Tuesday 29 April 2014

Diving Equipment: The basics

What is Scuba?

Scuba is the acronym that we use to describe the equipment we use to go Diving underwater. It stands for Self Contained Underwater Breathing Apparatus. I promised in my last blog that, for those not in the know, we would look at the Diving Equipment Basics.

The Scuba Equipment we use has evolved quite a lot since the days of Jaques Cousteau and today comprises of several individual pieces of kit that link together to create a streamlined unit allowing us to breathe underwater.

8 scuba diver cylinders with valve at the dive centre Cylinder

The first thing we need to go Scuba Diving is a cylinder of air.

Anyone who has put their head underwater in a pool or in the bath knows for sure that a human being cannot breathe in water, so, much like astronauts on a foreign planet, we have to take our own gas supply with us. This usually comes in the form of a rigid steel or aluminium tank of air (NOT oxygen) that we wear on our backs.


The tank of air isn't much good to us if we cannot access the gas to breathe it. To facilitate this we use a set of regulators

A set of regulators is usually made up of a 1st stage, which connects to the valve on the cylinder of air. There are usually several hoses that come off the first stage, two of which are attached to second stages. One of these second stages is your primary regulator that you will breathe from while the 2nd is an alternate in case, for some reason, your dive buddy needs to breathe off your cylinder.

There is also a High Pressure Hose connected to a gauge that will tell you what air pressure you have in your cylinder and another Low pressure hose that connects to your Buoyancy Control Device.


mares bcd for scuba diving
The buoyancy control device is a jacket or wing that you can add and subtract air to/from to assist in controlling your position in the water.

As Scuba Divers, we don't want to be swimming at the surface and we don't want to be walking along the seabed (that is bad for the environment). Neither floating nor sinking but somewhere in the middle, which we call Neutrally Buoyant. Our BCD can help us achieve this.

On Descent, we add some air to the BCD and on ascent, we release air from the BCD and this will help us to maintain that mid-water positioning.

Wetsuit or Drysuit

diver in drysuitWater takes heat away from our bodies approximately 20 times faster that air does, so we get cold much wetsuit or a drysuit.
quicker underwater.  For this reason, we wear an exposure suit, which comes in the form of either a

A wetsuit works by trapping a thin layer of water between the neoprene of the suit and your body and this layer is warmed by you. This trapped, warm water will then keep you warmer for longer that water that is continually changing such as when you swim without a suit or water that is swilling in and out of a wetsuit that is too big. This is why putting a wetsuit on can be a challenge. They must be well-fitting to do the job they were designed for.

A drysuit does what it says on the tin. The whole suit is sealed off, keeping the bulk of your body dry and warm with a layer of air between you and the suit and the water.

Fins, Mask and Weights

The final three items are very important for scuba diving.

Our eyes cannot focus in water and so we need to create an airspace around them but we need to be able to equalise this airspace as we go deeper underwater and the water pressure pushes the mask harder onto our face. Enter the diver's mask, made with tempered glass to withstand the increased pressure underwater, with a soft squishy nose pocket that allows us to equalise our ears and the mask airspace.

With all the scuba diving equipment we use, you would think that we would all sink like a stone but unfortunately, we become quite floaty. This is why Divers usually have to add a couple of lead weights to their equipment to allow them to sink below the surface.

Finally, with all this diving equipment, you will not be going anywhere without size 2000 feet. Since adults average between size 5 and 12 feet, an easier option than plastic surgery is to buy a set of fins. These offer propulsion through the water allowing you to swim and glide with ease.

So, these are the basic pieces of equipment needed to go on a scuba dive. As you progress, you will get more essentials to add and as your diving career grows, so will your dive bag :)

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