Safety Notice

Before 2008 gets into full swing, this is a good time of year to review systems and techniques and here are some pointers, gleaned from our own experience, customer feedback and through our QA system.:

Preparation:

Proper preparation is the key to safe rebreather diving.

As divers, we need to practice deploying bailout and practice drills but bailout and drills are the fall back position when the preparation hasn’t been good enough. Get the preparation right and you will save yourself a lot of trouble.

Scrubber By-Pass (Vision owners only) :

Some time ago we brought it to the attention of the Inspiration/Evolution community via the Inspiration list that if the Temp-stik cable is not tucked away it can get caught under the peripheral O ring – the one that stops CO2 coming past the scrubber cartridge.

At the time, we recommended tucking the connector inside the sensor cover. Some divers argued they didn’t want to do that and I advised another method of removing the convoluted hose from the lid and pulling the connector up inside the sensor holder, ensuring that the cable and connector cannot interfere with the O ring seal, you keep the cable taught while you place the lid on the canister.

Since then, it has come to our attention that some divers still leave the connector laying between the sensor cover and the scrubber cartridge top - unfortunately in this position there is a risk that it may get trapped between the base of the sensor tube and the top of the temp-stik – effectively pushing the whole scrubber cartridge off it’s O ring – allowing catastrophic CO2 bypass.

We have to make our advice clearer –

1) Please, during assembly, after mating the connector push it gently inside the sensor cover, followed by as much of the cable as you can. The large opening is in-line with the solenoid when the sensor cover is aligned properly with it’s keyed slot. Once in this position it is easy to slot the connector through the large hole.

2) Do a pre-breathe to check the CO2 absorption prior to diving.

Accessories:

When you fit anything to the rebreather, you have to be sure it is not adversely affecting the rebreather.

Stainless steel backplates: this issue has been raised many times in the past and yet it still occurs: in one incident last year the diver had fitted a stainless steel backplate which impinged on the wing, allowing it to only achieve 1/3rd of it’s designed capability.

Big Wings: some divers fit a big wing from other manufacturers. IF you change the wing you must ensure the wing does not interfere with or squash the rear breathing hoses. (Personally I believe in getting my weighting right so I don’t need a big wing.)

Slide valves, such as the APD flow stop: useful little devices, but you have to make sure you know which way is which, practice, practice and practice again. A closed slide valve can be the catalyst for bigger problems.

Incompatible oxygen cells: the oxygen cells used need to be compatible with the electronics. The cell’s response time across it’s whole working range has to be compatible. Stick to the originals. We will not service a lid fitted with alternative cells. Our servicing is done on a fixed price system, based on known labour times. Once you place unknown cells in the rig, the testing has to be increased and then we are dealing with an unknown quantity and cannot predict the eventual cost.

Bailout: please practice the deployment of bailout to the extent of ensuring it reaches your mouth and the gas is turned on. If you inhale water, you need to bailout NOW –please make sure your bailout is ready.

Servicing: now is the time of year to get your gear serviced. Items should include: the Auto Air on your BC, servicing and renewing the oxygen clean status of your first stage(s), cylinder valve(s), and cylinder(s); check the date of the oxygen cells and quality of the connections, quality of the battery box and then when you’ve had it serviced try it all out in a swimming pool before you take it into open water. It might sound silly to some but I won’t even take a new mask on a Trimix dive unless I have checked it out on a less serious dive first.

Safe diving in 2008.

Martin Parker

Martin Parker
Managing Director
Ambient Pressure Diving Ltd