The following article illustrates my experiences with running stage bottles while cave diving, however the method the bottles are rigged and the marking procedures are suggested for any type of technical diving that involves the use of extra tanks.

Stage/Deco Bottle Rigging

Today there are many of us that wish to venture deeper into cave systems, and explore the vast amount of unmolested shipwrecks that lie in deeper waters. This type of diving almost always dictates the use of decompression mixes other than your backgas, as well as travel mixes that enable you to reach your objective.

Having the correct bottle rigging and markings are of paramount importance. If you have a poorly rigged stage bottle, it can quickly become a liability as an entanglement hazard. As well as, not having the bottle marked properly and prominently can be an invitation for a fatality.

Typically divers will use aluminum 80s for stage bottles, the reasoning here is this is the largest "manageable" size. However, I myself use aluminum 40s at times for planned decompression dives, as they are easier to negotiate and stream line a bit better. One important note on tanks, never use steel tanks for deco or stage bottles. Their negative bouyancy characteristics can easily become a liability.

(fig. 1) This is a properly configured aluminum 40 deco bottle. Note the length of the high pressure hose leading to the secured pressure gauge (6"). Also the low pressure hose leading to the second stage is a 40" hose, this permits routing the hose around the back of the head so that it is in proper alignment when breathing. (Some auxillary second stage hoses are of proper length, but I have found a 40" hose to be most comfortable.)

I would also like to point out a couple of other pieces here. Notice the hose clamp on the bottom is covered with a cross section of tire innertube, this prevents the sharp edges from cutting you or worse yet, cutting your guideline. You will also notice that I use a piece of surgical tubing to secure the long hose, many prefer just to use another cross section of innertube, either method works fine. Take a look at the bolt snaps, the top snap (somewhat obstructed from view in this picture by the hose) is closely attached to the tank as it begins to curve in towards the valve, and the bottom bolt snap has about 2 to 3 inches of "tail". This allows the bottle to be snug to the chest, and the bottom enough play to find its best position in the water. When measuring for the position of the bolt snaps, the top should be able to fasten to your left chest D-ring, and the bottom snap should be able to fast to your left waistband D-ring.

The necessary parts needed to rig your bottles in this method are as follows:
(2) s/s bolt snaps (size depends on usage)
7 feet of 1/4" braided nylon rope
large s/s hose clamp (size depends on bottle)
1 foot of clear vinyl tubing (3/8" inner diameter, available at Home Depot, Lowes, etc)
some inner tube cross sections and 1 1/2 foot of surgical tubing
s/s split ring (optional)

(fig. 2) To begin, I normally take my section of nylon rope and fold it so I have two equal lengths, I then take the loop section and feed it through the clear vinyl tubing (use a coat hanger, easiest method I have found). Once I have a section of it through, I go ahead and loop it through a bolt snap (this will be the bottom snap) and secure it using the hose clamp, once completed, it should look a little something like this.

A good rule of thumb, the bolt snap on the bottom should hang almost even with the bottom of the tank when it is secured with the hose clamp.

This picture is for illustration, but normally you would have a section of innertube under the hose clamp as well, this prevented marring of the tank finish, as well as any possible galvanic action that could occur between two dissimilar metals.

Once you have the bottom secure, you are now ready to move to the top bolt snap. I normally loop the nylon rope through the bolt snap at the point where the tank begins to curve in towards the valve. This brings the take right up under your arm while swimming, and seems to produce the least drag. Once you have the bolt snap secured, you then proceed to tie the nylon rope off by looping it around the tank valve. It is critical that you get the rope as tight as possible here, to eliminate as much slack as you can. I also attach a small s/s split ring here (optional), this allows me to quickly "park" a reg on the bottle. Your finished product should look like figure 3.

Notice also how I have positioned the rope and bolt snaps in relation to the tank valve. In this configuration, you can operate the tanks valve with your left hand very easily. This is advantageous in the event you have a free flowing regulator and are not able to rectify the situation, you can manually control the flow of gas with your left hand while still keeping your right hand free for other things.

I have had people ask what the clear vinyl tubing is for. Well, simply, it is a handle. It allows easy control of the bottle while in water, I have seen people carry their bottles by this handle above water, which is a big no-no. It stretches out the nylon, and well, then you have to adjust everything again. The tubing actually does have a secondary use, that is it keeps the rope together and free of entanglements in your gear. (Reels, lights, knives, etc.)

Once you have completed all the above, your bottle should be at this stage in the configuration process. (fig. 4)

The only part that is left to complete is the configuration of your regulator and pressure gauge. Once again, I would like to stress the importance of a short high pressure hose. If you are using a standard length hose (and Ive seen it done, many times) keep in mind it needs to be tightly secured to the bottle by numerous pieces of surgical tubing or tire innertube. The high pressure line, in my opinion, if left at full length turns into one of the most notorious entanglement hazards that you can have. Also, if you are diving on a wreck or in a cave with sharp rock, it can easily get cut if you are not paying attention.

When securing the pressure gauge, I use a small loop (approximately 6" in diameter) of surgical tubing. Position the pressure gauge behind the 1st stage, and take the loop of surgical tube and hoop the pressure gauge with it, and stretch it forward until it loops under the front of the 1st stage. This gives a very secure attachment, it is very low profile, and places the pressure gauge in the best alignment for viewing. Once attached it should look like figure 5. (Sorry about the out of focus picture ;-p)

Stage bottle rigging is not rocket science, simple is better. The other warnings I would give are, stay away from suicide clips. They will get you hung up quicker than a buddy that has never ran a reel!

If you have any questions, comments, or corrections, feel free to contact me at webmaster@technicaldiver.com.

© 2000, David O'Daniel