Roll offs and routing LP hoses.... the assumptions

[rjack321]

In fact, in my experience it works exactly like that. I would agree that until you've had it happen a couple of times you might not recognise it right away but that's a training issue.

I don't want to insult anyone but if I can train my OW students to respond to me hammering the inflator when they don't expect it and deal with it by venting, exhaling and unclipping the hose then I'm sure that divers with 1000 times more experience shouldn't be taken by surprise by it.

I'm gathering that since you said the same thing that Rainer said that this is how you're taught to deal with it. If you want to do this, ok. I don't care. Whatever works works, right? I'm just saying it isn't necessary.

R..

Ummmm no. Dumping with the inflator and trying to disconnect with the same hands requires you to really be "on it", if you're not you are going up. Depending on how you grab the power inflator under diress and the particular brand, it can actually inflate faster than it dumps too. This becomes a reaction speed issue on whether you can disconnect fast enough or not. The only additional help you get will be from the suit venting.

Instead, I can dump from the buttdump all day long while the wing self inflates. Those ALWAYS dump faster than the power inflator injects, otherwise the wing would burst. There is no longer a reaction speed issue on whether you can disconnect fast enough with drygloves, cold hands, whatever because you can dump and shut down the post at the same time and stay relatively stable in the water column. Whatever positive buoyancy you have accumulated you can compensate for by finning down. Or better yet scootering down.

Going head-up fins-down vertical in a decompression situation with multiple bottles, with a scooter, in a cave or wreck, etc. is a mistake. I have seen many many tech students try just this scenario in shallow water and they all cork. If they don't cork because they are in an actual overhead, they have now crashed valves & regs into the ceiling and kicked up the floor. Bad.

Kick down, dump with the left hand, shut down the right post & switch to your backup with the right works in all environments.

 

[TSandM]

I think pitching head up and venting wing and dry suit is your only real option with a single tank, because the only definitive solution is to disconnect the hose. But in doubles, you do have the advantage that you can assume a position where you can swim downward, and in that position, still stop the runaway inflation. It works really well. And in that circumstance, you DO have to have your left hand on the butt dump and your right hand free to close the right post. Having the hose on the left post would take away that option.

I was also taught that you have your primary functions -- breathing and buoyancy -- on one side, and your backups on the other. Since the wing is a much more effective buoyancy compensator than a drysuit is, it's primary, and therefore on the right. That's probably more of a cognitive thing than a functional one, though.

 

[jjones9527]

In fact, in my experience it works exactly like that. I would agree that until you've had it happen a couple of times you might not recognise it right away but that's a training issue.

I don't want to insult anyone but if I can train my OW students to respond to me hammering the inflator when they don't expect it and deal with it by venting, exhaling and unclipping the hose then I'm sure that divers with 1000 times more experience shouldn't be taken by surprise by it.

I'm gathering that since you said the same thing that Rainer said that this is how you're taught to deal with it. If you want to do this, ok. I don't care. Whatever works works, right? I'm just saying it isn't necessary.

R..

Nothing that I was taught, more a conclusion that was arrived upon after trying various methods over a few dives. Certainly experiences vary, but trying to unhook an inflator that may be frozen, while wearing bulky dry gloves, is just not an option for us.

 

[Cave Diver]

Incidentally, maybe this is a picky point, but you don't have to go to any convolutions to maintain depth if your inflator starts to freeflow like leaning down, finning and reaching for the butt valve. The inflator itself can dump as fast as it can fill. They're designed like that.

So working under the assumption that the inflator can dump just as fast as it can fill, how long can you do this? You still have to do something to stop the freeflow, (valve shutdown/hose disconnect) and if you're just holding down the deflate button to maintain your position, you're going to empty the contents of a tank pretty fast.

Maintaining depth is secondary to maintaining gas supply, IMO.

 

[techintime]

Reviving an old thread, but so what. As a slowly advancing technical diver I like reading the opinions of others...and the T2T forum hasn't seen much activity recently. So here goes.

I know that shoulder dumps are frowned upon because they create an additional potential failure point. I traded my shoulder dump inflator for a simple J-fitting, but didn't like it and switched back. Not making a mountain out of a small issue but I find it easier and quicker to vent the wing with a little tug versus raising the inflator hose and pushing the button. Quicker, less steps, less motion. I have made the personal, conscious decision to accept the risk of the additional potential failure point for the additional benefit as I see it. My shoulder dump and my Poseidon regs are my two divergences from an otherwise standard setup.

In the run-away wing inflator situation mentioned here, a shoulder dump would seem to be of benefit. A good first reaction for me is to pull and hold on the shoulder dump with my left hand and disconnect the inflator hose with my right hand...and both components of this maneuver are right there together. Same reaction for both a single tank and manifolded doubles. The shoulder dump is similar in design to the rear dump and seems to vent just a quickly, and since it is in line with the gas stream trying to get into the wing, an open shoulder dump will keep any additional gas from going into the wing. If I can't get the LP hose off of the inflator, then I can keep the shoulder dump venting with my left hand and surface/air share to the surface (single tank), or shut down the right post with my right hand and switch to the backup second stage on the necklace (manifolded doubles).