Scuba mask with tanks

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I'm glad to hear that it is possible to make a safe ascent with one of those things (given that some people will doubtlessly buy one), but I'd still rather invest in a pony.
 
3cf of air is enough to get you topside from 90fsw, useing a 30f/m accent and a 3 minute stop at 15 feet if your sac rate is about 0.29. Not a whole lot of paniced, OOA divers are going to have a SAC of 0.29. Not a whole lot of divers have a SAC of 0.29 sleeping on a deco bar.


Here are some questiosn to ask if your contemplateing buying one:

What am I trying to fix with it?
What are my alternatives?
Do they solve my problem better, easier and cheaper?

No mater how you look at it, a pony bottle is a better answer, and a cheaper answer than Spare Air. If your answer to question 1 didn't involve something like "more gas" then an H-Valve is even cheaper and easier than a pony. If it did involve more gas.. they do make tankes bigger than AL 80's. The way most ponys are used, you are likely better to get a bigger single tank with an H Valve or double up some smaller tanks with a manafold.


I await to hear UP tell his Spare Death encounter.
 
Unfortunately the general populous gets exposed [pun intended] to improbable TV programs or films like "Baywatch" that show people diving with Spare Airs as if they were REAL air sources.

Frankly, I'm not surprised that there was a posting operating on this assumption.

It's up to us to educate these people to the contrary.

So be gentle! :wink:

~SubMariner~
 
Originally posted by Goldminer
He is a scuba shop owner, instructor and experienced diver. He told me that, as a test, he used one to make an ascent from 90 ft. in the Great Lakes

instructor, experienced diver, test...

Ok... sure, with a 6 cuft bottle you can pull off 10.31 'units' with a SAC of .6. But the key there is 'test' and 'experienced'. Being a test, he probably breathed as slow as possible and was completely relaxed in the knowledge that he had plenty of gas if he didn't make it. Where when that is _all_ you have left, hitting a .6 SAC is gonna be a challenge.
 
This should probably be the subject of a seperate thread, but...

When was the 3 minute "safety" stop established?

(If memory serves me correctly)
Looking back at the US Navy Deco tables, the first deco stop after crossing the DNL was only two minutes at 10 fsw. There was "no stop" if you were under the DNL. (Feel free to correct me if I'm wrong, I don't have my deco tables here at the office).

Soooo.......the 3.0cf (or 6.O cf) could get you to surface from 60 fsw (or 90swf) without a safety stop (No, I don't recommend it but it could work). And that is better than a "direct (read uncontrolled) emergency ascent or drowning.

Jarhead
 
When faced with a situation of no buddy and no gas at 90 fsw.. would I turn down a spare death device? No. Hell it would probably even get me into a chamber ride instead of a body bag.

But, why would I ever want to put my self into that sitation in the first place?

Dive with someone whos you trust your life to.
If you must dive solo dive with a redundant system (H-Valve/Manafold).
Heck, dive with a redundant system AND a buddy. :)
Use good gas managment.


If 3cf of air will make or break you, you probably want to rethink your diveing habits. If your contemplating buying one, contemplate that $600 bucks over to something valuable like training...
 
Originally posted by JimC
If 3cf of air will make or break you, you probably want to rethink your diveing habits. If your contemplating buying one, contemplate that $600 bucks over to something valuable like training...

I paid $600 for my pony bottle and Apeks ATX-50 reg. You can easily get a pony bottle or stage bottle with reg and some way to attach it to yourself for $600. Why pay the same for 3 cu ft of air as you could for 40 cuft?

Sure, if I was Kayaking, or free diving, then it could be worthwhile, but not scuba diving....
 
Originally posted by Jarhead
Soooo.......the 3.0cf (or 6.O cf) could get you to surface from 60 fsw (or 90swf) without a safety stop (No, I don't recommend it but it could work). And that is better than a "direct (read uncontrolled) emergency ascent or drowning.

Jarhead

Yea but when choosing your life support equipment I don't think "better than nothing" is a good thing to keep uppermost in one's mind...

Much better to bite the bullet and get the right stuff the first time.

Tom
 
Originally posted by WreckWriter


Yea but when choosing your life support equipment I don't think "better than nothing" is a good thing to keep uppermost in one's mind...

Much better to bite the bullet and get the right stuff the first time.

Tom

I don't on or use a Spare Air.

That paragraph was the by-product from the question about the origin of the 3-minute safety stop. Which spawned out their gas consumption formulas. I was just curious about when the safety stop was established.

Thanks,
Jarhead
 
https://www.shearwater.com/products/teric/

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