If you could change one thing about dive training...

[TMHeimer]

That's on your instructor. I teach this in Try Scuba sessions as the third option for regulator recovery: arm sweep, reach behind, alternate.



No, I'm definitely not saying you'd be holding your breath. That would be fatal. As you ascend, the air in your lungs expands, and you can continue to exhale as this happens. The act of exhaling will mostly relieve the urge to exhale from built up CO2.

But breathing BCD bladder air is bad for many reasons. Even if you keep it clean with antimicrobials, have you ever turned your BC upside down and opened a dump valve after a dive? There's usually a ton of water that comes out, so you're going to be aspirating that if you try to breathe off the bladder. And reserving enough air in your BC that you'd be able to take a breath off of it risks having that air expand as you ascend and turn your CESA into an Out-of-control ESA.

No I think John may have thought you were holding your breath. I know what you meant.
Yes, I dump the salt water out of the BC (as much as possible) at the end of a dive day. Makes sense before you add fresh water and baby shampoo to rinse the inside.
Are you saying you will only inhale water at depth if you try to breathe from your BC? Orally inflating at depth would seem not as easy as it actually is.
But you may well be correct saying that you'd have to have mostly air in the BC and not say, it's half filled with water in order to successfully inhale air. I would think that is the way it normally is, otherwise there wouldn't be much room in the bladder to add air foe buoyancy changes.

Well I dunno, breathing from the BC is something that I've never done and 99.99999 sure I never will. But, if it seemed to me at some rare occasion to be my best shot at survival I'd sure give it a try.

Good on you for including breathing from your alternate. In my time I have assisted maybe 13 instructors, only one of which mentioned this. And IMO, they were all pretty good instructors.

 

[jejton]

Certification, at any level I've completed (PADI OW, AOW, Nitrox, SSI Rescue) should include more hours of practical time. Most of my training consisted of checking boxes down a list, the bare minimum instructional time, bare minimum dive time required, and handing me a card. I never ever left a class (except for my rescue class) feeling comfortable or competent. Then we are told the only way to improves skills is by diving, but repeating any skill (diving or otherwise) without some sort of feedback and correction does not really lead to improvement in skill. You can throw 1000 free throws but if you don't have a coach, or a skilled observer of some sort, you will only get incrementally better unless you are already starting at an more advanced level. This is similar to how life support classes are taught (ACLS, BLS, PALS, etc etc). The end result is that you have a lot of certified health care workers and/or lay people who possess a certification card but two weeks later are often useless, or worse, in a 'code' situation. So I guess not only would I like to see more hours required (or at least offered) but more opportunities to hone skills in a supervised setting without shelling hundreds more for it. Maybe I'm asking too much.

 

[TMHeimer]

Certification, at any level I've completed (PADI OW, AOW, Nitrox, SSI Rescue) should include more hours of practical time. Most of my training consisted of checking boxes down a list, the bare minimum instructional time, bare minimum dive time required, and handing me a card. I never ever left a class (except for my rescue class) feeling comfortable or competent. Then we are told the only way to improves skills is by diving, but repeating any skill (diving or otherwise) without some sort of feedback and correction does not really lead to improvement in skill. You can throw 1000 free throws but if you don't have a coach, or a skilled observer of some sort, you will only get incrementally better unless you are already starting at an more advanced level. This is similar to how life support classes are taught (ACLS, BLS, PALS, etc etc). The end result is that you have a lot of certified health care workers and/or lay people who possess a certification card but two weeks later are often useless, or worse, in a 'code' situation. So I guess not only would I like to see more hours required (or at least offered) but more opportunities to hone skills in a supervised setting without shelling hundreds more for it. Maybe I'm asking too much.

I agree with you on all points. CPR courses are great, but taking one every 2 years without practicing the stuff or at least re-reading it means you may be unprepared for an emergency.
Likewise, yes you must dive regularly to keep what skills you have in shape.
I agree that all courses, especially OW course, should be considerably longer. Such as the previously discussed inclusion of basic rescue skills.
I also agree that you are asking too much. Extra time beyond the hours the OW course is now means the instructors need pay to compensate. Their pay is so low now I wouldn't expect they would do it for even less. I wouldn't.
Maybe some old salts from the 70s or before could mention what the lengthy courses back then would cost in today's dollars.

 

[Blackcrusader]

When the negative aspects of breathing off a BC/ABLJ became known BSAC dropped the skill from the syllabus. Its history came from the days before SPGs and when a dive was terminated when divers went onto their reserve.

You mean like back in the 1980's when I was taught? The good 80's and J valves and such things.
Also I had the benefit of being in a BSAC club where regular training was done twice a week. That is not something people do with padi. IT's do a quick 3 day course and off to the AOW or doing some dives. There is no follow up with regular classes or retraining of skills.

The thing about an emergency ascent is that you would be in the vertical position finning upwards, no more horizontal trim in that situation and water is heavier than air so any water in your BCD will bit at the bottom of the BCD and not be sucked into your lungs. Has nobody practiced oral inflate of the BCD underwater?

Anyway for an extreme last resort measure I would use my BCD to rebreathe the air in there. Beats drowning any day and it will have usable O2, something water doesn't seem to have if you fill your lungs with it. I know it can be done. I've never been in OOA myself, but as a last resort with no buddy nearby ( As another poster mentioned people can and do get separate) I will do so. I'll leave the drowning to those that won't use the perfectly good air in their BCD. And for CPR you can use Staying Alive by the Bee Gees but for an emergency ascent I prefer Queen's Keep Yourself Alive

 

[Blackcrusader]

I have no idea about the percentages of divers who use pony bottles or are in twinsets/sidemount. It makes a lot more sense to have redundant air (something I advocate in all my courses as buddy separation does happen, even with highly trained DIR folks).

To me, redundant air is a kind of seatbelt.

That's why people are supposed to have dive buddies nearby, for redundant air, hopefully. I've never seen any recreational diver in Asia bring along a pony bottle unless they were solo certified. Others with twin tanks were normally doing deep deco dives which doesn't fit in your average no exceeding NDL recreational dives.

 

[Scuba Client]

My oddball opinion has always been that any student who "flaps around like an untrained seal" should get some comfortability in water BEFORE signing up for scuba. I know that would cut down on business. My somewhat unpopular opinion also is that if you have a lot of "water" experience beforehand, it's not such a big deal whether you're taught neutrally or on your knees. You all know that I do think neutrally is better though.

Good point but rarely spoken about by desperate dive shop owners. Their main concern is to get your deposit.

 

[Scuba Client]

You mean like back in the 1980's when I was taught? The good 80's and J valves and such things.
Also I had the benefit of being in a BSAC club where regular training was done twice a week. That is not something people do with padi. IT's do a quick 3 day course and off to the AOW or doing some dives. There is no follow up with regular classes or retraining of skills.

The thing about an emergency ascent is that you would be in the vertical position finning upwards, no more horizontal trim in that situation and water is heavier than air so any water in your BCD will bit at the bottom of the BCD and not be sucked into your lungs. Has nobody practiced oral inflate of the BCD underwater?

Anyway for an extreme last resort measure I would use my BCD to rebreathe the air in there. Beats drowning any day and it will have usable O2, something water doesn't seem to have if you fill your lungs with it. I know it can be done. I've never been in OOA myself, but as a last resort with no buddy nearby ( As another poster mentioned people can and do get separate) I will do so. I'll leave the drowning to those that won't use the perfectly good air in their BCD. And for CPR you can use Staying Alive by the Bee Gees but for an emergency ascent I prefer Queen's Keep Yourself Alive

Any Navy diver will tell you that training agencies today don't certify qualified divers. They only certify you to dive.

 

[Edward3c]

Any Navy diver will tell you that training agencies today don't certify qualified divers. They only certify you to dive.

That may be true in Australia, but not everywhere. As an Advanced Diver I'm certified to organise and manage diving expeditions; in addition to administer O2 and use an AED, not forgetting the international certificate to drive the boat

 

[lowwall]

kmarks was talking about your body can handle 2 minutes without fresh oxygen. Then he said he can hold his breath for two minutes. I think he meant he could go without inhaling fresh 02 for 2 minutes.
You don't think I (or he?) really meant we are holding our breath during a CESA, do you?

Yes, if your lungs are not completely full during a CESA, or at anytime, you can inhale. If they're full with air coming out as you say the ole ah...........during a CESA you could inhale some if now there is tank air available. If your lungs are completely full at some point you can't inhale, no? If your lungs are completely full but air is coming out because of the pressure change as you ascend, then your lungs are not completely full at that point.
What am I missing here, and what does this have to do with whether you should or shouldn't ever breathe BCD air?

I think what you are missing is that a CESA is nothing like holding your breath. The reason for this is the expansion of the residual gas in your lungs, even after an exhalation. While lung capacity is around 6 liters, you can't actually use all of it. Normal breathing only covers the range from around 2.9l (after inhaling) to 2.4l (after exhaling) of gas.

So a few seconds of ascent will increase the volume of gas in your lungs as much as an inhalation would at a static depth. The slow exhalation you should be doing will be draining off excess CO2 which will also keep you from feeling like you need to inhale.

This is why the horizontal CESA in training is a poor substitute for the real thing. IMO, they should either train with an actual vertical CESA or not do it at all, but either way they should make it clear that you don't have to worry about running out of breath if you do need to attempt one. The real concern is not exhaling as that 2.4l at 100' will turn into 7.2l at the surface. If some of that is not released into the water, you will suffer a severe injury.

Watch the sub escape video. It really brings the point home of how much excess air needs to be vented during the ascent due to expansion.

 

[boulderjohn]

If they're full with air coming out as you say the ole ah...........during a CESA you could inhale some if now there is tank air available.

That would only be true if your lungs were not full. If you somehow did expel sufficient air during your ascent and felt the urge to breathe, then, yes, you could get air. If your lungs are full, you cannot inhale.

If your lungs are completely full at some point you can't inhale, no? If your lungs are completely full but air is coming out because of the pressure change as you ascend, then your lungs are not completely full at that point.

You ascend and your lungs become full, and as you continue to ascend, they become overfilled. If you hold your breath, you get a lung overexpansioni injury. If instead your airway is open, then the excess air comes out of your mouth. Your lungs are not only full, they are overfull, and keeping your airway open allows the excess air to escape safely.

What am I missing here, and what does this have to do with whether you should or shouldn't ever breathe BCD air?

If you follow the evolution of this in the thread, it was because people like you were praising the idea of sucking air out of your BCD, and others were pointing out that there are much better, safer alternatives.