The Tank Valve Feathering/Modulation Technique

[Storker]

.

You have to exhaust the expanding air Bob . . .or do you like use your Drysuit all the time for buoyancy, surfacing bloated like the "Michelin Man"?

Frankly, if I had an emergency like OOA or a free-flow I'd be heading for the surface ASAP per my (apparently inferior) training, and venting my DS would be pretty low on my list of things to do while ascending in such a situation. Not being able to hold a safety stop due to my suit air expanding on the way up would probably be among the least of my worries.

Methinks you might be trying to argue yourself out of being totally wrong WRT which way DS air changes volume upon ascending, but totally failing to do that...

 

[Diving Dubai]

So let me get this straight.. you could teach all OW students a complicated method requiring some degree of contortion to get to the surface when their buddy has left them... I would still like to see teh great man do this on a safety stop and fire an SMB too

I have a more radical suggestion. You could teach them to carry a secondary air source - it could be a small cylinder with 1st and second stage - perhaps 6 litres capacity at 232 bar, which would give them more than enough air for FREE FLOW. Furthermore my new revolutionary idea could be the basis of deco courses. I'm clearly a genius and will instantly market my idea to everyone I might even call it self reliant or solo diver - I wonder why it hasn't been thought of before...

 

[Kevrumbo]

.

Frankly, if I had an emergency like OOA or a free-flow I'd be heading for the surface ASAP per my (apparently inferior) training, and venting my DS would be pretty low on my list of things to do while ascending in such a situation. Not being able to hold a safety stop due to my suit air expanding on the way up would probably be among the least of my worries.

Methinks you might be trying to argue yourself out of being totally wrong WRT which way DS air changes volume upon ascending, but totally failing to do that...

With regard to drysuit diving, you purge all gas out before jumping in and descending; when at the surface again post-dive, all gas should be near exhausted from your drysuit if you did a nominal ascent with safety stop (or even in a controlled emergency ascent, you should have been venting gas from your drysuit).

The problem with being "shrink-wrapped" and with no compressed gas remaining in your tank is that you cannot inflate your drysuit for additional positive surface buoyancy. You better be able to drop your weights and orally inflate your BCD if you had to CESA, conventionally breathing off a free-flowing reg all the way to the surface, finally exhausting your cylinder pressure completely if you even made it to the surface. . .

---------- Post added April 26th, 2014 at 11:30 PM ----------

So let me get this straight.. you could teach all OW students a complicated method requiring some degree of contortion to get to the surface when their buddy has left them... I would still like to see teh great man do this on a safety stop and fire an SMB too
...

Nope . . .only did a short pause 30sec safety stop. Didn't need to deploy an SMB because I was diving at shore/dockside next to the dive-ops.

 

[TONY CHANEY]

... If a novice diver on single tank at basic OW depth 18m/60' --with no buddy in sight-- has the option & ability and can successfully make the effort to conserve as much free-flowing gas by the valve modulation/feathering breathing technique, what he gains is time --time for the Buddy to find him and gas share. If not, then perform a "modified" Controlled Emergency Swimming Ascent (CESA) while taking breaths as needed by the valve modulation technique as described above. If possible & skilled enough to hold depth, do a safety stop. At the very least, the main objective is to safely reach the surface without suffering an AGE and with some tank pressure left to adequately inflate your BCD and Drysuit. You don't want an "out-of-the-frying-pan-into-the fire" SoCal worst case scenario of surfacing with an empty tank; getting tangled in kelp; inability to orally inflate the BCD because you're out-of-breath having just performed a conventional CESA; shrink-wrapped drysuit hampering mobility; and working hard treading water to maintain positive buoyancy in a typical prevailing 2' to 4' afternoon swell & wind chop --you had better at least be able to drop your weights!

The actual incident that happened:
Cozumel 2006, my adjustment knob on the second stage blew-out resulting in a catastrophic nonfixable free-flow, on a single-tank dive in 6m of depth, during a weightbelt lead check. I actually could see the gauge pointer/indicator hand on the SPG sweeping from 200 through 150 bar literally in an instant before reaching back to shut-off the cylinder valve. Switched to my bungied back-up reg around my neck and then modulated/feathered the tank valve behind my head while doing a CESA. (Again, this should be a skill regularly practiced starting in basic open water).

Part 1: Really? Novice diver, cold SoCal water, 60 fsw down, single tank, kelp overhead, no buddy in sight, a nonfixable free flow, in drysuit, inability to orally inflate, shrink-wrapped drysuit without much mobility, working hard to treading water, 2-4' swells and wind chop!

Pure BS in trying to create the worse situation. Yea, novice divers do this type of dives all the time.

Part 2: Really? You were only at about 16 fsw! Do you really expect us to believe all of that BS you did while only 16 fsw down. So please tell us just now many feathers you performed during this rather deep ascent. I would not even brag about a free dive to this depth. ROTFLMAO!

 

[Kevrumbo]

Part 1: Really? Novice diver, cold SoCal water, 60 fsw down, single tank, kelp overhead, no buddy in sight, a nonfixable free flow, in drysuit, inability to orally inflate, shrink-wrapped drysuit without much mobility, working hard to treading water, 2-4' swells and wind chop!

Pure BS in trying to create the worse situation. Yea, novice divers do this type of dives all the time.

Part 2: Really? You were only at about 16 fsw! Do you really expect us to believe all of that BS you did while only 16 fsw down. So please tell us just now many feathers you performed during this rather deep ascent. I would not even brag about a free dive to this depth. ROTFLMAO!

Yea Tony and you've never dove the Channel Islands of Southern California, some of the best kelp forest diving in the world, and visited every weekend by novice -Groupon/Living Social- divers in those exact sea state & wind/weather conditions described above.

And I did what I did & survived --that's all that matters whether you believe it or not.

 

[Storker]

With regard to drysuit diving, you purge all gas out before jumping in and descending; when at the surface again post-dive, all gas should be near exhausted from your drysuit if you did a nominal ascent with safety stop.

Wow! Rly?



FYI: You don't have to lecture me on basic dry suit diving. Dry suit is what we dive up here, right from OW class and onwards. And the "condescending" trick doesn't work very well, either.



--
Sent from my Android phone
Typos are a feature, not a bug

 

[MXGratefulDiver]

You have to exhaust the expanding air Bob . . .or do you like use your Drysuit all the time for buoyancy, surfacing bloated like the "Michelin Man"?

Of course you do ... that still won't leave you with a "shrink-wrapped" drysuit on the surface. Also, try that sometime while you've got your right arm up over your head fiddling with your valve on the ascent ... let us know how that works for ya.

That's your problem, Kevin ... you come up with some complicated "solution" to a problem and then get all insulting when people point out the flaws in your approach.

You're full of nice slogans ... among other things ... didn't they ever teach you the one about moving the cotton?

... Bob (Grateful Diver)

---------- Post added April 27th, 2014 at 04:46 AM ----------

The problem with being "shrink-wrapped" and with no compressed gas remaining in your tank is that you cannot inflate your drysuit for additional positive surface buoyancy. You better be able to drop your weights and orally inflate your BCD if you had to CESA, conventionally breathing off a free-flowing reg all the way to the surface, finally exhausting your cylinder pressure completely if you even made it to the surface. . .

Well gee ... of course you'd better be able to ... those are skills we actually do teach people in Open Water class ... for very good reasons ... because it's a way more reliable emergency procedure than shutting down your only source of breathing gas on an already stressful ascent.

Seriously Kevin ... you need to discuss this idea of yours with an instructor you respect ... if such a person exists. I'm certain someone like Andrew could explain to you why it's not a good idea for an Open Water level diver ... if you can manage to shut up long enough to listen.

... Bob (Grateful Diver)

---------- Post added April 27th, 2014 at 04:58 AM ----------

Part 1: Really? Novice diver, cold SoCal water, 60 fsw down, single tank, kelp overhead, no buddy in sight, a nonfixable free flow, in drysuit, inability to orally inflate, shrink-wrapped drysuit without much mobility, working hard to treading water, 2-4' swells and wind chop!

Pure BS in trying to create the worse situation. Yea, novice divers do this type of dives all the time.

Yea Tony and you've never dove the Channel Islands of Southern California, some of the best kelp forest diving in the world, and visited every weekend by novice -Groupon/Living Social- divers in those exact sea state & wind/weather conditions described above.

And I did what I did & survived --that's all that matters whether you believe it or not.

... so would the diver who simply follows their training, go and blow ... no CESA needed as long as there's enough air in your tank to make a direct ascent. Once on the surface, drop your weights, as you've been taught ... once your weights are gone, no matter how "shrink-wrapped" your suit (which is pure BS, apparently you've never actually tried it) you'll still have adequate buoyancy due to your undergarment to maintain positive buoyancy without needing to use your fins.

Kelp isn't an overhead ... I've surfaced in kelp many times, both in the Channel Islands and here in our bull kelp, which is much more difficult to swim through. You can, with care, make your way through the stuff if you have to. If you don't have to, then stay put ... you're on the surface and breathing ... the boat crew will figure out how to get you out of it ... probably by tossing you a rope with a buoy attached and pulling you through it, like they did us at Italian Gardens. Worst case, jettison your rig ... then swimming through the kelp is a pain in the butt, but perfectly doable.

Under no circumstances will an ascent "shrink-wrap" your suit to the point where it impedes your ability to move ... that's a figment of your rather overactive imagination. Suggest you try it sometime ... you'd have to actively squeeze the air out of the suit to make it that tight at the surface.

... Bob (Grateful Diver)

 

[scubadada]

In my own NAUI BOW class way back in 1997, we were drilled on turning on/off our cylinder valves at depth. We also did the four corner confined underwater swim at 3m/10' --swimming to & breathing off of four tanks consecutively before a "blow & go" to the pool's surface. Even did the old LA County equipment "ditch n' don" drill. (Only regret was the valve feather ascent technique wasn't taught). A very comprehensive and challenging course back in the day --and NAUI BOW at the time was considered soft compared to LA County's basic Scuba certification (both agency certs required Skin Diver prereqs to begin with).

Y'all as present day "advanced open water divers" have no excuses. . .

I was certified by the LA County Underwater Unit in 1970. It was a great course. I learned and practiced many things that are not, or superficially taught today, but, I did not learn how to feather my valve to control a free-flowing second stage

 

[T.C.]

With regard to drysuit diving, you purge all gas out before jumping in and descending; when at the surface again post-dive, all gas should be near exhausted from your drysuit if you did a nominal ascent with safety stop (or even in a controlled emergency ascent, you should have been venting gas from your drysuit).

Yes, but you are also supposed to add air to your suit as you descend. That's what will shrinkwrap you- forgetting to add gas. On your way up, you vent; but due to the fact there is alway some water pressure, you will never vent all that air out- and that air will expand. And if the diver is worried about your reverse physics shrink-wrapping, all they have to do is stop venting the last few feet up. Mythical Problem Solved.

Now go take a basic physics lesson on how air expands under less pressure.

The problem with being "shrink-wrapped" and with no compressed gas remaining in your tank is that you cannot inflate your drysuit for additional positive surface buoyancy.You better be able to drop your weights and orally inflate your BCD if you had to CESA, conventionally breathing off a free-flowing reg all the way to the surface, finally exhausting your cylinder pressure completely if you even made it to the surface. . .

=Shockingly enough, but these ARE OW skills. A novice diver should be able to perform them. With a drysuit, just ditching weights will give you crazy amounts of bouyancy.

Yea Tony and you've never dove the Channel Islands of Southern California, some of the best kelp forest diving in the world, and visited every weekend by novice -Groupon/Living Social- divers in those exact sea state & wind/weather conditions described above.

Do all these Novice divers lose their buddy, get freeflowing regulators at depth and magically lose their ability to conduct a REAL OW skill like oral inflation?

And I did what I did & survived --that's all that matters whether you believe it or not.

What, from 6m? That's a little over 18 feet! I had dives at Blue Heron Bridge deeper than that.

Nope . . .only did a short pause 30sec safety stop. Didn't need to deploy an SMB because I was diving at shore/dockside next to the dive-ops.

From 18 feet? You did a safety stop for an 18 foot dive?

Wow, I can smell the BS from over the computer.

Face it; this was a stupid idea. You lost the argument on the Basic forum thread, and you lost the argument here.
Give it up already, you're really embarrassing yourself.

 

[Kevrumbo]

I was certified by the LA County Underwater Unit in 1970. It was a great course. I learned and practiced many things that are not, or superficially taught today, but, I did not learn how to feather my valve to control a free-flowing second stage

Like I said, too bad it wasn't taught even back then. (Never implied that LA County taught the technique; the context was in relation to "ditch n' don") which isn't taught anymore in any of the commercial agencies --not sure if LA County teaches it anymore either. You ever been on the Catalina Chamber Volunteer Crew?


---------- Post added April 27th, 2014 at 06:30 AM ----------

Yes, but you are also supposed to add air to your suit as you descend. That's what will shrinkwrap you- forgetting to add gas. On your way up, you vent; but due to the fact there is alway some water pressure, you will never vent all that air out- and that air will expand. And if the diver is worried about your reverse physics shrink-wrapping, all they have to do is stop venting the last few feet up. Mythical Problem Solved.

Now go take a basic physics lesson on how air expands under less pressure.

=Shockingly enough, but these ARE OW skills. A novice diver should be able to perform them. With a drysuit, just ditching weights will give you crazy amounts of bouyancy.


Do all these Novice divers lose their buddy, get freeflowing regulators at depth and magically lose their ability to conduct a REAL OW skill like oral inflation?


What, from 6m? That's a little over 18 feet! I had dives at Blue Heron Bridge deeper than that.


From 18 feet? You did a safety stop for an 18 foot dive?

Wow, I can smell the BS from over the computer.

Face it; this was a stupid idea. You lost the argument on the Basic forum thread, and you lost the argument here.
Give it up already, you're really embarrassing yourself.

Don't displace your own inabilities, and lack of will & motivation on me. I did it and you can't --get over it.

Of course you do ... that still won't leave you with a "shrink-wrapped" drysuit on the surface. Also, try that sometime while you've got your right arm up over your head fiddling with your valve on the ascent ... let us know how that works for ya.

That's your problem, Kevin ... you come up with some complicated "solution" to a problem and then get all insulting when people point out the flaws in your approach.

You're full of nice slogans ... among other things ... didn't they ever teach you the one about moving the cotton?


... Bob (Grateful Diver)


---------- Post added April 27th, 2014 at 04:46 AM ----------


Well gee ... of course you'd better be able to ... those are skills we actually do teach people in Open Water class ... for very good reasons ... because it's a way more reliable emergency procedure than shutting down your only source of breathing gas on an already stressful ascent.


Seriously Kevin ... you need to discuss this idea of yours with an instructor you respect ... if such a person exists. I'm certain someone like Andrew could explain to you why it's not a good idea for an Open Water level diver ... if you can manage to shut up long enough to listen.


... Bob (Grateful Diver)


---------- Post added April 27th, 2014 at 04:58 AM ----------


... so would the diver who simply follows their training, go and blow ... no CESA needed as long as there's enough air in your tank to make a direct ascent. Once on the surface, drop your weights, as you've been taught ... once your weights are gone, no matter how "shrink-wrapped" your suit (which is pure BS, apparently you've never actually tried it) you'll still have adequate buoyancy due to your undergarment to maintain positive buoyancy without needing to use your fins.


Kelp isn't an overhead ... I've surfaced in kelp many times, both in the Channel Islands and here in our bull kelp, which is much more difficult to swim through. You can, with care, make your way through the stuff if you have to. If you don't have to, then stay put ... you're on the surface and breathing ... the boat crew will figure out how to get you out of it ... probably by tossing you a rope with a buoy attached and pulling you through it, like they did us at Italian Gardens. Worst case, jettison your rig ... then swimming through the kelp is a pain in the butt, but perfectly doable.


Under no circumstances will an ascent "shrink-wrap" your suit to the point where it impedes your ability to move ... that's a figment of your rather overactive imagination. Suggest you try it sometime ... you'd have to actively squeeze the air out of the suit to make it that tight at the surface.


... Bob (Grateful Diver)

Bob I didn't realize you are the resident expert on SoCal Channel Island Kelp Diving, all the way from up there in the Pacific NW -just because you did a few trips down here. And if your kit & rig is properly balanced, weighted & trimmed, you will have a snug drysuit on splash-in/descent (inflating just enough to offset suit squeeze) and snug post-dive on the surface --it sounds like you're overweighted from carrying too much spare extra lead for your students Bob.

And my drysuit exhaust valves -both cuff and shoulder- are on my left arm. It automatically exhausts suit gas at the same time when I raise the hose to dump wing gas. Is yours on the right arm? --perhaps that's your mistaken impression.

Finally and again, if you have proper gas planning -which I know you teach very well Bob- then why let it run dry on a non fixable free-flow? If a novice has the ability and makes the effort to learn the technique effectively as another viable option outside & apart from, or on post-graduation of an agency's formal Scuba training program --well kudos to him/her-- and that's probably gonna be the only way to acquire this skill because of dismissive attitudes (and liabilities) of current Agencies and their Instructors. It's difficult to perform, and even more so in a drysuit, but with practice can be done. . .

The difference between a successful person and others is not a lack of strength, not a lack of knowledge, but rather a lack of will.
-Vince Lombardi