Shutting off a single tank diver's air supply in a free-flow?

[Web Monkey]

But what do I know -- I'm not a highly trained professional who has been through this scenario numerous times. I'm just your average techreational diver who tries to think about things now and then.

The people who want to try to figure out what's wrong and fix it underwater most likely do not do a lot of diving with students and and brand-new divers. And while thinking about things is great, the average "I just got certified and now I'm going on vacation to look at cool fish" diver will be doing very well if they just remember the stuff they learned in class and don't try to over-think the problem.

New divers are taught "something bad happened = go up" and "OOA = "share air, then go up" or just "go up". Teaching a new diver to do a safe ascent followed by power or manual inflation and maybe weight ditching on the surface is a lot of task-loading for someone who could easily only have 15 or 20 dives.

The "up side" of a rec diver doing what they've been taught in an emergency is that they'll be on the surface, breathing and floating. The "down side" is that the tank might need a VIP. This sounds like a good trade to me.

The "up side" of a rec diver playing with their valves underwater is that they might save part of an air fill and get to dive a little longer. The "down side" could be a single or double fatality.

I'll take the "Follow OW training" route for new OW divers. When they get into more advanced classes, freeflows can be dealt with differently (and hopefully eliminated as a possibility). However new (the original scenario), divers will be safer if they do what they were taught.

Considering that quite a few OW fatalities are from people who make it to the surface and forget to ditch their weights, I think asking them to do anything more complicated is looking for trouble.

Terry

 

[rawls]

we should simply accept that divers are taught to do one thing, and that's what they'll do.

I am simply saying that this is the way most students are trained right now, and this is a reality we have to accept until it changes and as it stands right now it hasn't. Again, I am not against other options. You are putting words in my mouth that I did not say, but I personally feel the way it is taught right now is not a bad method at all.

may experiment with other solutions and practice skills they otherwise might not...

I assume you mean experiment after having been properly instructed by a dive professional who can teach these skills. Otherwise you will have a diver with a high risk of being in a world of hurt...or dead.

but no mention was made of what one did after that -- Go to buddy? Go to surface? -- and I do not recall any discussion of how long you have to make that decision, although my husband says the classes he's DM'd, they DO talk about how fast the gas escapes.

Very good point. We cover it in the didactics as well as confined water, but I feel there are alot who do not.

it has to do with how people react in the real world.

Hopefully the way they were trained.

is faced with a sudden free flow will immediately (if not calmly!) tilt her head, pull the reg part way out of her mouth and start a controlled ascent while sipping the free flowing air -- nor would I want her to do that!

Why would you not want her to do that? And you do not have to pull the reg out of your mouth at all...You can simply put your tongue against the back of the second stage and breathe off of it that way.

I'd hope the diver would first go "***!!!!!"

That's probably a given

Honestly, I can't imagine that it would take less than 15 seconds for anyone to actually start up -- and in those 15 seconds you've lost a lot of air (and of course it could be a lot more than 15 seconds).

Hit the purge valve against you hand a couple of times. If that doesn't work, then signal your buddy and up you go with your buddy at 60 ft/min and you are at the surface in no time. If one maintains the rule of 1000psi on beginning ascent they should have plenty of air to get to the surface without once having to share air...If not, then share air....

Use a different method...feather, valve off and on, etc... That is fine but get the training first.

 

[ArcticDiver]

Perhaps one fundamental concept has been lost in this discussion. That is the reason why different divers are taught different procedures.

"Technical" divers are taught to fix things under water so they will be mentally and mechanically capable of solving problems when they are in environments where prompt access to the surface isn't possible. In other words when they are in an overhead environment.

"Recreational" divers are taught to promptly go to the surface when they have a problem simply because the surface is promptly available to them. In other words they are not in an overhead environment.

In neither case is dive length a determinining factor. It is the cirumstances under which the malfunction occurs and the most effective and safest way of dealing with the problem, not "saving a dive".

 

[Tigerman]

The people who want to try to figure out what's wrong and fix it underwater most likely do not do a lot of diving with students and and brand-new divers. And while thinking about things is great, the average "I just got certified and now I'm going on vacation to look at cool fish" diver will be doing very well if they just remember the stuff they learned in class and don't try to over-think the problem.

New divers are taught "something bad happened = go up" and "OOA = "share air, then go up" or just "go up". Teaching a new diver to do a safe ascent followed by power or manual inflation and maybe weight ditching on the surface is a lot of task-loading for someone who could easily only have 15 or 20 dives.

The "up side" of a rec diver doing what they've been taught in an emergency is that they'll be on the surface, breathing and floating. The "down side" is that the tank might need a VIP. This sounds like a good trade to me.

The "up side" of a rec diver playing with their valves underwater is that they might save part of an air fill and get to dive a little longer. The "down side" could be a single or double fatality.

I'll take the "Follow OW training" route for new OW divers. When they get into more advanced classes, freeflows can be dealt with differently (and hopefully eliminated as a possibility). However new (the original scenario), divers will be safer if they do what they were taught.

Considering that quite a few OW fatalities are from people who make it to the surface and forget to ditch their weights, I think asking them to do anything more complicated is looking for trouble.

Terry

New divers ARE taught to do safe ascents and it needed ditch weights and manually inflate the BC. They are NOT taught to "go straight up" other than a very last resort. And please enlighten me on how you intend to "remove equipment failures as a possibility".
You can have redundancy, but you can NOT remove the possibility of an equipment failure such as a freeflow..

 

[Doc Harry]

Perhaps one fundamental concept has been lost in this discussion. That is the reason why different divers are taught different procedures.

"Technical" divers are taught to fix things under water so they will be mentally and mechanically capable of solving problems when they are in environments where prompt access to the surface isn't possible. In other words when they are in an overhead environment.

"Recreational" divers are taught to promptly go to the surface when they have a problem simply because the surface is promptly available to them. In other words they are not in an overhead environment.

In neither case is dive length a determinining factor. It is the cirumstances under which the malfunction occurs and the most effective and safest way of dealing with the problem, not "saving a dive".

Interesting assessment, food for thought.

 

[Web Monkey]

New divers ARE taught to do safe ascents and it needed ditch weights and manually inflate the BC. They are NOT taught to "go straight up" other than a very last resort..

Yes they are, which is why I was recommending that they did not spend time underwater messing with valves and sharing air while trying to fix a problem that they probably don't really understand, and instead, follow training.

Also, I used "up" as a direction, not as a speed indicator.

Terry

 

[Web Monkey]

You can have redundancy, but you can NOT remove the possibility of an equipment failure such as a freeflow..

I never said you can prevent all failures. Those are your words. However you can prevent a cold water freeflow by using a regulator that's built for the conditions you're diving in.

Terry

 

[String]

And speaking of reality...How many recreational divers carry side gas String!!!!

A fairly large % here at least carry ponies. Buddys can't be 100% relied on, a single source of gas can't be 100% relied on so taking a redundant air source makes sense. A 3l tank is no real extra bulk or effort to use. You see far far more people with "standard" setup of 15l+3l pony than you do twins or others.

 

[sglake]

1st I believe if you did have a free flow, shutting off the valve and then seeing if that would fix it isn't an option! This would be an equipment failure and would end the dive. Divers should have been trained to breath with a free flow and there for be able to surface using their own air providing they have enough to surface with. I had a free flow at 120' on very well maintained equipment and was able to make a safety stop and surface , my buddy did surface with me and was there just in case I did become ooa.

 

[Dtaine]

1st I believe if you did have a free flow, shutting off the valve and then seeing if that would fix it isn't an option! This would be an equipment failure and would end the dive.

If I've got plenty of gas left, and can fix the regulator underwater (or make a reasonable attempt to), why shouldn't it be an option?

Not saying a brand new OW diver could do it, but since my buddy and I are capable of it, why not?