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Tried manifolded twin 7's in SDS yesterday, oh what fun! They were mounted on a BCD style wing using the cam-bands as they didn't have one set up on a backplate for me to try...

Anyway, isolating the manifold was relatively easy by hitching the unit up on my back and reaching over.

But, try as I might, there was no way I could reach the cylinder isolators!! I actually thought they'd be the easiest to reach...

It may have had something/alot to do with the daft BCD/Wing which seemed to push the cyliders away from me when i hitched it up - but anyway, does anyone have any specific techniques/advice on reaching the cylinder valves...?

Thanks,
 

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Fitting a cage can help as you can grab the gage and pullthe rig tawards you. But obviously this cost money

Alternativly, place your oposing hand on the bottom of the oposing tank and lift and twist the twin set in the direction of the valve your trying to reach. Use the other hand to reach the valve. This is what I do.

Main new to twin set error is trying to reach out and around your own sholder. Its better to put your arm straight back beside your ear. I watched Bob Cooper yesterday and he streached his arm straight out in front of him then lifted back from the sholder before bending at the elbow to finish the job. It looked a very efficient way of prepairing the arm for the job.

Note that it is much easier to do shut downs horizontal than it is to do them in the near vertical position.

Get some help and if all else fails you can always invert.  


ATB

Mark Chase
 

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Mark...can you please not do that...I just did the extended arm and over the shoulder exercise that Bob did, as you described and i've knacked myself in....all without leaving the comfort of my chair.

I need to exercise more.

Graham
 

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Justin,

Don't apply surface logic to an underwater situation - you don't need to be able to reach the isolator in the shop, you need to be able to reach it underwater.

Try it on in the pool and see how you get on then. I can't get near my valves standing up, but can reach them easily when in the water.

Chris
 

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Justin,

try reaching your valves while horizontal in the water, not while vertical on dry land. It's a lot easier when you don't have gravity working against you.

In addition doing it in the water will also show you if your dry suit or undersuit is going to restrict your movement.

I would also look at the positioning of the cylinders on your back. Moving them up or down a couple of inches can make a big difference in how easy they are to reach.

Moving them up and down will also help you adjust your trim in the water.

There is no substitute for getting in the water and practice, practice, practice.

Good Luck

Mark Powell
Dive-Tech: Technical Diver Training
 

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Justin,

I have a hard time reaching my valves as well.  I've found that if I don't have enough air in my drysuit to take out the squeeze, I can't reach them at all.

Like many people, my main problem is with my left valve.  So I've been doing some stretching.  Also, if I'm doing a left valve shutdown, I grab the right valve with my right hand and try to pull the tanks up a little so my left hand can reach the left valve and turn it easier.  When doing an isolator or right valve shutdown I do the opposite.

Hope that helps,
Sacramento Tony
 

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[b said:
Quote[/b] (kinetic @ Dec. 07 2003,19:18)]


Mark...can you please not do that...I just did the extended arm and over the shoulder exercise that Bob did, as you described and i've knacked myself in....all without leaving the comfort of my chair.

I need to exercise more.

Graham
Sorry about that M8

I tell you what, my back is killing me today. I am not sure if it was the carrying the twinset, nearley cripling my self on the shutdown drills, or doing the whole dive head up hands locked and buttocks clenched to try and impress Bob


ATB

Mark Chase
 

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Cheers guys, I was doing what Mark was saying and trying to twist my arm away from my shoulder.

Chris - I know the shop isn't the best place to try but it was that or simply spend the money blind on twinset/wing etc and find it in the pool! Didn't want to make an expensive mistake!!

Anyway - think i'm gonna be ok and will be ordering my wing once the combro arrives...!
 

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I've seen people doing stretching exercises[URL http://www.divefitness.com URL] Some buy a slob knob. Others go out and get made to measure dry suits with extra large shoulders to give them the freedom of movement.  I couldn't do a shut down drill without a great deal of difficulty and after playing with position of the cylinders and trying both neoprene and tri-laminate dry suit options the only practical working solution I could find was to invert the cylinders and have the valve knobs right by my hands.  I can now run open or shut down drills standing up on surface or in the water.
 

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I also have the same problem with my twin 7s I cannot reach any of the valves so I dive with the manifold shut ,and use them as 2 independant  cylinders ,so at least if there is a failure on one of them I will have some gas in the other cylinder as I  breath each cyliner down at the rule of 3rds . any problems with one cylinder I switch to the other and abort the dive . for me this seems to work ,as even if I could reach the valve by the time I realise what is happining and workded out which one has gone wrong and struggled to turn it off . all the gas would have gone .
 

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I have recently started playing with twin 7's after using inverted twin 10's for some time.

I found I could shutdown all valves first try, however it was a bit of a struggle.  Since then I have moved them up in the bands so the top band is about 1" below where the cylinder starts to round off.

The shutdowns are easier, quicker (Although definitely not as quick as on my inverts)  Also it has moved the weight distribution a bit so I am not as feet heavy.

My 10's are staying inverted though as my trim is fine and shutdowns are a PIA with them valve upwards.

Daz
 

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Go Daz!!

The few seconds longer that it may take isn't a real concern Daz as it takes ages for a free flowing reg to spew forth all of ones air.... During our fundy class we had to dump air down to 35 bar for a weight check and I couldn't believe how long I was hanging there with the purge button depressed.... everytime I looked at my spg it had hardly moved.

God know's what people on the surface were thinking because there were three of us hovering at 6m purging like crazy... it must of looked like white water on the surface.... Although saying that nobody attempted to come to our aid.. lol.. bastids!  
 

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Having tried both methods I will vouch for the fact that shutdowns on a traditional rig are perfectly adaquate as long as you can actually shut them down and the rig is comfortable.  How low the cylinders are and any restriction in the suit can make a world of difference.

Having said that the 10's are at this time staying inverted.  Performing shutdowns is just not happening unless I move them much higher up.  If I move them higher up on my back I end up head heavy and plowing a furrow with my face.   And to improve trim by adding weight near the waist area I just end up over heavy.

So 2 morals to this story....

Don't use twin 10's.  If you can lift 10's you can probably lift 12's.  (Don't suppose anyone want's to swap a set of 300 bar 7's for a set of twin 10's do they
)

If you can't do shutdowns no matter what you try.  Then give it a go with inverts as long as you are willing for the extra cost of valve guards, custom hoses etc.  


Daz
 

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[b said:
Quote[/b] (Dave Williamson @ Jan. 16 2004,11:59)]The few seconds longer that it may take isn't a real concern Daz as it takes ages for a free flowing reg to spew forth all of ones air.... During our fundy class we had to dump air down to 35 bar for a weight check and I couldn't believe how long I was hanging there with the purge button depressed.... everytime I looked at my spg it had hardly moved.
Dave,

I must give this a try sometime just to get an idea of how long it takes (Should scare the crap out of my buddy as well  
)..

I would hazard a guess that certain regs such as Poseidons and Oceanic Omegas may be able to lose more gas more quickly due to their design (OK I know the DIR answer to this one  
).

Just one observation,   surely there is a reasonable difference between how much air is lost from a freeflowing reg at 6m and a freeflowing reg at 35m.

Still the bottom line is that I can do shutdowns on my 7's,  I can shutdown the isolator reasonably quickly as well,  well quick enough for me not to consider inverting (Ask me again after I have a freeflow at 30m  


Daz
 

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[b said:
Quote[/b] ]I would hazard a guess that certain regs such as Poseidons and Oceanic Omegas may be able to lose more gas more quickly due to their design (OK I know the DIR answer to this one   ).
Hi Daz,

There is a letter on DNet from a chap that purged his Poseidon regs at 30 odd metres in Stoney Cove (in response to an article about shutdown drills) and noted the results:

Here

It seems that Poseidon regs will bin the contents of your cylinder that much faster than other regs.

HTH,

Fraser.
 
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