Your BC fails now what??

[Diver Dennis]

The basic idea is that when you are in a heavy wetsuit that will compress at depth and lose bouyancy. Add on top of that the weight of the air in the tanks (could be upwards of 18 to 20 lbs) and you could have a rig that you cant swim up at depth.

Are you sure the gas can weigh that much? Think of using up the majority of your gas on a dive and being that much more buoyant.

 

[JeffG]

Are you sure the gas can weigh that much? Think of using up the majority of your gas on a dive and being that much more buoyant.

1 lb for each 13ft3

If it was a helium mix it would be less negative.

 

[beautybelow]

If I am not carrying exta weight for divers I rarely put any air in my bc down to 100ft. If I put any, it is very little. That said, if it didnt hold the air. just swimming up a few feet would gain me all the bouyancy I would need to do a slow, safe ascent. Most people carry too much weight I think.
My bc has had a leak in it since I took it out of the box.

 

[KMD]

Are you sure the gas can weigh that much? Think of using up the majority of your gas on a dive and being that much more buoyant.

x-120's can swing to 9 pounds more negative when full. x2 gives you -18 lbs when full.

Plan for the worst case at the begining of your dive when you are most negative.

 

[Adobo]

x-120's can swing to 9 pounds more negative when full. x2 gives you -18 lbs when full.

Plan for the worst case at the begining of your dive when you are most negative.

And some people get cave fills in those big a55 steel tanks.

 

[robbcayman]

That's what I did when my BCD failed to hold air on a 130' wall dive.

Apparently the pull dump got snagged or somebody manhandled it on the boat. It was working that morning, but when I added some air around 65' to slow my ascent it bubbled back out and my descent sped up again. Only after repeating this cycle again did I fin to stop and check things out. I found that the pull dump was stuck open. Inspection after the dive revealed that the pull dump wire cable was broken and stuck beneath the dump valve, thereby holding it open.

Although I was negatively buoyant it was well within the range of my control, so I went ahead and went down the wall of Molokini to 130' to look at the shark condo. I did find it more convenient to then ascend to up around 50-60' where, with a full full lung, I was almost up to neutral buoyancy. Had I really needed to I could have stayed at 130', although it would have been enough work that the dive wouldn't have been enjoyable.

This was with a 5mm full wetsuit. Someone with two layers of 7mm would have to work a lot harder. Someone just wearing a 3mm shorty or other thin wetsuit would find it really easy.

It's pretty easy to do a drill to see how difficult it would be for you to have a BCD failure --- simply empty all of the air out of your BCD while at depth with a nearly full tank and see how hard it is to hover and ascend.

Charlie Allen

Wow, good post that really clears it up for me. I'm going to try that drill and see what happens. Sorry for such a dumb question. Thanks guys

 

[1_T_Submariner]

It's not a dumb question (a question that should have been covered in OW class maybe). Just make sure to plan the drill with your buddy before trying it.

 

[Gary D.]

It will be a very rare day when a BC fails. It will be even a much more rare day when it fails to the point it will not hold any air at all.

Even with a major rip in one they can still hold enough air to help with some lift. Even if the entire top ripped open turn the thing over and blow bubbles into it. Where there is a will there is a way.

So if you have a failure it shouldn’t be a reason to abort a dive. Some people yes but the majority no. The important thing is to just think about what’s going on and what you need to do to correct it if anything.

Even a submarine, if it has proper ballast for the depth, can power to the surface. So can you and with a lot less effort than you think.

Remember the true definition of SCUBA is a container of air and a way to get it into your body. Everything else is an unnecessary option.

The BC is one of the most used latest options developed.

Gary D.

 

[Diver Dennis]

x-120's can swing to 9 pounds more negative when full. x2 gives you -18 lbs when full.

Plan for the worst case at the begining of your dive when you are most negative.

I see, I was thinking single AL80.

 

[lamont]

We tested buoyancy failures recently. With double steel 130s full of nitrox (about 20# negative) and all the air I could get out of my drysuit and nothing in my wing I could still swim up the tanks. Holding depth was about as difficult as treading water in the pool or light jogging. Doing the test using the drysuit as buoyancy control was annoying but worked fine -- no issues with feet-first ascents, no blown neckseals, drysuit works fine as backup floatation.