View Full Version : Set Ups'
Chris aka divingchef
24-03-2006, 19:57
Hi all
To follow on loosly on the "freeflow" theam, the recommended set up here is the cylinder with a "Y" pilar valve. So 2 first stages are required along with the 2 second stages.
The upside is that if one should need one's buddies octo you can be assured that as there is only one first stage the delivery of air will be ok.
The downside is that if a first stage should "pop" it's nearly imposible to isolate it before it runs out, so good buddy practise is required.
The other downer is the cost of purchasing two first stages, I wonder who thought that one up !
Personally I will stick with my pony up to 30 mtrs !
David Walker
24-03-2006, 21:15
Recommended by who? I'm guessing the Y valve isn't considered nearly so important if you've got a pony, since thats providing far better redundancy than a Y valve anyway.
Wouldn't worry too much about it, thousands of divers over here manage just fine without a Y valve, so unless there's some rule saying you HAVE to have one, then if you're happy without then personally i'd keep it that way :)
David
Adrian Kelland
25-03-2006, 09:45
Recommended by who? I'm guessing the Y valve isn't considered nearly so important if you've got a pony, since thats providing far better redundancy than a Y valve anyway.
Wouldn't worry too much about it, thousands of divers over here manage just fine without a Y valve, so unless there's some rule saying you HAVE to have one, then if you're happy without then personally i'd keep it that way :)
David
Hi David,
Did anyone recommend a cylinder with a single valve to you? I suspect not and you got your first because that is what everyone else has over here.
In parts of Europe I have been to, the Y valve is pretty common. So much so that a couple of French members in my club bought Y valve cylinders straight off. Definitely a YMMV issue.
Adrian
Hi all
To follow on loosly on the "freeflow" theam, the recommended set up here is the cylinder with a "Y" pilar valve. So 2 first stages are required along with the 2 second stages.
The upside is that if one should need one's buddies octo you can be assured that as there is only one first stage the delivery of air will be ok.
The downside is that if a first stage should "pop" it's nearly imposible to isolate it before it runs out, so good buddy practise is required.
The other downer is the cost of purchasing two first stages, I wonder who thought that one up !
Personally I will stick with my pony up to 30 mtrs !
Interesting comments.
Firstly about isolating, plenty of people can isolate quickly with a Y valve. Loads of people regularly practice isolating with twinsets and the Y valve is in about the same place as the Y of a single setup. So this should not be a problem for a diver in practice with a normal range of movement.
Secondly about the cost: Single and Pony = two first stages and three second stages, two cylinder servicing bills. Y valve = two first stages and two second stages, one cylinder servicing bill. So actually cheaper to dive the Y valve. Also most people with Y valves seem to dive a 15 so you have slightly more cost than the "standard" 12, but you save the cost of the pony so the cylinders will be less to buy as well.
I think there are disadvantages to a Y valve setup (more complex hose routing, higher skill level required in order to do shut downs, vunlnerability to cylinder neck O ring failures, etc.) however I think the two you mention are not problems.
Interesting comments.
I think there are disadvantages to a Y valve setup (more complex hose routing, higher skill level required in order to do shut downs, vunlnerability to cylinder neck O ring failures, etc.) however I think the two you mention are not problems.
One reason that Y valves are popular on the contintent, is that in some countries (france for example where I worked), an instructor has to have two first stages.
A 6 metre try dive / 10metre shore dive is a pleasure on a 10 with a Y value, rather than the hassle and weight of a twin or pony (or a bouteille enfant- i.e. we used ponys in france for the kids !)
Most incidents are human error, not equipment anyway. I often take a pony because I can't be bothered to reconfig my (twin set) gear, I don't think it is any safer having a pony than a single on a 10 metre dive.
Tony
Chris aka divingchef
25-03-2006, 15:10
Recommended by who? I'm guessing the Y valve isn't considered nearly so important if you've got a pony, since thats providing far better redundancy than a Y valve anyway.
Wouldn't worry too much about it, thousands of divers over here manage just fine without a Y valve, so unless there's some rule saying you HAVE to have one, then if you're happy without then personally i'd keep it that way :)
David
Hi Dave
Just to clarify as I've been a bit vague.
The actual recomendation is for divers to have two indepentant set of regs, and aperars in the spanish diving legislation. I can point you to the right link if you want ?
So most divers over here opt for this and also, more to the point they are whats available.
Chris
Ben Panter
25-03-2006, 19:39
Pretty common in Germany - and it's what we teach with on the ice diving course.
Ben
Recommended by who?The techie agencies tend to recommend Y and H valves as the minimum level of gas redundancy.
I'm guessing the Y valve isn't considered nearly so important if you've got a pony, since thats providing far better redundancy than a Y valve anyway.Common misconception amongst UK divers that one.
A Pony offers less redundancy than a dual outlet valve on the main cylinder. The dual outlet valve allows all gas in the cylinder to be made available in the event of a single (regulator) failure - providing you isolate.
E.g:
15Ltr + dual outlet: Your reg fails with 110bar left. You lose 20 bar isolating, leaving 15Ltr x 90 bar (1350Ltrs) available.
15Ltr + pony: Your reg fails with 110bar in the main. You only have access to 3Ltr x 232 bar (696Ltrs).
So the pony offers less gas redundancy. It's basically a redundant reserve (1/3 of 10Ltr, 1/4 of 12Ltr, 1/5 of 15Ltr) and you can not adjust the reserve according to the dive.
Pony cylinders have a couple of dubious advantages over dual outlets:
1. You don't need to learn to isolate
It's not difficult. Just needs practise.
2. You don't rely on a single point of failure at the neck o-ring
People tend to fit octos to the main, because of the pony's limited capacity...which introduces a whole raft of additional failure points which are far less robust than a cylinder neck o-ring and sort of defeats the object.
Makes me wonder why we are so wedded to 3Ltr ponys over here, the Euros have it right IMVHO.
Nigel Hewitt
30-03-2006, 16:25
Makes me wonder why we are so wedded to 3Ltr ponys over here, the Euros have it right IMVHO.Only if you load the numbers by postulating an ultra rapid shutdown when you have a lot of gas left.
The poor old pony comes in for a lot of stick but it always delivers what it has on the SPG. It won't do for deco diving but for ordinary nostop diving it converts a desperate race to isolate into a resigned shrug followed by an ascent. 3/232 is masses of gas to get out of a dive unless you postulate a huge panic which, if you have a pony, you don't do.
I can't reach to shutdown on doubles so I wouldn't have a chance on a Y-valve. Also figuring which valve to turn, behind my head with a frightening wooshing going on would add to the fun.
Martyn Ward
30-03-2006, 22:27
Pony cylinders have a couple of dubious advantages over dual outlets:
1. You don't need to learn to isolate
It's not difficult. Just needs practise.
How can an advantage be dubious :confused:
Wether you dive with a single and Y valve or a single and pony is irelavent, surely? What matters is being able to get out of the s**t if you get in it and as Nigel H says, a pony does just that.
Personally, if my primary lets go, I'm quite happy to switch to the pony and head upwards, because in the event of a problem, the surface is the place to be for me. Incidentally, my little pony NEVER gets wet unless it's showing well over 200 on the SPG, (ooh, an SPG? not very DIR isn't that :D ). As I use it regularly at home to, err, inflate things :o , I'll quite happilly pay to top it up before a dive. Call it "peace of mind".
Martyn.
How can an advantage be dubious :confused:An advantage of a large DSMB is that you can ascend and hang negative. Learning to ascend and stop neutral is safer though. An advantage of a manifolded twinset is that you don't have to change regulators. You still need to do it when something goes wrong though. So these are dubious advantages. Accepting the limitations and disadvantages of a pony rather than learning to isolate is also dubious.
Wether you dive with a single and Y valve or a single and pony is irelavent, surely?I dived with a pony alongside my single 10Ltr and 12Ltr for a few years - this was before 15Ltrs got so popular. The dives were limited by the capacity of the main cylinder and the pony provided a useful 1/3 or 1/4 redundant reserve (70 or 60 bar). Next to a 15Ltr the reserve provided by a pony starts to look stretched (49 bar). The 15Ltr main cylinder is potentially capable of going futher than the pony can get you out of.
Cases of divers breathing from the pony when entering the water and running OOA shortly after reaching the bottom are a regular feature in the annual incident reports. Similarly, divers have run OOA and swapped to their octok, rather than their pony. Others have given their octo to an OOA buddy and had the 1st stage go into free-flow due to the increased demand - the HSE recently recommended all divers carry a redundant breathing system to avoid this particular risk. None of these risks are present with a dual outlet equipped single set up.
The fact people have died and similar less tragic incidents occur regulary as a result of risks introduced by using pony cylinders is very relevant AFAIC.
What matters is being able to get out of the s**t if you get in it and as Nigel H says, a pony does just that.Absolutely agree. I responded to the claim that pony's offer better redundancy than dual outlets. Comparing like for like, they do not.
You do need to isolate a dual outlet rapidly, the same as you need to isolate a manifolded twinset rapidly. Nigel neglected to mention that he has an old shoulder injury (IIRC) and inverted his twinset because of it. Desperate rushes to do anything underwater tends to indicate a lack of practise IMVHO. I find H and Ys much easier to shut down than the pillars on my twins. I used to be suspicious of dual outlet valves until I used one in France. I went with the intention of assembling an indi twinset for the deeper dives. After using a Y valve on the checkouts I was so impressed I used a Y equipped single 18Ltr for the workups and deepies.
(ooh, an SPG? not very DIR isn't that :D )Neither am I :D If you have thought about the alternatives and made your choice accordingly absolutely fine by me. Personally I would have liked to have been told about the alternatives.
Next to a 15Ltr the reserve provided by a pony starts to look stretched (49 bar). The 15Ltr main cylinder is potentially capable of going futher than the pony can get you out of.
This is called planning (bad in this case). A pony does a good job in the right circumstances. Taking it beyond what it can safely get you out of is stupid. People can be stupid however their kit is rigged
Cases of divers breathing from the pony when entering the water and running OOA shortly after reaching the bottom are a regular feature in the annual incident reports. Similarly, divers have run OOA and swapped to their octok, rather than their pony.
Again bad planning, if a pony is rigged correctly neither of these is possible. When I used to dive a single and pony the pony reg was necklaced same as my backup is now. Do that and there can be no confusion which reg you are breathing. The same is true of a side slung pony. There are of course other ways of rigging a pony that are equally safe.
Others have given their octo to an OOA buddy and had the 1st stage go into free-flow due to the increased demand - the HSE recently recommended all divers carry a redundant breathing system to avoid this particular risk. None of these risks are present with a dual outlet equipped single set up.
But with a properly setup buddy pair both with ponies then the buddy does not need the octopus so the issue does not arise.
The fact people have died and similar less tragic incidents occur regulary as a result of risks introduced by using pony cylinders is very relevant AFAIC.
Yes it is relevant in the same way as introducing any new kit and using it incorrectly is relevant.
The bottom line is a muppet is a muppet what ever kit they are using, be that an incorrectly planned and used pony or a Y/H valve that they can not shut down. It is not appropriate to knock a piece of kit just because it is sometimes used incorrectly when that kit can be a life saver if used correctly.
Thats why i just got a 7L as my pony, lol.
1470L of gas (with 20 bar reserve) in case of a bailout situation, am not really gonna need much more than that if it all goes fubar at 25m.
The whole diving reliance on buddys is overrated. I think if you cant get yourself out of some dodgy situation on your own, then you shouldnt really be diving anywhere but a swimming pool.
I think i sway more towards diving with a buddy but following some of the principles of cave divers, ie, your kit is your life, if you screw it up, you lose it. The only time you should rely on your buddy is if you have no other option.
Ben Panter
31-03-2006, 17:16
The whole diving reliance on buddys is overrated. I think if you cant get yourself out of some dodgy situation on your own, then you shouldnt really be diving anywhere but a swimming pool.
Rubbish.
There are a whole host of situations where a buddy can rescue you which you will not be able to deal with on your own. I have in the past dived without a buddy, and perhaps will again, but not to acknowledge the facts is sheer stupidity. You can have all the gas / equipment redundancy you want, but there are situations where it won't help you one iota.
What are you going to do if you black out due to a dodgy fill?
What are you going to do if you slip on a rock on entry and knock yourself out?
What are you going to do when you get completely tangled in monofilament and can't even reach your snips?
There are far more potential pitfalls in diving than running out of air.
Ben
As far as im aware, you dont dive if the gas tastes off, or it gives you any weird sensations. I tend to get a good few deep breaths in before i dive on air and if it tastes off or theirs anything weird going on with it i dont dive on it.
I cant say i'd be using a slippery rock entry either. Been their already and i didnt enjoy having to crawl into the water.
Monofilament situation i believe is part of most cave diving training, except they switch your air off while your tangled. And if you cant reach a knife or line cutter then your configuration is wrong.
As it goes im not totally slating buddys, im just saying that their are times when being able to sort out your own problems without their help is better. Whether its air, or caught in lines, testing your gas at the start of the dive (or calling the dive if you have a problem after starting the dive).
I know what your saying Ben, but i dont totally agree.
Ben Panter
31-03-2006, 18:35
As far as im aware, you dont dive if the gas tastes off, or it gives you any weird sensations. I tend to get a good few deep breaths in before i dive on air and if it tastes off or theirs anything weird going on with it i dont dive on it.
If there is carbon monoxide in there (from compressor exhaust fumes for example) you won't know about it till you get a bit dizzy and then fall unconscious, then die.
I cant say i'd be using a slippery rock entry either. Been their already and i didnt enjoy having to crawl into the water.
So you've already identified a situation in which a buddy would be appropriate. That's good.
Monofilament situation i believe is part of most cave diving training, except they switch your air off while your tangled. And if you cant reach a knife or line cutter then your configuration is wrong.
No. Monofilament is unlikely to be found in caves, as it is a type fishing line. You have a hard job seeing it, because it's transparent and very, very thin. It's also very, very strong. You will not break it with your own strength, or by inflating your jacket. I wear a pair on snips on both arms, and have still needed assistance to get out the stuff. The problem is that you don't know you're in it till it's too late, and then if you're unlucky, every move gets you in tighter. It's found on lots of wrecks around the coast.
As it goes im not totally slating buddys, im just saying that their are times when being able to sort out your own problems without their help is better. Whether its air, or caught in lines, testing your gas at the start of the dive (or calling the dive if you have a problem after starting the dive).
Not quite. What you said was:
The whole diving reliance on buddys is overrated. I think if you cant get yourself out of some dodgy situation on your own, then you shouldnt really be diving anywhere but a swimming pool.
Which, together with your comments on another thread, worried me sufficiently to point out that a buddy, especially in the first couple of hundred or so dives, is critical. Not just from a gas planning situation
Incidentally, after those first couple of hundred or so, you may have accrued enough brown trouser moments to decide that having a buddy from thereon is also useful.
Ben
I've so far had one such moment.
Diving to 25m (if i'd followed the group i'd have been at 30m+) when i was qualified to 20m, on my fifth ever open water dive, in cuba, in the sea, abandoned by my group/buddy. My resolution, ascend to 20m, do a slow ascent to 10m, potter around and watch fish and cudas for 20 mins, ascend to 5-6m for a 10 min safety stop and surface. It scared me for all of 10 secs, then i didnt really care after that.
Sixth dive i did similar but i found someone also qualified at the same level and we messed about at 18-20m for 30 mins before doing an ascent.
So far i havent made it to wreck diving, and when i get that far i'll add a wreck diving/penetration qualification to my current array, and maybe get some dives in with people who do dive profiles that include that type of thing. I'm not just going to go dive a wreck on my own, im not crazy (yet).
If you wish to discuss the other thread, lets do it on pm. I've hijacked this thread enough.
Martyn Ward
31-03-2006, 21:14
Rubbish.
There are a whole host of situations where a buddy can rescue you which you will not be able to deal with on your own. I have in the past dived without a buddy, and perhaps will again, but not to acknowledge the facts is sheer stupidity. You can have all the gas / equipment redundancy you want, but there are situations where it won't help you one iota.
What are you going to do if you black out due to a dodgy fill?
What are you going to do if you slip on a rock on entry and knock yourself out?
What are you going to do when you get completely tangled in monofilament and can't even reach your snips?
There are far more potential pitfalls in diving than running out of air.
Ben
Ben, at first I thought what a load of cobblers you'd written but when I checked your profile and saw your age, the penny dropped. As you're obviously a product of the abhorrent "nanny state" that we have to suffer these days, you place great faith in a system that absolves you of blame or responsibilty, ie: the buddy system.
Being a shade older than your good self, I consider myself very fortunate to have been brought up to think for and look after myself AND to be responsible for my own actions and hopefully, this carries through to my diving. Is it not better to enter the water happy and relaxed with the knowledge, experience and eqipment that you can get yourself out of the poo rather than rely on someone else's abilites?
On the other hand, you could rely on a buddy and give yourself one of MattS's "dubious advantages" :D and to be honest, I have in the past dived with people who weren't really fit to walk down the street on their own, let alone dive!!
None of which has anything to do with the original thread, just me having a rant :mad:
Apologies one and all and, errr, carry on!
Martyn.
Alan Ewart
31-03-2006, 21:26
Rubbish.
There are a whole host of situations where a buddy can rescue you which you will not be able to deal with on your own. I have in the past dived without a buddy, and perhaps will again, but not to acknowledge the facts is sheer stupidity. You can have all the gas / equipment redundancy you want, but there are situations where it won't help you one iota.
What are you going to do if you black out due to a dodgy fill?
What are you going to do if you slip on a rock on entry and knock yourself out?
What are you going to do when you get completely tangled in monofilament and can't even reach your snips?
There are far more potential pitfalls in diving than running out of air.
Ben
Maybe Ben, Maybe. There are also a whole load of situations where redundancy will get you out of the Poo when a buddy won't.
Ever lost a buddy on a dive Ben?
What happens if you do and it all goes horribly wrong....
Ben Panter
01-04-2006, 09:32
Ben, at first I thought what a load of cobblers you'd written but when I checked your profile and saw your age, the penny dropped. As you're obviously a product of the abhorrent "nanny state" that we have to suffer these days, you place great faith in a system that absolves you of blame or responsibilty, ie: the buddy system...
Not quite sure where you get the impression that I wish to be absolved of responsibilty. Load of tosh. Anyway, to clarify:
I'm all for personal responsibility, in all things in life. I also prefer to dive with as much self-reliance and independence as possible. However I also accept, and was trying to illustrate, that there are some situations where no matter how much air or whatever else you have with you a buddy would still be useful. Bad Things Happen - fact of life - and having extra tools availiable to you when it does is a good thing.
Sure - I've done plenty of dives where I've hardly even seen the buddy, or they've been a liability. In that situation you're practically diving on your own - in fact many times when teaching too. It's a situation that I am, in general, fine with - I trust myself and my chosen kit to get me out of most things. I also accept that the situations I outlined a few posts back are then more likely to end in severe problems without a buddy.
Ben
Ben Panter
01-04-2006, 09:46
Maybe Ben, Maybe. There are also a whole load of situations where redundancy will get you out of the Poo when a buddy won't.
Don't get me wrong. As mentioned in the other reply I'm all for self-reliance and independence, and a buddy is certainly not a panacea for all diving problems. All I'm trying to do is point out that there are a number of situations where they have their uses.
Ever lost a buddy on a dive Ben?
What happens if you do and it all goes horribly wrong....
Of course, yes. I've also done dives where I didn't take one with me. In that situation I hope I have the right kit and mentality to get out of the problems that may occur, while accepting that there is now one less tool in the toolkit for sorting out whatever problems may occur.
Ben
(and yes, working that analogy further there are certainly some buddies who I've dived with who have been complete tools :rolleyes:)
This is called planning (bad in this case). A pony does a good job in the right circumstances. Taking it beyond what it can safely get you out of is stupid. People can be stupid however their kit is riggedThis points interesting because we now teach maintaining a 1/3 reserve from OD upwards. Next to a 15Ltr cylinder a 3Ltr pony is only 1/5th. So one interpretation is that a 15Ltr + 3Ltr is never the correct circumstances. Yet it's still a very common configuration within BSAC clubs.
Don't disagree
The bottom line is a muppet is a muppet what ever kit they are using, be that an incorrectly planned and used pony or a Y/H valve that they can not shut down. It is not appropriate to knock a piece of kit just because it is sometimes used incorrectly when that kit can be a life saver if used correctly.I am not knocking the humble pony cylinder. I was just trying to dispell a misconception...and wondering why people get so protective of a 3 ltr cylinder. If you want to use a pony use one.
There are some interesting thought processes that go on where ponys are concerned though;
I want access to my main cylinder so I will fit an octo increasing the risk of the most common gas failure (2nd stage freeflow)
I will side sling it because backmount upsets weighting
I will bungee the reg into my side sling because the hose is not long enough to allow the 2nd stage to be stowed effectively
I will turn the valve off because the purge is exposed because it's side slung
Because my pony is side slung I now believe being able to hand off a 3Ltr pony to an OOA buddy is an advantage
I will maintain a 1/3 redundant reserve except on deeper dives because I want to breathe more from the main to get a decent bottom time
I will run my 2nd buoyancy from my main because I do not want to deplete my bail out..although oral inflation at depth will probably deplete it more
I will not check my bailout is full because the dive shop charges for the fill
I will fill my bailout with 50% because I did a combined course and now want a safer decompression and I read on the internet that it's fine to exceed the planned Max PPO when there is an emergency as long as you don't breathe it too long.
OK my tounges in my cheek a little but all of these potential debates/mistakes go away with a dual outlet valve - at the cost of having to isolate.
I guess it is easy to read incidents and think 'They were a muppet. I am far too good' Well no one gets in the water thinking they are about to injure or seriously upset themselves. Incidents afflict experienced divers as well as the inexperienced. Take what you want from that fact but I tend to think we are all capable of a bit of muppetry from time to time...or maybe it's just me then ;)
Don't get me wrong. As mentioned in the other reply I'm all for self-reliance and independence, and a buddy is certainly not a panacea for all diving problems. All I'm trying to do is point out that there are a number of situations where they have their uses.With you completely on that one. A buddy can make the difference between mere embarrassment and positively life threatening. A point not lost on me when the pair descending the shot behind me dragged the line over my manifold looping round the isolator leaving me strung up like a chicken. I could have cut the line, I might have been able to create some slack to disentangle. As it was my buddy unhooked me in 2 seconds...oh how we laughed!
Chris aka divingchef
02-04-2006, 12:04
[QUOTE=Chris aka divingchef]Hi all
To follow on loosly on the "freeflow" theam, the recommended set up here is the cylinder with a "Y" pilar valve. So 2 first stages are required along with the 2 second stages.
The upside is that if one should need one's buddies octo you can be assured that as there is only one first stage the delivery of air will be ok...............................]
__________________________________________________ ____________________________________
Morning all
Not really sure where to tag this one on to so here goes !
Firstly thanks for all the contribuitions, certainly a lot to think about.
Secondly; a case of suck it and see, I tried both the "Y" & "H"
The "Y" was fine in reaching but the right hand side knob turned the opposite way to the left and I managed to jam it open.
Yes I can hear you all saying "skills, skills, and more skills"
The "H" was a challenge, the valve on the stem fine easy, the valve on the pillar no chance, got water up my cuff in the bargin.
I was in the pooh once, caught up in a line, it pulled my main reg out of my mouth and my hands were a bit busy, but as my pony reg is on a bungee around my neck I am able to take it hands free, although my buddy was offering his second stage.
I see the pony more of a stop gap between the s**t hitting the fan and my buddy reacting and catching up with me to offer his second stage.
Having said that the same applies to "Y" & "H" valves if you can shut them down quick enough.
Chris :) :) :)
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