My SCUBA Diary

Learning to correctly assemble your SCUBA gear is definitely a life-saving lesson. You need to be absolutely sure that your SCUBA is working correctly before you dive!

It’s all very well discovering a fault while diving in the relative safety of a swimming pool, you can safely and quickly surface, but discovering the same fault at 30 metres could be severely life limiting.

A visual check of the your SCUBA components is an obvious start; Does everything look OK? Are any of the hoses worn or loose? Are there any cuts, tears or abrasions in your BCD? Is your cylinder in good order?

Now check the pillar valve on your cylinder, is the rubber O-ring in place? If it isn’t your SCUBA gear will leak air noisily at an alarming rate! Is the O-ring clean and in good condition? Would now be the time to remind you that it was a fault in a simple rubber O-ring that caused the Space Shuttle Challenger disaster?

Fit your regulator set onto the cylinder pillar valve, align it carefully and don’t over-tighten the fitting… you need to be able to get it off again!

Now press the front of your contents gauge against the side of your cylinder or other solid surface and turn on the air. Open the cylinder valve all the way to the stop and then turn it back one quarter of a turn. In case you’re wondering, holding the glass front of your contents gauge against a solid surface protects you from injury should a fault have developed in the gauge causing the glass to fly out as you apply compressed air.

Now… Shhh… Listen carefully? Is anything leaking? Hopefully not, but if it is then you need to find out what and fix it before you go a step further.

Pick up your demand valve and release some air through it by pressing the purge button, the air should flow freely. Now smell the escaping air, is it clean? It shouldn’t smell of anything. This is a good time to discover that a faulty compressor has filled your cylinder with contaminated air!

Check that both your DV and Octopus are working correctly. Watch your contents gauge as you breath in and out through both valves, the gauge should remain steady, if it drops rapidly or fluctuates as you breath then something is wrong.

Now turn off the air supply and check the contents gauge, the pressure should remain stable, if it drops away then your SCUBA gear is leaking somewhere.

Press the purge valve on your DV to exhaust all the pressurised air from the system, the contents gauge should fall to zero if all is well. At this point try breathing through both your DV and the Octopus, you shouldn’t be able to suck any air through either, if you can then the valve is faulty.

Now turn on the air again, remember to follow the same safety procedure as before.

This time inflate you BCD. Does it inflate smoothly? Can you hear any air escaping? Once it’s fully inflated leave it for a minute or so and make sure it stays inflated, if not then find the leak… Release the air from your BCD before climbing into it.

I’m assuming at this stage that you’ve fitted your BCD onto your cylinder and the band is tight and secure? You don’t want your cylinder falling out of the band while you’re diving (trust me… it’s more than annoying…). Getting the cylinder is exactly the right place takes time and experience, it’s not life threateningly crucial but it can be annoying if your cylinder is too high or too low, it affects your attitude in the water and can restrict your head movement making it hard to look directly forward when swimming horizontally.

Now have your buddy hoist your SCUBA onto your back. Exactly how you do this depends on your SCUBA gear, needless to say it’s a cumbersome and mostly inelegant procedure for anyone new to SCUBA… only time and practice will improve matters.

Now you’re ready to carry out your buddy check…