Scuba Diving Equipment – an overview
Scuba diving equipment is designed to overcome the limits of human physiology in the submarine world and although the number of items may seem daunting to the beginner, everything has a clear purpose. Below we look at the main items of scuba diving equipment used in recreational diving.
Divers wear a face mask for the simple fact that it allows them to see underwater. The human eye is not designed to see in water, which has a different optical density to air. By simply having an air space between eyes and water the mask allows the diver to see, although the optical density means that all objects appear larger or closer when underwater. Traditionally masks were constructed from neoprene, which tended to age relatively quickly. Today's scuba masks generally consist of a lightweight plastic frame, glass lenses and a silicone rubber skirt that seals against the face. Modern masks also allow a smaller volume of air between the water and the face, which is an advantage because it means it is easier to equalize the pressure in the mask and simpler to clear of water.
While a wet suit is the most common type of suit worn in recreational diving, it is not the only type. Primarily to prevent the diver from losing body heat to the water, which conducts heat from the body at a much faster rate than air, a wet suit consists of a layer of low density neoprene which acts as an insulator and traps a thin layer of water between the neoprene and the diver's skin, also helping to minimize heat loss. The secondary function of a wet suit is to protect the diver from abrasions and other injuries, including stings and venoms.
When the water is too cold for a wet suit to be used divers can wear a dry suit, which as the name implies keeps the diver dry by sealing at the neck and wrists, while in warmer water divers can wear a lycra body suit which provides no thermal protection, but prevents against scrapes and stings as well as sunburn.
In the same way that fish glide through the water by moving their fins, scuba divers are able to propel themselves through the water by kicking their fins. Usually made of neoprene for the foot and rigid plastic for the blade, there are two main types; full foot and adjustable. With the former the diver simply places the boot of the fin over the bare foot, while adjustable fins have an adjustable heel strap and are usually worn over wet suit boots.
The scuba tank – also commonly known as a cylinder or a bottle – contains the divers breathing gas at high pressure. Usually the breathing gas is air, although in some circumstances other mixtures are also used.
The standard configuration in recreational scuba diving today attaches the tank to the BCD (buoyancy control device), often known simply as a jacket. The tank is attached to the rigid backplate with an adjustable strap and the BCD is then worn like a waistcoat and fastened at the front with a cummerbund.
As well as providing harnessing the scuba tank, the BCD is designed to allow the diver to adjust buoyancy in the water by either adding or reducing the amount of air held inside. Many modern BCDs also have pockets to hold lead weights, traditionally worn on a belt around the waist.
The first stage regulator is attached to the top of the tank and reduces the pressure from the tank to supply the second stage as well as providing the air for BCD inflation. The latter supplies the diver with air at ambient pressure and is located in the mouthpiece on most modern equipment.
Scuba diving computers
Until relatively recently divers used tables to plan their dives, designed to reduce the possibility of decompression sickness. A depth gauge a dive watch were essential items to ensure the dive was within the limits of the table.
While divers are still taught dive table theory, most recreational divers quickly move on to buying a dive computer, which effectively calculates a custom table for each dive. More sophisticated models also connect to the air supply, so that they act as timer, depth gauge and air pressure monitor all in one.
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ABOUT THE AUTHOR
David Leigh usually dives year round in the Costa Brava in Catalonia. You can find more information about scuba diving equipment at www.CostaBravaScubaDiving.com.