redundancy?

They were at 9m - not 90m. Students do a CESA at almost this depth during checkouts for OWD. Without complicating factors such as overhead, entanglement hazards, etc, I see no need for redundancy at this depth.

 

[letterboy]

They were at 9m - not 90m. Students do a CESA at almost this depth during checkouts for OWD. Without complicating factors such as overhead, entanglement hazards, etc, I see no need for redundancy at this depth.

really . . . no reason at all?

 

[Tigerman]

Just a heads up, Ive requested discussions about redundancy, overheads and other things irrelevant to the original post moderated as they are offtopic..
Do feel free to discuss these things in another thread referring to this one though

 

[dumpsterDiver]

However, this thread was never about the buddy system or overhead enviroments to begin with, it was about what will actually happen to your air if you blow your o-ring and how fast youre screwed..

skip to 1:40, I caught mine on video..
Scuba Failure at 80 feet: GoPro Hero 2 - YouTube[video=youtube_share;Bap2PxetarQ]http://youtu.be/Bap2PxetarQ[/video]

 

[InTheDrink]

Just a heads up, Ive requested discussions about redundancy, overheads and other things irrelevant to the original post moderated as they are offtopic..
Do feel free to discuss these things in another thread referring to this one though

Sounds like you dealt with this really well. Not sure tho why you'd post in the forum and then want offshoots like redundancy pushed to other threads. For me at least this is a primary and natural extension of your post.

I nearly always dive with gas redundancy even on shallow dives. A primary driver for this has been the knowledge that even if rare o-rings do blow (as well as a range of other potential failure points). Relying on a buddy is great if your buddy system is working well but in many cases, especially in good viz like the Red Sea, or if you are the guide/instructor you typically end up diving solo irrespective of semantics.

Having an additional gas source makes a lot of sense to me.

I'm very tempted to take a side-mount class for this very reason.

Anyhow I'm really glad that your preferred form of redundancy worked out well and it sounds like you're a very awesome buddy!!

John

 

[Freezerbrn]

Keeping on topic great job of buddy breathing and OOG ascent. :cool3: