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Scuba Equipment

You are a novice scuba diver and you’re about to embark on your first dive, what do you wear? Scuba equipment of course! Scuba is actually an acronym that stands for self contained underwater breathing apparatus. Try saying that five times fast and you’ll immediately understand why the word scuba became so popular.  What the novice may not know is how recently most of modern scuba equipment was born.

If the modern scuba movement can be said to have parents, they would undoubtedly be Jacques-Yves Cousteau and Émile Gagnan. Cousteau was a French navy diver, and Gagnan was a French-Canadian engineer.  In the years following WW II Cousteau worked extensively with aqua lungs. Aqua lungs were a 19th century invention that allowed a diver to breathe underwater from a compressed canister of air. Cousteau and Gagnan improved upon existing designs by adding pressure adjusting delivery. This was the first attempt at solving the depth issues suffered by divers.

Pressure adjusting delivery is an important aspect of modern scuba equipment because it allows the system to adapt to different ocean depths. The human lung has difficulty working against outside pressure, at a depth of as low as 8 feet below the surface, breathing through an unpressurized tube becomes difficult. Diving of any great depth with breathing assistance requires that you can take in air at the same pressure that the water is exerting on your body.

The invention that allows all this to be possible is a piece of scuba gear called a diving regulator.  The diving regulator consists of a series of valves between the air supply and a diver’s mouth piece. The valves lower the pressure from the extremely high level found in the canister down to a breathable pressure. The last valve is attached to an ambient pressure sensor which allows it to ramp the pressure up as a diver descends.

Aside from his work in modernizing scuba equipment Cousteau also was an active promoter of diving. He shot underwater film, did undersea archeological digs, wrote books, and conducted research the world over. He was very active in promoting and improving scuba until his death in 1997. He left behind more than 120 documentaries and 50 books, as well as the environmental protection foundation he founded.

While the delivery of air to the body at ambient pressure was a major innovation in scuba equipment, perhaps a bigger shift occurred in the move away from compressed air. Even before Cousteau’s time governments were researching the use of other gas mixtures than those found in air to aid deep sea diving. The problems they were trying to surmount were the toxicity of oxygen and nitrogen at high pressure. Past the pressure of about 1.5 atmospheres nitrogen becomes toxic in its natural concentration of 78% of air. Shortly thereafter a concentration of 21% oxygen also becomes toxic. Early deep sea diving research attempted to reduce the concentration of oxygen below normal atmospheric levels.  They found that by reducing the oxygen to 16% concentration in a mix, the pressure at which the oxygen became toxic became correspondingly higher. Modern deep sea air mixtures contain no more than 16% oxygen and oftentimes contain no nitrogen at all, substituting non-toxic gasses such as hydrogen and helium in their place.

 

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