Open Water Diving - refresher

If you've not dived for some time (for me it had somehow been five years since I completed my Open Water course, and I'd done nothing since), I'd recommend taking a "Refresher" course - you get to try the equipment out in a pool first, then take a 12m dive. I also asked to borrow the Open Water book the day before, and skimmed through it all again, which was very useful.

In the future I want to be more ready for my first dive, so I've written the following notes as a refresher for myself.

If I've missed anything out, leave a comment :)

NOTE: I am not any sort of authority on diving, these are written for my own usage and only as supplemental notes for anyone who might find them useful. You should already know how to dive. If you have not dived in a while, I highly recommend taking a refresher course yourself.

Morning of the dive

I recommend not drinking coffee before a dive, and absolutely not being hung-over or sick. You should be able to clear your ears easily. Go to the dive center wearing swimming trunks, take sunscreen.

Rehearse the underwater communication gestures beforehand.

Preparation of equipment:

  • Take your wetsuit and put it on, waist high. Attach your weights, arranging the weights evenly and generally evenly between around the hips. The release for the weights should be openable with your right hand (because the BC is opened with the left hand, to avoid confusion).
  • Inspect the seal of the air tank to make sure the rubber is still good and the gauze is not green.
  • Put the BC over the top of the tank and use the velcro to strap it on, leaving a four-finger sized height gap between the velcro and the top of the text printed onto the tank.
  • Put the pressure gauge inside a pocket of the BC, because once we put pressure into the regulator, if there's any damage to glass it could shatter.
  • Attach the low-pressure inflator hose to the BC (can be tricky - pull back and push in)
  • Attach the regulator to the tank valve, to a two-finger-and-thumb tightness - do not over tighten it.
  • Open the air, initially a bit to check nothing bad will happen, then open all the way, with a half-turn back again so that it's easy to check it's open later on.
  • Check the gauge, it should register the pressure properly (it should be > 100 PSI).
  • Take three hard inhales and exhales in the primary and secondary regulator "demand valves" and ensure that the needle doesn't (or barely) move on the pressure gauge. Test the purge function on both, as well.
Breathe the air through the regulators to ensure that it is fresh and dry: impure air is extremely dangerous underwater, but can usually be recognized through an unpleasant, often oily, taste or smell.
— https://en.wikipedia.org/wiki/Buddy_check
  • Inflate the BC and check it's not leaking air. Deflate it. (Blow it up again using your mouth. Deflate.).
  • Tuck the Primary & Secondary regulators into the BC jacket, as well as the depth gauge.
  • Turn the air off again.

On the boat trip out

  • Add soap to your goggles, wait a bit, then rinse it out well.
  • Put on your fins and zip up the wet suit.
  • Get yourself into a zen mode, you should be ready to dive and not stressed or worried.

Before diving

Wikipedia: Buddy Check.

  • Test inflation and deflation of the BC. Inflate orally. Check dump valves work. The BC should be inflated when you enter the water.

> B> ruce > W> illis > R> uins > A> ll > F> ilms:

- BCD 
- Weights 
- Releases 
- Air
- Final Check
  • Buddy check - do the same for your buddy.
  • Two fingers over the mask, hold the regulator in your mouth, cross your legs, roll backwards off the boat.

Descending

  • Once in the water, hold a fist to your head to indicate that you're okay to the boat.
  • Let all air out of the BC (hold inflator hose above head, let air out with deflate. Or, press the dump valve)
  • Breathe out to sink
  • Your speed will increase as the buoyancy of the wet suit decreases. Thus, add a small amount of air to bc to control descent.
  • When at correct depth, add air to BC (if needed) to establish neutral buoyancy.

Neutral Buoyancy

  • when going deeper, add air to BC to avoid sinking
  • When moving upwards, release air to prevent yourself bubbling upwards.

Under Water

  • If you feel like you can't breath, are panicing or freaking out - breath slowly outwards, and slow the breathing down. Excess CO2 in your lungs is what gives that suffocating sensation. Possibly take a break - if you're out of breath you need to get your breath back.
  • Never bolt for the surface.
  • 50PSI means the dive is over, prepare to ascend.

Ascending

  • Be neutrally buoyant before starting
  • Kick upwards gently to start ascending

Returning to the surface

  • Don't forget the safety stop on the way up: 3 minutes at 5 meter depth.
  • On reaching the surface, immediately inflate the BC so that you don't sink again.

Getting on the boat

  • Pass the equipment up in this order: weight belt, fins, BC & tank.

Packing up the equipment

  • Lay the weight belt open on the floor
  • Turn off the air supply, purge the remaining pressure from the regulator, then unscrew it. Use a little air to blow-dry the cap of the regulator, then screw in the cap.
  • Detach the regulator's low-pressure hose from the BC, then remove the regulator and hang it on the hanger.
  • Hang the BC on the same hanger, then lie this down on top of the weight belt
  • Wrap the fins with the mask and lie this inside the BC.
  • Wrap the weight belt around this all to form a package which can be easily moved around.

Cleaning & storing the equipment

(Presumably it's the same everywhere)

  • Take off the wetsuit and soak it. Wash the mask and fins.
  • Lie the regulator to soak in the water, with the valve out of the water on the side.
  • Wash the BC, then open the oral-inflation valve and fill it ⅔ full with water using a hose. Inflate it with your mouth, then swill the clean water around inside. Deflate it & let all the water out - holding it upside down over one shoulder with oral inflation valve held open downwards works well.
  • Hang up the wetsuit.