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

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So I am off to the Caribbean for a vacation and want to do a little diving. What are my alternatives in case of an emergency with equipment.
Take my doubles with me which I don't have anyway and if I actually did I couldn't afford the weight overage.
Do a CESA.
Hope my instabuddy stays close and his rental octopus has been maintained and not dragged in the sand.
Breathe out of my rental BC which if I am properly weighted probably does not contain even one cf. air and also probably hasn't been cleaned since it was put into rental a few years back.
Pack a small pony bottle in my luggage.

Decisions, decisions, decisions. What should I do.

A diver showing up on a tropical dive op with a pony is overdressed for the occasion, shorts and t-shirt will do but if you show up with a tuxedo, who am I to tell you to what to wear?

I have summerised all mentions of pony in 2016 report as well. First case is a fatality where victim has a pony but it does not change the end result. There is 1 case where pony was useful but likely an octopus would also do. 1 case pony was actually the trigger of the problem, diver using wrong regulator. 1 case diver had pony but despite that, end result was violating mandatory stops. 1 case pony had somewhat negative impact because diver decides to not take it for the dive but gets into trouble due missing weight of it. Rest are neutral or pony is not playing important part.

August 2016 16/151
Two divers had carried out a hardboat dive to a maximum depth of 21m for a dive time of 33 min including a safety stop of 3 min at 5m. After a surface interval of 2 hours 2 min they entered the water to carry out the second dive which was a shallow drift dive on a flat seabed at around 14m. They descended to 13m on an SMB and began the dive. One of the divers approached his buddy after 5 min to show that he only had 75 bar left in a 232 bar 12 lt cylinder. The buddy could see a stream of air coming from the regulator clamp on the cylinder valve and presumed the 'O' ring had blown. The buddy immediately indicated to ascend and they proceeded to the surface with the buddy reeling in the SMB line. On the surface the buddy shouted to the diver to put his pony cylinder regulator in his mouth and inflate his BCD but the diver just stared blankly at him. The buddy continued to shout to the diver to put his pony cylinder regulator in and inflate his BCD. The buddy was holding onto the diver to keep his mouth out of the water when the diver turned toward the buddy and snatched his regulator from his mouth. The buddy switched to his own pony cylinder regulator at which point the diver snatched that from his mouth and started pushing the buddy underwater. The buddy pushed the diver away just as the hardboat reached them and the crew managed to grab the buddy at which point the diver sank below the surface. A shot was deployed at the location and a 28 min circular search conducted around the shot but to no avail. Two other pairs of divers entered the water and conducted searches for 18 min and 19 min, again to no avail. The Coastguard had been called and four lifeboats and a helicopter searched for seven hours. Two days later a team of six divers conducted a grid search of the area and located the body of the diver

June 2016 16/114
Two divers, one diving twin independent 12 lt cylinders with air and the other diving a 15 lt cylinder with nitrox 32 and a 3 lt pony, carried out a hardboat dive to a wreck in 30m. At 26 min the divers began their controlled ascent on the shotline and completed a 5 min stop at 5m and a 3 min safety stop at 4m.
They were recovered by the hardboat, de-kitted and had a hot drink. Approximately five minutes later the air diver complained of pain in his left upper arm and two minutes later indicated that he did not feel well. His buddy informed the skipper and the diver was put on oxygen but shortly after began to vomit and complained of dizziness. Another diver aboard the boat was a hyperbaric nurse and she took over monitoring and recording the diver's condition and completed a full body check for further symptoms. Because of the left arm pain and no obvious reason for DCI based on the dive profile the concern was that there could be a cardiac problem. The nurse contacted a doctor at a hyperbaric chamber and the skipper called the Coastguard to notify them of the problem. The decision was made to send a helicopter and the diver was airlifted to the chamber where he received recompression treatment over four days. The diver was diagnosed with a vestibular DCI in his left inner ear possibly caused by a PFO so he was due to undergo further tests.

August 2016 16/254
A diver and her buddy were diving from a RHIB on an offshore pinnacle where it was noted there was a long swell and some tide running. The diver decided not to carry her steel 3 lt pony cylinder. On entering the water the diver had to swim hard into the current in order to maintain contact with the shot and avoid pulling it off the top of the pinnacle whilst descending. As a result it had not been obvious to the diver that she was underweighted. At around 8m the buddy pair managed to get into the lee of the pinnacle and checked everything was OK. Due to the swell and water movement it was difficult to check their
buoyancy. The pair then explored the reef following the southern edge reaching a maximum depth of 31m. As the divers made their way back up the reef they found themselves on a small shelf at a depth of 20m but could not see the main wall and so deployed a DSMB. The pair had not incurred any mandatory decompression stops. During their ascent the diver got caught in an up-current caused by the tide hitting the reef wall and she began to ascend faster than normal. The diver tried to dump excess gas from her suit dump valve but was unable to control her buoyancy and surfaced having missed her planned safety stop. The diver was recovered to the RHIB but did not display any symptoms. She was placed on oxygen as a precaution. On returning to shore a hyperbaric facility was contacted and advised that the diver should not dive for the rest of the day. No ill effects were experienced by the diver.
 
Apologies, I hit first time to the limit, I am editing this and will not post the rest, instead I will just give the dates of the incidents so that you can find the incidents here: Annual Diving Incident Report

March 2016 16/144
March 2016 16/055
November 2015 16/010
June 2016 16/175
 
Yoke orings must be blown into sealing position by opening the valve quickly
 
Simply impossible for a resort where diving was the main attraction for more than half of the customers...
And when diving was already included in the "full inclusive" package.
On the other hand, with more than 100 tanks been used every day, a failure of just a couple or three of them (and usually on the boat) is statistically a low value. And, as proper redundancy was always employed, none of the almost 10 in-water O-ring failures happened in one month resulted in more than a minor inconvenience.
Also when proper O-rings arrived, I still did see a couple of O-ring extrusions in the following two months. A failure ratio much smaller, but not zero. Yoke O-rings sometimes do extrude, even if of good quality...
And, apart O-ring extrusions, I did see also other first-stage failures: clogged filter, air leakage from the piston O-ring, and at least three ruptures of the hose close to the first stage. In all these cases, the availability of a second valve and a second first stage allowed to solve the situation in seconds and with minimal risk. But if the second valve and second first stage had not been available, then only a pony tank could be the solution.

Thanks for clarifying Angelo. I must have glanced past the part in your original post where you mentioned the two independent first stages as a redundancy, which now that I read it again, is a great story of how redundancy can turn a potential massive air loss into an just an annoyance.

Do you think your resort would have given every divers pony tanks if your tanks did not have the capability for two regs?
 
Thanks for clarifying Angelo. I must have glanced past the part in your original post where you mentioned the two independent first stages as a redundancy, which now that I read it again, is a great story of how redundancy can turn a potential massive air loss into an just an annoyance.

Do you think your resort would have given every divers pony tanks if your tanks did not have the capability for two regs?
Well, a good question. At the time (1986) pony tanks were of common use, but usually attached to a back-mounted twin tank. The typical setup was with ARALU tanks (2x9.5 liters plus a 4-liters pony tank):

s-l640.jpg

At Maldives we did not use (nor need) such a large tank. Customers were given a 10-liters Cressi tank, and we (instructors) had a 15-liters tank, both a 200 bars, both with twin valves plus reserve:
449e213785161d456dd51319ec2a0dd5_thumb.jpg

No pony tank was available. When we had a customer who was an air hog, we did give him an instructor-size 15-liters tank, or, in the worst case, two 10 liters tanks.
At the time side-mounting was not in common use, and the BCD was the collar-horse type:
GAV-Cressi.png

This BCD had an optional small air tank in a pocket (you see its valve on the left), but we were usually NOT using it, relying just on the "power inflator".
As this BCD was not attached to the tank, it was possible to use the second 10-liters tank as a slung pony bottle. This indeed was not done for getting redundancy, but for dealing with deep dives (down to 50m and with "light" deco obligation, which, at the time, was the limit for fully recreative diving).
Although this was a procedure allowed, I did never had any of "my customers" using this additional slung tank, and in case of "air hogs" I was simply giving them a 15-liters tank, mounting the two independent regs on its two valves.
Safety is never enough, but an additional large tank attached on the side of a collar BCD results in terrible balance and trim.
There is an additional point: as DMs and instructors were carrying a tank 50% larger than customers, it was quite common to give some air to customers for completing the deco obligation without emptying entirely their tank. The rule was that, after pulling the reserve, the diver who first entered in reserve had to come close to a dive master, and possibly get his THIRD reg.
In fact dive masters were also employing an octopus, with a long hose and mounted on the left shoulder (wrong for them, but easier to use for the customer) in addition to their two main regs on the right shoulder.
The entire group did start ascending, and reaching the deco bar equipped with additional tanks. Giving air to the customer who was already in reserve ensured an additional safety for the whole group, and reduced the need of employing the additional tanks for completing the deco.
 
But if the second valve and second first stage had not been available, then only a pony tank could be the solution.
The incident from August 2016 16/151 is a fatality and the gas loss assumed to be blown o-ring. Pony did not help in this case. I would not assume it is the solution.
 
So I am off to the Caribbean for a vacation and want to do a little diving. What are my alternatives in case of an emergency with equipment.
Take my doubles with me which I don't have anyway and if I actually did I couldn't afford the weight overage.
Do a CESA.
Hope my instabuddy stays close and his rental octopus has been maintained and not dragged in the sand.
Breathe out of my rental BC which if I am properly weighted probably does not contain even one cf. air and also probably hasn't been cleaned since it was put into rental a few years back.
Pack a small pony bottle in my luggage.

Decisions, decisions, decisions. What should I do.

I do get the sarcasm, but there could be some people trying to learn on this thread. New divers should ask, before they plan what equipment they will bring or rent, what type of diving they will be doing.

Diving the "Caribbean" could mean shallow reefs close to shore, or drift dives far from shore, cave dives, deep wall dives......best to know what the dive plan is, rather than showing up and being surprised.
 
This thread began in the Basic Forum and was moved to the Advanced Forum but was started in reference to "recreational" divers. I do not understand why it is drifting off into the world of tech and planned deco and twinsets. Many recreational divers ride their computers, right or wrong, another discussion, drifting into deco perhaps momentarily while still early in the dive and with still plenty of air on hand via themselves or their buddy. I have rarely seen manifolded twinsets or independent twinsets used for recreational, sport SCUBA diving and that is the intent of the OP to discuss.

I think it's a good discussion, with some great points of view presented, though we should all be mindful of becoming "POV warriors." I believe where different people see the different gear configurations as optimal relative to rec, tech, gray areas between rec and tech, etc., is a useful, advanced scuba discussion.

Just because we have rarely seen something doesn't mean it isn't more common somewhere we don't dive.
 
While I agree with many of you that a "new" diver should never be in a position to need a pony as they should be fairly shallow and close to their buddy, however, sometimes stuff happens. I wear one quite a bit but much of my diving is kinda gray area between tec and rec. Usually over 100fsw and almost always hunting or looking for sharks teeth.

I agree that failures leading to catastrophic gas loss or the inability to access gas are very rare. I also agree that a diver should have a gas plan and monitor their gas closely. That said, with the exception of some of the divers on SB; divers are human. Sometimes you lose your buddy. Sometimes you get distracted and fail to monitor gas closely. This happens to divers of all experience levels but it only has to happen once under the right circumstances to be a problem. Having a pony in that circumstance may be the difference in reading a "close call" post or an obituary.

I would suggest that a "brand new" diver should not be in situations where they would need a pony but I would not be so presumptuous as to tell any reasonably experienced diver what he/she should carry. In a perfect world with absolute adherence to training, a pony would be unnecessary. Unfortunately, most of us don't live in that world.

Dive safe,

Ken
 
In a perfect world with absolute adherence to training, a pony would be unnecessary. Unfortunately, most of us don't live in that world.

We can strive for it, though. We can throw up our hands in exasperation and adjust our diving to the way we see it happening out there--a race to the bottom?--or we can strive to improve it for ourselves and our buddies and to make good examples for new divers. And by "improve," I mean attempt to maximize both of the goals of fun and safety. It's easy to take so much gear and prepare so thoroughly for any given dive that it diminishes the fun--ask any tech diver. The question is about finding a balance.
 

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