Spare Air – The Best Item in Your Scuba Toolbox

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

DiverWire

Contributor
Messages
295
Reaction score
47
Location
Arizona
By Melinda Herndon, Director eScuba Pty Ltd and Dive Instructor I purchased my first Spare Air during my inaugural year of diving…directly after a much more experienced dive buddy had an out of air emergency and scared the hell out of me by grabbing my primary and bringing me to the surface too fast.  I was so freaked out, that it took me half a minute to even sort out getting my octo in hand and it was flooded & I was too green and anxious to remember to purge, so I aspirated on the first breath. The spare air was recommended to me by a friend whose life had been saved by the thing after a catastrophic equipment failure.  I used the products provided out of the box to craft a slick behind body position for the s...
Keep reading: Spare Air – The Best Item in Your Scuba Toolbox on Diverwire.com

More...
 
Also from the article "After a decade and a half of use, I accidentally left my original spare air behind on a dive trip and decided to replace my 3.0 tank with a 1.7. "

Any recent OW grads care to do the math on how long 1.7 cft will last at say 60ft, 100ft?
 
Well, some might say a gear solution for a training issue. As an instructor, I hope you train your students better than the training you received. The Spare Air will be flooded the same as your octo was, so I don't understand why it would be a better option.

I am not a detractor of the Spare Air, I own one, but I prefer a 19cuft pony when I need redundancy. As an aside, the pony reg will be flooded as well.



Bob
--------------------
I may be old, but I'm not dead yet.
 
Also from the article "After a decade and a half of use, I accidentally left my original spare air behind on a dive trip and decided to replace my 3.0 tank with a 1.7. "

Any recent OW grads care to do the math on how long 1.7 cft will last at say 60ft, 100ft?

I am not a recent OW grad, but perhaps I can help.

In planning emergency ascents and air shares, technical divers generally assume a surface air consumption rate of 1.0 cubic feet per minute. You have to multiply that by the average ambient pressure and time to see how long that will last.

At 100 FSW, you are under 4 ATA. on your way to the surface, you will be at an average depth of about 50 feet, or roughly 2.5 ATA. If you ascend it 60 FPM, it will take you about 1.5 minutes to reach the surface. That means you will need 1 X 2.6 X 1.5 = about 4 cubic feet to get to the surface. If you switch to the 1.7 Cubic foot spare air, you should run out of air again at somewhere in the vicinity of 60 feet. That's when you go to the CESA you could have done in the first place.

You are much better off if it starts at 60 feet. (Let's make it 66 feet for easier math.) You are OOA at 3 ATA. It will take you one minute to get to the surface. That makes the math really simple: 1 X 3 X 1 = 3 cubic feet needed to get to the surface. You won't run out again and have to do a CESA until you are at about 30 feet.

Or you could just learn to do a CESA and save the money.
 
By Melinda Herndon, Director eScuba Pty Ltd and Dive Instructor I purchased my first Spare Air during my inaugural year of diving…directly after a much more experienced dive buddy had an out of air emergency and scared the hell out of me by grabbing my primary and bringing me to the surface too fast. I was so freaked out, that it took me half a minute to even sort out getting my octo in hand and it was flooded & I was too green and anxious to remember to purge, so I aspirated on the first breath. The spare air was recommended to me by a friend whose life had been saved by the thing after a catastrophic equipment failure. I used the products provided out of the box to craft a slick behind body position for the s...
Keep reading: Spare Air – The Best Item in Your Scuba Toolbox on Diverwire.com

More...
I totally agree. Best item in my toolbox. But then my divebuddy continues to feed 3 long haired cats. We're talking a virtual sea of hair balls and tumble weeds!

But no worries. SPARE AIR (tm) to the rescue! A few quick squirts and those nasty tumble weeds are sent on their way. I find it extremely convenient to keep several SPARE AIR (tm)'s around the kitchen. Tumble weed in yur eggs at breakfast? Not a problem! One quick blast drives that nasty tumbler over onto your divebuddy's plate.

SPARE AIR (tm): A thousand household uses!

Disclaimer: SPARE AIR (tm) has not proven to be effective in treatment of crabs. Do not try this at home...

P.S. Can I report my own post? I thought this was the Pub.
 
You are much better off if it starts at 60 feet. (Let's make it 66 feet for easier math.) You are OOA at 3 ATA. It will take you one minute to get to the surface. That makes the math really simple: 1 X 3 X 1 = 3 cubic feet needed to get to the surface. You won't run out again and have to do a CESA until you are at about 30 feet.

"Spare Air: when running out of air once on a dive, just isn't enough."

By Melinda Herndon, Director eScuba Pty Ltd and Dive Instructor I purchased my first Spare Air during my inaugural year of diving…directly after a much more experienced dive buddy had an out of air emergency and scared the hell out of me by grabbing my primary and bringing me to the surface too fast. I was so freaked out, that it took me half a minute to even sort out getting my octo in hand and it was flooded & I was too green and anxious to remember to purge, so I aspirated on the first breath. The spare air was recommended to me by a friend whose life had been saved by the thing after a catastrophic equipment failure. I used the products provided out of the box to craft a slick behind body position for the s...
Keep reading: Spare Air – The Best Item in Your Scuba Toolbox on Diverwire.com

More...

You could also try:

  • Monitoring your remaining gas so you don't run out in the first place.
  • Sharing air with your buddy
  • Sharing air with someone else.
  • Bringing along a suitably sized alternate air source that actually contains enough to get you safely to the surface from any point in your dive.
 
Last edited:
"Spare Air: when running out of air once on a dive, just isn't enough."
You could also try:

  • Monitoring your remaining gas so you don't run out in the first place.
  • Sharing air with your buddy
  • Sharing air with someone else.
  • Bringing along a suitably sized alternate air source that actually contains enough to get you safely to the surface from any point in your dive.
Agree, few issues should happened or serious equipment failure, that diver suddenly in out of gas situation. In normal dive with monitoring it may not happened.
Anyway simple calculation from "boulderjohn " just shows that not 1.7 cu and not 3 cu enough for 100 ft (recreation) deeps.
I think both sizes are very dangerous for 100ft deep. It give confidence for diver that he/she has redundancy air, but actually not.
Two Out Of Gas situations in one dive are too much.
If diver thinks about air redundancy in recreation dive, I think it should be 19 cu or more.
 
Don't know about the rest of you, but if I were at 100' and had to resort to using my Spare Air for whatever reason, common sense would dictate that I head for one of my dive buddies who would be no more than about 5 divers lengths away and calmly rip their primary from their cake hole whilst still breathing from the Spare Air..........but that's just me.:D
 
https://www.shearwater.com/products/peregrine/

Back
Top Bottom