Do you actually see people diving with pony bottles?

[gcarter]

I put my faith in buddy diving. 2/3 of my dives have been with my son. 90% of the rest have been with people who I know very well. The rest where I have insta buddied have not been particularly difficult dive conditions.

I will bring the stage when I believe the combination of temperature and depth creates a free flow risk. Anything 8C and above is a pretty low risk for that.

 

[johndiver999]

I dive doubles, but I really haven't been trained yet to diagnose failures and shut down valves. At my level, GUE still considers me a rec diver, and as a rec diver I'm trained to rely on my teammate to donate gas to me in the event I need it, and we're to then call the dive and ascend--for which we presumably have planned to have enough gas. So I find it odd that a dive boat would say that as an alternative to a pony I can use doubles to provide redundancy. No, my buddy is my redundancy, per my training, and it doesn't matter whether we're diving doubles or singles. As far as I'm concerned, my doubles serve as one big tank. And no, I'm not going to bring a pony along with the doubles.

Your doubles have an isolation manifold, but you don't know how to use it and would not use it in an emergency? Is that a DIR idea to use a type of gear you are not yet trained to use? I'm confused?

 

[ChristophScuba]

We required it for solo divers, and I've never met a diver from Jersey anyone wanted to dive with.

(That's a joke, son. Mostly)

 

[lermontov]

Your doubles have an isolation manifold, but you don't know how to use it and would not use it in an emergency? Is that a DIR idea to use a type of gear you are not yet trained to use? I'm confused?

yes likewise- I was somewhat surprised by that post especially with @Lorenzoid dive experience - my other question is why not just go out and practice its really not that hard ?

 

[CWK]

There is a video of someone living with a pony

 

[Wookie]

There is a video of someone living with a pony

My trimix instructor had a very similar thing happen on my third dive for class. We had just finished skills at 170 or so feet, and were in the process of settling in to finish the dive when he blew a diaphragm on his primary Apex. We watched him zoom tot he surface in a cloud of bubbles, and come back down. He wasn't on his pony, it took him an uncontrolled ascent to 100 feet before he got the post closed and his gear back under control. This was in the warm clear of Cozumel.

 

[Gareth J]

I just thought I would add this point.

Regulators failures are rare, especially mechanical failures of the first stage. However, I have had a buddy have a catastrophic failure of a first stage, as others have also discussed here.

Most problems are either hose failures. Or Free flows.
Free flows are generally occur in cold water. This is due to ice forming, either in the second stage or first stage. The ice forces the valve open.
Ice formation is due to the gas freezing any water molecules in the air within the regulator. The gas temperature drops as the pressure drops from high pressure to low pressure through the first and second stages. This is what causes the freezing. First stages are designed to heat sink, actually warm the first stage from the surrounding enviroment. An issue with the early generation of composite material first stages was they failed to conduct the cold away from the internal mechanism and where more prone to freezing.
Thinks that significantly increase the risk of freezing are.
1. Cold regulators (storing them in the car overnight in cold weather).
2. Water vapour within the air in the cylinder.
3. High gas flows. (The faster -more- gas that flows through the first stage, the colder it will get and the increased risk of freezing).
4. Breathing off the first stage in very cold weather PRIOR to submerging (The exhaled breath introduces water vapour into the second stage, which is a potential freezing point).

Point 3 is important.
Venting a first stage, for a prolonged periods of time increases the risk of free flow. i.e. Filling a DSMB.
Heavy breathing increases the risk.
AND IMPORTANTLY - two people breathing off a first stage doubles the gas flow (even if they are both relaxed - the likely hood is the Out of Gas diver will have an elevated breathing rate). This significantly increases the likelyhood of a free flow in cold water.

A point to remember - once the second stage ices open, the first stage will ice open very quickly afterwards.

I have witnessed this issue a number of times.

Example 1.
Two Pairs started a 35m (105feet) dive in a freshwater quarry in February in cold fresh water.
Pair 1 one diver had a freeflow. He switched to his buddies AS. As they started the ascent, the buddies regulators started to free flow. The second pair assisted, each taking a buddy on to their AS. One diver immediately switched from his primary regulator to his pony. All four divers commenced the ascent.
At approximately 10m the pair sharing the same first stage had another free flow. They made the surface OK.
The other pair stopped at 10m did a short stop, then ascend. One on the pony, one on his buddies AS.

After exiting, checking they where all OK, they decided that any more diving was probably not advisable, so retreated to the pub.

Example 2.
On a winter dive. I looked up at my buddy, air was slowly dribbling from his second stage exhaust port. As I closed on him, the rate of air leaving the exhaust increased. As I presented my long hose regulator, his regulator disappeared in bubbles as the first stage iced fully open. We made a controlled ascent.
We dived a bit later having swapped to a new regulator set.


This is part of the reason British divers like their Twinsets (Doubles) or Pony's

 

[Lorenzoid]

Your doubles have an isolation manifold, but you don't know how to use it and would not use it in an emergency? Is that a DIR idea to use a type of gear you are not yet trained to use? I'm confused?

I am trained to use it, but only in a certain way--as one large tank--at this juncture in my road to being fully tech-trained. I believe there are divers out there who are content to use doubles as one large tank for purely recreational dives, and per the rec protocol, simply call the dive and ascend upon a failure. (For all I know, there are some who believe they know how to do valve shutdowns and are simply not very good at it. Are they more safe than we are on this kind of dive?) Anyway, my point is that my buddy and I have our emergency protocol for rec dives down pat, and we don't need some NJ dive boat's "requirements" telling us how to dive. If it's a rec dive, i.e., direct ascent to the surface is possible, then we're good to go as far as we and our training agency are concerned.

 

[Lorenzoid]

yes likewise- I was somewhat surprised by that post especially with @Lorenzoid dive experience - my other question is why not just go out and practice its really not that hard ?

GUE makes everything hard.

 

[Gareth J]

I am trained to use it, but only in a certain way--as one large tank--at this juncture in my road to being fully tech-trained. I believe there are divers out there who are content to use doubles as one large tank for purely recreational dives, and per the rec protocol, simply call the dive and ascend upon a failure. (For all I know, there are some who believe they know how to do valve shutdowns and are simply not very good at it. Are they more safe than we are on this kind of dive?) Anyway, my point is that my buddy and I have our emergency protocol for rec dives down pat, and we don't need some NJ dive boat's "requirements" telling us how to dive. If it's a rec dive, i.e., direct ascent to the surface is possible, then we're good to go as far as we and our training agency are concerned.

I would strongly recommend that you dive your twinset as two independent cylinders, if you are not comfortable at shutting down the manifold. NEVER dive it as ONE big cylinder.

i.e. CLOSE the manifold. Dive cylinder 1 down a small way, then switch to the second, then back to the first etc.

If we use bar for pressure. Starting pressure 230 bar.
Cylinder 1 breath to 200 bar. Switch to cylinder 2, breath to 150bar. Switch to cylinder 1, breath to 100 bar. etc.
When I dived independents, my preference was always to descend the shot on cylinder 2, at the bottom, immediately switch to cylinder 1 (then i knew both where fully functional). Then do the above.

This way if you do have a failure your manifold is closed, you will only loose gas from one cylinder at worst, and should be able to make a safe ascent on the other cylinder.