Opinions on the Spare Air by SSI

[DevonDiver]

.... a small "spare air" type set up is a valid option. i do not think anyone here would be nieve enough to think that a diver can do a controlled ascent from 100 feet plus do any and all safety stops on a 3cf bottle. but it should be enough to make it to a buddy or to the surface on shallower dives....

So, in a nutshell, the Spare Air is only useful within depth ranges from which the diver could reasonable be expected to complete an easy CESA... but is insufficient at depths at which a CESA may not be a guaranteed effective option.

A bit like designing a car air-bag that only works at speeds less than 15kmph....

 

[DandyDon]

You guys remember that he did get a 6 cf.

We have plenty of other discussions about the 3 cf SA being worthless and even dangerous.

 

[DevonDiver]

You guys remember that he did get a 6 cf.

We have plenty of other discussions about the 3 cf SA being worthless and even dangerous.

SPARE AIR ASCENT CALCULATOR (xls link)

 

[DandyDon]

SPARE AIR ASCENT CALCULATOR (xls link)

The SA site Spare Air Models - 300 Standard & Nitrox and Model 170 plus Part and Accessories says that their 3 cf holds 85 liters @ 3,000psi, so on your chart it would be good for a bailout from 26m/85 ft.

SA seems to have stopped making the 6 cf, the only possibly reasonable model they had, but still - the one we are discussing here - and I presume it holds 170 liters @ 3,000psi, good for bailout on your chart from 40m/131ft. For leeway, one could still finish with a CESA.

Side not: As far as the joke of the 3 cf SA, they do make 2 dumber models: the 1.7 cf and their Nitrox model that no fill station is going to partial pressure fill and loses its O2 clean status the first time you breach it for a trip - how lame. But the OP here does have a 6 cf model he found somewhere, so he does have a good tool to assist with a fast ascent I think.

 

[DevonDiver]

The SA site Spare Air Models - 300 Standard & Nitrox and Model 170 plus Part and Accessories says that their 3 cf holds 85 liters @ 3,000psi, so on your chart it would be good for a bailout from 26m/85 ft.

That's dependent on the SAC that you use. As mentioned already on the thread, it would be imprudent and unrealistic to expect a normal SAC in the event of sudden OOA emergency at depth.

SA seems to have stopped making the 6 cf, the only possibly reasonable model they had, but still - the one we are discussing here - and I presume it holds 170 liters @ 3,000psi, good for bailout on your chart from 40m/131ft. For leeway, one could still finish with a CESA.

Again, dependent on SAC and no delays in ascent. Prudence demands the expectation of a delay to ascent, especially at deeper depths.. which is why 'Rock Bottom' always includes a 1 min 'fudge factor' at depth.

There's a factor of time allocated to 'shock'....."waaaah!"

Then another period allocated to 'emergency recognition'.... "why can't I breath? ... thump the regulator...check the SPG... that can't be right... how can I be out of air?"

Then there is 'denial'... "this can't be happening... it can't be happening to me..."

Then there is 'acceptance'...."I need to get my act together... or I might die today..."

Then there is 'problem solving'... "how deep am I? what resources do I have? what did I learn in training?"

Then there is a 'first reaction'..."where is my buddy? I can/cannot see them... can I swim to them? Can I get their attention?" [tries to get attention...fails]

Then there is a 'resolution'..."I need to ascend.... I need to use my Spare Air now".

Then there is 'preparation'.... [deploys Spare Air]

Then the ascent happens....

... in reality add "gasp...gasp....gasp" of stressed breathing throughout the duration of this....

... for some divers, the response to any of the above phases could lead to panic - Spare Air would be forgotten anyway...

For the SA to have any relevance as an emergency ascent device, the diver would need to make an instantaneous decision/reaction to ascend. My opinion is that possession of a SA would actually delay that reaction - unless the user was meticulous in drilling and rehearsing an ingrained OOA reaction, specifically utilizing the SA. From experience, the sort of diver who would have that meticulous, preparatory nature is not the sort of diver who'd either need, nor rely upon, a device like the Spare Air.

Yes.... in a perfect scenario.... the diver would instantly recognize and correctly respond to an OOA... immediate uncompromised ascent, deploy Spare Air on that ascent... regulate a slow, calm breathing pattern throughout the event.

How many divers would realistically be able to ensure that 'perfect scenario'? Are they the sort of divers who'd rely on a Spare Air?

The most critical factor in a diving emergency, especially OOA, is TIME. Gas gives you time. Time to think. Time to react. Time to regain emotional control. Time to plan. Time to problem solve. Time to ascend.

Spare Air doesn't give you TIME... it just supports an immediate ascent, that has to be done perfectly, first-time, no errors, no delays.

 

[DandyDon]

A very good, well thought & written post Devon. Personally, I never feel comfortable going deeper than 30 ft without my pony, and it amazes me that hardly anyone bothers to carry them. I like my 19 cf for recreational diving, but they do make smaller ones - and even a 6 cf is more than nothing.

Yes.... in a perfect scenario.... the diver would instantly recognize and correctly respond to an OOA... immediate uncompromised ascent, deploy Spare Air on that ascent... regulate a slow, calm breathing pattern throughout the event.

You know, it worked for me. Now I do encourage all recreational divers to breath down a tank all the way as practice, with a bailout bottle handy & ready, so they will actually know the feeling of a hard to breath reg. I knew from a prior screwup, but anyway...

When I screwed up a few years ago without my pony (got in too late to get it filled overnight) at 50 ft and hit that hard draw feeling on my reg, I took once glace at my Spg, saw the needle down, and hit a fast CESA. I actually got another breath on the way when I ascend slow enough that I ran out of lung air, and end up on top with enough air to inflate - but at the first hint of screwing up, and I knew I hadn't watched my spg like I should have, I was gone!

Then a couple of years ago when I had some confusion with my bud, gave up on him intent to follow the DM closely thru one more swim thru, left him with the DM and started a solo ascent - I hit that hard draw feeling and just calmly switched to my pony for the continued ascent and SS. All these things can be drilled.

 

[rick00001967]

So, in a nutshell, the Spare Air is only useful within depth ranges from which the diver could reasonable be expected to complete an easy CESA... but is insufficient at depths at which a CESA may not be a guaranteed effective option.

A bit like designing a car air-bag that only works at speeds less than 15kmph....

i am not sure i would totally agree with that whole statement, but i think it is fair to say.

btw......not everyone drives their car at 100mph and not all divers like to dive at 100 feet +. your equipment should make you as comfortable as possible (not lazy and forget to plan properly of course). and it should match your experience level as well as be adequate for the type of diving you do. not all gear set ups are sufficient for all divers. a tech diver, or cave diver for example will need certain gear to feel comfortable and be able to dive as safe as possible. a newly certified open water diver who is only comfortable in depths of 30 to 60 feet can be just as comfortable, and just as safe with a lot less gear. while an intermediate diver (maybe like myself) who is fine with dives up to 100 feet, with some current, maybe swimthroughs, and the odd cavern here and there might want to add a little something extra to remain comfortable while maintaining a certain level of safety. these decisions are up to each of us to judge and make for ourselves. as long as people do not rely on their back up or spare gear, and plan as if it is not there, i see no harm.
personally, i felt a 3cf was not worth the money or the hassle. so i settled for the 6cf with the right gear to upgrade later if i choose to. that is what i felt was right for me. that is what i think each diver needs to do.....what they feel is right for them.

 

[DevonDiver]

that is what i think each diver needs to do.....what they feel is right for them.

Yes, if based on an actual need - and definitive research.

No, if based on paranoia, lack-of-confidence, a skill deficit or cynical and misleading advertising.

In my day-to-day business as a dive pro, I see plenty enough disenchanted folks.... who have wasted money on something in a mistaken belief, or through lack of market research. "Awww...crap.... I wish I'd known that when I bought __________ , now I need to go shopping again..."

 

[rick00001967]

Yes, if based on an actual need - and definitive research.

No, if based on paranoia, lack-of-confidence, a skill deficit or cynical and misleading advertising.

In my day-to-day business as a dive pro, I see plenty enough disenchanted folks.... who have wasted money on something in a mistaken belief, or through lack of market research. "Awww...crap.... I wish I'd known that when I bought __________ , now I need to go shopping again..."

i would def agree with that statement. well said.

 

[matt_8777]

Thanks for all your information. I know the surface supplied air situations are different from an OOA situation with SCUBA at deeper depths. I have had the situations where my air was gone instantly several times and have stayed fairly calm. I consider myself very confident with my skills but very cautious also. I stay within my limitations. I have no cave diving training so I won't be doing a cave dive expecting 6cf to get me out of trouble. No overhead obstructions with the exception of a wreck which I am very familiar with. I am a gauge hawk so I won't ever burn my air up without being aware of it. I know the SpareAir doesn't give me enough air to do a proper decompression ascent, but in an emergency I would rather have 20-40 breaths than 0 breaths. I will be doing my divemaster training in August in Florida and will try out the "time" I have with the bottle. I will probably take 4-5 quick draws on the bottle and then try a controlled ascent to my safety stop depth. Won't be planning a dive with the SpareAir as part of that plan. I hope I NEVER have to use it in an emergency situation. Again, thanks for the input.