Would there be anything wrong to dive independant doubles without a manifold?

[Jackknife]

If manifolds can fail, why not just use independant doubles, and carry say 3 or 4, 2nd stage regulators and breath from two different tanks?

Just want to hear some personal feedback with experience and why you choose your method of equipment setup?

 

[MechDiver]

I see no reason to screw with independant doubles when there are iso manifolds available.

Why would you carry "3 or 4" regulators

Do you have a real point you're trying to make?

MD

 

[Jackknife]

I hear that when you install the manifold you have to remove all the air, remove the isolator and the bands all the time. But if I just dive independantly I wouldn't have to do all that and it would still be easier for me to just loosen the bands and then remove my tanks for single diving.

 

[metridium]

Lose one first stage of an independent kit and you've lost half your gas supply. Lose one on a manifolded kit and you can shut down the reg while keeping your entire remaining supply.

Then there's the fun of continuously having to switch between independent tanks when diving overheads in order to maintain reserves.

I can tear down my 104s into singles, but I think I'll get a new tank instead.

 

[omar]

Oh brother... This is called majoring in the minors.

When you setup doubles you are not planning on taking them apart for single tank diving. Most folks only tear them down on an annual basis. I go longer because I am not restricted by the dive shop pay me money or I won't fill your tanks game (also known as a visual inspection).

Carrying extra regulators which are much more prone to failure than a manifold adds a lot of task loading as well. How do you know which one to use and which tank is it for and is hooked up?

omar

 

[MikeFerrara]

Some problems with backmounted independant doubles....

If a tank must be shut down you no longer have access to the gas in that tank. While with manifolded doubles you still have access to all your gas through the one reg.

Gas management is more difficult. With non-manifolded tanks you must always switch regs to keep the presure in the tanks nearly equal. This also effects emergency procedures. Do you have one long hose or two? Do you donate the reg in your mouth? is it the long hose or does it change every few minutes? Is one reg on a short hose bungied around your neck? Can you donate that one at all?

You need two presure gauges instead of one.

 

[MechDiver]

Jackknife once bubbled...
I hear that when you install the manifold you have to remove all the air, remove the isolator and the bands all the time. But if I just dive independantly I wouldn't have to do all that and it would still be easier for me to just loosen the bands and then remove my tanks for single diving.

As the others have said, there are many cons to diving ind doubles. Also, I don't think any of us routinely break our doubles down to dive singles. We have tanks to do both.

MD

 

[SimonN]

Gas management is more difficult.

Not really, just different to when using a manifold.

With non-manifolded tanks you must always switch regs to keep the presure in the tanks nearly equal.

Kind of, but nowhere near as bad as it sounds. Some people I know breath one tank down until there is enough gas in it for bailout and then swap - that's only one reg swap.

On the rare occasion I dive independents I'll breathe one down to 150bar, swap, breathe the other to 100 bar and then, in theory, would swap again (in theory because I am normally doing deco by that stage, so don't need to swap again). This is 2 swaps.

Neither is really task loading.

This also effects emergency procedures. Do you have one long hose or two?

Only people who have never dived independents ask this.

Firstly, it is a lot less likely that you will need to donate when diving independents because the chance of having a catastrophic failure is a lot lower. However, as planning for a catastrophic failure is a neccesity.

Only have one long hose.

Do you donate the reg in your mouth? is it the long hose or does it change every few minutes? Is one reg on a short hose bungied around your neck? Can you donate that one at all?

I have the regs hogath-like (even wrapping the long hose, but with 2 SPGs obviously), but I also have the addition of a occy holder type thing on the long hose reg which fits over the mouthpeice and is made from very thin bungie cord and a brass clip. The brass clip hangs out of the way when breathing from it and the thin bungie does not get in the way either.

If you are breathing from the long hose, you donate it. If it's clipped off it is just like having an occy recreational style.

 

[Jackknife]

Common sense would tell me that yes there are positives and negatives with both. But I don't plan on diving doubles all the time. Maybe out of my 50-80 dives a year, I would only use them 10 times for deep dives, external wreck or checking out the bottom. The rest of my dives are for hunts or just sightseeing.

That's why I don't need a permanent "double setup" it would not be cost effective for the style of diving I normally do.

 

[scubaredneck]

it might be easier to just get yourself a single tank and then set yourself up some doubles and use them as needed or use the doubles even if you don't need to. I have a buddy who keeps a set of Al 72's set up all the time but also has 2 or 3 single Al 80's that he dives with most of the time.

JMHO