Can you reach your tank knob to turn it on?

[do it easy]

Oh, shucks. I've been worried senseless about that for nothing. What if I were upside down and scraped the bottom?

In a single, you would have to be scraping while moving backwards... I suppose it could happen.

 

[TheRedHead]

Anyways, if by an odd chance you dive in an environment where this could actually happen, then you're probably diving with a pony too (or some redundant source).

- ChillyWaters

Nope, people go through swimthroughs all the time without any redundancy. But Do It Easy is Right. Rolling off should not be a concern with a single tank, I think.

 

[Rick Inman]

If you're upside down in the Devil's Throat practicing your backwards frog kick and you roll off your post, then you'll sure be glad you have this skill down!

 

[TheRedHead]

In a single, you would have to be scraping while moving backwards... I suppose it could happen.

I'm really trying to help ChillyWaters out here. He might be a blues singer...help us come up with something.

 

[TheRedHead]

Rick has the answer, Chilly.

 

[do it easy]

Rolling off shouldn't be an issue with a single tank because the proper redundancy in an overhead environment will make this a survivable event. Now, back in reality, I think that Devil's Throat is a popular deep swim through, so as long as the divers don't go through it backwards, they should be OK. If they are going through it backwards, they are probably not OK to start with.

 

[TheRedHead]

Ok what about this scenario: You're going through Devil's Throat and meet a giant green moray eel coming from the other direction. Is it more prudent to practice this skill and go backwards or take your chances? :rofl2:

 

[do it easy]

Okay, but I said I don't see a reason that reaching your valves is necessary. Sure, there is that VERY odd chance that it MIGHT be useful, but generally, I don't buy it.

To the others that have replied to the thread, specifically stating that turning on the valve of a single tank is useful: Why is it so imperative to reach the valve?

- ChillyWaters

I had to turn my air on once- I was diving a single in a pool and a friend snuck up and turned my air off while I was at the surface. I got a few breaths underwater before I realized that I was OOA. In hindsight, she got me good!

While diving doubles, I've had to manipulate deco bottles and argon bottles, but those are slung/mounted, so are much easier to reach.

 

[dherbman]

Oh, I don't know. If your buddy isn't there, you can't shut it down yet anyway, cause you'll need his air. Once he's there, he could shut you down if you needed.

Sorry, but that's just a bad alternative to shutting down and feathering the valve till he gets there.

This link is for the post quoted below.

I tried that last summer with a Scubapro Mk25/S600 and timed 90 seconds to from 3000 psi to 500 psi with purge fully depressed. Nice layer of ice built up on the outside of the reg too. Not enough time to safely ascend if you are at 100 feet and plan to ascend 30 ft/min and do a safety stop.

On saying that, I was told by one diver that he had a reg free flow in cold conditions. He claims to have shut the valve down, and waited for a minute (holding breath) then turned the air back on. This "rest" had cleared the first stage of its cold water freeze-up and the reg breathed again.

Not only do I doubt this actually occurred, it seems stupid as hell, unless his buddy was right there was an extra reg outstretched in case the air didn't "restart".

We have regs freeze frequently in the winter. Almost always on the surface, but do something at depth that gets your reg to freeflowing and it will freeze. This happened to a guy last February at a local river where I was diving. Shutting it down for a minute might be long enough to thaw, but it's not a problem if it took ten minutes if you can reach your valve.

 

[meekal]

How about this one: You're at 80' and you get an uncontrollable free flow.

grab my spareAir