personally, i've had 2 over several thousand dives. one was just a couple weeks ago on a trimix dive, actually. but I've seen at least 5 others.
Questions about Dual bladder wings
- Thread starter Antagonist
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personally, i've had 2 over several thousand dives. one was just a couple weeks ago on a trimix dive, actually. but I've seen at least 5 others.
dumpsterDiver
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I've seen stuck inflators MANY times...Too many to count although I've only had it myself a few times. However, I thought the arguement of a runaway inflation on the second bladder was VERY weak. Does anybody really, hook up inflator hoses to both bladders? I mean think about it... if an inflator stuck and started to inflate, you might not know which one to disconnect and by the time you figured out which one was the problem, they would probably both be unhooked and the BC would be full.
TONY CHANEY
Contributor
Agree with Kierentec and DumpsterDiver but again I have yet to see one. Together these two very well divers state over 10,000 dives, one had a few and the other had two stuck inflators. I'll leave it up to you but 5 or even 8 in 10,000 dives?
Yes they happen, despite their rarity they are serious business mid-water with a lot of stops above you. Just as a disconnected secondary inflator is possibly not going to go together well as you plummet down a wall with your failed primary wing. I suppose if you wanna sound like Richard Pyle at Christmas Island freezing your nuts off in a paper thin wetsuit at depth by all means go ahead. Drysuits with really thin undies are actually pretty damn comfy in the tropics and do double duty since its a lot harder to get chilled (which is not good for off-gassing) and eliminate the need for a special wing. Knock yourself out, my normal one inflator wing + drysuit works everywhere.
DevonDiver
N/A
The exact requirement is for "redundant buoyancy", not a dual bladder wing. However, unlike other agencies, PADI do not accept the use of a lift-bag as a redundant buoyancy option. Drysuits are permitted however.
IMHO, this is a typical 'paditude', which discourages skills solutions to problems which can otherwise be solved with equipment.
This may be an indictment on the faith they have in abilities of their instructors..or their expectations of student capability... or it may be a genuine effort to K.I.S.S. their training. I know my assumptions skew towards the first two factors...
...but, never let it be said that PADI might factory produce tec instructors or skew their tec marketing to attract students below what might otherwise be considered a prudent and reasonable level of experience/ability....and therefore have to compromise on the depth (pun intended) of skill that training can attain
Personally, I wouldn't agree with this concern. A catastrophic 'tear' is most likely to originate from a materials or construction failure - LPI/OPV tearing free, glued/welded seams splitting etc. These would probably only affect one bladder. Smaller failures might originate from external factors; punctures are generally localized and minor (needle pricks).
Not really true. The majority of agencies insist on 'redundant buoyancy'. There are others which want a definitive solution; not accepting the use of lift bags except as a final (not immediate) contingency. Drysuits are universally accepted by all agencies, as far as I know.
GUE and other 'DIR' agencies are the exception. They promote skills, not equipment, solutions to the issue. The primary recourse being the construction of the "balanced rig".
Personally, I see those "seconds" as a major downside. For instance, when holding a 6m stop on 100% O2. It's not that simple. The diver needs to start prioritizing their responses. Gotta switch off deco gas and onto a back/lean(er) deco gas first....dropped a few meters..ears need clearing now...gotta locate the redundant LPI...ears need clearing again as still sinking...
What about overhead environments? A "few seconds" can mean a plummet into the silt.
It's the sort of "no downside" issue that can go badly wrong for a less experienced tec diver.
This is a skill that I see causing significant issues for tec divers in training...it's something they struggle with... especially when other (realistic) factors are presented in unison.
What I see a lot... is that there is always a proportion of divers who (post-training) opt for convenience a leave it plugged in. Like others, I've seen plenty enough 'real' stuck inflators and/or slow trickle leaks. That's presents a real danger for those divers. And...there'll be another proportion of divers who dive with the LPI disconnected... but never give it another thought... no practice, no skill retention. The redundant bladder becomes a 'complacency' - something that is relied upon, but shouldn't be relied upon (due to skill degredation).
Yes, several.
Also.. many more instances of "trickle" leaks. Something the diver doesn't necessarily notice at the bottom, but can catch them out big-time on ascent when that air accumulated in their redundant bladder starts to expand...
PfcAJ
Contributor
The lift bag idea is the most ridiculous of all. Do you really think you'll be able to get out and fill a lift bag as you're lawn-darting to the bottom?
The short answer to all this is al80s with the wetsuit, drysuit with everything else, and stay away from dual bladder wings and lift bags. Balanced rig and all that.
The short answer to all this is al80s with the wetsuit, drysuit with everything else, and stay away from dual bladder wings and lift bags. Balanced rig and all that.
Completely agree that the answer is al80s and a balanced rig, but I have used a lift-bag for emergency buoyancy and it works - at least, in open water. The key is easy access and plenty of practice to ingrain the muscle memory needed to locate and deploy the bag fast while swimming like a madman to stay in place in the water column. Not fun or a great solution in a silty environment, but it worked for me when I had a catastrophic wing failure while diving twin al C95s (6lbs negative when full) with two S80 decos. It did encourage me to switch from the higher-capacity, heavier tanks to 80s and a stage if necessary when diving wet, though...
Not sure why the dual bladder argument always seems to come down to 'it'll auto-inflate if you leave it connected' vs 'if you leave it disconnected you'll plummet to your doom while trying to connect LPI'. Weren't we all taught oral inflation in our Open Water courses? Or is the assumption that all dual-bladder wings are bungeed, 100-lb-lift lifeboats of doom that you give yourself apoplexy trying to orally inflate?
PfcAJ
Contributor
I think orally inflating a wing from empty to 'enough to get neutral' with heavy steels is a tough order.
Best to skip all that and dive a balanced rig to begin with
Best to skip all that and dive a balanced rig to begin with
dumpsterDiver
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I think orally inflating a wing from empty to 'enough to get neutral' with heavy steels is a tough order.
Best to skip all that and dive a balanced rig to begin with
Sounds tough? That sounds like a skills issue that you could work on in the pool. It is not that hard to orally inflate a BC.. I remember inthe good old days, students were actually taught this skill. I have orally inflated my BC over 6 times since I got certified. you should try it some time!
PfcAJ
Contributor
How many times have you done it with steel doubles?
