BCD Failure

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jejton

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Messages
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Location
Florida
# of dives
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I dont know if this is the proper subforum but here's the story. Was doing a dive last week with an experienced dive buddy. Surface chop was a bit rough. The boat did not use a tag line for divers waiting their turn in the water. My buddy and I both ascended and I proceeded to board the boat. After sitting down, I looked and saw a different diver boarding. I figured the guy just skipped ahead of my buddy (as happened to my on a previous dive). I didnt see my buddy but figured it was the choppy water and my angle of vision obscuring him. He did board a minute or two later and turns out the rear shoulder dump on his Mares BCD came completely unscrewed allowing the air out and water to fill his BCD. He didn't realize what had happened and kept sinking despite repeatedly inflating his BCD and finning. After dropping 30ft, he dropped his weights and surfaced. Once on the boat, the failure became apparent. The BCD is only a few years old and had been serviced about a year ago. How often does this occur and how does one prevent it from happening?
 
Unless the dump valve was damaged otherwise highly unlikely.
So he was NOT panicking and had the clear mind to dump the weight.
Many incident happened after service!
You should routinely check your bc by fully inflated it and leave it overnight. A thorough visual inspection is also a good practice eg pre-flight external check.
 
I have noticed that the dump valves on my BCD occasionally get a bit loose and need tightening. I check them every time I wash the BCD. But to come off altogether is weird. Bet your buddy will check them once in a while from now on.
 
  • If you're appropriately weighted, a deep breath and keeping high ~80% lung volume should keep you positively buoyant at the surface, especailly at the end of a dive with an empty tank. Not saying it's comfortable, but it's an option & a strong reason to try to not dive over-weighted.
  • If you don't have ditchable weights, a backup plan is to remove your harness underwater, and remove weights that way. Practicing don-ing and doff-ing underwater is a useful skill (which I haven't practiced enough myself). It's great for other things including various equipment issues, and some entanglements, so worth practicing.
  • If you carry an SMB / DSMB, that makes a great backup bouyancy device. I can be used underwater for bouyancy, but may be difficult to control. At the surface, the two ends can be placed under your arms, and used as a sort of life-jacket or pool-noodle. Since my BCD & weighting tends to tilt forward at the surface, I really like using my SMB that way if I have a longer swim back to the boat.
 
...How often does this occur and how does one prevent it from happening?

Dump valves can loosen over time. Just check that they're screwed on finger-tight at least once in a while.

This can be on the shoulder and rear dump valves, as well as an SMB.

Also bolts and nuts between a bp/w, some weight pockets, etc. Check that they are finger tight every once in a while. You can use lock washers and/or consider using a thread locker like Loctite.
 
It appears your buddy is carrying too much lead for single tank recreational diving. Here is some great advice on how to correct that from @Eric Sedletzky in post #79

Messed up and ascended like a missile
 

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