Catastrophic BCD Failure questions

[oly5050user]

Hello,

I'm new to diving and encountered a BCD failure that quickly became an emergency.

I had my brand new BCD modified by a dive shop. They changed the hose out to make it longer for me given my height. I lightly inflated the BCD before jumping in from a boat and was positively buoyant in the water for a few minutes. I noticed that I was quickly becoming negatively buoyant and began struggling to stay near the surface. I was pressing the inflator button and nothing was happening. I wasn't sure what was going on but was getting exhausted kicking my flippers to stay near the surface. I then looked down to see what was below me if I sank and then saw that the hose had separated from the inflator section and seawater was pouring into the BCD. I was able to get the attention of my Instructor before sinking and he and I both began working to unstrap the BCD from my body. We got it off and it quickly sank to the bottom. The Instructor towed my back to the boat.

The dive boat operator rescued my rig from the bottom and examined it. He noticed that the 2 clips that securely hold the hose and inflator together was missing and he'd never seen that before. It's likely that connection was only hand tightened by the repair shop and he commented that without those clips it was going to fail at some point soon. He also said that it is virtually impossible for those clips to come off in the water if attached correctly

Questions (1) has anybody seen this before? (2) best guess on how much water a BCD would hold if full of water? (3) can a BCD become permanently damaged when filled with water?

Sounds like you had way too much lead, a BCD full of water should not cause you to sink so much if you are properly weighed .Sounds like this was a training dive, Did you and instructor perform proper buoyancy weight check at start of dive? The water in BCD will displace same volume of water it has in it and should not cause you to be so negative to cause you to be unable to stay on surface, also to my thinking instructor reacted incorrectly to situation. Instead of removing scuba unit instructor should of simply had you dump weights. Would of solved issue instantly , there was no need to waste the time removing scuba unit.

 

[oly5050user]

Why did your instructor have to tow you back?

Because student was over weighed with lead and instructor failed to have student release lead.

 

[johndiver999]

Sounds like a close call with the shop failing to do proper maintenance, the student being unfamiliar wit how to check the gear and the instructor deciding to ditch the scuba unit instead of ballast is also potentially questionable, particularly as a first response.

Those cheap plastic, mechanical clamps are very robust and I often use them and have never seen them fail (yet). Cheap zip ties seem like a poor choice of hardware to attach mouth pieces and bc hoses. Of course, forgetting to use them is a pretty significant failure. A good reminder to check your gear.

 

[gbf]

Get Thomas and Betts zip ties. "Ty-Rap" is their trade name. A little more expensive, but stainless locking tabs, extremely durable.

I get them at Home Depot, or you can order a life-time supply online.

Short story from a check-out dive years ago on Bonaire...

I was attaching a bolt snap to a weight using a Ty-Rap zip tie so I could carry it in case one of my family needed the extra weight. The instructor we had booked to do AOW for one of my children came along and said "those things will break" and grabbed the weight. Before I could say "don't do that" he twisted and yanked - the traditional way to break a zip tie.

The Ty-Rap didn't break, but he did cut his hand pretty deeply.

Ty-Raps are not indestructible, but a lot more so than the generic General Cable ties you get from the big box stores.

 

[johndiver999]

Yes I recently went looking for those,’they were a lot more
Expensive than the cheap ones from harbor freight. Probably worth the extra cost for life support applications.

This incident is one more example of why I prefer to have some lead available to be dropped.

 

[ReadyDiverOne]

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Sounds like you had way too much lead, a BCD full of water should not cause you to sink so much if you are properly weighed .Sounds like this was a training dive, Did you and instructor perform proper buoyancy weight check at start of dive? The water in BCD will displace same volume of water it has in it and should not cause you to be so negative to cause you to be unable to stay on surface, also to my thinking instructor reacted incorrectly to situation. Instead of removing scuba unit instructor should of simply had you dump weights. Would of solved issue instantly , there was no need to waste the time removing scuba unit.

Agreed, you shouldn't sink like a rock at the surface, you should be slightly negative such that when you exhale you sink/descend. And +1 on all the comments re ditching your weights--first thing should do.

 

[Soloist]

I realize this incident frightened you, but this type of failure should never escalate to a “catastrophic” event. Glad you are alright. As many have already stated, if you were not able to maintain your head above water with a single tank while finning you were overweighted. How do I know this? Because my forth dive as a newbie turned into a major cluster due to me being extremely overweighted. Unfortunately this is commonplace with beginning divers. The additional weight makes things easier in many ways for both you and the instructor during OW class. However, you will quickly discover it creates numerous unnecessary complications and unpleasant issues when you actually start diving. It’s not difficult to accomplish proper weighting if you work at it and the results will make you a safer, trim and more satisfied diver.

@Eric Sedletzky in #79 Messed up and ascended like a missile posted a method for getting properly weighted. Maybe your instructor can help you with this. If not, get a new instructor! I typically do negative entries and add a touch of air to my wing at depth only to be released during the dive as my tank becomes lighter. This allows me to maintain proper trim with a minimal amount of air in my wing. For the most part my wing is unnecessary. By the end of the dive the wing is completely empty and I ascend to my safety stop in complete control. As you progress work towards becoming less and less dependent on your BC during a dive.

Warning: as a beginner, always remember to purge air from your BC as you ascend to your safety stop otherwise you risk an uncontrolled assent.

 

[W W Meixner]

Hello,

I'm new to diving and encountered a BCD failure that quickly became an emergency.

I had my brand new BCD modified by a dive shop. They changed the hose out to make it longer for me given my height. I lightly inflated the BCD before jumping in from a boat and was positively buoyant in the water for a few minutes. I noticed that I was quickly becoming negatively buoyant and began struggling to stay near the surface. I was pressing the inflator button and nothing was happening. I wasn't sure what was going on but was getting exhausted kicking my flippers to stay near the surface. I then looked down to see what was below me if I sank and then saw that the hose had separated from the inflator section and seawater was pouring into the BCD. I was able to get the attention of my Instructor before sinking and he and I both began working to unstrap the BCD from my body. We got it off and it quickly sank to the bottom. The Instructor towed my back to the boat.

The dive boat operator rescued my rig from the bottom and examined it. He noticed that the 2 clips that securely hold the hose and inflator together was missing and he'd never seen that before. It's likely that connection was only hand tightened by the repair shop and he commented that without those clips it was going to fail at some point soon. He also said that it is virtually impossible for those clips to come off in the water if attached correctly

Questions (1) has anybody seen this before? (2) best guess on how much water a BCD would hold if full of water? (3) can a BCD become permanently damaged when filled with water?

Bill...

It sounds to me...when the shop exchanged the corrugated inflator hose they forgot/omitted replacing the zip ties that secure the hose to the bottom power inflator...and possibly the top elbow as well...there is no hand tightened...most manufacturers use zip ties...a few manufacturers like Scuba Pro have a proprietary plastic hose clamp with a stainless steel set screw... in the attached photo you can see the ''one way barb'' on the attachment tube end of the power inflator...the hose clamp/zip tie has to be on the bottom end of the barb...

If your BCD has a power dump valve at the top elbow...you also have a cable that runs inside the corrugated hose between the bottom power inflator and the top elbow...if the shop installed a longer corrugated hose...the cable would also have to be extended...as well as replacing the LP inflator hose with a suitable length hose...

Your BCD inflator hose needs to be thoroughly inspected by a shop tech who knows what they're doing...and not the shop that changed the hose...if they are a manufacturers rep for your BCD...they should be reported to the manufacturer...if their not a manufacturers rep...they should not be selling the product...and reported to the manufacturer regardless...

Your height should have absolutely nothing to do with the length of your inflator hose...

Your BCD should not have been damaged...although it will need a thorough cleaning inside the bladder...

Best...

Warren...

 

[Celt]

But how did the water get past the dump valve? Was the corrugated hose so long that it activated the dump? If you make an adjustment to the hose should you not make an adjustment to the dump cable?

 

[JackD342]

But how did the water get past the dump valve? Was the corrugated hose so long that it activated the dump? If you make an adjustment to the hose should you not make an adjustment to the dump cable?

Yes, the cable should be changed with the longer hose. If the photos in post #4 are the actual BCD, then it looks like it was done, and attached. Also, if not attached he would have list the inflator, which is not what the OP described.
The dump valve does NOT open in order to inflate, either oral or power. Water passed through the open end of the corrugated hose.