Sheri SGR
Contributor
You can view the page at http://www.scubaboard.com/forums/content.php?r=409-Redundant-Air-Systems
Article: Redundant Air Systems
- Thread starter Sheri SGR
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Nice report.
However, gear maintenance and reliability was not addressed. We have tested and used the spare air and the H2O system. The spare air is a combo 1st and 2nd stage that we found to be unreliable and a repair nightmare.
We had similar problems with the H2O system.
Moreover, the pony system gives you a complete redundant reg. that in a pinch you could use to replace your primary reg that failed your pre-dive check. Of course, you lose your redundancy.
Furthermore, the pony system lends itself to using a transmitter for computers that can read more than one tank.
However, gear maintenance and reliability was not addressed. We have tested and used the spare air and the H2O system. The spare air is a combo 1st and 2nd stage that we found to be unreliable and a repair nightmare.
We had similar problems with the H2O system.
Moreover, the pony system gives you a complete redundant reg. that in a pinch you could use to replace your primary reg that failed your pre-dive check. Of course, you lose your redundancy.
Furthermore, the pony system lends itself to using a transmitter for computers that can read more than one tank.
I'm glad you did a review.
But there are many statements in the introductory portion of the article with which I strongly disagree. And I remain convinced that, rather than spend really ridiculous amounts of money on gadgets designed to make up for poor buddy skills, people should improve their situational awareness, finning techniques, and buoyancy control so that they DON'T end dives they began as as buddies, as solo divers.
Oh, and I'm about to do a trip to MX where our gas plan involves diving single 80's . . . with slung 80's. I guess I'm not in my right mind.
But there are many statements in the introductory portion of the article with which I strongly disagree. And I remain convinced that, rather than spend really ridiculous amounts of money on gadgets designed to make up for poor buddy skills, people should improve their situational awareness, finning techniques, and buoyancy control so that they DON'T end dives they began as as buddies, as solo divers.
Oh, and I'm about to do a trip to MX where our gas plan involves diving single 80's . . . with slung 80's. I guess I'm not in my right mind.
cmulvaney
Contributor
From your Pony Bottle A Super-Sized System review:
We’re not sure our 13-cubic-foot bottle could have done that for us, but it did offer a lot of breathing time. At a depth of 60 feet we were able to get 60 breaths off our test system, although we expected to get a few more breaths than that, due to its size relative to the other systems.
In the video @ approximately the 1:00 mark you can see the air leak on the pony bottle. If your diver was down for a bit during the tests this could be why you didn't get what you expected. IMHO
Scuba Gear Reports - Redundant Air System - YouTube
---------- Post added ----------
http://www.youtube.com/watch?feature=player_embedded&v=UZRWELhst48#t=59s
We’re not sure our 13-cubic-foot bottle could have done that for us, but it did offer a lot of breathing time. At a depth of 60 feet we were able to get 60 breaths off our test system, although we expected to get a few more breaths than that, due to its size relative to the other systems.
In the video @ approximately the 1:00 mark you can see the air leak on the pony bottle. If your diver was down for a bit during the tests this could be why you didn't get what you expected. IMHO
Scuba Gear Reports - Redundant Air System - YouTube
---------- Post added ----------
http://www.youtube.com/watch?feature=player_embedded&v=UZRWELhst48#t=59s
ianr33
Contributor
Having a pony mounted to your tank, and no way to read the pressure in it during a dive is just dumb IMHO. (I didn't see an spg in the video,correct me if I'm wrong)
Ask Dandy Don how that can work out.
Found It: http://www.scubaboard.com/forums/ne...sometime-s-just-one-things-after-another.html
Ask Dandy Don how that can work out.
Found It: http://www.scubaboard.com/forums/ne...sometime-s-just-one-things-after-another.html
Last edited:
DaleC
Contributor
Honestly, I thought the article was poorly written. Your style of writing is glib which comes off wrong when attempting an analysis of safety equipment and your expressed understanding of safe diving procedures (especially the buddy system) is appalling. Oh, and I also dive occasionally with a slung Al80 - thanks for the insult.
Scuba gopher
Registered
I always dive with my 20cuft pony. It is mounted on my back next to my tank. i have installed as SPG on a hose that comes in front of me along with my regulator. I have been with divers who say that that also dive with one but they only turn it on when needed. When I go into the water i make sure my main bottle is on and my pony is on. I dont want to be out of air and having to turn it the pony on before i get air. It already is.
dumpsterDiver
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So this is what we did: after fully topping off our test RAS units using the manufacturer-recommended fill method, we took them down to a depth of 60 feet, which is generally accepted to be a typical diving depth for today’s average recreational diver. Then, after using one breath from our primary tank to clear the RAS second stage, we counted how many breaths we could get off each system using consistent three-second inhalations. Once these capacity tests were completed, we returned to our own tank, and breathing at the same three-second inhalation rate, and using, as consistently as possible in a real-world situation, a 30 feet-per-minute ascent rate, we counted how many breaths it took to reach the surface (as it turned out, it took 16 breaths).
While not scientific, and without taking into account air expansion or contraction due to shallower or deeper depths, these breath counts for air capacity taken at 60 feet, coupled with a breath count for a standard ascent from 60 feet to the surface, provide us with a picture of the relative air capacity of each system and how close to the surface each might be able to get a diver. Hopefully, this info will help you gauge whether one, all or none of these redundant air systems would suit your individual diving style.
I found the write up ridiculous! The "stuff" above sounds like a 3rd grade science fair experiment.
I've been trying to follow some of the SGR releases, but this one almost ranks up there with the glowing review of the bladed dive light...
While not scientific, and without taking into account air expansion or contraction due to shallower or deeper depths, these breath counts for air capacity taken at 60 feet, coupled with a breath count for a standard ascent from 60 feet to the surface, provide us with a picture of the relative air capacity of each system and how close to the surface each might be able to get a diver. Hopefully, this info will help you gauge whether one, all or none of these redundant air systems would suit your individual diving style.
I found the write up ridiculous! The "stuff" above sounds like a 3rd grade science fair experiment.
I've been trying to follow some of the SGR releases, but this one almost ranks up there with the glowing review of the bladed dive light...
elmer fudd
Contributor
I've picked up 4 Spare Airs over the years at an average price of $50 each and I love the things, but $300 is insane.
Primarily, they make great toys. Take one swimming in warm shallow water, (just fins, a mask and a SpareAir), and you'll have a blast. It's like free diving but without holding your breath. It's amazing how fast and effortless swimming is when you lose the drysuit and 80 lbs of gear.
I've also used them while testing vintage regulators that I have rebuilt myself. Nice to have it under my chin when my 50 year old DH with a homemade diaphragm stops breathing.
As a bailout bottle from more than 60' however I would be hesitant. I've made an ascent with one from 30' including a safety stop, but I was just testing it and was completely relaxed at the time. It had something like 4 breaths left in it at the surface. From 100', while in a panic and breathing like a Hoover, you could probably get to the surface alive, but I wouldn't want to bet on not being a little bent afterward. If you're planning on a dive that deep then why not take something with you that you can rely on getting you safely back to the surface? After all, if things go wrong at that depth you may no longer be within NDL limits.
Also, I've had a couple of repair issues with them but I was able to repair them myself both times. They aren't particularly well built, but they are simple.
Primarily, they make great toys. Take one swimming in warm shallow water, (just fins, a mask and a SpareAir), and you'll have a blast. It's like free diving but without holding your breath. It's amazing how fast and effortless swimming is when you lose the drysuit and 80 lbs of gear.
I've also used them while testing vintage regulators that I have rebuilt myself. Nice to have it under my chin when my 50 year old DH with a homemade diaphragm stops breathing.
As a bailout bottle from more than 60' however I would be hesitant. I've made an ascent with one from 30' including a safety stop, but I was just testing it and was completely relaxed at the time. It had something like 4 breaths left in it at the surface. From 100', while in a panic and breathing like a Hoover, you could probably get to the surface alive, but I wouldn't want to bet on not being a little bent afterward. If you're planning on a dive that deep then why not take something with you that you can rely on getting you safely back to the surface? After all, if things go wrong at that depth you may no longer be within NDL limits.
Also, I've had a couple of repair issues with them but I was able to repair them myself both times. They aren't particularly well built, but they are simple.
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