inverted manifolded twins

[ucfdiver]

this thread is a real head scratcher...

Not for me. There's a word for this.

 

[rjack321]

I have never found trim to be effected with either configuration. Besides, easily reaching valves during an emergency in confined spaces trumps trim considerations in my mind..

Shove your arm between your legs back to your arse and now you have a leak, lots of flailing about, no or lower vis, and a tough time staying with the line cause your head is in your belly button. Since you shut down the isolator first, your buddy will never see any of your leaks in the now cruddy vis even if it was simple, obvious and within sight. Other than all that your "anal ysis" is spot on.

 

[rjack321]

Not for me. There's a word for this.

Scubaboard is one word right?

 

[Slamfire]

Guys, you have to keep in mind that it is most likely that the OP is not asking his question within the context of overhead environments. Most of the divers in the world do not dive caves. The diver in question probably does not have to worry about losing a line because he had to go between his legs to reach the isolator. It may very well be that for the diver in question inverted doubles is a valid option.

 

[rjack321]

Guys, you have to keep in mind that it is most likely that the OP is not asking his question within the context of overhead environments. Most of the divers in the world do not dive caves. The diver in question probably does not have to worry about losing a line because he had to go between his legs to reach the isolator. It may very well be that for the diver in question inverted doubles is a valid option.

Its just as bad an idea to be going all pretzel through your legs in a wreck. And it seems that OMS isn't even making slobwinders anymore, another anachronism thankfully bites the dust.

 

[PfcAJ]

The length required is the same if the objective is for the other diver to be to your side rather than above you.

Until the diver needs to be in front of you...then what? Lemme guess, you go infront and then swim off without them? Win for everyone...

I have never found trim to be effected with either configuration. Besides, easily reaching valves during an emergency in confined spaces trumps trim considerations in my mind.



IMHO, that is a stretch. Sound transmission underwater is such that 2' more from your ear is irrelevant. You and your buddy will hear a significant leak, like a torn IP hose, and should shut isolation valves before trying figure out which diver it is coming from — unless maybe you feel the end of the hose whipping you black and blue. Nobody is going to hear a small leak unless your primary is a rebreather. Besides, your buddy's head will be out of your view either case so communication is the same.

Bull. I can hear even a small leak, and I only dive OC. Guess why? My manifold is by my ears. I fix leaks when they happen, there is no "is this significant or not" guess and check bafoonery. I communicate with my buddy when an issue arises like that and we face each other so I know whats going on and so does he.

Protection from impact and entanglement is my primary reason for preferring valve-down, ergonomics is second. I find your dismissal of the experience of firefighters, mine safety crews, commercial divers, and a lot of advanced sport divers in the North Sea is not driven by sound situational analysis.
The valve up configuration makes a lot of sense for diving from shore. You are far more likely to get knocked on your butt transiting the surf. That is the main reason that the valve up configuration dominates recreational diving all over the world. Wreck, cave, commercial, military construction/salvage, and boat diving invert the equation favoring valve-down. This is not something deemed law by King Neptune, but there is a lot of analysis supporting the option.

I know a cave diver or two, and they all use valve up config. I also know a few wreck divers. Same thing. Inverted is never favored. Hmm...

I really don’t care other than I don’t like to see insufficiently supported statements go unanalyzed on an international forum like Scubabaord.

Valves are up for a few simple reasons. You can hear leaks, your buddy can see them without swimming around to your butt, valves are easy to shut down, right post rolls on, hoses are easy to find for replacements, and nothing is in a place where I can't get to it.

Also, shutting down the isolator first is nonsense. Tank O-rings rarely extrude, and even more rarely underwater. However, regulators fail and become dislodged way more frequently. You can save MORE gas by shutting down the proper post (you can hear it when its by your head) and working with your team mate to see it it can be fixed or not. I prefer to have more resources at the end of any issue than less.

This is a primo example of convolution after convolution based on topside logic being applied underwater.

 

[ucfdiver]

Scubaboard is one word right?

Not the word I'm thinking about, but it did start with an S!

Also, shutting down the isolator first is nonsense. Tank O-rings rarely extrude, and even more rarely underwater.

Agreed. A friend of mine had his doubles come out of the back of his truck bed while driving and not a single cu ft of gas leaked out. I've seen valves bent at a 90 degree angle from smacking the ceiling hard on a DPV, but not a single cu ft of gas lost there, either. 99.99999% of the time it's a reg, I don't see why anyone would deal with a statistically impossible failure before dealing with the most common one (reg freeflow or bubbling).

For some reason, all too many tech divers have a bad habit of fixing problems that don't exist. I think topside boredom causes this. Standard gear configurations exist for a reason, and that reason is that people who've "been there done that" have agreed on standards based off of much bigger dives, and in a much larger variety of environments than most any of us will ever experience.

 

[Slamfire]

Its just as bad an idea to be going all pretzel through your legs in a wreck.

Wrecks are still overhead environments.

Until the diver needs to be in front of you...then what? Lemme guess, you go infront and then swim off without them? Win for everyone...

If you don't dive in constricted spaces you wouldn't need to have a diver go in front or behind you. What if the diver in question does solo diving? No need to have somebody in front or behind. I've dove with Dale as a buddy. I could post a question relating to Dale referring to him as my dive buddy. Guess what -- Dale dives solo a lot. I'm sure his personal configuration has to take the rigors of solo diving into account.

Bull. I can hear even a small leak, and I only dive OC. Guess why? My manifold is by my ears. I fix leaks when they happen, there is no "is this significant or not" guess and check bafoonery.

AJ, you are right. I have heard and detected very minute leaks because my manifold is by my ears. It happened three weeks ago. However, being right should not constitute a license for replying back with an abrasive tone. All you have to do is state the facts. Others, like me, may come up and confirm your facts. The OP or the diver in question will then be informed and can then chose to follow or not follow your advise. It is his choice and there's nothing you can do about it. Being abrasive will just bias your counterparts against your advice.

I know a cave diver or two, and they all use valve up config. I also know a few wreck divers. Same thing. Inverted is never favored. Hmm...

Again, guys, most divers in the world are not cave or wreck penetration divers. Let's move own beyond our own little microcosm and try to open our minds to the possibility that people doing things differently from the way you do them may still work and does not necessarily mean an automatic death sentence.

 

[Slamfire]

Standard gear configurations exist for a reason, and that reason is that people who've "been there done that" have agreed on standards based off of much bigger dives, and in a much larger variety of environments than most any of us will ever experience.

What if the diver in question is not a "standard" diver. Standard configurations assume the standard diver will be able to reach his valves. The OP mentioned reaching valves is a problem with the diver in question. There was some good advice about looking at the dry suit/undergarment fit, stretching exercises, etc. But what if the problem with reaching valves goes beyond that. I had a friend in college that lost a lot of mobility in one shoulder after a bad car accident. Other than that, he was very fit and capable physically. I know there is no way this particular friend could have reached valves at the top. Probably even sidemount valves would be a problem. I would have to say that if this friend was a diver, inverted valves would probably be his best bet.

Not the word I'm thinking about, but it did start with an S!

Is there really a need to publish this?

 

[rjack321]

Wrecks are still overhead environments.
Again, guys, most divers in the world are not cave or wreck penetration divers. Let's move own beyond our own little microcosm and try to open our minds to the possibility that people doing things differently from the way you do them may still work and does not necessarily mean an automatic death sentence.

Nobody called it a death sentence. But I'll go out on a limb and say the reason most UK divers are using doubles and getting into deco is to see wrecks.

Why chose a configuration that is suboptimal (bordering on dreadful) for wreck penetration when something as simple as changing the undergarment or drysuit can remedy the issue of reaching the valves in their upright orientation. I ordered a UK made drysuit once (Northern Diver) and it was cut just awful for reaching valves so its not too big of a leap for me to suspect that the OP's issues could be readily solved with a better suit.

If that doesn't do it stretching can really help too.