We had been encouraged to undertake a few specialised courses as part of our Dive Masters Training, and the dive shop offered Deep Dive, Nitrox, and being a O2 (Oxygen) Provider.
Deep diving is considered as anything over 18 metres in Recreational Diving. At depths of up to 40 metres you lose colour, the temperature will be colder, and you may experience ‘Narcosis’. Getting narced is similar to being drunk except the symptoms fade as soon as you ascend a few metres. Six months ago we went down to 30 metres where our instructor got us to do a number test (your reaction time usually slows down), and showed us the effects of the water pressure on a raw egg (it keeps its shape, just like how i would imagine a raw egg in space!). Lionel got quite narced, and experienced extreme happiness and calmness. To the point where he wanted to stay down at 30 metres forever! It can get quite dangerous underwater especially if you suddenly lose yourself and forget important things such as keeping the regulator in your mouth, being aware of the time you’ve been at that depth, or get distracted by some pretty coral.
Nitrox Diving is diving with a special blend of air in your tank. In normal air that you breathe, it’s 21% oxygen and 79% nitrogen. People generally use this percentage in recreational diving. In Nitrox blends, you can increase the oxygen (most common is 32% or 36%), thus, decreasing the amount of nitrogen you are breathing, thus, lessening the amount of nitrogen in your body, which may cause decompression sickness (DCS – very bad). Using a Nitrox tank means a few things, you can stay at depth for longer, you have less surface time in between dives (to allow the excess nitrogen to leave your body), and you may have less chance of DCS. It is pricier, so we use it rarely.
We also undertook a one day class in being an Oxygen Provider. Our boat has two tanks filled with 100% oxygen, which you need to administer to a victim who may have experienced near drowning or someone who may have DCS. We are also now EFR (Emergency First Responders) trained, which can only be a good thing!
All in all, a few days of studying and then diving. Not a bad way to spend a week on Koh Tao.
