Friday, 5 October 2012

HOW TO: SET UP A STAGE CYLINDER - PART 1: RIGGING KIT

This article is designed to allow the reader to make the perfect rigging kit for their stage/decompression cylinder.  Although there are many rigging kits on the market, most are not fit for purpose; the only ones I would use are made by Halcyon or DIR Zone. 

Overview
A correctly worn stage/decompression cylinder will be stable on the body and easy to manage, especially when using more than one.  Within most agencies the standard practice is to wear the cylinders on the divers left side (due to the long hose and the possibility of a scooter (DPV) on the right), clipped off to the left chest D-ring and left hip D-ring.  Any cylinders not worn here are usually towed behind on a leash.  When worn the cylinder (valve outlet) should face up, the valve hand wheel should be on the left making it easy to use. 

Construction
The rigging will also be made from rope and offer no metal to metal contact so all connections can be cut by a knife/cutter if required in an emergency.  The p-clips will be made from 316 marine grade stainless steel (not brass) with a 1” eye to aid clipping off.  This is to allow one finger to maneuver the cylinder whilst the thumb operates the gate.  Remember; despite its name, the handle is not to be used as such.as it loosens off the rigging.  The handle is designed to lift the stowage bands away from the cylinder allowing the diver to gain access with their finger/thumb to stow the regulator.

The following guide will allow you to construct a kit similar to the ones I mentioned above.
You will need the following to make the rigging:
1.
2m braided polyester line (I used this).
2. 2x 316 stainless steel boltsnaps (see below).
3. 12” of rubber fuel hose (I used similar to this).
4. 180mm 316 stainless steel jubilee clip.
5. 1” strip of racing bike innertube.
6  3x 1” strips of car innertube.

In addition you will also need to following to assist in the making of the rigging:
1. Lighter.
2. Scissors/knife.
3. 18” of cave line (the stuff from your spool).
4. Screwdriver.
5. Tin snips.

There are various types of p-clips on the market and on the right are a few of the most commonly seen. 
(From L to R) The first one is the ideal clip.  Its 1” eye means it’s easy to manipulate however the gate isn’t so large that you’ll accidently clip it to something you shouldn’t.  Although the next also has a 1” eye, the larger gate is a double edged sword.  It’s much easier to clip on than the previous clip however it’s also very easy to accidently clip it to something you shouldn’t.  Finally the last one whilst ideal for regulators, backup torches and SPGs, is very hard to manipulate and one would struggle to find the left hip D-ring.

Fold the line so that one end is approximately 9" longer.  Attach the length of cave line and use it to pull the thick line through the hose.

Pull about 20cm (8") of line through so you have enough room to attach the upper p-clip.

Attach the upper p-clip by using an overhand knot.

Place the rigging over the valve on the cylinder.  The p-clip should be positioned so it lies above the cylinders’ shoulder, on the crown.  If it's too low the bottle will cause a lot of drag once clipped to the diver.

Tie an overhand knot just below the hose.  Make sure the knot is tight as possible and that’s it’s as close to the hose as possible.

   
You can attach the lower p-clip so it's either removable or permanent.  I prefer the removable method as it tends to be easier to locate.

You want 3-4" of slack on the lower p-clip.  If you want it closer you can wrap the p-clip under the handle once the rigging is finished (see below).

Now we’re going to make a fishermans knot (two overhand knots) to hold everything together.

With the longer line, tie an overhand knot approximately ½” below the knot at the base of the fuel tubing.  Be sure the shorter section of line runs through the loop of the knot before it’s tightened.  Tighten this knot as much as possible.  The ½” space is where the hose clamp will be positioned.

Tighten the second overhand knot against the prior overhand knot, creating a fisherman’s knot. 

Try to make them "fit" together and be as tight as possible.

When you are satisfied cut of the excess line and burn the ends with a lighter.

The rigging is now complete. 

Undo the jubilee clip and slide the racing bike innertube over the clamp.

Place the rigging over the cylinder as before and slide a length of car innertube over the cylinder.  This will go underneath the jubilee clip to minimize corrosion between the 2 different metals.

Place the jubilee clip on the cylinder so it fits between the knots on the bottom of the rigging. Pull down on the rigging and tighten jubilee clip as tight as possible. 

Cut off any spare clip with snips.

Finally put on the car innertube strips over the handle for regulator stowage.

As previously mentioned if you want a shorter leash, wrap it around the handle.












Well done, your stage/decompression cylinder is now rigged ready for use.  Next we need to ensure it is correctly marked and the stage/decompression regulators are set up correctly.

The boring bit!
All opinions expressed in my articles are my own and may differ to other instructor’s and agency guidelines; by no means are they wrong and I would not wish to disrepute any of them.  This article is for information only and should not replace proper training.

Safe diving!

Timothy Gort
BSAC, PADI & SDI/TDI diver training
l Mob: 07968148261 l Email: tim@rectotec.co.uk l