TDI - Intro to Tech - Necessary?

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PfcAJ

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Have learned that… The more diving I do, the more I know I don’t know and the more critical I get of my existing skills.


Absolutely. Which is why we parted ways with fundamental differences of approach. I see standards as guidelines to be adapted as necessary; they (or at least one instructor who gave up teaching soon after) see standards as inviolate commands. Which is absolutely fine for both of us.

Maybe it was the end of the DIR Wars when the holy commander decreed they should wind their necks in lest it damages their reputation. Can think of at least one other agency which had the same dogmatic approach. In comparison, the likes of TDI, IANTD, et al are far more relaxed but just as effective and considerably more popular.



Just look at kit standards for a moment. DIR decrees all stages left, to leave the right side free for donation of the long hose. This ends up with stages which are far from streamlined and even a leash for the third stage. There’s absolutely no issues with carrying stages on the right, you just need to donate in the steps; donate then free the end of the hose caught under the RH chest D-ring. Nothing difficult nor dangerous about that whatsoever.

What about sidemount bungee techniques for streamlining and reduction of snag hazards in confined spaces. DIR say no. What about sidemount anyway. Again DIR say no.

Donation on a rebreather is easy and automatic straight from the bailout bottle with no complications. DIR, more specifically GUE, say no and have developed a very non standard configuration almost as a belligerence to force in the longhose including forcing the donor off the loop at a time of great stress.

Leave the best to last. UTDs sidemount configuration. Apparently the shutdown is so ingrained that UTD divers are incapable of adapting to the pretty much standard sidemount config, so they need a manifold behind their heads.
There’s more reasons to not wear a stage on the right.

Blocks long hose (really important). Inhibits your scootering arm. Requires non-standard hose routing/config.

For what? “Streamlining?” Right. Dudes have been crazy far using DIR techniques. Stages on left is not a hindrance. Same with the silly bungee thing. For what? It’s just added faf and complication.
 

Wibble

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There’s more reasons to not wear a stage on the right.

Blocks long hose (really important). Inhibits your scootering arm. Requires non-standard hose routing/config.
A RH stage doesn’t block the longhose. It requires a second phase after you’ve shoved it into the face of the OOG diver (have you ever donated for real?).

Scootering. Nope. It’s fine with a sidemounted + bungeed RH stage as it’s held back and higher under your armpit, i.e. out of the way.

For what? “Streamlining?” Right. Dudes have been crazy far using DIR techniques. Stages on left is not a hindrance. Same with the silly bungee thing. For what? It’s just added faf and complication.
When you’re inside a wreck or smaller cave/mine the last thing you need is to contact the sides/ceiling, or worse still jam up.

Streamlining is very important for minimising drag and maximising efficiency. As you fin forwards, a flappy stage moves backwards then drops back down thus absorbing some of the energy.

Maybe you should try a sidemount configuration before knocking it. You should love the stability, ease of use, redundancy and flexibility it gives.

When using a rebreather it makes even more sense to use stages left and right — lean left (bailout), rich right (deco). And definitely with bungeed stages to tidy things up.

1640653260799.jpeg
 

ginti

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A RH stage doesn’t block the longhose. It requires a second phase after you’ve shoved it into the face of the OOG diver (have you ever donated for real?).
I am not going to answer the others since I am not at that level yet, but I have donated for real. The last thing that I wanted was to do extra stuff after giving the regulator to my buddy - on the contrary, I just wanted to find a way out of that situation, as fast AND efficiently as possible. So, yes, I am very happy with not having any obstacle on the right.

Although I don't dive with more than one stage, I doubt I will change my mind after my previous experiences...
 

Wibble

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RH stage mounting and longhose…

It is quite possible to clip a right hand stage on and not foul the longhose. Needs one to get the stage nose clip over the longhose when clipping on.

Alternatively don’t bother when clipping on…. You can do the first part of the donate as one normally does (reg out of mouth, over head, thrust into face of OOG diver, pause).

The second phase is to unhook the longhose from under the battery and get the umbilical untangled ("under way") from the longhose.

With a stage cylinder right, the second phase is pretty much the same except it may need the longhose pulled under the nose clip (pull the longhose out against the clip, umbilical under, unclip the nose clip from the RH chest D-ring, pull hose through and re-clip). It’s very simple and no hassle.

Obviously with a rebreather there’s no longhose as the emergency gas is on the one cylinder on the LHS — pull out, donate, hand over stage to OOG, ascend, when on boat present them the bill for the fill and putting the cylinder back in test…
 

ginti

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RH stage mounting and longhose…

It is quite possible to clip a right hand stage on and not foul the longhose. Needs one to get the stage nose clip over the longhose when clipping on.

Alternatively don’t bother when clipping on…. You can do the first part of the donate as one normally does (reg out of mouth, over head, thrust into face of OOG diver, pause).

The second phase is to unhook the longhose from under the battery and get the umbilical untangled ("under way") from the longhose.

With a stage cylinder right, the second phase is pretty much the same except it may need the longhose pulled under the nose clip (pull the longhose out against the clip, umbilical under, unclip the nose clip from the RH chest D-ring, pull hose through and re-clip). It’s very simple and no hassle.
The way I see it is that it is simple and easy, but it is still something extra to do; in an emergency, I personally do not care how easy something is - if it adds even one single step without providing significant benefit, I just avoid it.

Anyway, probably this point is debatable: how do you evaluate whether a benefit is significant or not? But the entire discussion was born due to the rigidity of GUE with respect to standards at the fundamental level (cause this option was proposed to the OP); and at this level, stages' positioning doesn't play any role at all. The only fairly rigid point for the fundamental is about side-mount configuration.
 

rddvet

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RH stage mounting and longhose…

1) It is quite possible to clip a right hand stage on and not foul the longhose.

2) Obviously with a rebreather there’s no longhose as the emergency gas is on the one cylinder on the LHS — pull out, donate, hand over stage to OOG, ascend, when on boat present them the bill for the fill and putting the cylinder back in test…
1) (I numbered your comments above) It's quite possible, but that doesn't mean it's without it's faults. Left hand stages are a tried and true method that always works

2) You may dive ccr without a long hose, but many of us don't and don't agree the fix for OOA is to pass a tank. I always have a long hose ready to be deployed on ccr. If my buddy goes out of air and they're on ccr there is usually a cascade of events that lead to being OOA. You can typically spot the OOA coming faster than on OC. So if my buddy is having an issue, I try to help all while maintaining readiness to pass the long hose. If after my buddy is on my long hose we can't diagnose and resolve the problem, then it's possible passing a bottle is the right choice. For many of us, we are diving heavy steel tanks or are diving onboard dil in 50s ala GUE style. In those instances, passing a bottle isn't realistic. If I'm carrying a stage, passing the stage is realistic, but would be step 3 after first controlling the situation with the long hose and then diagnosing if it's a correctable issue. I'm a proponent of everybody in the buddy team having a way of using the same offboard gas connection (as in everybody has QC6s) that way I can pass you a bottle and if your ccr still works, you can plug that gas in and stay cc (obviously that is only if the situation allows for it).
 

Wibble

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1) (I numbered your comments above) It's quite possible, but that doesn't mean it's without it's faults. Left hand stages are a tried and true method that always works

2) You may dive ccr without a long hose, but many of us don't and don't agree the fix for OOA is to pass a tank. I always have a long hose ready to be deployed on ccr. If my buddy goes out of air and they're on ccr there is usually a cascade of events that lead to being OOA. You can typically spot the OOA coming faster than on OC. So if my buddy is having an issue, I try to help all while maintaining readiness to pass the long hose. If after my buddy is on my long hose we can't diagnose and resolve the problem, then it's possible passing a bottle is the right choice. For many of us, we are diving heavy steel tanks or are diving onboard dil in 50s ala GUE style. In those instances, passing a bottle isn't realistic. If I'm carrying a stage, passing the stage is realistic, but would be step 3 after first controlling the situation with the long hose and then diagnosing if it's a correctable issue. I'm a proponent of everybody in the buddy team having a way of using the same offboard gas connection (as in everybody has QC6s) that way I can pass you a bottle and if your ccr still works, you can plug that gas in and stay cc (obviously that is only if the situation allows for it).
Agree to a certain extent.
1) Diving with a couple of Ali80 stages slung left works. Most of my normoxic two-stage OC diving was done like that. It was when a third Ali80 was added for a bottom stage that the need to move it over to the vacant RH side became apparent -- especially as the bottom stage is pretty much emptied and thus gets exceedingly floaty, so needs the RH waist clip to be moved forwards or a bungee to hold it back.

My point was that it's pretty straightforward to deploy an emergency longhose and absolutely nothing to concern someone with the reasonable skills such as one would expect to see at those depths.

2) Some people want to dive with a twinset + rebreather...

However, the vast majority of rebreather divers don't dive like that and in fact dive with a bailout stage, generally stage-mounted on the LHS. Prior to seeing a single GUE-modified JJ (in a quarry), I had never seen one like that in the hundreds of rebreather's I've seen in my diving career. Similarly on ScubaBoard where a few people dive twinset+rebreather, the the vast majority or ScubaBoard rebreather divers dive with a stage-mounted bailout.

When moving past MOD1 into MOD2 diving down to 70m/230ft a second decompression stage is absolutely required. Given that the primary bailout is left-mounted and there's no longhose, it makes complete sense to mount the decompression stage on the right hand side. This means you've unfettered access to the primary bailout, not only for yourself but for any other 'needy' people. Manipulating the one stage is far easier than grabbing one regulator from two bunched together AND THEN doing a pre-switch gas checking drill -- time is utterly of the essence.

With a single left-slung stage (and deco stages to the right) you know it's breathable gas because you've checked and validated it when you put it on; you've checked and validated it when you did your bubble & bail drill (6m/20ft or on the bottom); and in my case it's a sidemount config which will only hang on the LHS due to the modular valve pointing out (the deco cylinders point the other way).


Anyways, peace and goodwill to all. My point is it's not hard to be a little less DIR and a little more more pragmatic.
 
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