2nd air source question

[sologuy]

shore diving or boat diving? in most cases at 60ft, you are going to be able to make a CESA or at least have sufficient amounts of breathing gas to make a normal ascent. May not necessarily be where you want to come up, but you can. If you need to make it back from where you started, then yes, redundancy is necessary and if you're shore diving you may well need 30cf to get back to the beginning

How do you have "sufficient amounts of breathing gas" ? I said "In case of a primary air failure for whatever reason"

Your profile says your a tech instructor, so you should know a LOT more about CESA, DECO, (all dives are deco dives) than avg guy.... CESA can lead to all sorts of problems,,which I wont list...The idea of an extra air source eliminates this and is MUCH preferred... I am actually blown away you even said what you did, we are talking Solo diving...The reason we use redundancy is to give us time- gas is time correct ? A CESA allows no safety stop, no time to think, no problem solving- nothing... if your on a second dive of day, and make a CESA.... no thanks, Ill keep my pony, all 30 CF of it all day sir... BTW - No disrespect to your training or level of diving meant, I just strongly feel your answer, and further comments are misguiding people reading this as to what is safe- a CESA is never a good thing...
If I recall CESA is only suggested (in an OW manual) in 30-40 feet or less ? Id have to dig out an OLD OW manual for that fact check, Im sure its changed but I doubt to a deeper factor...I do recal a CESA was way down the list of options... anyway- lets abte this and get back to my orig question please.....

 

[tbone1004]

@sologuy I am a technical instructor, and as such I don't believe in pony bottles.

CESA per NAUI is from "shallower depths up to 60ft" which is from the instructor manual fwiw, so it's a perfectly reasonable ascent strategy if doing NDL diving in 60ft of water where that is an option. That does imply that you can make a safe ascent from that location *may not due to boat traffic or surface conditions*, and the odds of you have a failure where you are unable to get any air is incredibly small.

If you are concerned that you are going to have to make a truly OOA ascent, then you should use either an H-valve or some sort of fully redundant equipment. I will make solo dives to ~100ft in OW without any redundant equipment based on the negligible risk of a true OOA event from the equipment. If it starts freeflowing due to IP creep, then you feather the valve and make an ascent or just head on up, something we teach in overhead diving especially for sidemount. Is it a PITA? yes, but it is what it is. Worst case I do know that I can make a CESA from 100ft and the DCS risk is negligible if you're within NDL's. Embolism yes, but that's operator error.

With your 30cf, just rig it like a normal DIR stage bottle and put a piece of 1/4" bungee in a loop on the side of your backplate and sidemount it, very similar to how we sidemount bailout bottles on rebreathers and doubles.

Looks like this, though I recommend tying a bolt snap to the loop so you can clip it to your shoulder d-ring. It comes out really easily if you aren't using the pony bottle as well. Make it long enough so it barely reaches the shoulder d-ring. When you don the bottle, just snap the loop over the valve knob and you're good to go

 

[Addicted2H2O]

FWIW.....NAUI CESA as per the NAUI Rescue course is 33 ft or shallower. Per the NAUI Rescue Instructor slides:

NAUI Worldwide recommends that an emergency swimming ascent be used primarily from a depth of less than 10 meters (33 feet). If a diver finds himself unable to draw breath from the regulator, and out of position to request timely assistance from a buddy, swim to the surface at the recommended rate with the mouthpiece in place, exhaling through the regulator throughout the ascent.

 

[tbone1004]

FWIW.....NAUI CESA as per the NAUI Rescue course is 33 ft or shallower. Per the NAUI Rescue Instructor slides:

NAUI Worldwide recommends that an emergency swimming ascent be used primarily from a depth of less than 10 meters (33 feet). If a diver finds himself unable to draw breath from the regulator, and out of position to request timely assistance from a buddy, swim to the surface at the recommended rate with the mouthpiece in place, exhaling through the regulator throughout the ascent.

in the newest OW instructor manual. Unit 3, page 37
Emergency Swimming Ascent (ESA):
Emergency Swimming Ascent is done from shallower depths 18 meters (60
feet).
Look up to maintain an open airway.
Keep the regulator in your mouth.
Exhale as you ascend.
Be ready to vent the BC to control your ascent.
You will discover that the expanding air flows out from your lungs almost
naturally with very little effort on your part.

 

[sologuy]

tbone - I know some do not believe in pony bottles, heck Im a huge DIR fan so I subscribe to the thought, Im just trying to be TRULY independent... I agree with having a true OOA event given proper gas management and up to date equipment is rare, but it DOES happen (o-rings etc) so maybe the pony is as much a feel good thing (which is not bad) as anything. If I was sidemount, sure no prob, but Im spearfishing sometimes so - no sidemount. As fas as staying in DCS limits, I dive way inside intentionally for that reason. I use EAN for that reason as well, not to extend dive time but as a buffer... I just want to be safe - period... given that I do what I do, I am always pretty much solo, and tired of not diving.... so Im going solo- slow n steady... but headed that way- I appreciate your answers BTW, even though ya had me rearing back =)

 

[uncfnp]

tbone - Seriously ? On a Solo dive, your really asking ? Please dont be sarcastic in my thread please...

Tbone is genuine with his post. I am at times a solo diver and SDI Solo certified. Its by the book to always take redundancy on solo dives but my personal choice is typically no redundancy on dives that I would feel comfortable with an urgent ascent. As some say, the surface is my redundancy. And when I do a 13 or 19 is my tank of choice.

It all depennds on your skills, comfort level, risk tolerence and of course the dive conditions of each specific solo dive.

 

[Addicted2H2O]

in the newest OW instructor manual. Unit 3, page 37
Emergency Swimming Ascent (ESA):
Emergency Swimming Ascent is done from shallower depths 18 meters (60
feet).
Look up to maintain an open airway.
Keep the regulator in your mouth.
Exhale as you ascend.
Be ready to vent the BC to control your ascent.
You will discover that the expanding air flows out from your lungs almost
naturally with very little effort on your part.

I'm not doubting you by any means. Odd, though, that NAUI sort of contradicts itself between the OW course and the Rescue course. I do seem to remember it being 18 meters in the OW course when I first got certified. I'm just not certain why they would give two different recommendations. Maybe just more conservatism for the rescue course? Maybe that's a good question in the NAUI forum. I'm looking at the actual NAUI eLearning rescue course right now and it says CESA for <=33' and Emergency Bouyancy ascent beyond that because the diver may not be able to maintain consciousness.

 

[tbone1004]

@Sh0rtBus unsurprised there are contradictions unfortunately

Either way, an EBA has the same procedures as an ESA with the addition of weight ditching, but it's the same general procedure of get to surface. I don't agree with weight ditching and don't teach it from depth. No reason you should lose consciousness

 

[rjack321]

Tbone is genuine with his post. I am at times a solo diver and SDI Solo certified. Its by the book to always take redundancy on solo dives but my personal choice is typically no redundancy on dives that I would feel comfortable with an urgent ascent. As some say, the surface is my redundancy. And when I do a 13 or 19 is my tank of choice.

It all depennds on your skills, comfort level, risk tolerence and of course the dive conditions of each specific solo dive.

I don't often dive solo but I agree that redundant gear is overemphasized (especially on SB). Most of my solo diving is in caves so I have redundant stuff for that. But when I'm in <60ft of water with <NDL durations I don't bring a redundant gas source because: 1) a sudden termination of my gas supply is really implausible and 2) I can CESA if I really had to. If I really wanted a redundant supply, or for some reason a charter insisted I have one, I would probably use a 19 for that kind of dive. Or better, small sidemount 45s.

 

[sologuy]

Good stuff....