Should I get a Spare Air?

[turnerjd]

Mario - no problem!

In The UK PADI certifies about 70% of Open Water divers, but when it gets to advance and rescue that has fallen to about 20-30%, and they certify less than 10% of instructors at the moment.

Whilst they are big worldwide, they have had success getting people to dive in the UK, but are having big problems retaining them. In the end it comes down to cost I think. I know that going diving through a club is far cheeper than going away on a comercially booked trip. Also, the cost of further training through clubs if far less than through shops.

Jon T

 

[I GO DOWN !]

Thanx to all of you and your input, as well as many others I've spoken to, I am the owner of a new 13cf pony... while I had come to the conclusion that a 3.0 spare air would have been adequate for an emergency ascent from the depths I dive, I felt that for quite a bit less than the cost of the spare air I would have more than 4x the air available... one last question though... would you recommend I keep an octopus attached to my primary air, as well as a reg on the pony, or just stick with the pony setup??.... I guess I just dont see the point of carrying 3 regs...

 

[Rob Falk]

OK wait... let me figure this out. The spare air is going to work for me like this?

I run out of air at 100 ft. Bone dry. All in one smooth move I am supposed to: spit my reg, grab my spare air and take ONE breath, and commence a CESA. At about 50' when I feel the need for another breath, and I'm cool and calm and not exceeding 60ft/min at all, and I just take another casual sip off the ole spare air, and immdediately begin exhaling as I continue my CESA to the surface?

1. Didn't I maybe use up the entire spare air when I sucked on it at 100'?
2. At 50' if there's another breath anywhere, isn't it probably in my tank - except I don't have my reg in my mouth now...
3. Am I really only doing 60ft/m, or am I more like a rocket approaching escape velocity? Maybe I'd do better if I just didn't inhale...

Just wondering. If the "extra breath in a deep CESA" is the only scenario under which spare air is thought to aid a diver, I think I'd pass

Watch your gauge, enjoy the dive, watch your gauge.

 

[Mario S Caner]

Hello Rob, welcome to the boards.

Now let's get down to business. How is it you can possibly get just one breath at 100 feet I do not understand. You are supposed to be able to get 48 breaths on the surface (1ATM) which would mean that amount of air (3cuft) will yeild 12 breaths at 99fsw (4ATM). Even if you were to argue that you could take a 50% larger breath of air than anyone else... That would still give you around 8 full breaths to get to the surface. At an ascent rate of 60fpm, it should take you 1 min 40 seconds to reach the surface. That's a full breath of air every 12.5 seconds if you "hoove" it up or a full breath every 8.3 seconds if you relax more.


I GO DOWN, Yes it is a good idea to carry your octo in addition to the reg on the pony bottle. I choose to carry an analog gauge on my 30cuft pony as well. The key to survival at depth is practice, the right gear and redundancy.

 

[turnerjd]

Mario,

There are many definitions of a breath. If you want to get the lowest volume, (or the largest number of breaths of a fixed volume) you quote the mean tidal volume. This is the volume of a normal breath.

If you want the largest volume, ie the lowest number of breaths, you quote the reserve volume.

This is basically the difference between taking normal resting shallow breaths (which will be what spair death advertise) and deep heavy breaths during exercise.

RMV is about 400-500ml
Max vol is about 3000-4000ml

So, the 48 breaths advertised by Spare death could be as little as 4.8 breaths for someone that is breathing to their maximum. (normally

Its just a matter of definition. you choose how to define a breath. just don't tell people you are using the smallest.

Jon T

 

[dsquid]

And a pony bottle or spare air is just a band aid for poor dive planning and poor skills. Except for as I stated above, in an instructors capacity or DM.

Nobody plans to run out of air. Be it stupidity, entanglement, equipment malfunction, or distraction. The particulars are unimportant.

Having a backup air supply is a *really good thing*. I hope I never have to use mine, but I'm glad it's there.

The poorest dive planning, the poorest display of "skills" is to be so confident in your ability or planning that you think that an OOA situation cannot happen to you.

Bill

 

[neil]

To all:
I have read this post and there's some interesting ideas. A wise man once said, "a single measurement is worth a thousand guesses". I am an instructor (NAUI and PADI) and to be able to answer the question about Spare Air I took one, filled it and sucked it dry in the shop showroom. 30 breaths my a**! I got 12. Now, I'm a big guy, and I breathed hard to simulate some "uneasiness" but that's still not a lot of air at 100'. Conditions during an out-of-air emergency would have to be pretty much ideal to safely and comfortably ascend with a Spare Air. "Safely and comfortably" includes a safety stop in my book. If you're looking for backup for anything except shallow diving, get a pony bottle, IMHO.
Neil

 

[Black Halo]

Just a question about a pony bottle setup.

Are you just carrying a 1st and 2nd stage regulator set on top of a smaller bottle?

or

Is there a different setup for a pony bottle (1st stage integrated on the pony bottle)?

 

[mark hamon]

Hi everybody

Its good to see divers displaying common sense, I personally congradulate everyone who prefers a pony bottle over spare air. I was in the Royal Australian Navy as an aircraft technician, I had played with the HEDS bottles (spare air units)and they are only designed to be operated by the navy aircrew to escape from a sinking helicopter, that is most oftenly just below the water line by a few metres. The navy only recommends using them at almost surface level just to escape a sinking aircraft.
Since leaving the navy I have been doing a batchelor of nursing degree here in Australia, where in my final semester I am focusing all my research, literature reviews, health promotion assignments on diving injuries, What kills people more than anything is PANIC, the psychological security of breathing through a PONY bottle that resmebles your main rig is more comforting than breathing through something thats a little bigger than a pregnant aluminum straw. When you panic your body speeds up and the air pig takes over. Considering it only takes 3 minutes to drown and I would put that even less than a minute in people with no air panicing at 30 metres its nice to have a unit with more air than required. I spent a few dollars extra and bought a 100 cubic foot steel cressi sub tank, than the standard 85, my gauges are sherwood so I know they are reliable, I see the larger 100 cubic foot tank as an 85 cubic foot with with its own built in 15 cubic foot spare air. I have made my own pony bottle with reliable parts, I had a brand new steel bottle and bought a smaller reg hose kit not as bulky as the conventional ones used on the main tanks from an english diving manufacturer. this unit gives me heaps of air with the reliability of a pony but not as big. This unit uses stainless steel rings and quick release system for instant use.

 

[Iguana Don]

During all of these out of air situations that have been described........where is you buddy?

ID