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Crystal Dive > News Archive > 2016 > January 22nd


Scuba Diving A-B-C


Do You Know Your BCD From Your SPG?


When you start diving, it can be a little overwhelming when you hear all the jargon, abbreviations and acronyms that we use. It sounds like a new language that only scuba enthusiasts or professionals understand.


Let's have a look at some of the specifics and allow me to break it down for you so you know what things mean in layman's terms.


Firstly, let's start with what the word SCUBA means....


SCUBA stands for Self-Contained Underwater Breathing Apparatus, which basically means having the ability to breathe underwater using specialized equipment and a cylinder that is filled with compressed air. One item that is part of the specialized equipment I have just referred to is a BCD. BCD stands for Buoyancy Control Device.


The BCD looks a bit like a waistcoat that you can inflate with air, so it's basically a balloon that you wear. You control how much air goes in and out of your BCD depending on what you are doing at that particular time. You would fully inflate your BCD whenever you are on the surface, which will make you positively buoyant or as you would call it, float.



To inflate your BCD we use our LPI. LPI stands for Low Pressure Inflator. It is basically a hose that connects your BCD to you tank of air. It has two buttons - usually one button is red and one button is grey. The red button inflates your BCD. This button should only be used when you are on the surface, or to slightly adjust your buoyancy under water, as you will be taught during the open water course.


The grey button deflates your BCD. This is used when you descend for a dive so you can release the air, and become negatively buoyant, thus sink below the surface. We also release any air still in our BCD when we ascend from a dive. The LPI hose should always be hel up vertically when releasing air from the BCD.



Next you have your Reg or regulator, which is the piece of equipment that you breathe through when you are under water. I'm sure you've noticed already how many short abbreviations and acronyms there are. It only makes sense then to shorten the word regulator to Reg.


You also have a gauge called an SPG, or Submersible Pressure Gauge. This is the device that tells you home much air you have left in your tank. It is important to monitor this gauge frequently throughout the dive.


Now that we have discussed some of the equipment, you need to do a buddy check to make sure all your equipment is in good working order.


We use an abbreviation "BWRAF" or "Bangkok Women Really Are Fellas", which stands for:


W: Weights
R: Releases
A: Air
F: Final Check (fins and mask)


Once you and your buddy have performed this pre-dive safety check, you are A-for-away to go diving!


A sneaky acronym that we use when we are preparing to descend for a dive is SORTED, which stands for "Signal OK to go down", "Orientate where you are going", "Regulator in", "Time", "Elevate LPI hose", "Descend", don't forget to equalize your ears.


That is an easy way to remember all the key aspects for a safe descent.


Before completing your dive, it's always a safe habit to release an SMB, which is a Surface Marker Buoy, which lets boats know that divers are planning to ascend from a dive and should stay clear for safety.


Some refer to this as a "safety sausage" or "red rocket".


The acronym "STELLA", is used for a safe ascent. It stands for "Signal OK to go up", "Time", "Elevate LPI hose and your other hand above your head", "Look and Listen for any boats or obstructions", "Ascend at a slow controlled pace".


Another important abbreviation is NDL, which stands for No Decompression Limit. This is especially important when diving to deeper depths or doing multiple deep dives in a day. There is the NDL number on a dive computer that decreases with the depth and time of the dive.


It is important to watch this number closely.


And finally the world's most popular training organization is PADI – Professional Association of Dive Instructors. PADI offer the most recognized and comprehensive system of scuba education and…yes, you guessed…..some of these courses are abbreviated too!


Here is a breakdown of some of the courses that are available:


DSD - Discover Scuba Diving
OW - Open Water
AOW - Advanced Open Water
EFR - Emergency First Responder
Resc - Rescue Diver
DMT - Divemaster Training after which you qualify as a DM (Divemaster)
IDC - Instructor Development Course
MSDT - Master Scuba Diver Trainer


Author: Heather Nicholson (PADI DM #370231)





..January 2016


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