Just a question??

[MikeFerrara]

I dive a dry suit and I can get back with that. However even with a balanced rig you can be negative. I wonder how it would be trying to get a couple thousand feet out of a cave if you were even 6 or 8 pounds heavy. I'll bet it could be pretty tough. I guess you could rock climb out but you might be in Zero vis. The silt could be several feet deep on the floor. Divers would be complaining about the mess you made of the cave for years to come. The line might be 20 ft off the bottom and that would make line contact a little hard.

Just thinking out loud...

 

[MrBlue]

faye once bubbled...
**snip**
a sword fish makes a wrong turn into my bladder
I am now 12 pounds heavy and have to abort
I CAN swim up 12lbs...I think...I hope...

Half way through the dive
BOOM
My buddy spontaniously becomes - magnatized, and his knife is + charged. My bladder absorbes the projectile.
I am -6lbs
**snip**

by the way does the GUE trainning go over diving wet, I would really be interested in "the doing it right" answer?

Yes, Gue training does go over diving wet. My Tech 1 course was done diving wet with AL80's in Ft Lauderdale, and have since gone gas diving with the GUE guy in the caymans.

As for your examples. YOu have 6lbs of ditchable weight to dump in the first example. This leaves -6 which *could* be reduced by bleeding off backgass right?

Since you would immediately end the dive, your deco is going minimal to non-existant. YOu get to 70ft or your first gas switch (70ft most likely in Tech1 depth ranges). Now you *could* bleed off backgas to get yourself more positive if needed.

From your example I take away that because of the gas 'swing' and because you can hold 20fsw with 500psi or so in your backgas you need -6 at 20fsw to hold a stop (your ditchable weight). Well, you're there with full tanks and dumping the 6lbs of ditchable weight (-6 of backgas is the same as -6 of lead and empty tanks).

For your second example. You're really not -6 lbs overweighted, you've aded positive buoyancy to your rig with the depletion of backgas.

That is the beauty of a balanced rig.

 

[padiscubapro]

MrBlue once bubbled...
I'm still not completely following your logic though. If you dive a balanced rig and you have thought out failure scenarios, how does depth make a difference on this topic?

QUOTE]

depth affect buoyancy, the deeper you go the less you have..whats balanced at one depth is overweighted at another depth..


80s aren't bad, but lets say you have 4 80s, thats 16-20 lbs negative at the start, plus your light thats another few pounds.. we will assume you CANT ditch it beacuse you need the light..
your regs are at least 2 lbs negative each thats another 8 lbs, we will assume an alum backplate thats 3-4 lbs.. 1 dive reel another 1lb or two..if you use brass guages add another couple of pounds.. this all adds up and so far none of it is ditchable because you need it.. thats at least 36 lbs negative.. your suit at depth will give you little help until you get shallower, can you do your deep stops, are you going to have enough gas because you are working all the way up, not an easy ascent..

its all about contingency planning.. I rather be prepared.. the odds are my bladder is going to be fine but murphy is always lurking around the corner..

I don't have anything against DIR but it leave no room for individual customization for enviromental conditions and concerns.. you dive it the standard way or you are a stroke..

There have been other successful training methodologies.. when GUE (or any other agency) can claim one thing that only ANDI can claim.. ANDI has NEVER had an insurance claim in its history and thats since 1988 and encompases 100M training on OC and closed ckt.. As far as I know the longest any other agency has gone is 4 years.. I also don't know Of any training accidents period.. Everyone always says how hard its to become an instructor with GUE, ANDI is probably the most difficult to become an IT, ANDI only makes about 7 ITS a year.. and you bust your as* to get it.. The quality and safety is there EVERY SINGLE tech student gets a detailed questioneer, so any person who shortcuts is taken care of.. I don;t think I have ever see GI3 rant about ANDI..
That training accident that GUE had with a diver that toxed (but was saved due to instructor skill), Its an ANDI training violation if all gas is not analyzed.. No matter who blended it(in the prev case the toxed diver blended the gas)... We are required to have every student sign off on every gas they get.. we also go through a detailed gas switch protocol..

I have had only 1 bladder failure in 15 years, I didn't have a redundant bladder (plus I was in a wetsuit)I had to swim my twin 95s up(and stages)it wasn't pleasant, and the deeper deco stops were terrible.. since then I have never dove without a redundant bladder.. it would have been easier in a drsuit but would have been quite unconfortable..
I learned from my mistake.. luckily I was able to overcome it..
The faliure couldn't be avoided, the elbow just seperated from the bladder.. it held no air..

I am also required that all students above the entry level tech class have a redundant buoyancy source whether a second wing or second cell within the same wing.

Sorry for the rant..... I have been holding that in way to long....

 

[faye]

Rant away!!!

Mabey it would be safe to say that the idea of having a single bladder is limited to open water diving (ie: no overhead) without substantial DECO??

It think it would be safe to say that if you have a considerable DECO obligation, a redundant form of boyancy would be in your best interest?? yes...no...mabey so

Does GUE say that you must use a drysuit for the above situations??? PSP has a point about carrying 4 cylinders. That is a lot of weight to balance a rig with while diving wet.

Diving dry for the soul reason of having no other alternative for bouyancy compensation due to its percived risk seems....well....

Again I have to reiterate, this is not an attack on GUE. I just want to hear some opinions.

 

[MrBlue]

PSP,

Rant away, this is how everyone learns.

In your example. Why can't you drop your cannister light? You're in open ocean, and you have an emergency. If diving DIR (and that is what we are debating), your buddy knows there's a problem already (that's one of the first things that is going to happen). Even if we add now, that you have many many stage/deco bottles, and it's now a night dive, your buddy know's there's a problem with your wing and you have an issue.

In your gear configuration you have brass gauges on your stage bottles, that's a no-no in DIR land. You should have light weight plastic gauges. In any case, your wing fails. You dump any ditchable weight (including pricey canister light). You also dump any stages you don't need (which are neutral to positve anyway, if you are diving luxfer 80's with He), as you don't need anymore bottom gas...you are now heading up. How can you be now 36lbs negative? You should have some deco gas (1 or 2 stages) and your backgas nothing more.

Anyone can add extraneous gear to make a point, but that distracts from the DIR balanced rig argument. I could easily say my 300+ foot dive was to recover an anchor and my wing fails and I'm 200+lbs negative with the anchor, how do I survive? That's just not fair.

In your case, with multiple stages, what do I need them for? I'm not extending my bottom time, I'm aborting the dive....why not dump them. If I'm truly diving a DIR system, I have alternatives, deco'ing on back gas deco'ing via buddy breathing, having a support diver provide the needed gas. Taking into account DIR which was the root of the question, we are also limiting ocean dives to 90 minutes total runtimes (that's a DIR thing too). So, why would you have 3 or 4 bottles AL80's on you?

You mention your personal experience of a wing failure, you were diving steel doubles (95's I think). That in itself goes against the DIR standards (no steel doubles with a wetsuit).

I still fail to see in a truly 'DIR system' and adhering to DIR/GUE standards where a wing failure is going to cause such a problem where a redundant wing is the solution.

Believe it or not, I'm all for adopting/modifying my gear rigging and philosphy if and when it makes sense. But at this point, I've not been convinced that when diving a true DIR/GUE system any modification is required.

Maybe a more realistic example can be offered that is within the orginal posters question cam be offered up. This is the only way we all can learn and grow.

 

[Divesherpa]

Seems like a lot of reasons to dive dual wings to me. If anyone has ever tried to navigate tight cave with many depths changes with multiple bottles using only a drysuit for buoyancy, then they will testify to the unnecessary hardships that arise. I've done it for kicks and it SUCKS!!!
Try holding stops following any bubble model using only a drysuit for buoyancy.


Simple solution: double wing. Doesn't take up much room and the ends definately justify the means.

 

[padiscubapro]

I never knew GUE had a 90 minute run time limit in open ocean..
Thats some pretty limiting dives.. You keep under this limit, someone with good gas consumption doesn't need more than 3 cylinders.

Run the numbers even in bubble models, deco on hypoxic mixes doesn't go well.. you end up having to share deco gas with your buddy and hopefully enough was planned..


Thats shorter than my run times in the classes I teach...

WHen I say you cant dump your light I'm thinking about either a night dive or limited viz dive.. backup lights don't work very well in low viz and if you somehow get seperated from your buddy you may be in for more of a problem,,

The steels/wet suit was many years ago,, That is definately a no no know...

I also never knew GUE was agains using brass SPGS, I knew no metal to metal which I strongly ageree with... I rather stay with the best eqpt anyway.. Brass guages are much more solid...

 

[MrBlue]

padiscubapro once bubbled...
I never knew GUE had a 90 minute run time limit in open ocean..

Run the numbers even in bubble models, deco on hypoxic mixes doesn't go well.. you end up having to share deco gas with your buddy and hopefully enough was planned..


Thats shorter than my run times in the classes I teach...

WHen I say you cant dump your light I'm thinking about either a night dive or limited viz dive.. backup lights don't work very well in low viz and if you somehow get seperated from your buddy you may be in for more of a problem,,


I also never knew GUE was agains using brass SPGS, I knew no metal to metal which I strongly ageree with... I rather stay with the best eqpt anyway.. Brass guages are much more solid...

The 90 minute run time is for Ocean dives only, where conditions can change so rapidly that a long deco in bad seas or bad conditions just isn't safe.

I agree that deco on backgas/hypoxic mixes is not feasible most of the time. And, I'm not advocating dumping deco gas to get more neutral, if that was the impression my apologies. When I meant dumping stages, I meant bottomgas stages.

As for the light, I would never want to dump it (a thousand dollar piece of ditchable weight is too much to swallow). But I would if it meant life or death. With a good buddy, it shouldn't be an issue as they are going to be on you like glue if something major happens (wing failure, loss of buoyancy, light loss...etc)

GUE is against the brass gauges for stage/deco bottles. They add extra weight to the nose of the bottle. Plastic are the choice. I'm not so sure that a plastic gauge isn't the best equipment for the job of a stage bottle. It's not getting beat up, or having tanks set down on it, as it's literally tied to the first stage. Maybe I'm wrong here.

 

[padiscubapro]

MrBlue once bubbled...


The 90 minute run time is for Ocean dives only, where conditions can change so rapidly that a long deco in bad seas or bad conditions just isn't safe.

I agree that deco on backgas/hypoxic mixes is not feasible most of the time. And, I'm not advocating dumping deco gas to get more neutral, if that was the impression my apologies. When I meant dumping stages, I meant bottomgas stages.

As for the light, I would never want to dump it (a thousand dollar piece of ditchable weight is too much to swallow). But I would if it meant life or death. With a good buddy, it shouldn't be an issue as they are going to be on you like glue if something major happens (wing failure, loss of buoyancy, light loss...etc)

GUE is against the brass gauges for stage/deco bottles. They add extra weight to the nose of the bottle. Plastic are the choice. I'm not so sure that a plastic gauge isn't the best equipment for the job of a stage bottle. It's not getting beat up, or having tanks set down on it, as it's literally tied to the first stage. Maybe I'm wrong here.

In my experience I find quite the opposite. many of the boats here put everyones deco bottles together. in rough seas they get beat to hell since they are usually put in bins while the twins are relatively safe.. If I'm traveling I'll use plastic guages to cut my travel weight down..

 

[nradov]

faye once bubbled...
Tanks add 6lbs when full
they lessen 6lbs when empty

Those buoyancy numbers are a little off. I assume you're thinking of an air or nitrox fill, but for any dive that would require more than minimal decompression you would have some helium in the mix. The real world buoyancy swing for an 80ft^3 tank would be closer to 4lbs.

Keeping the gas weights down is a necessary part of having a balanced rig. A lot of divers seem to miss that point.

-Nick