re: Best Valve for Single Cylinder

[Rick Murchison]

Uncle Pug once bubbled...

In what way is 130' recreational dive too deep for a CESA using a single tank with single regulator set up? (I don't want to get into why I think 130' spearfishing is a really a 150' dive.)

I don't agree with single tanks in an overhead environment.

My personal limit for diving without redundant regs is 110'. What's yours?
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What do you mean you don't agree with single tanks in an overhead environment? I truly don't understand the objection. Single with "H" valve and manifolded doubles are no different except for the amount of gas in the system at the beginning of the dive. A single 104 at 2000 psi has as much gas as double 80's at 1500 psi - are you saying there's a difference?
NSS/CDS, NACD and TDI do not agree with you, by the way; all allow - indeed encourage - training to conduct cave dives with single tanks as well as doubles.
Rick

 

[Uncle Pug]

Rick Murchison once bubbled...
My personal limit for diving without redundant regs is 110'. What's yours?
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What do you mean you don't agree with single tanks in an overhead environment?

My single tank dives are all done on EAN32... therefore my 1.4 MOD is 110fsw but I am not adverse to taking it to 120~125fsw for a short period... however in reality most of my single tank time is spent <100fsw.

I don't use a redundant 1st stage with singles as it makes no sense to me. Within the recreational limits my buddy is all the redundancy I need.


What I mean by "I don't agree" is that I don't share the same opinion as you on this subject... but I still love ya

 

[Uncle Pug]

DiverBuoy once bubbled...
IMO - I disagree with the idea that a pony is insufficient as a redundant air source in recreational diving for several reasons.

This is what I wrote:

if you need a redundant air source neither ponies nor spare airs are sufficient IMO. The way to go is a proper set of doubles.

Which is a far cry from saying that ponies are insufficient as a redundant air source in recreational diving.

My opinion is that recreational diving does not require a redundant *air source* other than a good buddy and good buddy skills.

Any diving that requires a redundant *air source* falls outside of what I consider recreational diving and I am of the opinion that for such dives ponies are insufficient... doubles are the tool of choice.

BTW: my DIR rig that I use for recreational dives has a single tank and a single first stage regulator.... not doubles as you might suppose.

 

[DiverBuoy]

Uncle Pug once bubbled...
My opinion is that recreational diving does not require a redundant *air source* other than a good buddy and good buddy skills. Any diving that requires a redundant *air source* falls outside of what I consider recreational diving and I am of the opinion that for such dives ponies are insufficient... doubles are the tool of choice.

Your opinion may not be shared by the vast majority. IMO - A redundant air source (totally independant loop) is always a good idea - with or without a buddy - recreational or not. Having a redundant air source in my opinion does not by any means fall outside of recreational diving.

 

[MikeFerrara]

Don't feel one needs an h valve for a reasonably planned rec dive but I use one. Most of my diving is in doubles so the h valve lets me move my regs over witout changing a thing. As long as I have it the redundancy isn't a bad thing.

There are also special applications. I do some ice diving in a single tank. Sometimes I need to carry the equipment a long way so a single tank is easier. Here I really like the redundancy.

 

[DiverBuoy]

Uncle Pug once bubbled...

BTW: my DIR rig that I use for recreational dives has a single tank and a single first stage regulator.... not doubles as you might suppose.

I'm interested in the DIR rig, and I think it is cool that it can be used with single or doubles. Is it an easy transition?

 

[Dryglove]

DiverBuoy once bubbled...


I'm interested in the DIR rig, and I think it is cool that it can be used with single or doubles. Is it an easy transition?

I dive with a halcyon pioneer.to convert it to doubles requires removing the single tank bands and bladder.Takes about 2 min.

Install a explorer double tank bladder and bolt your doubles to the backplate.About another two min.

And of course doubles require to seperate first stages which is my reasoning for wanting to go to an H or Y valve on my single tank.It makes going from singles to doubles a lot easier without changing the regs or hoses around.

 

[Uncle Pug]

Mike... I'm ignorant of what it takes for ice diving... but I can see that a redundant first would be a good idea.

DB... it really is no big deal to change over from singles to doubles... for me... I keep both rigs set up

It wouldn't take much effort to switch over however... especially if you were using an STA. The necklaced back up and SPG would have to be moved over to the right post first stage to use it on a single... unless of course you had and H valve

I don't know if you have read any of our pony discussions here on Scuba Board... but I see them as a liability rather than an asset for recreational dives.

Shane and I regularly practice OOA scenarios at depth with 30' seperations so we are comfortable using one another for redundancy. We are also practiced in air sharing ascents doing stops along the way. The 7' hose makes it a lot easier.

 

[DiverBuoy]

Uncle Pug once bubbled...
Shane and I regularly practice OOA scenarios at depth with 30' seperations so we are comfortable using one another for redundancy. We are also practiced in air sharing ascents doing stops along the way. The 7' hose makes it a lot easier.

I'll take your advice, and if I can ever get into a DIR rig I'll get a chance to see the advantages of the long hose.

 

[Uncle Pug]

lal7176 once bubbled...
my reasoning for wanting to go to an H or Y valve on my single tank.

I'm not so sure I like the idea of having extra weight up there. And I'm not so sure that it is really easier to take two regs off my doubles and then put them on a single and then take them off the single to change it out for the second dive. I think that just switching two hoses once has the advantage there.

TIP: if you are drysuit diving then use the left post first stage and switch the long hose and wing inflator hose over to that one.