A 'solo' hello, from a newbie to this forum

[Tod]

Glad you completed the course--good for you--but pray tell what is the logic for turning your air off? I don't do that at all. I figure if I might need it I want it then and there, nope, I see no reason for that. That must be some individual instructors criteria.

You're absolutely correct, it was the individual instructor's criteria. His reasoning was that if the valve (on the back-up) was left on during the dive and if something were to go wrong (without the diver knowing), there would be only an empty tank there if one needed it. I could see that regardless of whether you prefer to leave it on or off before the start of your dive, it would be handy to be able to reach the valve in the event there was a free-flow of your back-up regulator and you could then shut it off quickly. But beyond that, I am like you and prefer to have it on and ready when needed. I can also say that on the three dives I did after the course was over, I put the pony back up-right and left the valve on! Individual student's criteria ;-)

On my particular pony set-up, it has a very short regulator hose (so that it doesn't get caught on everything I swim past). When he made me flip my pony upside down, my regulator hose would not reach my face. (And yes, I did try moving the tank up higher to minimize the distance.) So I had to swap with someone else's regulator (with a really long hose) to get through that part of the class. With my 3mm shorty, I can reach the pony tank valve. But in my 7mm full suit, I can barely reach the back of my head!

 

[barc802]

His reasoning was that if the valve (on the back-up) was left on during the dive and if something were to go wrong (without the diver knowing), there would be only an empty tank there if one needed it.

I dive with my stage bottle off for the same reason. My friend leaves his on.

 

[Creed]

Glad you completed the course--good for you--but pray tell what is the logic for turning your air off? I don't do that at all. I figure if I might need it I want it then and there, nope, I see no reason for that. That must be some individual instructors criteria.

I imagine that he wanted to make sure that the diver could manipulate their redundant air source. However, I would be leery of that. With no pressure, it would be a lot easier to get some seawater or grit into the first stage.

 

[Nemrod]

I really don't have a feel for it and was mostly just curious as to if he really had some compelling reason other than "just cuz I said so". If I have a free flow of my redundant air etc I think I would notice it or hear it and that would be reason to call the dive quits. Here is one reason why I think the air should be on. I have had very few equipment failures/o-ring failures, diaphram (1st) or piston O-ring failures while diving with the regulator air on and being used or on standby. When I have had failures is when I first turn the air on---kkaaaaa poooppppppp--it has happened several times. In fact, recently, this past spring in prep for a dive my backup regulator blew an O-ring in the first stage immediantly upon turning the air on!!!! If I had needed this unit and turned it on at the intended 110 feet kinda back in a cave (ledge dive) then I would have had a problem. As it was I switched out regs and did the dive. This is not a first time this has happened. The analogy for this is kinda like flying a twin engine airplane but not testing the other engie or even running it until the other engine fails--what is that logic (I am a pilot)? That is my compelling reason to TURN the air ON and LEAVE it on until completion of the dive.
Also, since your pony is not part of your actual "main" air supply, your main supply should still follow a rule of thirds or something similar then at any point your pony dumps it's air, well, you still have your main supply and if your main fails then what is the likely hood of dual failures of two unrelated systems. Nope, I have a logic for leaving the air on for my redundant supply. Yeah, it is possible both systems could fail, then in that case my logic is that a person needs either new equipement or a better maintenance program up front. N

 

[Glaucus]

If I had needed this unit and turned it on at the intended 110 feet kinda back in a cave (ledge dive) then I would have had a problem.. N

I lean toward agreeing with you, Nemrod. I too dive with my spare turned on. Less to think about and more sure of equipment operation. (I sling a 30.) Though I'd like to hear more about the rationale for leaving it in the off position until you need it - especially for those who rig it on a back mount. In a sling it's a minimal task to twist the valve. If one were concerned about blowing a ring or having a reg problem but still wants the valve off I wonder about turning the tank on during your pre-dive check then turning it off but leaving the pressure in the regs and hose?

 

[barc802]

I wonder about turning the tank on during your pre-dive check then turning it off but leaving the pressure in the regs and hose?

That is exactly what I do. I am worried the 2nd stage might bump it and cause a free flow which could freeze the 1st stage. I also sling a 30 and the 2nd stage is tied up to the opposite side of the knob. I pressurise the system and test, then I turn it off but do not purge the line. I have never had a problem doing it either way but beleive this method is more conservative.

 

[Tod]

Though I'd like to hear more about the rationale for leaving it in the off position until you need it - especially for those who rig it on a back mount.

I can say, because I asked him that very question, that his ONLY reasoning was that he wanted to be sure we had a FULL spare tank/back-up if we ever needed it. However, after advising us of his opinion, he did state that "if we already had our own systems that we were already comfortable with/acostomed to, then he felt that it'd be best if we maintained that practice" as this is more likely how we'd instinctively respond if there ever was an emergency. Notwithstanding, for the required two dives of the Solo Certification class in the ocean, we were required to run with spare/back-up air source in the OFF position and show how we would be able to turn it on and switch regulators in a mock out of air situation. After that second dive, we are now free to make our own choices.

Like anything, there are pros and cons to this idea. And in either instance, there is a right way and a wrong way to do things. Deep down (pun intended), I believe our instructor was just trying to show us there were other ways to do things and he wanted to make sure we could do them (sometimes differently) if we needed to. The most important thing for solo diving is to be prepared. Ninety-nine percent of the required tasks in that class were only intended to show the instructor that we were capible enough divers to deal with problems, rather than panic... even if the "problem" was a new form of gear set-up!

 

[Toolbox-13]

Hello, to all the solo divers here, I mostly do solo dives just to get wet in my area, local swimming holes around 30 feet deep. I basicly do it to relax and keep my skills up. I never had a problem finding a buddy on a dive boat, and do enjoy diving with a buddy when I can, but when I need to blow bubbles...I need to blow bubbles...

 

[captndale]

Though I'd like to hear more about the rationale for leaving it in the off position until you need it - especially for those who rig it on a back mount.

The reason for leaving a back-up, stage or deco bottle off until needed stems from the use of staged bottles in technical diving. If you take a bottle off and stage it, you cannot be sure that it is not free flowing when you are not there to see it. Turning a back-mounted bottle off would not have the same benefit, because you would be able to hear or see the bubbles if the regulator free-flowed. Also, since the back mounted pony is your back-up, you want that regulator to be instantly available and ready to breath in an emergency.

This brings up a point that is often missed by divers using ponys. Many divers have their basic recreational set-up, with primary, octo and spg mounted on their main tank. They then mount a pony with a 2nd stage and spg along side. This leads to confusion. If you are using more than one tank you should have no more than one 2nd stage on each. You should also have no spg's mounted on long hoses on pony's. I have seen too many near accidents caused by the confusion of having too many pieces of equipment to choose from in a stressful situation.

 

[Tod]

This brings up a point that is often missed by divers using ponys. Many divers have their basic recreational set-up, with primary, octo and spg mounted on their main tank. They then mount a pony with a 2nd stage and spg along side. This leads to confusion. If you are using more than one tank you should have no more than one 2nd stage on each. You should also have no spg's mounted on long hoses on pony's. I have seen too many near accidents caused by the confusion of having too many pieces of equipment to choose from in a stressful situation.

I just use one of those mini gauges that mounts directly to the primary (first stage) regulator so I can check (the pony) if the tank if full while I am setting it up. I use an intergrated octo (Sherwood Shadow) with my BC's inflator hose and then rig my pony's second stage up like a second octo.

While it's only happened to me once, when I was with an OOA diver, I gave them my primary second and switched to my primary octo while the other diver sorted things out. The pony sat in reserve the whole time. (Turns out his double manifold was shut off when he was filling his tanks and *thought* he was filling both. I don't know when he decided to check his pressure gauges for the first time during the dive, but when he did he was frightened when he discovered he was almost out of air. It was good for a laugh back on the surface and probably resulted in him learning to double-check from now on!)