Twin set [Archive] - BSAC Scuba Diving Forums

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tom scales

11-11-2003, 21:28

Any advice on configuration of twin 12's i.e. how many 2nd stages per reg'/1st stage. I have an isolation manifold!! Thanks for any advice!!

Adrian Kelland

11-11-2003, 22:50

Any advice on configuration of twin 12's i.e. how many 2nd stages per reg'/1st stage. I have an isolation manifold!! Thanks for any advice!!

I would say that most of us have 1 second stage on each first stage. I have not seen different, but this does not mean that someone, somewhere has something different.

Adrian

angiemac

12-11-2003, 08:55

Any advice on configuration of twin 12's i.e. how many 2nd stages per reg'/1st stage. I have an isolation manifold!! Thanks for any advice!!

A simple suggestion - go to the dive show and watch Jack Ingles talk on technical diving kit configuration. Very interesting and it will make you think alot about your kit. Failing this do the ERD or a technical course and the instructors will not only help you configure your kit to suit you but will also teach you how to use it properly.

Barry Goss

12-11-2003, 14:14

Any advice on configuration of twin 12's i.e. how many 2nd stages per reg'/1st stage. I have an isolation manifold!! Thanks for any advice!!

Oh what a can of worms.
Ok, Read this:: <a href="http://www.gasdiving.co.uk/pages/misc/kit.htm" >http://www.gasdiving.co.uk/pages/misc/kit.htm</a>
Then this: <a href="http://www.bentleytech.com/cave/stroke/index.html" >http://www.bentleytech.com/cave/stroke/index.html</a>
then all of this: <a href="http://www.ukrs.org.uk/links/links04.html#Technical_topics" >http://www.ukrs.org.uk/links/links04.html#Technical_topics</a>

and take any piece of information on there that you think is a good idea (whether or not that is the opinion of the writer) and use it on your kit.
Then dive your kit somewhere safe and shallow, do about 20 dives and each time you get out of the water think about changing an item on your kit. Either position or type. At the end of this process you will have the kit that suits you.

I could just recommend - read the first url and set up your kit as described there, but you won't know why you have it set-up like that.
Experience is the only way to work out what works for kit config.
HTH
Barry

derek perry

14-11-2003, 02:17

Chris Tibble

16-11-2003, 23:53

matt

17-11-2003, 10:31

Personaly I have twin 300bar 10's with an isolation manifold between.
I dive with the isolator closed so both tanks are independent.
I have an Air 2 and 2nd stage on one and 2xsecond stages on the other.
Plus my dry suit connected to one and my BC to the other so I always have access to bouyancy.
I am now in the postition to continue a dive if anything happens to either DV, after cosideration to air left etc.

Do you really mean 'continue a dive' or do you mean 'abort the dive in a controlled manner'?

If one DV fails I still have 2x2nd stages on the other, which is the same configeration as single tank divers.

If this is a justification for not aborting, it appears you are taking a twinset on dives which require only a single set. You may be adding considerable complexity for no discernable gain.

If one DV fails and I can get the tank turned off quick enough the I can open the isolation valve to access all the available air in both tanks and still have 2x2nd stages.

But you simply do not need two second stages. If one DV fails you switch to the only other DV you are carrying and abort the dive.

Hope this helps

It is your kit and your life. I personally would not buddy someone in the kit configuration you describe for any dive that warrants a twinset. IMVHO it is overly complicated and adds more risk than it removes. There are more things to go wrong and you may be faced with choices (stress) which you can avoid. For instance 2nd stages often suffer minor problems. With 2 regs the problematic reg is the 'other reg' with 4 regs it is 'one of 3 others'.

There are lots of things that advanced (technical uggh) divers argue about. Keep It Simple Stupid is not one of those issues. Take what you need and only what you need. Make sure it works. Stow it where you can use it.

YMMV.

derek perry

19-11-2003, 01:59

derek perry

19-11-2003, 02:12

:=Personaly I have twin 300bar 10's with an isolation manifold between.
:=I dive with the isolator closed so both tanks are independent.
:=I have an Air 2 and 2nd stage on one and 2xsecond stages on the other.
:=Plus my dry suit connected to one and my BC to the other so I always have access to bouyancy.
:=I am now in the postition to continue a dive if anything happens to either DV, after cosideration to air left etc.

Do you really mean 'continue a dive' or do you mean 'abort the dive in a controlled manner'?

:=If one DV fails I still have 2x2nd stages on the other, which is the same configeration as single tank divers.

If this is a justification for not aborting, it appears you are taking a twinset on dives which require only a single set. You may be adding considerable complexity for no discernable gain.

:=If one DV fails and I can get the tank turned off quick enough the I can open the isolation valve to access all the available air in both tanks and still have 2x2nd stages.

But you simply do not need two second stages. If one DV fails you switch to the only other DV you are carrying and abort the dive.

:=Hope this helps

It is your kit and your life. I personally would not buddy someone in the kit configuration you describe for any dive that warrants a twinset. IMVHO it is overly complicated and adds more risk than it removes. There are more things to go wrong and you may be faced with choices (stress) which you can avoid. For instance 2nd stages often suffer minor problems. With 2 regs the problematic reg is the 'other reg' with 4 regs it is 'one of 3 others'.

There are lots of things that advanced (technical uggh) divers argue about. Keep It Simple Stupid is not one of those issues. Take what you need and only what you need. Make sure it works. Stow it where you can use it.

YMMV.

Matt

Been there done it, and tried my configuration in every way describable for over 35 years.
It's horses for courses and I like back up as I've seen many things go wrong. One thing I believe in is self reliance and this offers the best. I know loads of divers who dive with ponies and air 2's and the only additional thing I have is a second second stage on my other rig.
You do it your way and I'll do it mine and I guess we'll never be diving together!!!

Good diving

Derek

Chris Tibble

19-11-2003, 22:41

Both primary 2nd stages over my right shoulder, octo stage over my left and my air 2 is on my left as well.
Right tank contents under right arm and left tank contents under left arm.
Very easy and lots of back up. My buddy knows to grab any DV not in my mouth

Hope this helps

Derek

Man that sounds complex! Do you have any long hoses?

Chris

matt

20-11-2003, 12:47

Derek

Been there done it, and tried my configuration in every way describable for over 35 years.
It's horses for courses and I like back up as I've seen many things go wrong. One thing I believe in is self reliance and this offers the best.

Similarly I have seen plenty of problems. Self reliance has been a particular interest after a buddy almost drowned me 9 years ago.

I can not see a reason for more than two 2nd stages on a twinset. Unless you were planning to continue the dive after a problem has forced you onto a single cylinder. Given 2nd stages are one of the most problematic pieces of scuba equipment I see a good reason to use the minimum number required. If you know something different I would very much like to hear it.

I know loads of divers who dive with ponies and air 2's and the only additional thing I have is a second second stage on my other rig.

The pony cylinder has a limited volume relative to the main so you may want a method to allow both divers access to the larger cylinder. One advantage an Air2 has here is that your unlikely to pick it up by mistake.

You do it your way and I'll do it mine and I guess we'll never be diving together!!!

Oh I don't know. I would be happy to dive with you using your config in say 10 to 15m.

Good diving

Derek

TUE

23-11-2003, 13:15

Personaly I have twin 300bar 10's with an isolation manifold between.I dive with the isolator closed so both tanks are independent.

So why bother? Why not use independant twins

Right tank contents under right arm and left tank contents under left arm.

If you dived with the manifold open as designed you only need 1 guage.

Your task loading must be emense even on a 6m shore dive LOL.

derek perry

24-11-2003, 11:12

Personaly I have twin 300bar 10's with an isolation manifold between.I dive with the isolator closed so both tanks are independent.

So why bother? Why not use independant twins

Why not?? If one side were to fail and I had to shut it down I could then open the manifold between and have access to all available air. In your situation you would have air you couldn't get at and that could mean the difference between life and death.:=

Right tank contents under right arm and left tank contents under left arm.

If you dived with the manifold open as designed you only need 1 guage.

Your task loading must be emense even on a 6m shore dive LOL.
Horses for courses, personaly I don't have any problems and have been well into of an 'incident pit' (caused by another diver) and not had the 'Task Loading' you are suggesting.
I am not suggesting that someone goes out buys my configuration and jumps into a 50 mtre dive. I have developed my own system over 35 years of diving, that I am more than comfortable with. If I felt there was a problem I would change it. When I see people with twin sets like mine PLUS 2 or even 4 side hung tanks then that looks like 'Task loading' to me. However if that's how they are used to diving then great, but not for me.

Derek

derek perry

24-11-2003, 11:31

Derek

I can not see a reason for more than two 2nd stages on a twinset. Unless you were planning to continue the dive after a problem has forced you onto a single cylinder. Given 2nd stages are one of the most problematic pieces of scuba equipment I see a good reason to use the minimum number required. If you know something different I would very much like to hear it.
I use very good quality DV?s and have never had any fail on me.(Famous last words!!). One thing that hasn?t been mentioned is that I use a different make of DV for each cylinder which makes it easier to remember what DV comes from what tank. Even the air integrated computers are different for that reason. There we have another aspect of it. Two computers in case one fails, which happens 2 or 3 times a year amongst my branch members.
I was once involved in an incident when my buddy had a free flow at 20 metres. We had only just arrived at the bottom when his 15 litre tank emptied in about 90 seconds. That is a frightening thought and one that provoked me into thinking about self reliance and having two separate air supplies. In fact it caused everyone in our branch to either twin up like me or get a pony.
I think what people have to remember is that everyone is different and have different experiences that cause them to configure their kit the way they do.

:=
:=Good diving
:=
:=Derek

matt

24-11-2003, 18:33

:=Derek
:=
:=
:=I can not see a reason for more than two 2nd stages on a twinset. Unless you were planning to continue the dive after a problem has forced you onto a single cylinder. Given 2nd stages are one of the most problematic pieces of scuba equipment I see a good reason to use the minimum number required. If you know something different I would very much like to hear it.

I use very good quality DV?s and have never had any fail on me.(Famous last words!!).

I guess I don't think quite like that. I see 2nd stage problems farily regularly so I tend to think that all 2nd stages are a little fragile irrespective of make or servicing regimen. I have never had one fail, as in stop working completely, but I have had freeflows and minor leaks. So I see 2nd stages as a potential source of problems. OK I need to carry two, but 4 just doubles the problem potential.

One thing that hasn?t been mentioned is that I use a different make of DV for each cylinder which makes it easier to remember what DV comes from what tank.

There is a case for keeping all your valves the same and preferably with major components that can be swapped underwater. I don't do this at the moment but I am aiming to replace all my valves with one model...if I don't buy a CCR in the meantime. To differentiate I keep primary to the right and secondary to the left. With only two valves it is pretty straight forward anyhow.

Even the air integrated computers are different for that reason. There we have another aspect of it. Two computers in case one fails, which happens 2 or 3 times a year amongst my branch members.

The phrase I like is 'Two is one and one is none' If you need it to complete the dive then take two.

For monitoring decompression requirements I carry;
One Computer
One Slate
One Watch
One Air + 80 table
One Air + 50 table

I was once involved in an incident when my buddy had a free flow at 20 metres. We had only just arrived at the bottom when his 15 litre tank emptied in about 90 seconds. That is a frightening thought and one that provoked me into thinking about self reliance and having two separate air supplies. In fact it caused everyone in our branch to either twin up like me or get a pony.

I think that some form of redundant reserve is sensible just as soon as you reach a depth from which you would not be confident to make a free ascent. I guess the alternative is to tie your redunant supply to the end of a buddy line ;-)

I think what people have to remember is that everyone is different and have different experiences that cause them to configure their kit the way they do.

I somwhat, but do not completely agree. Some things definately are the only way to do it. Some things are debateable and other things are just not worth arguing over.

When deciding how to do things I start by looking at how other people who are using a similar config are going about it. Often there is a concensus view which has resulted from a combined experience greater than any one diver's. I am not saying that you have to slavishly copy what you see but if there is a concensus then there is usually a reason for it. Watever reason there is for doing it differently should be damned convincing.

TUE

24-11-2003, 20:13

:=Personaly I have twin 300bar 10's with an isolation manifold between.I dive with the isolator closed so both tanks are independent.
:=
:=So why bother? Why not use independant twins

Why not?? If one side were to fail and I had to shut it down I could then open the manifold between and have access to all available air. In your situation you would have air you couldn't get at and that could mean the difference between life and death.

Ok. I dive with twin 12ltrs with a manifold. I dive with the manifold OPEN. If one side fails I shut down the offending valve and still have all gas available to me.

Does this mean that when you dive you have to keep switching tanks to keep gas usage the same in each tank? Or, do you breath one down then switch? Or do you get one tank low and abort the dive?

justin owen

26-11-2003, 20:32

There is a an argument for two 2nd stages on the left hand post. If your diving within a BSAC environment, everyone is trained to look for the AAS on the left handside. We're not trained to rip the 2nd stage from your buddies mouth.

So, I see it as perfectly acceptable to have one 2nd stage on the right post in your mouth, one on the left post necklaced, and another on the left post clipped on you left as an AAS for your buddy?

After all, most of us are not cave diving or doing penetration dives.

I currently don't dive a twinset, but have been doing as much research as possible before I do. Just my thoughts.

:)

iainmsmith

26-11-2003, 20:47

There is a an argument for two 2nd stages on the left hand post. If your diving within a BSAC environment, everyone is trained to look for the AAS on the left handside.

Really? A lot of people are set up and trained for an AAS on the right hand side. And an increasing number are using primary/backup combinations, especially at SD and above (ie at a level where you're likely to find twinsets)

> We're not trained to rip the 2nd stage from your buddies
> mouth.

But for a lot of us, that is _exactly_ what we brief our buddies to do.

So, I see it as perfectly acceptable to have one 2nd stage on the right post in your mouth, one on the left post necklaced, and another on the left post clipped on you left as an AAS for your buddy?

Or just go to a long hose and backup. Apart from its advantages, should you really be doing that sort of diving if either you (or your buddy) can't cope for a couple of seconds with no DV in your mouth?

After all, most of us are not cave diving or doing penetration dives.

Most twinset divers seem to regard wreck penetration as entirely commonplace.

I currently don't dive a twinset, but have been doing as much research as possible before I do. Just my thoughts.

See: <a href="http://www.gasdiving.co.uk/pages/misc/kit/hoses.htm" >http://www.gasdiving.co.uk/pages/misc/kit/hoses.htm</a>

Iain

Justin Owen

27-11-2003, 11:28

I understand what you're saying Iain, but I was trying to be 'BSAC' in my comments.

I want a twinset, but I'll be the only person in my club who will have one and dive it regularly. Potentially I'll be diving with inexperienced Ocean/Club divers - I can tell them what to do in OOA/freeflow situation (i.e. remove reg from my mouth) but who's to say that's what there gonna do? Also, it means I can't go training with a twinset in the proper configuration - as it doesn't match what is needed to do the training properly.

Anyway, as I say, my comments were more my opinions on what could possibly be best for a (potential) twinset diver in a club environment.

Regards,

TUE

27-11-2003, 12:42

Anyway, as I say, my comments were more my opinions on what could possibly be best for a (potential) twinset diver in a club environment.

I only dive my twinset on dives where I am with another diver of similar level and kit configuration. For a club dive I would simply use my single set. The only time I use the twinset in the club enviroment is a 2 dive day where getting a fill could be difficult.

Just as a note my single tank has a double pillar valve so I can use the same reg configuration (2 1st stages with long hose, back up around neck) on all dives. Buddies are told on check which reg to take, and all have experience of taking the reg after pool sessions trying the various methods (even the Ocean divers).

see link for gear configuration. Note single setup was done before I changed to double valve.

Digger

27-11-2003, 14:56

Justin Owen

27-11-2003, 15:09

: Justin, please bear in mind that 35 years of experience may seem well thought out, but in reality isn't conventional or sensible in my opinion.

You know me Digs - i'm still researching twin-sets now and still haven't decided yet. My thoughts were simply that, thoughts, ideas. Most 'club' divers have three 2nds stages (with pony) so is there anything drastically wrong with it on a twin - diving with other 'club' divers in sub-35M dives...?

I'm not saying i'm going to do it, or looking for an argument. When I get sorted my gear will be configured in a way i'm happy with. Or, then again I may decide a twinset isn't for me and carry on using a single 12+pony for my diving...

See ya soon!

Digger

27-11-2003, 16:04

3 2nds with a pony is fine. I can see several good arguments for that. I dive with 2 2nds, usually as twins, but also when diving single and pony etc.

I pretty much never dive single tanks now. It's too easy for regs to go messy, and I have good reasoning behind my way of doing it. That said, it really comes down to not wanting to reconfigure everything every time I go from twins to singles and ponies, as the difference for me is very slight.

Tiewrapdiver

27-11-2003, 17:36

I'm still fairly new to the diving game, only been diving for over a year and not done much deep diving. But i'm looking at getting a twinset have already setup a number a possible kit configurations, and they do only include having 2DVs, infact i've changed my single tank setup so that i ahve one DV on my main tank on a 2m hose and a DV on my side-slung pony. Some people will argue with that possibly Digger will (hes my housemate) but we always talk over possible kit configs and see where things go wrong.

I'd actually like to see this 4DV twin rig because it sounds like a right cluster F*** to me and i really can't picture it.

See ya soon

justin owen

27-11-2003, 18:51

: Some people will argue with that possibly Digger will (hes my housemate)

How do you cope....?

:>

iainmsmith

27-11-2003, 23:42

I understand what you're saying Iain, but I was trying to be 'BSAC' in my comments.

While we may not be allowed to teach it, it doesn't stop us, as BSAC members, from diving a sensible reg configuration.

I want a twinset, but I'll be the only person in my club who will have one and dive it regularly. Potentially I'll be diving with inexperienced Ocean/Club divers - I can tell them what to do in OOA/freeflow situation (i.e. remove reg from my mouth) but who's to say that's what there gonna do?

Chances are, they will in any case. On top of that, they've pretty much got to go through your primary to get to your backup. To aid this process, make sure your primary is the one with the bright yellow front on it.

Also, it means I can't go training with a twinset in the proper configuration - as it doesn't match what is needed to do the training properly.

Do you allow the requirements of training at low levels to dictate how you configure your kit for more adventurous diving? Equally, should one be teaching with a configuration that one has rejected?

Anyway, as I say, my comments were more my opinions on what could possibly be best for a (potential) twinset diver in a club environment.

You've already had my answer.

Iain
AD/OWI/NXI/ex-TO/ex-DO

Steve Walker

28-11-2003, 11:52

For reference, I've got inverted twin tens, one DV per PV, got 1ry long hose (2m) and necklaced 2ry DV with 1.5m hose. I used this config for instructing raw trainees last winter and none saw it as a problem to take the 1ry for OOA drills.

However, in the event that someone should see this as a problem it takes only a few seconds to change the position of the 2ry into the "usual" upside-down octopus config as most of us were taught to use. Works well for me...
Cheers
Steve

terryh

28-11-2003, 12:04

At the risk of starting a flame war (please don't) I genuinely
want you Iain, to awnser this question.

I believe that you and others apply the "if it's not good
enough for me" doctrine, as the reason for advocating donate
primary.

Equally, should one be teaching with a configuration that one has rejected?
:=

So based on that premis are you saying that we must reconfigure
ALL (and I mean ALL) kit from day one to be the optimum in
what each of us consider to be the safest rig?

If that's indeed the case how are we going to get to this
stage of Nervana, when it's nigh on impossible to get agreement
on what is the safest configeration?

TerryH AD/OWI/NXI/ex-DO/Current-TO&EO.

terryh

28-11-2003, 12:10

"as most of us were taught to use"

Didnt do you any harm to learn the old way then Steve and you
quite happily have adapted your rig to suit your way of diving.

So you learnt on the "shock gasp" old way and are now happy
using the new way. Isnt that what all of us have been doing for
years without any problems whatsoever?

Rgds
TerryH

iainmsmith

28-11-2003, 15:29

I believe that you and others apply the "if it's not good
enough for me" doctrine, as the reason for advocating donate
primary.

I'm not sure to what you are referring when you talk of an "'If it's not good enough for me' doctrine". However I try to interpret it, I can't see it approaching any of the reasons that I advocate donating the primary. Could you clarify, please?

:=Equally, should one be teaching with a configuration that
:=one has rejected?

So based on that premis are you saying that we must
reconfigure ALL (and I mean ALL) kit from day one to be the
optimum in what each of us consider to be the safest rig?

No - what I was responding to was the rational for rejecting the "primary/backup" configuration as being that it was "non-BSAC" and the statement that: "I can't go training with a twinset in the proper configuration - as it doesn't match what is needed to do the training properly"

The use of "proper" was that of the poster to whom I responded, not mine. If one believes that there is a "proper" way to do something, why would you teach something else?

If that's indeed the case how are we going to get to this
stage of Nervana, when it's nigh on impossible to get
agreement on what is the safest configeration?

One assumes that all instructors within a Branch teach the same technique. If not students are going to get rather confused! So one has therefore achieved concensus at local level.

Variation between Branches is less of an issue, as unqualified divers tend not to do that much diving outside their own Branch.

Of course, eventually everyone will realise the One True Way...
:-)

Iain
(also not up for a flame war, but not quite sure what you're asking me)

iainmsmith

28-11-2003, 15:34

For reference, I've got inverted twin tens, one DV per PV, got 1ry long hose (2m) and necklaced 2ry DV with 1.5m hose. I used this config for instructing raw trainees last winter and none saw it as a problem to take the 1ry for OOA drills.

Likewise. However, there may now be a little problem with doing that... (see link)

However, in the event that someone should see this as a problem it takes only a few seconds to change the position of the 2ry into the "usual" upside-down octopus config as most of us were taught to use.

Is your backup hose long enough to allow you to do that effectively? Mine is a conventional "primary" length with is a little short, IMO.

Iain

matt

29-11-2003, 11:54

There is a an argument for two 2nd stages on the left hand post.

No there isn't! There are lots of justifications but they crumble when taken apart in detail.

If your diving within a BSAC environment, everyone is trained to look for the AAS on the left handside. We're not trained to rip the 2nd stage from your buddies mouth.

BSAC training was; you signal OOA and your buddy donates the reg you should be breathing. Training is now that you signal OOA and if your buddy fails to donate you help yourself to their 2nd. To be compatible with BSAC taining your 2nd needs to be removable.

So, I see it as perfectly acceptable to have one 2nd stage on the right post in your mouth, one on the left post necklaced, and another on the left post clipped on you left as an AAS for your buddy?

Lets go back to your justification. You say you need the third so that your buddy finds an AAS 2nd stage easily.

About the worse place to put an AAS 2nd stage (barring hiding it) is low down and to the side. Your buddy will only see it if they come at you from that side. You are less likely to spot if it has come adrift. Your unlikely to hear or see if it develops a leak (the bubbles will stream behind you). Should you move on to using stages your 2nd is around the same position as your non breathable deco mixes and that can't be a good idea.

About the best place I can think of for an AAS 2nd stage is high on the body around your buddies eyelevel. Your buddy is most likely to close horizontal looking for eye contact. If they come from behind they are still going to turn you around and look for eye contact. Once you accept that there is only one good location to stow an AAS reg there is no point having that third. So for a single clip the AAS off on the shoulder. When you use twins and a necklace the AAS is pretty much still in the same position. Your allowance to be BSAC compatible is nothing more than a necklace from which the 2nd stage can be removed.

After all, most of us are not cave diving or doing penetration dives.

Derek made the point that our config choices often come from the problems we see. When a SD, I ended up shoving a reg in an instructor's mouth after his main went tits up and he singularly failed to deploy one of the other three regs he was carrying. I have also seen a reg which had been functioning perfectly for 30 minutes, go into free flow immediately a buddy started to use the AAS and the demand was doubled. Both of these events happened on BSAC training dives around 20m. Both involved considerably more stress for the diver's involved than was needed.

I happen to believe that stress is the divers greatest enemy, it causes us to react badly to events. I also believe that risk is what we are trying to avoid, the risk of something going wrong and the risk of doing something wrong. I see the The incident pit as the combination of stress and risk. Both cause incidents, compound incidents and make the journey to safety considerably harder.

So my config choice is to rig in such a way as to reduce stress and risk;
1. In the event of an incident my self rescue requires little change of diving style.
2. I remove the possibility of my kit being expected to deliver significantly more during an incident.
3. I remove choice and thought on my part and my buddies.
4. I remove differences from one config (say single) to another (say twins).

The depth of water or distance from an exit has little to do with fundamental config choices.

I currently don't dive a twinset, but have been doing as much research as possible before I do. Just my thoughts.

I wish the Internet had been around when I went through the loop.

I think it is important that you go about these things progressively though. Diving indis for 6 months or a year will teach you gas management and reg drills which may save you when using a manifold. The latest incident I have seen involved a guy, with reasonable experience (100 deco dives) using a manifold. He did not comprehend his gauge reading full after 30 mins at 32m. His reg went tight and he bolted. I can't help thinking that had he dived indis for a while he would have worked out his manifold was closed and switched to his other reg.

So listen to what is said here, try stuff out for yourself, but remember kit is only as safe as you are.

Just my 2p

Steve Walker

01-12-2003, 16:44

Didnt do you any harm to learn the old way then Steve and you quite happily have adapted your rig to suit your way of diving.

quite so

So you learnt on the "shock gasp" old way and are now happy using the new way. Isnt that what all of us have been doing for years without any problems whatsoever?

I don't know, I can only speak for the club in which I'm most likely to be teaching, when I turned up to Wastwater last february with the inverts and long hose there was a fair bit of "WTF is that all about!"

Sorry Terry, I haven't got a handle on the intention/meaning of your post. Basically, I was intending to convey that my setup allows me to teach trainees in either of two ways without me having to faff about changing kit config (i) as if they were going to be diving with long-hosers as a matter of course as I know some clubs do or (ii) as if they're going to be diving purely within that Uni club where hardly anyone uses the LH, and those who do tend to only do so when with experienced divers and they usually reconfigure their kit "old-style" for the trainees.
Cheers
Steve

derek perry

03-12-2003, 04:01

Just wanted to get my iron in the fire here. Sorry derek, but your kit sounds like a recipe for disaster. I know you've survived on it for however many years, and it's been fine, but you've got more backup 2nds than you could ever need.

Why you dive with an isolating manifold and keep it closed I will never know.

OK I speak from personal experience of a buddy whose tank emptied in 90 seconds from a free flow. So if I keep the isolation manifold closed I keep one side safe and no matter how long I take to close down the offending side I CANNOT lose all my air. Once closed down I can then open the manifold and have access to all available air (only if there is any left in the offending side). In your configuration you will never be able to get to any air you may have in the offending tank. This need of mine to have 'access to all available air' comes from a second experience I had. I came across a tangled diver (complete stranger not from our club or boat) at 12 metres who had actually run out of air and was for all intense and purposes dead. I had to cut him free and send him to the surface where he was recovered and survived. It made me realise the importance of having access to all available air in an emergency.

Your justification just doesn't make sense to me. It seems to be the wort of both worlds. I dive indies as I've seen enough manifold problems in one week of diving to know that they're a problem I can do without.

Interesting experience because we have several manifolded twins in our club and I have never once seen a problem

I also like to know I have two completely redundant sets. Task loading is not a problem for me, even with stages, torches and all sorts.

I don't understand why you would need more then one DV for one tank. Please explain how this could be necessary.

I was given an air 2 and as it makes hardly any difference to having a normal BC inflator I can't see why not. The other second DV is in fact more to do with the fact that this is the DV I would use if I had to use a single tank and wouldn't have all tha hassle of adding another 2nd stage. I have also stated it only means I have one more DV than most twin set divers I know anyway as most have air 2's.

It would require the failure of 2 regs to put you in a serious position, and your buddy still has 2. One for him/her, one for you.

You didn't answer the whether you have a long hose question from a previous post. Do you? If so, where does it go in all this?

No I do not have a longer hose as one of my DV's is a posiedon which can be used either way round.
I realy do see problems with people who constantly think they know best. Most things in diving realy have to be looked at as 'Horses for courses'. What is right for one person might not be right for another. I know why I use the setup I use, as it makes me very comfortable and gives me far more options to get out of situations than other people. It works for me and the people I dive with are more than happy as well. You might take a leaf out of the 'Risk assessment@ idioligy currently flowing through all aspects of life;
'If you identify a risk you should take all steps to eliminate it. If you are unable to eliminate it then take as many measures as possible to minimise the risk'
That's what I do.

Justin, please bear in mind that 35 years of experience may seem well thought out, but in reality isn't conventional or sensible in my opinion.

You may be getting a certain amount of negative feeling in this post, and it's just becaue I get the feeling there have been people who have tried to explain this to you before, or there haven't because maybe they feel you are too experienced to question. Please take some of the posts on board, as 4 DVs is simply not necessary on any set.

I wouldn't dive with you, for the record, either.

By the sounds of it I am quite grateful, one risk eliminated!!!!
Derek

terryh

03-12-2003, 14:34

It really is the old argument Steve. One that has surfaced
(albeit in a slightly different form) with the insistance of
some of donating primary (which I dont agree with at base
levels BTW).

If you are teaching Ocean & Sport, your kit should be as close
to the students rig as possible. Once they have become trully
independent divers (I dont class Ocean as being independent),
then it's time to start introducing other variants.

So as an Instructor how are you helping your students by having
a rig that doesnt give them ANY visual refference when kitting
up and gives them even less help when demonstrating skills?

I dive exactly the same rig as the student. In fact many a time
I actually dive on club student rigs.
Yes I switch from 12 to 12+pony, 15+pony or twins when the dive
dictates it, but by then those that I am teaching are over 20m
and into DL territory and dont need any help from me on rigging
kit.

Bottom line here is that if you are teaching then kit prep (or
config) should be seen as part of lesson prep and if that means
"faffing" with a couple of hoses then so be it.

All IMO of course (but I do know quite a few who agree with
me).

Rgds
TerryH

Digger

04-12-2003, 19:24

:=Why you dive with an isolating manifold and keep it closed I will never know.

OK I speak from personal experience of a buddy whose tank emptied in 90 seconds from a free flow. So if I keep the isolation manifold closed I keep one side safe and no matter how long I take to close down the offending side I CANNOT lose all my air. Once closed down I can then open the manifold and have access to all available air (only if there is any left in the offending side). In your configuration you will never be able to get to any air you may have in the offending tank. This need of mine to have 'access to all available air' comes from a second experience I had. I came across a tangled diver (complete stranger not from our club or boat) at 12 metres who had actually run out of air and was for all intense and purposes dead. I had to cut him free and send him to the surface where he was recovered and survived. It made me realise the importance of having access to all available air in an emergency.

Derek, I don't see how you benefit over me. I can close an offending tank in the same way you can, without my manifold. if I can get the tank back online on the way up, great, but otherwise I have enough gas to get to the surface. I've been in some hairy spots, and my breathing rate doesn't go up sufficiently to cause a major problem. Good dive planning can prevent a large number of problems, and something that's going to come up a whole lot in this post is minimising risk. You're not minimising risk, you're using twisted logic to argue the corner for your setup.

Your justification just doesn't make sense to me. It seems to be the worst of both worlds. I dive indies as I've seen enough manifold problems in one week of diving to know that they're a problem I can do without.

Interesting experience because we have several manifolded twins in our club and I have never once seen a problem

There can be problems. I've seen them. Will you accept my word that it can happen? I don't dive in your club, but I've dived with plenty from all over, and they have had problems when I'm there, and I've had reported problems from others. Unlikely, and not a major failure point, but it is possible, and it is the sort of leak that you may well not notice.

I also like to know I have two completely redundant sets. Task loading is not a problem for me, even with stages, torches and all sorts.
:=
:=I don't understand why you would need more then one DV for one tank. Please explain how this could be necessary.

I was given an air 2 and as it makes hardly any difference to having a normal BC inflator I can't see why not. The other second DV is in fact more to do with the fact that this is the DV I would use if I had to use a single tank and wouldn't have all tha hassle of adding another 2nd stage. I have also stated it only means I have one more DV than most twin set divers I know anyway as most have air 2's.

Just because someone else does it doesn't make it ok. I just don't see the need for Auto-Air, Air2 or any other inflator/reg combo. I try and advise people to use normal inflators, one inflate, one deflate. Works fine for millions of divers all over the world, and if you have a reg off that pillar, the Air2 is no use. If one or the other goes technical, you've lost both. Same with the other side. 2 regs on one pillar is completely unneccesary on a manifolded twinset. You're doubling the chances of having a failure by having double the number of DVs.
Just because you were given an Air2 doesn't mean you have to use it. How fast can you purge air from a tank using one? I get the feeling you are taking every bit of dive gear you own on every dive.

It would require the failure of 2 regs to put you in a serious position, and your buddy still has 2. One for him/her, one for you.
:=
:=You didn't answer the whether you have a long hose question from a previous post. Do you? If so, where does it go in all this?

No I do not have a longer hose as one of my DV's is a posiedon which can be used either way round.
I realy do see problems with people who constantly think they know best. Most things in diving realy have to be looked at as 'Horses for courses'. What is right for one person might not be right for another. I know why I use the setup I use, as it makes me very comfortable and gives me far more options to get out of situations than other people. It works for me and the people I dive with are more than happy as well. You might take a leaf out of the 'Risk assessment@ idioligy currently flowing through all aspects of life;
'If you identify a risk you should take all steps to eliminate it. If you are unable to eliminate it then take as many measures as possible to minimise the risk'
That's what I do.

No, it's not. That's all I can say. You're not minimising risks. You're multiplying them.

On your series of solutions to get you out of dodge, what you realy need is one, or maybe two, simple solutions that work every time. That just work. Like "donate reg, switch to backup" or "give buddy AAS". Not "work out which AAS to give buddy, find it amongst the 2 from each side, give to buddy".

Are you really comfortable in all that kit? You could cut down a lot of that, and be dead comfortabel with only one reg from each side, with no cluttered 4-reg setup on your front, and without having to worry about regs dangling and dragging all over the place. Would you really notice if one reg was behind you leaking air?

:=
:=Justin, please bear in mind that 35 years of experience may seem well thought out, but in reality isn't conventional or sensible in my opinion.
:=
:=You may be getting a certain amount of negative feeling in this post, and it's just becaue I get the feeling there have been people who have tried to explain this to you before, or there haven't because maybe they feel you are too experienced to question. Please take some of the posts on board, as 4 DVs is simply not necessary on any set.
:=
:=I wouldn't dive with you, for the record, either.

By the sounds of it I am quite grateful, one risk eliminated!!!!
Derek

Please think about the way you dive. When's the last time you changed your equipment configuration? WHen's the last time you really thought about it? I'm trying to help, and though there is a lot of criticism, I hope you can see it as constructive.

derek perry

05-12-2003, 11:39

Derek, I don't see how you benefit over me. I can close an offending tank in the same way you can, without my manifold. if I can get the tank back online on the way up, great, but otherwise I have enough gas to get to the surface. I've been in some hairy spots, and my breathing rate doesn't go up sufficiently to cause a major problem.

I refer you to my previous answer. You say you can get access to your air IF you can get it back on line. Why risk IF, I CAN get access to my air no matter about the offending DV.
No matter how calm anyone?s breathing rate, if you run out of accessible air, as did the diver in my experience, then you are dead for the sake of not having a manifold to access your other air

There can be problems. I've seen them. Will you accept my word that it can happen?

Yes accepted you can have problems with any equipment. It was not intended to infer you were lying.

Just because someone else does it doesn't make it ok.

Correct, but it doesn't mean it's wrong either and it suits me.

I just don't see the need for Auto-Air, Air2 or any other inflator/reg combo. I try and advise people to use normal inflators, one inflate, one deflate. Works fine for millions of divers all over the world,

Er, I refer to your previous answer; 'Just because someone else does it doesn't make it ok.'

Air2 is no use. If one or the other goes technical, you've lost both. Same with the other side. 2 regs on one pillar is completely unneccesary on a manifolded twinset.

Sorry you are wrong. I've had buddies come up to me holding a dismantled second stage in their hand, which has come apart under water. This does not mean it will free-flow and if you have another DV on that tank then you can still access the air.

You're doubling the chances of having a failure by having double the number of DVs.

Yes point conceded, but outweighed by the advantages I have already mentioned.

Just because you were given an Air2 doesn't mean you have to use it. How fast can you purge air from a tank using one? I get the feeling you are taking every bit of dive gear you own on every dive.

I agree I probably would not have gone and bought one but again I see the advantages outweigh any disadvantage as I would still have to have an inflator so it's not any additional bit of kit hanging on me, just a different type, which can be disconnected just as quickly as a normal BC inflator in a fee flow situation.

Not "work out which AAS to give buddy, find it amongst the 2 from each side, give to buddy".

You make it sound difficult to find an appropriate AAS on my rig. You couldn't be more wrong. The main AAS for my buddy is the yellow Octo over me left shoulder. However I always tell them to grab the one they see first providing it's not in my mouth, as per new training. You seem to envisage complications where there really aren't any. You obviously haven't tried the configuration otherwise you wouldn't have that misconception.
Before you tell me to try your set up, don't forget when I started diving there was no such thing as Octo and no direct feed onto the BC. In fact the only jackets available were filled either by mouth or a CO2 cylinder. In those days it was deep and daring to go beyond 100 feet (30mtrs) on club dives. I have evolved through all types of diving configuration and really view mine as my ideal. Please note 'my ideal', I would not bang on to you about changing yours. You perceive my advantages as disadvantages and I likewise with you. I think we will have to end this where we agree to disagree.

Safe diving Derek

PS
Sorry couldn't resist partly quoting you here;
Are you really comfortable in all that kit? You could cut down a lot of that, and be dead !!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Point conceded!!!!!!!!!!!!!

andycarroll

05-12-2003, 14:52

Just because someone else does it doesn't make it ok. I just don't see the need for Auto-Air, Air2 or any other inflator/reg combo. I try and advise people to use normal inflators, one inflate, one deflate. Works fine for millions of divers all over the world, and if you have a reg off that pillar, the Air2 is no use. If one or the other goes technical, you've lost both. Same with the other side. 2 regs on one pillar is completely unneccesary on a manifolded twinset. You're doubling the chances of having a failure by having double the number of DVs.

Hi

Just a pointer to say that with a normal BC inflator you do actually have a third DV, you just press both buttons at once.

Possible application is when donating primary and backup reg fails. Its about this time when you are normally thinking of taking up golf :-)

Andy