Inverted Twins; Pro's & Con's

[Mal Bridgeman]

Originally Posted by ianfirmin

Faster shutdown

Less entanglement hazard

erm... that's all I can think of.

I would disagree with the faster point .... but I think that's possibly procedural and practice.... the same individual should be able to achieve the same time I suspect.

The entanglement hazard is more interesting though. In what way are inverts less likely to get entangled?

TIA
Mal

[ardhill]

Originally Posted by Mal Bridgeman

It's been an interesting debate....

I agree, it has.

an inverted set can offer you the ability to shutdown but does have a number of compromises ....custom hoses, halos, tailored procedures etc

Custom hoses? Not necessarily, different lengths to yours maybe, but mine are all off the shelf, and so do some other invert divers. If more people dived inverts, then you would get 1m LP hoses for inflation off the shelf too.
Halos - I personally know more divers who dive uprights with Halos, than inverts. As far as I know, they were originally designed for uprights.
Tailored Proceedures? C'mon, GUE have tailored preceedures galore. Each group of dives have their own way of doing certain things, that is hardly an argument Mal.

What I have not seen is a positive advantage of inverts over uprights. Did I miss that?

as has lready been said - fast shutdowns and less of an entanglment & damage hazard in an overhead or where here is loose net, mono filament etc. Oh and as I am a rubbish aim, I have bounced off rock and wreck a number of times with the base of my cylinders whilst trying to swim through a hole. I wouldn't have liked to do that with my valves

I know I am "pro" upright so it's my frame of reference that could be faulty here.....but the only pro invert reason I can see is if you really can't work uprights and need to be able to perform a shutdown....on that there is no debate.

Or because you want to, as there are not so many major drawbacks as some people would put across.

[ianfirmin]

what he said (ardhill)

[nigelH]

Originally Posted by Mal Bridgeman

I would disagree with the faster point .... but I think that's possibly procedural and practice.... the same individual should be able to achieve the same time I suspect.

I can't answer that as I can't touch any of the valves on a 'normal' rig but I'm paying for a mis-spent youth. A good miss-spent youth.

The entanglement hazard is more interesting though. In what way are inverts less likely to get entangled?

Well I've been nuzzling through netting and things for years and, frankly the bull bars mean that anything that slips over the tanks slips right off. The only time something snagged up it was on the manifold valve that pointed straight back at the time and I got my hands to it and pulled it clear. I can reach all round my valves and the bull bars.

Conversely I spent a lot of time bullying O2 into a guy that got his 'right way up' valves entangled and, when he finally got free, did a rapid from 45m and won a night in hospital. He could reach the valves but didn't have the movement to reach round them. I think he just pulled himself in the right direction in the end and was lucky. Solo diving.

[Mal Bridgeman]

Originally Posted by ardhill

Custom hoses? Not necessarily, different lengths to yours maybe, but mine are all off the shelf, and so do some other invert divers. If more people dived inverts, then you would get 1m LP hoses for inflation off the shelf too.

It's a fair point ... but a big "if".

Halos - I personally know more divers who dive uprights with Halos, than inverts. As far as I know, they were originally designed for uprights.

I don't know why people put them on uprights .... other than they looked nice on the Custom Divers stand .....

Tailored Proceedures? C'mon, GUE have tailored preceedures galore. Each group of dives have their own way of doing certain things, that is hardly an argument Mal.

What I was thinking of was in a mixed (uprights & inverts) team of three divers then the upright divers need to know two different protocols for dealing with OOG depending who goes out of gas .... the inverted diver only needs to know one

In a team of two mixed configs, the "upright" diver can easily be donated gas and fin if he is on the right of the donor but things get awkward if he is on the left or even worse if he is following line and needs to swap to the other side. It's still not easy for two "upright" divers to do this but at least they can start off easily either side and if they need to swap sides of a line for example they can do that more easily with the hose at the top.

as has lready been said - fast shutdowns and less of an entanglment & damage hazard in an overhead or where here is loose net, mono filament etc. Oh and as I am a rubbish aim, I have bounced off rock and wreck a number of times with the base of my cylinders whilst trying to swim through a hole. I wouldn't have liked to do that with my valves

I really do think shutdowns are product of practice and procedure and only the one part in the fault fixing process. Choosing which valve to operate is another. Having a buddy who can reliably analyse and identify the fault and fix it if it's fixable and not turn all your gas off is another....I am pretty convinced that the actual shutdown can be the same and that fixing the fault face to face is a lot easier and the overall duration is undoubtedly quicker.

Or because you want to, as there are not so many major drawbacks as some people would put across.

I have no issue with people wanting to do it that way or find it's the best way for them but I do feel it's unfair to suggest it as a first step for the reasons I've explained.

Mal

[milldog]

Originally Posted by Mal Bridgeman

What I was thinking of was in a mixed (uprights & inverts) team of three divers then the upright divers need to know two different protocols for dealing with OOG depending who goes out of gas .... the inverted diver only needs to know one

In a team of two mixed configs, the "upright" diver can easily be donated gas and fin if he is on the right of the donor but things get awkward if he is on the left or even worse if he is following line and needs to swap to the other side. It's still not easy for two "upright" divers to do this but at least they can start off easily either side and if they need to swap sides of a line for example they can do that more easily with the hose at the top.
.

Mal

Intresting point Mal but if your doing the types of dive that require twinsets etc surly you should be competent that you can deal with any situation? regardless of the setup, I mean if you were on a dive and come across a re-breather diver in trouble your not going to leave him because he has a box instead of a twinset on.

I would say as long as you were briefed up on the layout of the equipment then there wouldn't be an issue here

just a thought

Graham

[Mal Bridgeman]

Originally Posted by milldog

Intresting point Mal but if your doing the types of dive that require twinsets etc surly you should be competent that you can deal with any situation? regardless of the setup, I mean if you were on a dive and come across a re-breather diver in trouble your not going to leave him because he has a box instead of a twinset on.

I would say as long as you were briefed up on the layout of the equipment then there wouldn't be an issue here

just a thought

Graham

If I came across an RB diver the best I think I could do would be to donate OC gas and get him to the surface..... and hope for his sake, his deco schedule matched the gas I had available .... it's a bit of an unlikely situation though.....


oh and I'd be mercilessly ripping the proverbial, if it was you

Mal

[milldog]

Originally Posted by Mal Bridgeman

If I came across an RB diver the best I think I could do would be to donate OC gas and get him to the surface..... and hope for his sake, his deco schedule matched the gas I had available .... it's a bit of an unlikely situation though.....


oh and I'd be mercilessly ripping the proverbial, if it was you

Mal

Agreed as i would to you plus send you a bill for the gas

but thinking about this there are some very good arguments for the invert system, after all it has worked for the Navy for years!

there would be less intanglement due to the bottom of the cylinders being smooth unless you had boots???? and as for the hose routing you could always have a long hose yes it would have to be custom made but it's routing would be over the shoulder nice and snug as opposed to coming off the post,

Graham

[wilbo]

OK Mal thats all fair and well - but what would you do if you came across an out-of-bucket diver?

[Mal Bridgeman]

Originally Posted by wilbo

OK Mal thats all fair and well - but what would you do if you came across an out-of-bucket diver?

We'd negotiate the salvage fee before donating the gas
Seems fair to me!!
Mal