That is faulty thinking. The "air hog" needs to end the dive based on gas consumption using back gas and never rely on a pony for "extra" gas. A pony is used for equipment redundancy in the event of failure.
Should we get pony bottles?
- Thread starter phoenix31tt
- Start date
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
That is faulty thinking. The "air hog" needs to end the dive based on gas consumption using back gas and never rely on a pony for "extra" gas. A pony is used for equipment redundancy in the event of failure.
Mr. Black
Contributor
I never talked about money. Subcooled said "a pony filled last month..." and I just wanted to ensure that people don't take away from this that you can fill it and take it down on dives for a month without further interaction.
To be a reliable backup it needs to be tested as part of your descent check on every dive which means you will need to top it up every dozen dives or so or you may find that the one time you need to rely on it the diaphragm has dislodged or something else has happened to it that you were not aware of. In the course of these tests you will lose a few bar each dive. My 40 cu ft starts Monday mornings with 200 bar and ~25 dives later it is usually down close to 150 bar and ready for a top-up.
I have come across people on the boat who really just fill it once at the start of the season and take it down there all month long without ever testing it other than to pressurize it and read the gauge.
---------- Post added November 5th, 2013 at 03:04 AM ----------
+1. The gas in the pony is not part of the dive plan. We have a single 80 of back-gas and reserve 1/3 of that volume for contingencies. In other words, turn at 2000 PSI and be ready to climb back on the boat with 1000 PSI left. The pony is there for the unlikely event of a catastrophic equipment failure together with a break-down of buddy protocol.... And solo dives.
Solo anywhere below 80 feet you really don't want to be on a single AL80 without a pony unless you are some sort of CESA champion. It's very hard to make a civilized ascent from 100+ feet with no gas being delivered.
Diving gnome
New
Below 20m I would always have a pony. As you said you always dive in a buddy pair but consider a free flow from either a first or second stage failure on a single air source. You at this point are now totally reliant on your buddy and if this happens towards the critical part of your dive plan/profile you will be then breathing double the amount of gas as your both now breathing from one cylinder. Diving on a 12 ltr 232bar cylinder this gives you 2784 litres of gas. Go back to your training remembering your rule of thirds at this critical point you could have as little as a1000 ltr remaining. At 25m your breathing around 87.5 Ltr's of gas times 2 as your both now breathing from one cylinder = 175 Ltr's per min that gives you just over 5 1/2 minuets to ascend and incorporate either deco or safety stops............... You will be cutting it fine, to be safe give your selves that little bit extra and wear a pony.
Sent from my iPad using Tapatalk
Sent from my iPad using Tapatalk
Mike Walsh
Contributor
In open water it's a good idea . I have a 19 Cu. bottle mounted on my main tank . You do not even now it's there .
Diving industry do not teach the " WHAT IF'S " !! {1} what if you run out of gas {2} what if you get separated from your buddy & have a main stage malfunction WHAT DO YOU DO ?? Always expect the unexpected when diving . That a good diver .......
Diving industry do not teach the " WHAT IF'S " !! {1} what if you run out of gas {2} what if you get separated from your buddy & have a main stage malfunction WHAT DO YOU DO ?? Always expect the unexpected when diving . That a good diver .......
ams511
Contributor
If you run out of gas swim to your buddy give the out of air sign and get handed an octopus. If you are separated from your buddy them you are supposed to search for a minute or two and then surface. What is the probability of a first stage malfunction during those five minutes? Pretty slim. You can contrive a many different scenarios but with a remote probability so why waste valuable class time discussing them?
Mike Walsh
Contributor
My 1 St. failed on me about 7 years ago & had to make a emergency assent ..I was in 60 Ft. of water & my buddy was about 30 Ft away . Current was ripping North ..You got to make a quick desecession .. Do I try to get to my buddy make signal there is a problem & out of gas ?? Or do I make a emergency assent ??? NOW DO NOT FORGET CURRENT IS RIPPING !!!! By the time I get to him I would swim 50 + feet & make a signal..
DOES HE RESPOND FAST !!!! TIME IS AN ISSUE .. Now tell me "what would you do " ?????
DOES HE RESPOND FAST !!!! TIME IS AN ISSUE .. Now tell me "what would you do " ?????
If you run out of gas and have to look for your buddy you screwed up long before the gas ran out. unless it's a gear failure running out of gas should not happen. But if it does you make a controlled emergency ascent and you understand when your "buddy" refuses to dive with you again for being so incompetent.
Sent from my DROID X2 using Tapatalk 2
Sent from my DROID X2 using Tapatalk 2
GrumpyOldGuy
Contributor
I would type in really big, bright colored font
Seriously, if your not not in a committed relationship to you buddy (i.e. both of you stay close and aware of each other), then redundant air or staying within your CESA range is a really good idea. The OP however asked a specific question, described a reliable buddy (wife) and said they "would not travel with a pony".
Bhtmec2
Contributor
Similar threads
