Pony bottle skills

[lamont]

Let me clarify.

When I said practice, I meant with air in my tank, simulate being out of air by taking a breath and slowly exhaling while slowly ascending. After my 15' safety stop is done seems like a good time.

yeah, bad idea. you should be ascending slowly from your 15' safety stop. the closer to the surface, the slower you should go.

if you want to practice CESAs, do it when you don't have any nitrogen loading at all, do it shallow and have a buddy which is rescue trained at the least.

better yet, just make it a point never to do one...

 

[Soggy]

Let me clarify.

When I said practice, I meant with air in my tank, simulate being out of air by taking a breath and slowly exhaling while slowly ascending. After my 15' safety stop is done seems like a good time.

Actually, that's the worst time to do it....when you have the most gas load and when you need to be ascending most slowly. Remember, the greatest pressure gradient is in the first 15 feet.

It's a pointless skill...spend your time working on skills that prevent a CESA. There is never a need for it.

 

[ronrosa]

yeah, bad idea. you should be ascending slowly from your 15' safety stop. the closer to the surface, the slower you should go.

if you want to practice CESAs, do it when you don't have any nitrogen loading at all, do it shallow and have a buddy which is rescue trained at the least.

better yet, just make it a point never to do one...

I always slowly ascend after my saftey stop. I continue to breath normally without any thought while I'm slowly ascending.

My idea was to practice an out of air ascent AFTER I have completed my 15' safety stop. AFTER my stop is completed, take one breath and slowly ascend all the way to the surface.

I'm 15 ft. down, have > 500 psi of air in my tank, and I've already completed my saftey stop. Maybe I'm a total stroke idiot. Why is this not safe ? To me, it sounds like a good way to practice and get my mind/body convinced that out of air ascent can be done safely. At least from 15 ft.

Maybe I'm missing something.

 

[Daryl Morse]

I have a buddy I dive with near home, that I trust and would have no problem relying on.

However, all my warm water diving is with "boat buddies" and most of them can't even handle their own problems, so I don't rely on them.

Same here. At home, I dive regularly with the same buddy (he dives doubles) and it works well for both of us.

On the other hand, every time I've been on a boat, it's been away from home and with a buddy I've never met before. It's either dive with a buddy I don't know or don't dive at all. I'd rather dive.

Having experienced a buddy disappear, I can understand why someone might want a pony bottle.

 

[John C. Ratliff]

Let me clarify.

When I said practice, I meant with air in my tank, simulate being out of air by taking a breath and slowly exhaling while slowly ascending. After my 15' safety stop is done seems like a good time.

What I said earlier in this thread is that a competant diver should be comfortable with an emergency swimming ascent. I checked again, and the NAUI Basic Scuba course in the 1970s-1980s stated in the "Watermanship Evaluation -- Session 1" that for a scuba course, "Required swim skills to be covered during a basic scuba course" were:

1. Swim 220 yards, non-stop, any stroke
2. Use survival techniques to stay afloat 20 minutes...
3. Swim 20 yards underwater.
Boehler, Ted, NAUI, The Pro Manual, 1977, page III-7

Twenty yards is 60 feet, horizontally. I do not recommend that anyone practice an emergency swimming ascent in open water while not in a training session. If you wish to practice this skill, I suggest a pool. With your scuba gear on (but not necessarily your full wet suit--divers in cold-water areas have gotten overheated in full wet suits in the pool), you can practice an emergency swimming ascent. Remember that you have a tank, and at depth it also has air in it. That air will also expand, and give you a breath or two on the way up, even if you run the tank dry. Therefore, if you start in the pool's deep end, and swim toward the shallow end, exhaling as you go, figure you can take two breaths from your scuba on your way to the pool's end. You will be simulating the expansion of the air in the scuba tank and your lungs. If you cannot make it the first time, simply surface or start breathing more from your scuba. You can do the same with a pony bottle, or with an octopus, simulating a 60 foot ascent in the pool.

Joe Strykowski years ago published this recommendation on emergency swimming ascents:

EMERGENCY SWIMMING ASCENT

In the unlikely event of an equipment malfunction or the far more likely possibility of running out of air, the diver should signal his buddy and buddy-breath to the surface. Let's say your buddy has wandered off and isn't aware of your plight. Even if your scuba were hopelessly fouled, you could extract yourself and reach the surface by using the following procedure:

A) Unless your scuba is impossibly entangled, do not ditch it. The emergency swimming ascent is a controlled ascent. Personal flotation device, buoyancy compensator and diving suit are normally "trimmed" for neutral buoyancy at depth. Ditching a weight belt -- unless necessary -- may result in enough added positive buoyancy to carry the diver to the surface in an uncontrolled ascent.

B) Tilt your head back, extend an arm over your head, exhale and begin swimming to the surface. As you ascend, the expanding air in your lungs (Boyle's Law, again must be vented in a continuous exhalation. The head is tilted back to maintain a clear airway to the lungs.

C) If you feel a slight fullness in your chest, slow your ascent and blow harder. If you are blowing and seem to be running out of air, ascend a little faster.

In the July/August 1977 issue of NAUI News, NAUI, PADI, NSADS, YMCA and SSI published a joint article titled "NSTC Ascent Agreement." NSTC is The National Scuba Training Committee. I think this has been lost in time, so I'll present what they had to say without reproducing the whole article. The article had a flow chart of what to do. While it is a bit dated (it doesn't have the pony bottle & independent doubles options), it is correct in the initial phase. Let me quote the first two paragraphs:

The first step in evaluating an out-of-air situation should be the confirmation of the existence and nature of the apparent air loss. Before selecting a more radical or risky option, the diver should stop, think, consciously attempt to breathe, and, if successful in doing so, proceed with a normal ascent. Students should be made aware that many out-of-air situations lie with the diver and/or the situation rather than in equipment malfunction or actual depletion of the air supply. These human factors often can be corrected if first considered before resorting to emergency procedures.

Courses of action to be recommended to a diver in an out-of-air situation may be categorized as either dependent or independent. The most desirable option in the dependent category involves the use of an additional second stage (Octopus) which permits both divers to breathe with their own second stage during the ascent. Students should be encouraged to include this extra second stage regulator as part of their equipment.

Buddy breathing by regulator exchange under emergency conditions is the other dependent option and is the least desirable of the dependent options. Once a satisfactory breathing cycle has been established, buddy breathing should be continued with a reasonable rate of ascent to the surface.

An emergency swimming ascent, recommended as the primary independent emergency option, is accomplished by the diver swimming to the surface while exhaling continuously.

Another course of action is buddy breathing followed by an emergency swimming ascent. If this procedure is used, it should be initiated on the bottom, where buddy breathing is used to regain composure prior to the swimming ascent, and not resorted to during a beddy breathing ascent. Whenever divers ascend while sharing air, they should continue to share air until surfacing.

The final option, and no other options are recommended, is a buoyant ascent. THis is an ascent made by dropping weights, or by using some other form of buoyancy such as an inflated buoyancy compensator. A buoyant ascent is used when a diver seriously doubts the surface can be reached by swimming.

The flow chart, shown below, would have to be amended to fit our reality, but the main two top decisions would be the same, as would the branches for dependent and independent action. Under "Dependent Action," I think the next decision would be "Use of octopus, pony bottle, or redundant regulator." The last option would be "buddy breathing." Under "Independent Action," would be "Use of pony bottle, redundant regulator," and then the "Emergency Swimming Ascent" followed by "Buoyant Ascent."

This was long, and I apologize. I actually wanted to talk a bit more about why the pony bottle is now required on some dive boats, but I'll save that for another discussion. I wanted to get this out before someone decided, based upon what I said, to practice an emergency swimming ascent in open water without others monitoring the situation. More later on topics like the decompression chamber, and instructor requirements under OSHA.

SeaRat

 

[doole]

This is like arguing against air bags in cars since they're only used during collisions.

To me, it's more like advocating cell phone usage in a moving vehicle because it's got airbags anyway.

 

[John C. Ratliff]

To me, it's more like advocating cell phone usage in a moving vehicle because it's got airbags anyway.

Actually, it's more like arguing that you shouldn't need to know how to walk, because you can always drive your car. If you cannot make a free swimming ascent, don't know how to actually, you are neglecting one of the two branches of the flow diagram I posted above. You are essentially deciding not to have one of the escape methods available to you.

Today, I practiced breath-hold diving with two different sets of fins (I work on fin designs, and underwater swimming techniques). I must have swam 25 yards (22.8 meters--sorry, it was a yard pool; 75 feet) underwater about twenty or thirty times. A few times I swam 50 yards underwater, on one breath, using finswimming techniques (flipped the turn at 25 yards). While I don't expect many people to swim 50 yards underwater without training, 20 yards is fairly easy and should be achievable on two breaths pretty easily. Twenty yards is sixty feet, and a diver should be able to complete a free swimming ascent from that depth.

Now, one person above did bring up an interesting question. Many people are using "wings" for their BC, and along with that are very much overweighted. They don't descend by swimming, but by going negative and letting gravity make their descent. This is contrary to my basic philosophy, as I always try starting out neutally buoyant at the surface. I use the BC to compensate for the loss of buoyancy in my wet suit, and stay neutral at the bottom. But if someone is very negative, and descends expecting to use scuba air for buoyancy compenastion, it could cause problems.

SeaRat

 

[Web Monkey]

breath, using finswimming techniques (flipped the turn at 25 yards). While I don't expect many people to swim 50 yards underwater without training, 20 yards is fairly easy and should be achievable on two breaths pretty easily. Twenty yards is sixty feet, and a diver should be able to complete a free swimming ascent from that depth.

Anybody can make it to the surface. The trick is to do it without getting DCS.

Can you swim 60 feet in 2 minutes then stop for three minutes and wait while still underwater?

Now, one person above did bring up an interesting question. Many people are using "wings" for their BC, and along with that are very much overweighted. They don't descend by swimming, but by going negative and letting gravity make their descent. This is contrary to my basic philosophy, as I always try starting out neutally buoyant at the surface.

If you carry enough stuff, you're probably going to be negative.

A couple of steel tanks, an aluminum tank or two, a few regulators, a manifold, a couple of dive lights lights, a backplate, wreck reel, and maybe a camera and a couple of strobes while diving in fresh water would probably do it.

Terry

 

[jonnythan]

Now, one person above did bring up an interesting question. Many people are using "wings" for their BC, and along with that are very much overweighted. They don't descend by swimming, but by going negative and letting gravity make their descent. This is contrary to my basic philosophy, as I always try starting out neutally buoyant at the surface. I use the BC to compensate for the loss of buoyancy in my wet suit, and stay neutral at the bottom. But if someone is very negative, and descends expecting to use scuba air for buoyancy compenastion, it could cause problems.

SeaRat

That's an interesting philosophy, as it requires you to be very positive at the end of your dive.

 

[OE2X]

Now, one person above did bring up an interesting question. Many people are using "wings" for their BC, and along with that are very much overweighted. They don't descend by swimming, but by going negative and letting gravity make their descent. This is contrary to my basic philosophy, as I always try starting out neutally buoyant at the surface. I use the BC to compensate for the loss of buoyancy in my wet suit, and stay neutral at the bottom. But if someone is very negative, and descends expecting to use scuba air for buoyancy compenastion, it could cause problems.

SeaRat

Got to echo Jonnythan's thoughts.
If you start with your dive neutral with a tank that is 6 lbs negative, then how do you propose to stay under when you tank has shifted to 4 lbs positive at the end of your dive?

You want to be neutral at the end of your dive when you tank goes much more positive. Generally this means about a 10 pound swing.