spareair

[dabulltrouble]

any of you guys ever use spareair.will it get you to the surface from say 110 ft

[Reef Raider]

That depends on a lot of things better to just get a PONY like 30 cf
go to a 40% mix for the stops or if you go in to deco killing those 50lb+ gags. What got you thinking about this DT??

[Stone]

Here's a link to a page on my website that compares two ascents from 100 feet. One guy makes it, the other guy doesn't. Only difference is SAC. "Effect of Breathing Rate on a Marginal Bailout Bottle" (http://www.magnificentrelief.com/Dive%20Docs/Bail%20Out%20Final.htm).

If you do a search on "Spareair" on scubaboard.com, you'll get hours of reading pleasure.

[Steel Shootin']

Yes, I think they're affectionately referred to as "spare death" over there. Personally, I wouldn't use anything less than a 13cf for no-deco diving.

BTW, I've heard from two seperate dive shops that they have stopped carrying them due to failures and having to send them in for repairs. I'm not saying they failed on anyone in an emergency, I'm just repeating what I was told (no first hand knowledge).

[gulfdiver]

Take the bottle (pony)of your choice go down to 110ft, change over to the pony spend 2 minuets on the bottom, then make a normal assent. This will let you know for shure. MHO.

[Steel Shootin']

Stone,

Those SACs you used are pretty low for a stressed diver. Hell, my SAC is around .6 on an average dive, and up to .8 if I do something stupid like free shaft a jack (just call me "bubbles"). If I was a cave diver, I am sure I could get it down to .4 to .5, but running after fish increases it.

I think that graph shows specifically why a SPEARFISHERMAN should not use spare air, IMHO. I think our SACs are going to be higher than the average. I admit, that's part conjecture. I know some guys who make a full bottle last pretty long.

The other thing about spare air: forget even a brief safety stop. I'd like to at least be able to hang at 20 for a couple of minutes, especially if I just shot up at 60ft/min from 100 fsw. Of course, there are some oldtimers who dived their whole life coming up at 60ft/min, and didn't bother with any safety stops if they were within the no-deco limits of the dive tables. No thank you on that one.

Good job on that graph. Something to think about.

[Steel Shootin']

Originally posted by gulfdiver
Take the bottle (pony)of your choice go down to 110ft, change over to the pony spend 2 minuets on the bottom, then make a normal assent. This will let you know for shure. MHO.
I've thought of that too, however, SAC will likely be higher in an actual emgency.

[dothanfrogman]

I was once told that a Spareair had about three drags in it @ 100 fsw. I dont know about yall but that aint enough for me.

[johnhermes]

Where is G Puss when we need him?

[Stone]

Scott,

Just like it says on my website example "Imagine the result of panic on SAC."

Here's a family of SAC curves that I posted on Scubaboard, but not on my website. This graph even lets the divers ascend at 60 fpm.

[Steel Shootin']

Originally posted by Stone
Scott,

Just like it says on my website example "Imagine the result of panic on SAC."

Here's a family of SAC curves that I posted on Scubaboard, but not on my website. This graph even lets the divers ascend at 60 fpm.

Wouldn't you have to agree then that spare air, or any other 3 cf alternate air source, is about worthless (since were assuming a higher SAC)? I guess you could argue if it got you to 20 fsw you could CESA, but that's not a very cool plan. :D

[dlock]

what type of mount do you guys use for your ponytanks?

[Steel Shootin']

I have a scubaduba brand mount. They sell em at divers supply. I am thinking about clipping it off like a stage bottle, if I can figure out how to do it without screwing up my range of motion.

[greyface]

I use the "X" bracket for my 13.:D

[dlock]

dont you worry about entanglement with clipping the bottle to you? And there may be some "drag" issues too while swimming. Not sure just a thought.

[Divin' fool]

Sure seems like a stage bottle would be in the way all the time. I got so much crap hanging on me as it is.
I've seen some of the freedivers use the spare air...just in case of emergency. Just seems way too small to be a safe back up at 100'+.

[FredT]

Way back in the dark ages before the SPG made it's debut a "blow and go" ascent was taught, and regularly drilled simply by the type of diving and gear we used.

I have personally made a "blow and go" ascent (long story) from 136' starting with "empty" lungs. It was not fun, but the fact I'm typing this proves it CAN be done with proper gas management. Simply put your lung's residual volume at 100' will give you the equivalent gas of about 3 lungfulls of air as it expands. Manage that gas propelry and ESA is not too difficult.

A single breath at the start of this exercise would have been worth whatever it cost that day.

A small pony properly slung as a stage on the backplate rig rides mostly behind and under the arm along the shoulder strap line to reduce drag. The few I've seen used that way don't appear to be "in the way" once in the water but I don't personally carry one.

A SpareAir is great for getting out of flooded helicopters after an emergency water landing, and can be used to aid in the exit of a sinking ship or semi-contained toxic atmosphere (smoke filled compartment).

To expect to "breathe normally" off one on an ascent from a "deep" water dive all the way to the surface is insane. To those who believe it is a great idea, as a buddy says it's time to "pass the bong" 'cause whatever you're smoking in it HAS to be good!


FT

[Screen Name]

Thank you for your informative and entertaining posts!

John

[Steel Shootin']

I feel vindicated. See, I'm not a total moron for suggesting that I an going to try a pony rigged like a stage! And wait until you see the second stage bungied to my neck. I'm going to look like a hybrid DIR/Stroke in the same package!

By the way, Fred, sending you PM on BP info needed.

[Reef Raider]

dlock we got to take you diving with us soon you want drag how about that 50lb+ stinger I had one this week end that I could not lift off the deck for Shooter to take a pic of .

Dave what do you really want a redundent air source for???

Bail out
deco
peace of mind
put that FUNNY gas in it and take it to partys
some thing to sleep with
all of the above
none of the above

[dabulltrouble]

hey raider.went with a pony bottle,13 cui.just for peace of mind on the 100 plus dives.just in case a 1st stage ever fails.i dont have to worry about running my air down again now that i have the 100s.i didnt know anything about the spair air,i just saw a lot of them on ebay.didnt realize they werent made to bring you up from depth,but now i know.thats one thing this board is for,wright? to find out the facts before doing something stupid.thanks for the info.

[Reef Raider]

Good deal D.T. now have it 02 cleaned and fill with a 40%or 36% that way if you ever flip deco you can use it for your stops . As good as you are on air you might need it out in the M.G.

[blue gun]

Just wondering?? Has anyone ever thought about a sling-shot valve or an H-valve with two first and second stages. This is what they use for intro-cave class where you go into caves but only with one tank. As long as you don't run out of gas you are redundant. It's a lot less drag and easier to put together but again you have to watch your gas. You have to buy one for cave training but then a caver will usually never need it again after going to doubles so you can find them pretty cheap. I got one for 50.00.

When we were working with rebreathers I came up with an idea about a basic breathing loop or semi-closed circuit going through your bc and a small amount of scrubber (just for bail-out). If you ran out of air you just use your inflator hose to breath and the scruber would work like a filter.

[Reef Raider]

I thought about it but with no over head what I would want is totaly redundant air supply, and the higher mix for off gassing would seem to be a big ++++ too. As most of the dives in the GROUNDS are over 100fsw. If some one was going deeper than 150fsw I would think what you are talking about would be a good way to go , but they would still need something to help off gas or deco.