Rigging for slinging a stage bottle

[decompression]

I think some might say a equipment solution for a skills problem. Myself, I've rarely used shutoffs. Not in SM or BM.

 

[tbone1004]

when you install a shutoff valve you are supposed to put an OPV on the first stage in one of the LP ports which will blow upon reaching whatever PSI it is designed for. Poseidon incorporates these into the bottom of the 3960 and Xstream first stages, and some divers will replace them with the port design if the spring breaks or whatever.
It isn't a restriction, the design allows for the same volumetric flow rate as normal, which is well above what a diver can realistically use anyway. Failure point, there's not a lot inside of them and I believe they fail open. I haven't pulled all of them apart, but most of them function the same way as the QD's on the inflator hoses, they're just enclosed into one unit.

 

[mathauck0814]

How common is it to use an inline shut off valve for a stage bottle, or for independent doubles, or even sidemount?

I understand the reasoning (preventing loss of air if the 2nd stage leaks or freeflows), but just wonder about the wisdom of placing a restriction / possible failure point between the 1st and 2nd stage, which also eliminates the downstream "over-pressure valve" function of a 2nd stage in the event of IP creep or HP seat failure in the 1st stage?

Just curious what others think.

Best wishes.

I use them, especially useful when scootering or diving in current/flow. Discovering that your bottom bailout gas is empty at 100m after you've scootered like hell to get down the drop line is a bad thing.

 

[tbone1004]

I don't use them in OC. The +_ switch on jetstreams works very well for preventing freeflows and on my deco regs I keep them tuned pretty low to prevent freeflow. I can definitely see them being especially useful for CCR and stages that get left in caves when staging a bigger dive.

 

[stevensamler]

Keith,
go to the AddHelium.com website and look at their stage bottle rigging kits. They are not that expensive.
Also, you mentioned that you think that an ALU 80 is the best one. We don't use ALU 80's to sling our bail-outs but ALU 72's. They are neutrally bouyant. If you really decide to go with your 80, you might want to consider putting a 2 pound weight at the bottom of your tank.
Another recommendation is to add a shut-off valve to your bail-out regulator. This way you can keep the bottle on and charged but do not risk loosing gas in an unrecognized free-flow situation.

Happy Diving.

Claudia

Do you use a shutoff valve on your aas also?

 

[dreamdive]

Our team has been using shut-off valves for quite some time now without problems! As some of others here have already mentioned, discovering that you lost your bail-out gas (CCR) or your deco gas (OC) during a bail-out or deco switch is a really bad scene! It is a risk / benefit ratio and we choose the shut-off valve.

---------- Post added July 31st, 2014 at 08:09 PM ----------

Do you use a shutoff valve on your aas also?

I am not sure that I follow you as you could not possible be making an asinine comment.

 

[Keith.M]

Well, that was a real fun project!

I won't be using an OPV here as our gas plan is going to be to use the stage first, then go to the back gas where I will have two second stages. The stage bottle will only have one second stage.

So thanks to uncfnp for reminding me where I had seen the rigging I was interseted in, I was able to go out and get this configured.

Using the basic idea from dir-diver.com, here are the results.

I had already picked up my bolt snaps at the dive shop yesterday. A trip around town to Ferguson for the SS hose clamp, Home Depot for the vinyl hose and a couple of different types of bungee and then REI for some tubular webbing and some utility cord.



Now cut the utility cord and get the initial knot holding the top bolt snap in place.



Now cut the vinyl hose. One 13" and another 2" one to fit over the hose clamp screw.

Thread the utility cord through the long piece and tie another overhand knot at the base of the tube. Connect the bottom bolt snap to the long end of the utility cord. Then tie a fisherman's knotto connect both tag ends together. Then melt the ends of the lines on the fisherman's knot and using the side of the lighter, press hard back to the knot to create a nice mushroom head so the knot will not come undone. Much the way you would tie a bolt snap to anything using cave line.



Finished sling before attaching to the tank.



Prepare the hose clamp by running it through the tubular webbing and adding the 2" vinyl tubing.



Attach the sling to the tank.



I didn't want to have to go buy a large inner tube, so I decided I would use some bungee. I had picked up two different 48" bungees and decided I would go with the flat one. I cut it in half and then made them into loops, again using a fisherman's knot. As an extra measure against coming undone, I added a zip tie to each of the tag portions of the knot.

The vinyl tubing has an outside diameter of 3/4" and should easily allow me to manipulate the bungee with my gloves on.



I am all set now to give this a try tomorrow at Point Lobos!

 

[tbone1004]

I think some might say a equipment solution for a skills problem. Myself, I've rarely used shutoffs. Not in SM or BM.

how is this a skills problem? When scootering you have no control over the flow pushing open the inhalation diaphragm. If you leave the stages or deco bottles clipped to a line you have no control over some idiot causing a freeflow which if the valve is off could allow water into the regulator system. No skill problems there really. Some of that can be avoided, but not always

FWIW suspenders also work well for hose retainers if you have any sewing ability.

 

[decompression]

how is this a skills problem? When scootering you have no control over the flow pushing open the inhalation diaphragm. If you leave the stages or deco bottles clipped to a line you have no control over some idiot causing a freeflow which if the valve is off could allow water into the regulator system. No skill problems there really. Some of that can be avoided, but not always

FWIW suspenders also work well for hose retainers if you have any sewing ability.

No mention of scooters in OP, or even of dive types that would necessitate the use of shut offs.

 

[PfcAJ]

I use them, especially useful when scootering or diving in current/flow. Discovering that your bottom bailout gas is empty at 100m after you've scootered like hell to get down the drop line is a bad thing.

If only there was some way to rig your bailout so it wouldn't free flow and you didn't need those shutoffs...