Recreational Pony Bottles, completely unnecessary? Why or why not?

[grf88]

I used to think that one of the benefits of manifolded doubles was that they provided a degree of redundancy but I have since learned from hartattack and jadairii that they are only for stupid divers that fail to monitor their gas because there is never any need for redundancy.

 

[Bigbella]

I have carried pony bottles of various sizes, for decades, and only occasionally forego their use in waters, shallower than 15-20 meters -- about the depth limit that I am willing and / or have made controlled ascents in the past.

That said, I have never personally used my pony bottles for their expressed purpose; though, other divers certainly have used my tanks, on occasion, over the years -- whether through out-of-air situations; serious entanglements, in one case; or, very rarely, mechanical failures.

I wholly recommend them, to both novices and experts alike; think of them in the same manner as you would fire extinguishers . . .

 

[scubaozy]

Every dive is different, if conditions and the dive plan are calling for it, you can use redundant gas. But I also do not think it is right to say better to have redundant gas. Selecting right equipment for the dive is also a diver skill.
I glanced through bsac incident report from 2017 (last one listed here Annual Diving Incident Report) there are few free flows but no fatalities. Most of the divers seem to cope well with free flows using the octopus from the buddy.

 

[scubaozy]

I collected all mentions of pony in the same report:
September 2017 17/251
A pair of divers were diving from a charter vessel. The first dive of the day was to a maximum depth of 5m with a total duration of 62 min. After a surface interval of 75 min the pair entered the water to dive a wreck. They descended the shotline directly onto the wreck at a maximum depth of 25m, the visibility was poor and there was a moderate current. After 8 min one of the divers ran out of air and he assumed there had been a fault. He was carrying a 5 lt pony cylinder with a second stage clipped off to a ring on his BCD on his right shoulder but could not locate it. He signalled out of gas to his buddy and was handed his buddy's pony regulator as an AS which he switched to. The pair ascended slightly faster than normal taking approximately 2 min to surface omitting any safety stops. On the surface the diver inflated his BCD and the pair were recovered by the charter boat, safe and well. During the ascent the diver realised he might have started the dive breathing from his pony regulator by mistake and once back on the boat a check confirmed this had been the case. The diver had both regulators configured over his right shoulder and they both had similar looking mouthpieces.

October 2016 17/009
A diver and his buddy carried out a boat dive and descended onto a wreck at 26m. Prior to entering the wreck they circled the area to get a good understanding of the site but approximately 5 min into the dive and just prior to entering the wreck the buddy tapped the diver's shoulder indicating he had an issue with his air supply. The diver indicated to the buddy to switch to his pony cylinder and they started a controlled ascent. At 6m the pair levelled off and the diver asked to see his buddy's contents gauge. The gauge read zero but the buddy was calm and indicated he was 'OK'. The diver immediately gave his octopus regulator to the buddy and carried out an alternate source ascent. The divers surfaced with a dive time of 12 min to a maximum depth of 26m. Back aboard the boat it became
apparent that the buddy had descended on his 3 lt pony cylinder instead of his main cylinder. Both his primary and pony
regulators looked very similar and the buddy acknowledged he had made a simple mistake which could have become critical if the pair had entered the wreck or he had panicked.

July 2017 17/189
A diver using air and his buddy using nitrox 29 carried out a training dive from a boat which would include simulating the need of extra gas 30 min into their wreck dive when a cylinder would be lowered from the boat on a 9m line for the divers to ‘use’ when decompressing at 6m. The training exercise also included a simulated surface incident when the buddy pair would state they had missed stops. The pair carried out their dive and began their ascent from 31m after one of the divers deployed his DSMB. The ascent was slow due to the diver’s small reel which he found awkward to wind and his lack of buoyancy control making him heavy on the line whilst reeling it in. The pair arrived at the 6m stop and deployed a yellow DSMB up the DSMB line as the signal for extra gas. The buddy
thought this would also be useful as the diver was at 70 bar on his main 15 lt cylinder and had switched to his pony 3 lt cylinder. As they carried out their decompression stop whilst waiting for the cylinder to be lowered the diver’s depth varied from 5m to 8m. He was also pulled up as the drop cylinder was being attached to his DSMB line at the surface, which he corrected by letting out some slack in his DSMB line. The diver’s buoyancy was further compromised when the cylinder on its 9m line came down the DSMB line, passed the pair at 6m and dragged the diver down. The buddy immediately swam to the cylinder line and pulled on it to release the tension but, realising that the cylinder was quite heavy, he put more gas in his BCD to make himself more buoyant, pulled the cylinder up and attached it by a clip to the diver’s DSMB at 6m. As the buddy had pulled the cylinder up his knife on his lower right leg had become entangled in the cylinder's line. The buddy became buoyant and lowered the cylinder in his right hand as he tried to dump air from his BCD. The buddy let go of the cylinder and, unable to dump quickly enough from his BCD, he made a
buoyant ascent and surfaced with a dive duration of 34 min to a maximum depth of 31m. He signalled to the RHIB and as it came alongside he said he had made a rapid ascent and
missed decompression. He was recovered aboard and put on oxygen. The RHIB’s crew had realised that from the
appearance of the DSMB, the appearance of the yellow signal DSMB some 8 min later than expected and the buddy surfacing alone was not the given training scenario. The diver completed his decompression, surfaced, was recovered aboard and
confirmed not to have any issues. The buddy was asked to clarify what had happened and stated that he had carried out all his decompression obligations but in dealing with the cylinder had made an uncontrolled ascent. He was assessed during the return journey to port whilst remaining on oxygen. Back ashore the buddy went to a medical centre and was given the ‘all clear’.

Conclusion: in 2 out of 3 cases, pony was the trigger of the incident (yeah I know its the diver who makes the error).

 

[jadairiii]

If you'd even glanced at the thread you'd have seen that the issue is not forgetting to monitor gas, but rather the gas not being available (like failed reg) or suddenly lost (like massive freeflow or burst hose).

Since this is a recreational dive, a "massive freeflow" would be just an inconvenience as the diver would simply surface. A "burst hose" and a regulator that fails closed are those extremely rare "what if's" events to justify bringing gear a diver doesn't need, and it assumes the diver is diving solo. Dont forget, we are speaking recreational dives, not tech dives.

I dont dive with an attached shark cage, yet, it is a possibility that I could be attacked. Plan your dive based on your own personal experience and training, if one does not believe that they could successfully surface from a certain recreational depth due to your gear failure scenarios, then dive a depth you could. Just dont strap extra gear to make up for lack of training.

 

[tursiops]

Since this is a recreational dive, a "massive freeflow" would be just an inconvenience as the diver would simply surface. A "burst hose" and a regulator that fails closed are those extremely rare "what if's" events to justify bringing gear a diver doesn't need, and it assumes the diver is diving solo. Dont forget, we are speaking recreational dives, not tech dives.

I dont dive with an attached shark cage, yet, it is a possibility that I could be attacked. Plan your dive based on your own personal experience and training, if one does not believe that they could successfully surface from a certain recreational depth due to your gear failure scenarios, then dive a depth you could. Just dont strap extra gear to make up for lack of training.

Again, you really should read the thread.

 

[jadairiii]

Again, you really should read the thread.

I should, but 27 pages....uggg

 

[Nemrod]

I am of the mind that in recreational buddy diving, no pony or redundant air supply is needed as the buddy system provides the redundancy. Exceptions to any generalization when getting specific of course always exists. An example could be photo divers, teamed up, but playing more with their cameras than paying attention to each other can and often do drift apart further than would make possible a practical air share quickly during an OOA emergency. In such case, a pony bottle might be wise or perhaps wiser to stay close(er) to your buddy team mate. Another example is group diving where divers are just together, all of them a potential buddy but none specifically assigned to each other, yes, it happens often. I can see a pony bottle useful.

But, if a diver, feels they want to carry a redundant supply, go ahead. Regardless, if you are a part of a buddy team, there is a responsibility inherent to your buddy and to the buddy system and chief among these responsibilities is providing a redundancy to each others air supply. Solo diving is a different world, the SDI Solo manuals provides guidance there and per it all solo diving should have a fully redundant air supply sufficient to the dive. Since this is not a solo topic thread, I will leave that as it is except that, sufficient is still applicable. If your going to carry a redundant supply, it needs to be sufficient to the purpose! Taking the ubiquitous aluminum 80 cf tank, it is reasonable to think that 1/3 of your air supply might be enough for an emergency. That would be 27.7 cf I think. That leaves a choice between a 19 and a 30 cf pony. For me 60 to 80 feet among other factors is the cutoff on deciding 19 vs 30. Availability also impacts the choice.

If desination diving, hauling pony bottles or setting up twinsets is not always easy to accomplish. Possible usually, but easy no. In such case, there is the buddy system properly executed. The buddy system works and IMO obviates the need for self redundancy.

If buddy diving, then buddy dive, in the fullest sense.

James

 

[Rukkian]

I am of the mind that in recreational buddy diving, no pony or redundant air supply is needed as the buddy system provides the redundancy. Exceptions to any generalization when getting specific of course always exists. An example could be photo divers, teamed up, but playing more with their cameras than paying attention to each other can and often do drift apart further than would make possible a practical air share quickly during an OOA emergency. In such case, a pony bottle might be wise or perhaps wiser to stay close(er) to your buddy team mate. Another example is group diving where divers are just together, all of them a potential buddy but none specifically assigned to each other, yes, it happens often. I can see a pony bottle useful.

But, if a diver, feels they want to carry a redundant supply, go ahead. Regardless, if you are a part of a buddy team, there is a responsibility inherent to your buddy and to the buddy system and chief among these responsibilities is providing a redundancy to each others air supply. Solo diving is a different world, the SDI Solo manuals provides guidance there and per it all solo diving should have a fully redundant air supply sufficient to the dive. Since this is not a solo topic thread, I will leave that as it is except that, sufficient is still applicable. If your going to carry a redundant supply, it needs to be sufficient to the purpose! Taking the ubiquitous aluminum 80 cf tank, it is reasonable to think that 1/3 of your air supply might be enough for an emergency. That would be 27.7 cf I think. That leaves a choice between a 19 and a 30 cf pony. For me 60 to 80 feet is the cutoff on deciding 19 vs 30. Availability also impacts the choice.

If desination diving, hauling pony bottles or setting up twinsets is not always easy to accomplish. Possible usually, but easy no. In such case, there is the buddy system properly executed. The buddy system works and IMO obviates the need for self redundancy.

If buddy diving, then buddy dive, in the fullest sense.

James

Agree with all of the points. I have never felt the need for a pony (even though several dm buddies use them on every dive), have always relied on buddies, but have a few things that are making me reconsider some sort of redundancy. My normal buddy is cheap and does not maintain his gear at all. He simply buys whatever cheap gear he can find a "deal" on. I didn't really know this until we were doing our Rescue class together and I needed to use his octo. It breathed fine out of the water, but at depth, would gurgle some water, and was really hard to breathe. Turns out, it had a tear in the membrane (or whatever the piece is inside the octo). It was not a big deal, because we were in the pool at the time, but it just made me understand that relying on a buddy (any buddy really) is more risk than knowing what you have, and how well you maintain it.

I just completed sm training, and waiting for my bcd to arrive, and plan to work on that more now for redundancy for deeper dives to have a fully redundant system and be used to using it. If I wasn't going that route, I probably would have looked into getting a pony to use just for the added piece of mind, hoping to never actually need it.

 

[Lorenzoid]

I used to think that one of the benefits of manifolded doubles was that they provided a degree of redundancy but I have since learned from hartattack and jadairii that they are only for stupid divers that fail to monitor their gas because there is never any need for redundancy.

Hartattack bowed out of the thread, but I do not recall him taking that position on doubles.