Double Tank Manifolds, Bad Idea!

[OkByMe]

Let's see if this floats your boat... I have been thinking about this for a while. I have 2 Faber mid-pressure (2760 filled to 3000) 85cft. Tanks that I had manifolded. I took them apart and plugged the crossover port and am using them for side-mount. I do like my back gas, no fuss, no muss. swapping around on side-mount is a pain, so...

I have been thinking of drilling a #60 hole all the way through the plugs and then drill and tap for a 6 inch high pressure hose. The valve end of the hose would be drilled out to #60 as well. By installing a 6000psi stainless steel unidirectional ball valve on the end of each hose would seal off the tank for transport. Installing a quick disconnect between the valves would allow the tanks to be paralleled and equalize as the air is used from the one tank. I have seen the complicated low pressure manifold that is on the market, and don't like the configuration. I have also considered a "gas switch block". Occasionally I dive a full mask and that is not a side mount opportunity.

I have tested this out using 2 hoses and a disconnect on the HP port of the my Scubapro MK25's. The little hole in the HP port does not pass enough air to keep up and I'm NOT drilling it out, so I'm opting for the plugs. With the initial minimum restriction throughout the "manifold" initially set to .040, it could always be drilled to a larger size.

The procedure would be to install regulators on each post, open the valves, check for leaks, don the tanks, connect the QD, open both "manifold" valves, check for tank equalization, go diving. I'm going to hear "failure" points. Transporting/handling the tanks with the hose and valve attached would require more care. Plus, if you offered up the tanks in that manner to a dive op for fill, I wonder what kind of reaction I would get. I fill my tanks, but do travel with them, so I have to consider that unless I take my compressor too.

 

[pocky21]

You mean something like this:

Z Isolatable Manifold for Z Side-Mount System - Unified Team Diving


There have been a few pretty heated threads on here regarding that kind of setup, most of which will be repeated in this thread shortly.

 

[tskovan]

From the OP: I think it’s all been said, to sum it up

MD: a) A slight reduction in redundancy
b) Simpler gas management
c) The possibility of retaining more gas after a failure
d) More complexity under stress (managing a failure)
e) Twice the weight and bulk when filling, moving, storing, loading on or off a boat ect.

ID: a) Total redundancy
b) Higher task loading for gas management (not under stress)
c) Loss of half your gas after a failure
d) Less complexity under stress (managing a failure)
e) The simplicity of managing cylinders as singles, once removed from the bands

I choose IDs, you choose what you like, Thanks to all those who responded intelligently.

 

[Akimbo]

You mean something like this:

Z Isolatable Manifold for Z Side-Mount System - Unified Team Diving...

Why on earth would someone make a special valve and not move it to where it is easier to access? Now that is dumb.

 

[OkByMe]

You mean something like this:

Z Isolatable Manifold for Z Side-Mount System - Unified Team Diving


There have been a few pretty heated threads on here regarding that kind of setup, most of which will be repeated in this thread shortly.

Yes, that's it. With a little ingenuity, one could mount that across the front at the belt. I would opt for a gas switch block before I spent that kind of money.

 

[je76]

When I read this I almost read it as hyperbole it was so off the wall. I have a few hundred dives logged on manifolded doubles, I can reach all my valves, can turn them all off and on in under 30 seconds and can use my mirror if I hear a leak. I also work at an LDS and have no trouble filling my or anyone else's manifolded doubles. In the event of an emergency I can isolate and still have access to the entire amount of gas available in my tanks which can come in quite handy should I have any type of obligation.

I am not telling you to go out and buy a manifold but you most certainly are not going to use that argument to convince me to change over.

 

[tskovan]

When I read this I almost read it as hyperbole it was so off the wall. I have a few hundred dives logged on manifolded doubles, I can reach all my valves, can turn them all off and on in under 30 seconds and can use my mirror if I hear a leak. I also work at an LDS and have no trouble filling my or anyone else's manifolded doubles. In the event of an emergency I can isolate and still have access to the entire amount of gas available in my tanks which can come in quite handy should I have any type of obligation.

.

I am not telling you to go out and buy a manifold but you most certainly are not going to use that argument to convince me to change over.

Why is it "Hyperbole" and "so off the wall", to make a reasoned and logical argument for one type of gear config. over another-- Because it's not the one you use?
If you read the whole thread, there are many poeple who agree with many of my pointsI never tried to convince anyone to change anything, I wanted to see if someone could convince me that manifolds are better.......they haven't
Dive what you prefer, I do.

 

[DaleC]

Let's see if this floats your boat...

I did this to test a similar idea. All I needed was a male-male connector.



I believe the Z system was an attempt to allow SM divers into the UTD regime without compromising their air share, gas plan procedures. Instead they compromised the SM rig.

 

[befee]

How is gas sharing managed in ID's?

 

[nimoh]

How is gas sharing managed in ID's?

I don't dive IDs, but after reading this thread, I'll take a stab at answering.

It is managed in the same way as with MDs. You have a second stage coming off of each tank, and provided you have balanced the tanks well during the dive, you should be able to safely end the dive on either tank, or, in the case of sharing gas, on both tanks.