Is there a valid reason for a pony bottle

[CWK]

Or, take more gas, or leave the bottom with a reasonable contingency. The way you talk about ‘the washing machine’ makes it sound like a known hazard so being delayed in your ascent is a forseable risk and ought to be factored into your plan.

That is precisely what a pony does. It allows you to take more gas for a contingency. You can factor such hazards into your plan as a contingency. A contingency for which you would require the gas in your pony. Which is precisely why I carry a pony.

 

[Gareth J]

To answer a couple of questions I missed.
(I seldom dive twinsets now, I've switched to CCR for most diving, thats slightly academic).

1. Viable Depths for a pony.
I always reckoned that deeper than 30m, I would always be on a twinset, shallower than that, a pony as the Redundant Gas Source.

2. Planning.
Gas planning should always be the worst case scenario. i.e.
- if you only dive a single cylinder. you should reach the end of the dive with sufficient gas to get yourself and your buddy to the surface safely (using an octopus).
- if you dive with a pony, You should ensure that the dive plan will allow you to surface on the pony completing any penalty you have accrued.
- Twinset. At the end of the dive you should be able to ascend with enough gas to get yourself and your buddy to the surface, one on post A one on post B, completing any compulsory decompression required.
- Twinset and decompression stage. Two options, sufficient gas to get both divers to the surface without using the stage, completing all decompression required. Sufficient gas to get to the surface with diver A using the decompression gas Diver B remaining on Diver A's back gas, then Diver A switching back to back gas and diver B taking the decompression gas.
- There is always the case of staged cylinders, team bailout etc, but thats a very different matter, and certainly not recreational diving.

In case people have forgotten, a diver should not finish a dive by emptying his/her cylinder. They should ascend with a reserve in place (most contents gauges are marked red at 50bar). The convention is to ascend with 1/3 of their gas remaining, this should (by calculation) be sufficient to get both divers to the surface safely in the event of an incident.

3. Dives I regularly used a pony.
- When Instructing
- cold water
- wreck diving
- low visibility
- drift diving
- unknown buddy
- any dive over 20m
- any dive I carried a camera
- any dive my buddy carried a camera
- any dive involving search/lift/recovery

The above are assuming I wasn't using a twinset. I would say the vast majority of dives have been either on a twinset or a CCR. There are occasions I would have preferred either a twinset, pony, or stage, these have been on warm water holidays (Egypt, Asia, and the Med - blue water diving).

Ultimately, it's a personal choice. As I previously said in the thread, there are thousands of dives done on a conventional single cylinder setup without incident.

Carrying a redundant gas source is, I think, a product of diving environment, and diver training.
It is notable, that divers who normally carry redundant gas sources (pony's, twinsets etc), will often dive single cylinder with no redundant gas source well beyond their normal comfort levels in warm blue water - sometimes foolishly.

 

[Diving Dubai]

I took delivery of my new and larger pony toda

That is not a large pony, not for areas with significant currents.

Or, take more gas, or leave the bottom with a reasonable contingency.

Precisely: Hence I dive a 15L steel with a AL 40 pony. My wife uses a 12l and Al 30 and has remarkably low SAC. We plan to be on the boat with 100 bar after an hour. There have been times where the washing machine has taken over and we've hit th boat with 30bar, and once with o less than 20 bar in both cylinders havign also spent 15 mins at 6m on 100% all because of a down current that came out of no-where on a site we were very used too.

The boats we charter for 2 and 3 day cruises aren't dedicated dive boats, so no compressors, you bring everything you need onboard. SM and Back mount doubles logistically don't work especially because transfilling for top offs mean you have less total gas volume than our large backgas and slung ponies

 

[CWK]

That is not a large pony, not for areas with significant currents.

It’s 13 cu ft. Larger than the 6 cu ft pony that I was carrying in October, and much larger than my first pony which was 3 cu ft.

I can see myself moving onto a 20 cu ft pony but a 40 cu ft would be too large to carry around on international flights. I may do sidemount at some point if I feel the need for more gas.

 

[Diving Dubai]

I may do sidemount at some point if I feel the need for more gas.

Sidemount is the way forward, especially for travelling - I take mine to every overseas destination. There are no hassles with carting an empty cylinder around to destinations

Don't look at it as more gas. The fact that you have a greater reserve is the big factor, especially in areas of unpredictable currents, The fact you'll be surfacing with 125 bar in each cylinder (assuming the same dive profile as you would have diving a single AL80 surfacing at 50 bar) is only a good thing.

Because you have way more gas than you need each dive means you relax more safe in the knowledge that your gas consumption isn't a limiting factor in any way. I love my SM, I wish I could dive it more but logistics on the majority of our dives as stated above preclude it

 

[markmud]

I don't think that I'm "lashing out". It's a conversation. Anyone can leave it at any time if they get bored or offended. I still think that it's interesting, which is why I'm bothering to type this.

New divers read these threads, so that's why I'm making these points. Not everyone dives in the same environment. Sorry if I misunderstood, but it sure seemed like you were taking issue with the idea that a redundant gas source was helpful, as a general rule, based on the very specific type of diving that you do.

Of course, there are many types of dives where a pony bottle would be ridiculous, and other types of dives where it would be woefully inadequate. If you are going to significantly limit your N2 loading and ascend after using 1/3 of your tank, then yes, a pony bottle would be less helpful.

I'm really kind of surprised that this is so controversial. If I went to the CCR forum and said that I don't need bailout because I take good care of my equipment and I meticulously pack my scrubber, I don't think that it would go over well. Is OC gear really so bulletproof that a redundant gas supply is simply superfluous?

Remember, stuff happens fast in emergencies, and the best trained people often panic and forget their training and contingency plans.

Hi Doctor Mike,

I commend you for working so hard to get Max (et allia) to open up their minds and think a little bit. From psych classes I remember some terms, "psychological moratorium" and "personality moratorium".

I am starting to think that some psychosis is present here. Either a religious type belief based on faith or a "my way or the highway, because I am an SME" attitude.

We are not going to get them to see the light.

They will keep telling us that ponies are dangerous or just useless. For them, that may be a true statement. In their own little world it probably is true.

I am like the fly that keeps buzzing the bug zapper. I keep coming back to this train wreck.

I enjoy reading your posts.

markm

 

[Diving Dubai]

They will keep telling us that ponies are dangerous or just useless.

I don't think reading this thread, people are (for the most part) really saying this.

However people seem to jump to them as a panacea for all diving issues.

Having one does not replace, the need for good buddy procedures (both predive and underwater) , the need for maintaining, taking care of and being aware of the state of your equipment, nor for monitoring your gas and diving conservatively for the given conditions.

Some people jump into one as almost a "fashion statement", taking false confidence from wearing one. They are not kryptonite and do not make anyone immortal.
A pony isn't' any use if you don't' practice, and it's use isn't second nature and can be used automatically

I use a Pony, but having it is in addition to all of the above it points. Having a pony doesn't mean I can ignore them

 

[Ryan Mcshane]

Now we know where you are coming from. We don't all h
drink the Koolaid.

LOL. A smart diver decides if this makes any sense and doesn't just parrot the kool-aid.

Koolaid? Nah, science bruh.

 

[Fastmarc]

Option #1 - Don’t Dive.

So if if what he describes is my regular dive situation, I should quit diving?

 

[doctormike]

I think that a lot of the pony pushback posts here are straw man arguments: “ponies are fine but most people who use ponies don’t use them correctly, they think of them as a substitute for good diving practices”

I’m not sure where that comes from. I mean, they are a helpful tool in some but not all diving situations, they aren’t worn to look cool or to make all risks go away. To say that they aren’t useful in one very specific diving situation is fine, but not sure why the generalization.

The OP asked about valid reasons for a pony bottle. Saying that you don’t need one for your specific type of diving doesn’t really answer that question...