BCD malfunction on a discovery dive

[Sentic]

Hello Scuba Boards.


i did my first discovery dive last week with a friend and together with a PADI instructor. we did two dives, very relaxed atmosphere and i felt completely comfortable in the water. i did various skills with my instructor like reg retrieving, reg blasting and free flow, also complete mask removal and clearing. well anyway we got towards the end of our 2nd dive and we was 11.5 meters depth, and i guess around 50 minutes dive time just swimming around at the bottom looking around for octopus and i put a tiny bit of air into my BCD to to get over the top of a rock and BAM, i shot to the top, and all i could hear was a hissing sound. i ducked my head under the water so i could see my instructor and signalled him to come up because obviously i have a problem, anyway he come up had a look at my equipment and noticed the smallest of stones got lodged into my BCD where the inflation trigger is. after that we had to abort the dive even with 100 bars of air left in the tank. (our first dive was 1 hour which is normal at 12 meters right?)


I guess the question is, isn't this a protencial danger at a deeper depth? and how can it be avoided.

and, how should i go about taking my open water because i felt i had a good connection with my instructor and my friend she has various qualifications and come just to give me a taster and she recommended him.

Cheers
~Ads

 

[spectrum]

Wow those are pretty agressive discover dives! You got a good taste of the training, not just a chance to blow a few bubbles.

That situation is extremely dangerous. Uncontrolled ascents are a leading cause of dive injuries and fatalities.

As to the malfuctions, one of the skills you should learn is to immediately disconnect the inflator supply hose should the valve stick on. Using a dump valve concurrently or to manage a small flow can be part of the recovery. Many inflator hoses are connected to a shoulder dump by an internal cable. This lets you extend the hose to open the dump with one hand while the other releases the QD connector.

Once disconnected you can manage the end of the dive by inflating oraly. Depending on the failure mode of the valve that may not work perfectly either.

Of course paying attention to gear maintenance and keeping the valve out of the sand will virtually eliminate the chance of a repeat incident.

Pete

 

[Tortuga68]

I would've thought that was a pretty rare occurence (stone in inflator valve) so I wouldn't be concerned about any long term implications

For future reference, maybe purging your BCD would have avoided/slowed the descent?

Also perhaps you could have cleared the rock (that you were trying to get over) by inflating your lungs rather than your BCD, but that's not really the point here

Was your inflator secured, or was it dragging around? In other words, how/why did it get fouled

If you like the instructor, I wouldn't see this as a reason not to proceed with them

Lastly, the amount of air left in your tank is irrelevant; after a rapid ascent, the dive was effectively over (from a safety perspective)

HTH

 

[stefo2]

Also perhaps you could have cleared the rock (that you were trying to get over) by inflating your lungs rather than your BCD, but that's not really the point here

I think is is actually a point. While having a stone or sand stuck in the inflator valve is not really the instructor's fault, instruction about the basics is his or her responsibility. By the OP's accounts of the dives it seems like they obviously practised quite a few skills and did pretty long "independent" dives (as in controlling their own buoyancy and not maintaining touch contact), so I think they should also have been explained the basics of exactly that aspect - you do NOT inflate your BCD if you want to go up, but do it either by breathing in or by carefully finning up, and must in fact VENT air from the BCD when going up.
Even without a stuck inflator button, moving up AND putting air in can get you into an uncontrolled ascend very easily.

 

[String]

Ive never seen a BC rapidly inflate but i have seen a slow seep of air into it of the course of a few minutes. Sometimes **** just happens even with decently maintained kit. Thats why the proper course has BC disconnection drills.

Although its a DSD there do seem to be decent skills learnt here and it was dive 2 they hit 12m. Thats within standards (typically we used to do 6m max for the first dive and if they were OK 12m for the second dive...while maintaining touch contact).

 

[stefo2]

I guess the question is, isn't this a protencial danger at a deeper depth?

An uncontrolled ascend from any depth is a potential danger (and actually happens more frequently at shallower depths where the pressure changes are biggest): If you hold your breath - which may well happen, especially in an unprepared new diver...

 

[Sentic]

Ok well i was taking all the things that has been written in account.



no the BCD was not being dragged across the ground, i was given instructions to place it on a hook on my stab jacket.



Somebody said something about i shouldn't be using the BCD to get over the rock, how ever where i was diving there was about 4 meters decline, like a small cliff edge, is the best way to describe it. so i let a tiny bit of air out of my BCD to give my self a slightly negative buoyancy so i could slowly decline to get a look underneath the rocks then when i got about haft a meter from the bottom i touched the BCD again to equalize, and then up i went.

Also Tortuga, Purging did come into mind how ever that would of made a saw tooth profile. after lets say a 6 meter acend then let go of the purge, then realize im acending quickly again. i'm competely knew to diving but i have done my home work.

Also i stated the dive was over to show that everything was being conducted well, in my view. how ever, i have a friend called tony who stopped diving 5 years ago because he got the bends and was paralyzed for a good year told me all these horrible ghost story's and to be honest, im' not easily scared but i do feel more cautious. maybe that's a good thing, who knows.



Thanks for the advise i'm going get my head inside this 20 year old antique PADI OW manual, Reckon it will sell for much? it has all the old navy tables on 3 cards ^^

 

[stefo2]

Somebody said something about i shouldn't be using the BCD to get over the rock, how ever where i was diving there was about 4 meters decline, like a small cliff edge, is the best way to describe it. so i let a tiny bit of air out of my BCD to give my self a slightly negative buoyancy so i could slowly decline to get a look underneath the rocks then when i got about haft a meter from the bottom i touched the BCD again to equalize, and then up i went.

OK, that sounds different from how you first put in your OP. So you were actually negative and wanted to put in some air to become neutral rather than wanting to inflate your BCD to go from neutral to positive.

 

[Sintax604]

That particular malfunction wasn't covered in my OW course and it isn't something that I thought could happen. With 20 seconds to think about the problem the logical course of action is to unplug the BC from the air, but in a split second when the decision would need to have been made, I'm not sure I would have thought to do that. Many thanks for the post... ya learn something everyday.

 

[Spg01]

In my open water course we were taught NOT to inflate with the button and just put a breath in at a time, which would avoid a stuck/sticky inflator. At the surface the inflator button is fair game though.