A llittle leak might not be so innocent after all.

[raftingtigger]

On a recent dive with 2 teams of 2 I noticed a minor air leak from one of the divers on the other team sometime after we reached the bottom. The leak was coming from where the yoke met the valve. It was a simple dive, OW, with a plan not even approaching the NDLs, and the leak was minor (no significant air loss). The most common leak here is a dirty o-ring, so I noted the leak to tell the diver later.

Dive proceeded and finished without any problems and when back at the shore I mentioned the leak to said diver. He responded with "yes I know about it, this nut is a little loose" and pointed to the yoke retaining nut.

Yowzer!!! That is NOT a nut you want coming loose. If it gets loose enough the body of the first stage will part company - violently - with the yoke, and propel itself - forcefully - into the back of said diver's head. I can vouch for that behavior as I had the equivalent part on a DIN 1st stage come loose while bench testing, which had scared the cr.p out of me. As a result, now every dive that nut gets checked for security. And yes, I do use a torque wrench to set the manufacturer specified torque - so why it came loose over time I don't know.

 

[Doppler]

I knew one of the cords holding the canopy to my parachute harness was frayed, but I jumped anyway...

Let's get the message across loud and clear... Don't ****ING dive with gear you KNOW is broken/sub-standard/leaking/wrong

 

[tbone1004]

yeah, good lord, this guy is scary. If the nut is loose, even tightening it finger tight will get it snug enough to not leak. The torque is to make sure that it doesn't loosen itself when idiots try to turn the first stage when it is pressurized....

 

[redacted]

And yes, I do use a torque wrench to set the manufacturer specified torque - so why it came loose over time I don't know.

When the reg is under pressure, there is so much force sealing the tank valve with the din/yoke retainer that turning the first stage can result in the retainer turning within the 1st stage body. If the seal between the retainer and the body is on the end of the retainer, any looseness should show up rather quickly as a leak. If the seal is on the side of the retainer (like a Mk5 or Mk2) then the retainer may loosen quite a bit before it leaks.

I really think this may have contributed to the Mk20 retainer recall years ago which was blamed on heavy handed techs.

 

[raftingtigger]

When the reg is under pressure, there is so much force sealing the tank valve with the din/yoke retainer that turning the first stage can result in the retainer turning within the 1st stage body. If the seal between the retainer and the body is on the end of the retainer, any looseness should show up rather quickly as a leak. If the seal is on the side of the retainer (like a Mk5 or Mk2) then the retainer may loosen quite a bit before it leaks.

I really think this may have contributed to the Mk20 retainer recall years ago which was blamed on heavy handed techs.

The leak I had (on the bench) was a MK5 - there was no noticeable leak (it was out of water however) until it disengaged. OTOH the one underwater was a newer model/brand and so if AWAP is right (he usually is) then it wasn't as close to going as with a MK5. However the point is: what seems like a minor and inconsequential leak (eg a few bubbles from the HP spool) might not be so inconsequential. It might even be normal/desired as is with some of the Sherwood 1sts. Just don't guess, KNOW.

 

[RJP]

yeah, good lord, this guy is scary. If the nut is loose, ...

Sounds like the real "loose nut" was right behind the mouthpiece.

 

[raftingtigger]

yeah, good lord, this guy is scary. If the nut is loose, even tightening it finger tight will get it snug enough to not leak. The torque is to make sure that it doesn't loosen itself when idiots try to turn the first stage when it is pressurized....

Overall this diver, while new, is a pretty good guy and diver. He was just ignorant of the risks. He is learning, and seems to be receptive. For that matter (Nomex suit is on) I could have thumbed the dive for the group. We all learn through experience. The trick is to use someone else's experience for the OH, S..T lessons.

 

[redacted]

Overall this diver, while new, is a pretty good guy and diver. He was just ignorant of the risks. He is learning, and seems to be receptive. For that matter (Nomex suit is on) I could have thumbed the dive for the group. We all learn through experience. The trick is to use someone else's experience for the OH, S..T lessons.

This is one of those things where knowledge is important, along with understanding exactly where the leak is coming from (the cause). What 1st stage was your buddy using?

I figured you probably had a Mk5 and that one can be touchy. But if you buddy had one with the o-ring on the end, I would not be concerned as his risks were probably quite small. A small turn of the mounted 1st stage may well have stopped the leak. I was diving a Mk20 that leaked like that. I simply tightened it by hand and it was fine until I could get the proper tools.

 

[raftingtigger]

awap, I don't remember what brand/model he was using. Probably something not as touchy as the MK5. I didn't realize there was a big difference until you brought it up. It may not have been as unsafe with his leak as my first impressions - but it was a good learning lesson for both of us. I quietly told him this wasn't a nut to have loose, and why. Thought it was a nice tidbit to pass on for others to learn the easy way.

 

[TSandM]

I could easily see this happening. Relatively inexperienced diver, doesn't work on his own gear. Has a dive where he has a yoke o-ring leak, and the DM reassures him it's no big deal. Has another one, still no big deal . . . eventually the brain generalized into, "Small leaks from the yoke connection are no big deal," without understanding that there are leaks, and leaks.

Good post, but it might help newer divers if somebody put up a photograph of a yoke regulator to show what the parts are that we are talking about. (I'd do it, but I'm not home and have no access to my dive gear at the moment.)