Inverted Twins; Pro's & Con's

[jonny4846]

Having been advised by my Instructor that it is a bad idea to invert twins, I am doubting the idea myself. However, when I asked my Instructor why he thought it was a bad idea, his reply was, "you have to get long hoses and stuff, and its just a bad idea...". This reason is more of an inconvience than bad idea, nonetheless has wondering is there any potential flaws or obstacles when diving with inverted twins.

Have dived with twins for 10 months now (right way up) and have practiced shut downs. Although I can reach the pillar valves handy enough the manifold valve was difficult ( BTW I dive manifolded twins) and so made the poor choice of purchasing a CD slob knob which failed on a pre-dive check, resulting in me losing all faith in these contraptions (it was only 6 months old). So back to where I started from. Even though I can reach the manifold valve it is dificult to shut down and shut down quick. I have inverted the set on my back and can't believe how handy it is to reach the valves, although have'nt dived with them inverted. I am wondering but any REAL con's.....

All I can think of is that it goes against all the design purposes of the equipment, tanks, 1st stages and hoses. Which had used gravity to route convienently. However, rebreathers have been designed like this for years as the best design practice, and I am not comparing rebreathers to twins just an anology to design practice... that can be improved or acceptably modified.

Any input would be nice and much appreciated..... and would like to hear from anyone who dives inverted twins (i know there are some here at YD) and instructors who might have some concerns about students who dive with inverted twins....

Cheers Jonny.....

[Steve S]

I'm off to the vets in a minute so I'll post a reply on my return.

Safe diving,
Steve

[Fiona]

Originally Posted by Steve S

I'm off to the vets in a minute so I'll post a reply on my return.

Safe diving,
Steve

Good god Steve are you OK

[TerryH]

Originally Posted by jonny4846

Having been advised by my Instructor that it is a bad idea to invert twins, I am doubting the idea myself. However, when I asked my Instructor why he thought it was a bad idea, his reply was, "you have to get long hoses and stuff, and its just a bad idea...". This reason is more of an inconvience than bad idea, nonetheless has wondering is there any potential flaws or obstacles when diving with inverted twins.

Have dived with twins for 10 months now (right way up) and have practiced shut downs. Although I can reach the pillar valves handy enough the manifold valve was difficult ( BTW I dive manifolded twins) and so made the poor choice of purchasing a CD slob knob which failed on a pre-dive check, resulting in me losing all faith in these contraptions (it was only 6 months old). So back to where I started from. Even though I can reach the manifold valve it is dificult to shut down and shut down quick. I have inverted the set on my back and can't believe how handy it is to reach the valves, although have'nt dived with them inverted. I am wondering but any REAL con's.....

All I can think of is that it goes against all the design purposes of the equipment, tanks, 1st stages and hoses. Which had used gravity to route convienently. However, rebreathers have been designed like this for years as the best design practice, and I am not comparing rebreathers to twins just an anology to design practice... that can be improved or acceptably modified.

Any input would be nice and much appreciated..... and would like to hear from anyone who dives inverted twins (i know there are some here at YD) and instructors who might have some concerns about students who dive with inverted twins....

Cheers Jonny.....

Absolutely no probs with inverting at all.

I strongly believe that the best configeration is the one where you can
actually get to the valves in a fubar. If that's standard, inverted or
slob-knob who cares? Seen many a diver follow the crowd struggling to do
shutdowns in a training enviroment and you just know, that as soon as you
add the stress of a real-life incident its not going to be pretty.

Ok you can go to diver boot camp, rejig your kit, spend sheldoads of dosh
and yes that will make you able to shutdown.

Trouble is that many divers dont put the effort in, yet still follow the kit
configs etc. that you'd use on the above.

Whatever the reasons, all that matters is if you can shutdown, not what
is seen to be the latest vogue and if inverts do it for you, then go for it.

[Foggy]

Ok I'll bite....

I do not invert for diving, but do invert for BA sets.

BA is usually a single tank, and it is a lot lot easier to shutdown (in reality only likely to be a turn on, but you need to shutdown to do a whistle test).

Inverted twins put the valve handles left, right,and center, and when you add stages it becomes very difficult to reach (you have to go over the stage).

Inverted - can damage valves when donning or doffing the set. So usually include a valve guard - or to give it its other name an entrapment magnet, and believe me you may think it impossible for line to get tangled up there, but you're wrong and its a real headache to get rid of it where you cannot see it. Ok you'll never dive solo - I assure you when the shit really hits the fan loss of buddy will have been 3 steps before you get tangled.

Can't think of any more just now, i'm sure someone else will add their thoughts.

Cheers, Paul

PS I also agree with Terry's POV

[Buoyant Babe]

Originally Posted by Steve S

I'm off to the vets in a minute so I'll post a reply on my return.

Safe diving,
Steve

Not the mange again?

[Steve S]

Originally Posted by Buoyant Babe

Not the mange again?

My minge is fine thanks

Safe diving,
Steve

[MATTBIN]

I have inverted and non inverted twinset, I like them both. Personally I go with Terry on this, dive whatever you like so long as you are safe.
Flaws - yeah the piss taking, but I can handle that almost as easy as I can handle a shutdown.
Matt

[Bottle Maker]

The best reason I have seen for NOT inverting is if you ever need to borrow a twin set its a lot easier to find one thats the right way up. When I was open circuit gas diving I owned 2 sets of twin 12s and still ended up having to borrow cyliders so as not to waste expensive gas fills. That said if you are unable to reach the valves and do a shut down you are better off on independants, so rig the cylinders how you want them then hope you dont have a reg problem and need to borrow a regs.

Graham

[Paddy Diver]

Nothing wrong with inverted if it works for ya. I could not reach my valves at all so the only option was inverted and thats what I did. The cost, as you mentioned is not a con just an inconvience, and just like your CD slob knob mine failed too, on the bottom! I loved it inverted when I was just diving twins apart form the fact that the cage I used was a custom built job and it protruded abit and was pressing on my weight belt into my back which was sore form time to time.
But as my diving progressed and I started staged deco dives I found that the stages were in my way and my arms weren't long enough to reach aorund/over the stages to shutdown, and I found that sticking my arms between the stages and my back mounts really restricted my movement so I foolishly dived afew more deep (well for me anyway 55m) dives before I came to the conclusion that I was destained to have a accident if I contuined so in the last fews weeks Im gone back the orginal way up, but I have changed my suit in the mean while so now I can reach my valves agian.

The only real con I came across was that I found it a chore kitting up coz of all those extra long hoses, oh and I did notice a definate increase drag when I inverted them which ment alittle more work to cover the same distance/keep up with buddy so increased breathing rate.

Use my experience.

Ian