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LOOK THROUGH THE PAGES OF THE MANUALS of many training agencies and you'll see pictures of divers with their alternative air source in the form of an extra second stage, or octopus rig, configured to hang alongside their primary regulator. It all looks very neat and would make perfect sense if it was for you alone to use in an emergency caused by the failure of your primary second stage. The rubber parts of a second stage - that is, the diaphragm or the mouthpiece - may fail if there has not been a proper pre-dive inspection but would merely give you a damp breathe. However, the second stages of modern downstream regulators rarely if ever fail during a dive. Any failure that does occur is likely to involve the first stage causing a higher than usual interstage pressure and resulting free-flow. That might make breathing uncomfortable, but even if it does mean a rapidly diminishing air supply it should never be allowed to become disastrous. It's all or nothing. Either both second stages will work or they won't! So what is that alternative air source for? It's really for someone else. It's for someone else who has suffered a failure of his or her air supply. Take this on board and you begin to question the normal-style regulator as an alternative air source, rigged conventionally on the right. That's because, if it's rigged correctly for you, it is almost certainly not rigged correctly for a second party. Take that hose off and rig it to the other side of your first stage so that it hangs on your left. You suddenly realise how convenient it makes air-sharing with an octopus-rig. That said, there are several regulator designs that work both right and left-handed and can be positioned equally successfully on either side. Long hoses Some training agencies insist that you clip your octopus on in an uncluttered area of your chest. They call this the "triangle of visibility". The idea is that another diver, out-of-air and perhaps panicking, can find it easily and grab it. I would suggests that if circumstances have become so dire that the other diver is in a panic, it's most likely that you'll have your primary regulator ripped from your mouth. That will always be the one most visible, and visibly working too. For this reason, I believe it's most important that you can access the octopus rig easily yourself. But then, if it's rigged on your left, it will be the wrong way up. Well, you can still use it temporarily and wait until the panic has subsided before you both swap over. Better still, get a longer hose on that octopus-rig so that all the drama is taken out of sharing once and for all. Hoses of 1.5 or 2m length allow you to use the octopus-rig yourself, and so can another diver, who is able to swim conveniently alongside, or face-to-face, or even behind you while using it. But where do you stow an octopus-rig with such a long hose? Some divers like to clip off their alternative second stage in a place from which they can access it easily, and breathe from a primary regulator that is itself on the end of a long hose. A good place for a secondary second stage on the end of a conventional-length hose is to rig it conveniently on a necklace of thin rubber hose under the chin. Simply wind the long air-supply hose of the primary regulator around your neck. In the event of the panicking "diver out-of-air" situation occurring, the donor diver simply lets that OOA diver have the primary regulator from his mouth, unwinding the hose by allowing himself to be rotated or simply pulling the coil over his head. The donor-diver then swaps to the alternative second stage that sits ready and waiting. Others stow all the excess hose of an octopus-rig under a couple of bungee cords wrapped round the tank. The business-end is then stowed where you choose. You must be sure that the whole thing can be pulled out in a moment. The truth is, it's all a question of personal choice. Assuming that you are going to lose the regulator that's in your mouth during those first moments of another's panic, it's important that you can access the alternative, or you'll find that the panic is infectious! If there is no panic - and there really shouldn't be if the other diver is aware of a dwindling air-supply long before he needs to access yours - you have time to deploy your octopus-rig for him in any way you like. You may even want to agree in advance with your buddy that in an emergency you will take the other's primary regulator. Clipping it on How do you clip the alternative second stage in place? The simple necklace method appeals to me, or wear it tucked under a bungee-cord on the tank. Those hose-clips often supplied with BCs are almost useless. At best the hose slips through and at worst the hose just comes unclipped. Both eventually allow the business end to dangle and entangle. Photographs of divers with their octopus-rigs trailing are all too common. There are soft rubber ball-like devices that will hold a regulator by surrounding the mouthpiece. Be careful that the mouthpiece does not come away with the ball when it's grabbed in a hurry. However, you can still breathe off a regulator without a mouthpiece. It's better than drowning. Some companies make a device that clips to the BC but holds the second stage by forming a simple plug. It has the secondary effect of keeping the interior of the regulator free of detritus.  this octopus-holder forms a plug in the mouthpiece, also keeping it clear of detritus Built into the BC What of the alternative air-source that is combined with the direct-feed inflator of a BC, such as the Scubapro Air Two or Buddy Auto Air? These are convenient because they get rid of an additional hose spurred off from your first stage, but they are limited in that only the wearer of the BC can breathe from them. If you have only a conventional length of hose on your primary regulator, things can get very fraught in an out-of-air situation, with both divers uncomfortably close to each other and the diver in trouble having to deal with an awkward hose routeing. The best way to handle this is for the donor diver to approach the OOA diver from behind or the OOA diver to travel piggy-back style with the donating diver to the surface. That way, the regulator mouthpiece is offered with the right aspect. The way in which you rig your alternative air source becomes irrelevant if you don't have sufficient gas for two people, one of whom is breathing rather heavily. You need to plan your dive in such a way that you carry enough for such an eventuality. It is in out-of-air situations that a pony cylinder clipped to D-rings at the front of the harness really proves its worth. A pony is usually one of 3 or 4 litres capacity with its own independent regulator, and you can hand it off if necessary.  pony rig carried as a sling tank The OOA diver should be able take it from the donor diver and clip it to his own BC, making an independent ascent if required. A pony can also be mounted via a quick-release mount alongside the main tank. Whatever you decide, think it through for use at depth and try it out in confined water, sharing with another diver, before you settle on the most satisfactory method for stowing and deploying your octopus-rig.  |
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