Basic Terms to Know About Scuba Diving
Regulators / Regs – this is what you use to get the air from your tank into your mouth. They regulate the high pressure air in your tank, reducing it to the same pressure as the water that is around you, so that breathing is easy.
First stage (regulator) – this is the part of the regulator that attaches to the tank, reducing the air to the safe pressure for the hoses.
Second stage (regulator) – this is the part that goes in your mouth, the second part of reducing the air pressure to the correct pressure.
BCD / Buoyancy Control Device / Stab jacket – not some sort of fight protection, but a device that you wear (as a jacket) that helps you stabilise your buoyancy in the water. With many pockets to store other bits of gear in, you add air into it to increase buoyancy and remove air to reduce buoyancy in the quest for neutral buoyancy.
WingsAn alternative to a BCD, its shape means that the air pockets are either side of your tank (as opposed to surrounding you in a BCD). It gives a more face down swimming aspect, which is brilliant for diving, but can be a problem for the less experienced diver on the surface.
Buoyancy – are you floating, sinking, or swimming level? An object that is positively buoyant will float, one that is negatively buoyant will sink whilst a neutral one will hover in the water, which is what we as divers desire.
Gauges – how much air have you got left? Your gauges will tell you just that. A simple look will tell you how many bars of air you have remaining. You start off with about 200 (maybe even 300) bars and every breath slowly reduces the content of your air cylinder until it is empty.
Tank – contrary to many TV programs, the tank that we carry on our backs contains nothing more than normal atmospheric air, that has been dried. It is not an oxygen tank – if you breathed pure oxygen deeper than about 6 metres you would kill yourself. Unless you are trained to use Nitrox or other mixes, you are just carrying normal air.
Open water – you may here about Open Water certification, open water training, open water dives and so on. These are all just referring to bodies of water other than the confines of swimming pools. From quarries to oceans, they are all open water. And an Open Water certification is the basic PADI certification that allows you to dive without being accompanied by an instructor.
PADI / BSAC – these are two of the main diving organisations, but there are plenty more. They provide reference material, set the syllabuses for courses and monitor the dive centres.