Scuba Diving
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Scuba Diving Equipment

oxygen-tanks.jpgAdvances in diving gears have made it possible for every level of diver to experience everything the underwater world has to offer.

Diving gears, or better known as SCUBA gears, were perfected in 1939 by the United States Navy. SCUBA, is short for Self-Contained Underwater Breathing Apparatus.

A scuba set allows a diver to be self-supporting under water. There are two basic types of scuba sets:

  • Open circuit, often referred in Europe as the Aqua Lung, is a process of inhaling the gas and exhaling the waste into the surrounding water.
  • Closed (or semi-closed)circuit, often referred as a rebreather, processes the exhaled gas, and re-circulates it back into the system.

Open Circuit

Open circuit sets typically don’t last as long as a rebreather. Until the late nineties, when an enriched air nitro mixture of 21% oxygen/79% nitrogen became widely acceptable, most all sport scuba equipment used compressed air. This was due to the fact the United States Food and Drug Administration considered non-air gas mixtures to be drugs, which meant they fell under their supervision. By using compressed air, divers could avoid stringent regulations. With the advent of the new gas mixtures, however, many diving problems, like decompression, were solved. So far, the FDA is looking the other way.

Twin hose open circuit was the first type of open circuit system. It has a large regulator valve mounted on the top of the cylinders, and can be turned on or off by the diver. It has two large breathing tubes; one for intake and one for exhale.

Single hose open circuit are most often used today. A diving regulator has a pressure reducing valve positioned over the cylinder’s output valve. A small pressure hose connects this to the demand valve located in the diver’s mouthpiece.


Exhaled carbon dioxide is stored in a counterlung between breaths. The diver receives new gas from a cylinder, and the exhaled gas is passed through a canister filled with soda lime, known as a scrubber. This process turns the bad into good again.

Non-scuba diving

  • Free diving-diving using a single breath.
  • Snorkelling-the diver’s mouth and nose stay submerged underwater, while breathing surface air through a short tube.
  • Surface supplied diving-an umbilical line from the surface is connected to the diver. Originally used for longer or deeper professional dives, some tourist resorts use the method today to train inexperienced divers.
  • Atmospheric diving suit-the diver is protected from surrounding water pressure by an armoured suit.