Inverted Twins; Pro's & Con's

[ardhill]

Dive what is safe for you to dive.

As for some of the arguments against...

Custom Hoses - I didn't get any custom hoses actually for my inverted set. I did change a couple of hoses, but they were all 'off the shelf' ones.

Entanglement hazard - Rubbish! Diving with valves up and all those hoses exposed and ready to catch onto anything you swim through is more of a hazard than the clean base of inverted tanks. I have been entangled a number of times, and never has it been the valve guard, which keeps all the regs and hoses safe from entanglements and damage.

Shut Downs - Easy Even with stages and reels hanging off the back of my waist band I have no problem.

The only 'real' problems I have found with inverts are when using RIBS a lot - which I do all the time.

I rest them on the base of the tanks, then have to swing them round every time before donning, which can be a problem on a small RIB.

Moving them about on the RIB and getting someone to help you don your set is awkward as you/they don't have a manifold of valve to hold onto to move or stabilise the set.

Also if you do a lot of shore diving and have nothing but rocks to rest your set on whilst kitting up, this can be a bit of a problem too.

I changed to inverts as my last suit wouldn't let me do shutdowns. I have a new suit so am trying to dive them valves up to save on the hassle on a RIB, but as yet I have not convinced myself that this is a good idea. I will try for a while longer and see how it goes, but Inverts are rather nice otherwise. The jury is still out whether I leave them valve up, or invert them again.

If you have the accuracy and skill of a stampeding elephant when going through openings in wrecks, rocks etc, then having the base of your cylinders forward and not the delicate regs is a real plus Not that I know anything of this trim problem personally you understand

Oh, my valve guards are a couple of bits of 3mm stainless bent at right angles then fixed to the neck of the cylinders. They work and are cheap.

PM me if you want to discuss inverting your set.
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[wilbo]

Originally Posted by nigelH

A question....

Is standardisation worth slower? This is the very gas you are going to breath we are talking about here. Shutdowns only matter when it is you with the fault and the surface is a long way away. 'Easy and very quick' is life over death.

slower shutdowns? Yep - they are probably slower - but you could argue the toss over valve orientation, flexibility, memory muscle, how often you actually practice shutdowns.. etc..etc.. and people's mileage does vary..

I am happy. thats the important bit.

Originally Posted by nigelH

Also is standardisation worth anything if you dive with a competent buddy? They will buddy check you and know what is what. The only time standardisation might be needed is if you are a large support team and you need identikit divers so you can swap team mates in the water on the fly. Even then is it so hard? Do you expect your team mates to be working your valves?

In my view - my buddies are very competent and I'm lucky to dive with them. My style of diving is 'DIR' (lets not get into that) - so we practice drills and team diving ad nauseamn and follow the equipment standards set by the type of diving. So standardisation is a must.

If I have a problem then the team know straight away and move to a position where they can help. I don't have eyes anywhere near my valves - but my team do. If it is quicker to resolve they will take over.

Originally Posted by nigelH

The Hog rig contained a lot of good ideas but it is not enshrined as the only way for the rest of time.

I never said it was - but I like it.

[nigelH]

Originally Posted by wilbo

I never said it was - but I like it.

Thanks.

If we push this line any further we're into comparative theology which just muddies the water on the original question. I was just interested in a view from somebody who had gone from inverts to uprights. Most of the flak I had was from people who had never tried inverts on moral grounds so your opinion counts a lot more.

[Fiona]

Originally Posted by nigelH

I was just interested in a view from somebody who had gone from inverts to uprights. Most of the flak I had was from people who had never tried inverts on moral grounds so your opinion counts a lot more.

I didn't know Wilbo had been the invert route so I guess my route is exactly the same as his. I went invert because I had never done a shut down the otherway up and I had also never been shown how to, which is why I thought I couldn't do them. I am not sure I even tried, I went from a single - single and pony - twinset without giving it much thought.

I eventually and I mean after years of twinset diving I went to do a skills day with an instructor and frankly made a complete hash of the shutdown (inverts) - shutting down both valves on the ascent.

Since turning them back to the "upright" position and being taught properly I don't have an issue it just needs some practice.

[MATTBIN]

Originally Posted by nigelH

Thanks.

If we push this line any further we're into comparative theology which just muddies the water on the original question. I was just interested in a view from somebody who had gone from inverts to uprights. Most of the flak I had was from people who had never tried inverts on moral grounds so your opinion counts a lot more.

Nigel I have both at the same time, I dive inverted 10's with a manifold and non inverted 12's indy. I have reversed valves on the 12's so I can do a pillar shutdown if required on the 12's. I like the inverts because they trim nicely and I can shut the centre valve (and pillars) very easily, the 12's I didnt want manifolded because of the weight and I can then swop a thrid cylinder, I didnt want individual valve guards or to tie the cylinders together but I like the extra gas they give me without having to get them filled (lifted) as twinset. So both sets work for me personally. I wouldnt want a manifolded 12 set so the shutdown issue isnt a big one, if i was to dive them as a banded/manifolded set they would almost certainly get inverted, tbh I cannot see a good reason to NOT do it, however if people want to dive valve up and they can do a shutdown in the time it takes to save enough gas to make a manifolded set worthwhile then go for it. The Caveat there is that I dont think most people could actually do a shutdown and save the gas they think they will, therefore negating the manifold, but that is another can of worms for another thread (again).

Matt

[Fiona]

I never thought much about hose routings when I dived the inverts, the custom hoses weren't that much of an issue, although I wonder how many people dive inverts without a bungied wing.

I wouldn't go back to inverts because frankly the rig I was diving looks like a bag of sh*te

[MATTBIN]

Originally Posted by Fiona

I never thought much about hose routings when I dived the inverts, the custom hoses weren't that much of an issue, although I wonder how many people dive inverts without a bungied wing.

I wouldn't go back to inverts because frankly the rig I was diving looks like a bag of sh*te

True. 3/10 see me after class Ms Fiona.
Bit unfair really, you did the invert hose routing without reference to more learned people (by your own admission) then went and did a DIR course, where they showed you their hard learnt lessons, hardly comparing apples with apples is it.

(or should that be bannanas with bannanas)

Matt

[Fiona]

Originally Posted by MATTBIN

Bit unfair really, you did the invert hose routing without reference to more learned people (by your own admission)
Matt

Not true Matt I directly copied someone elses set.

[wilbo]

Oops.. I reckon 2 out of 10 then..

here is mine from August 2004. I was in the middle of sorting out the routing..



The horror of it..

[Fiona]

At least my right hand post is clear