There were screwed-up deco plans. There was one diver who went off tangent. There was one who threw up at 35m, and there was one who thought he had left the bottom when he was still there.
Narcosis? Maybe. But doing hard work swimming down to 45m is no joke. Free descent may not hit you hard, but having to swim 10 minutes to get to your bottom depth of 45m…the CO2 build-up, your hyperventilating etc, leads to narcosis.
It all began on Friday when the sea looked like it wanted to swallow the Panuba jetty. Four divers in twin tanks jumped into the sea for familiarisation and basic skills practice. It was simple skills, gas-sharing, valve drills, and trying to maintain buoyancy 0.5 meters above bottom.
The next day, it got more serious. This time we had to swim ON the line without touching it, then learn how to deploy the SMB. More gas-sharing drills, valve drills etc. Removing the BCD and wearing it again. All these skills were done while in a horizontal position, between 0.5m to 1.0m above the sea bed. Then we had to ditch and don. But this time was to ditch, do a CESA, take three gulps of air, and free dive down to the equipment and don it again.
This is a more extreme version of the Open Water course. In the OWD course, you kneel down and demonstrate the skills. In the Decompression Procedures course, you cannot even kick up silt, let alone touch the bottom. If you do, you’ll get a powerful reminder.
Kicking up silt, in tec dives such as cavern/cave or wreck penetration will put your dive team, and you included, in unnecessary but very dangerous situation. Hence, in this course, it is not breatheable gas/air that is the most important, but it is maintaining buoyancy in ALL conditions: normal and emergency. Other skills that you need to do is being able to dive in a stable posture, with your twin-tank assembly,and a stage tank. Then you add more tanks,until when you would be having 6 tanks, swimming comfortably and still maintain your buoyancy. Once in a while you would notice that you have “run out of air” and have to quickly get to your buddy to share gas.
To take this in a slightly more extreme manner, you will also have to swim, with your twins and stage tank, 15 meters to your buddy, on a straight line, with no regulator in your mouth, and hope your buddy is quick to push his mouthpiece into your mouth while you purge the regulator and breathe normally. Just when you thought that the worst is over, you have to repeat the same skill…this time without wearing a mask!
Diving past your non-decompression limit is unlike the deep dives you do in recreational diving. While at 30m you are taught that you can still shoot to the surface with a safety stop at 5m for 3 minutes, diving past your NDL means diving with a virtual overhead. Ascents, if not managed properly, can cause great pain, injure, maim or kill you. You cannot shoot to the surface in the case of an emergency. Therefore, buddy checks are more thorough, and knowing your buddy’s SAC rate should be like knowing the back of your hand, as your life may depend on how much air/gas he/she has left should you run out of yours.
The next day we practised doing deco stops several times and learnt who is Mr Bent, Mr Solo Diver, and Mr Okay-lah. Later that afternoon we were tested in real conditions. Bad viz, relatively strong current…the Sawasdee Wrecks. I was actually diving Trimix, as my tank had some 32% O2 and around 4% Helium, remnants from some dives done by B&J divers when they rented the tanks from Bali H’ai. I thought the air tasted different. Down at 30m, we were still being thrown at with several scenarios like out-of-air, and gas freeflow/leak. But once we passed the non-deco limit, the real test commenced. We had our deco plans…main and back-up. After getting off the bottom late to the first deco stop, we had to switch to a back-up deco plan and do stops differently than what was originally planned. At 21m we switched breathing gas from 21% to 50%. Moving up along the mooring line, none of us wanted to screw-up our buoyancy or deco plan.
That night, we did 5 deco plans including one for lost gas….that is if we run out of deco gas or lose the bottle totally, the rock bottom gas etc, for the last dive.
The last dive, we headed for the Soyak Wrecks. For this dive we were required to descend to 30m, then swim out to 45m, and do a free ascend (not holding on to any line) and maintain buoyancy while doing the deco stops. This was when one diver just went off-tangent, and another started throwing up the breakfast he had had earlier that morning. Me, it was hard to focus on the deco plans on my slate.I saw double and had to relax for a while. Finally, after 13 minutes and 20 seconds, we got down to 45m.
After 20 minutes at depth, we were supposed to leave that depth for our first deco stop at 24m. At 45m, you just cannot “lift” yourself off the floor. After some puffs of air into the inflator hose (I wanted to have a lot of padding air-wise), I managed to float to 24m..but had to go to the first back-up plan as we had left the bottom two minutes late.
At 21m, I had to remind myself of the acronym NOTOX, before switching gas. The other stops at 18m, 15m, 12m,and 9m were pretty normal. Then one diver ran out of deco gas and had to double his deco time at stop depth as he had to switch back to normal air.
So, what benefits do I think I gained from this course? A lot. It changes my whole perception of diving, and most of the knowledge gained I can pass on to others, especially to my two diver daughters. It teaches you to be a lot safer diver than when you were just a recreational diver. You also learn a lot more about your dive team members, their air consumption rate and so on.
I would like to thank my dive team members, Jim and Shah (Kudinne), for being good dive team members. At this juncture, I know I can rely on their help should I enter some life-threatening situation. I would also like to thank our “dive support member”, Anas, for being there to help us out with our stage tanks pre and post dives. Carrying three 12 liter tanks on you, plus up to 8kg weights (for those without a backplate), is no joke.
Would I recommend friends the course? Remember, decompression does not just happen to technical divers who dive really deep. It can also happen to recreational divers who spend too long a bottom time at shallower depths, especially those who do underwater photography. So, yes, I would recommend this course to my friends..they don’t have to become technical divers and go beyond this course if they want to stay as recreational divers; they can use the knowledge gained for their recreational dives. Believe me, you will feel a lot fresher coming out of deco dives than out of recreational dives safety stops, even without the use of Nitrox deco gas.
As for me, I’m tired of watching Nemo. Time to go a lot deeper.
SeaDemon Says 