What is Scuba?

Scuba (Self-Contained Underwater Breathing Apparatus) is an apparatus utilizing a portable supply of compressed gas supplied at a regulated pressure and used for breathing while swimming underwater. The apparatus is often called “scuba gear”, a “scuba system” or simply “scuba”. Scuba is also the common name for the sport (also called “diving” or “scuba diving”) which uses the apparatus for recreational diving.

Like other acronyms (such as radar) scuba has become such an ubiquitous term for underwater breathing equipment and the recreational sport of deep diving that it is usually written without capitals. Even though it is an acronym it has entered common usage in the English language and may be used as a noun or adjective.
There are two kinds of scuba equipment:

  • The Aqua-lung is a tank (or cylinder) of compressed gas (usually air or mixture similar to air) which is supplied to the diver through a regulator, which adjusts the pressure of the gas to suit the ambient pressure for comfortable breathing. This kind of scuba system is called “open circuit” because the exhaled gas is released into the water and lost. The open circuit aqua-lung is the most common type of scuba system used by recreational divers.
  • The Rebreather is also a tank (or cylinder) of compressed gas breathed by the diver through a regulator, but with other mechanisms that recycle the exhaled gas. This kind of scuba system is called “closed circuit”. The economy of reusing and recycling exhaled gases allows a diver to remain submerged for longer periods

Scuba diving is popular, scuba diving is easy and scuba diving is fun. Scuba diving as outdoor recreation is gaining in popularity, while participation in other pastimes is diminishing. Why is scuba diving so popular?

Over 70% of the earth’s surface is covered with water. The allure and mystery of the underwater world has inspired the human imagination since prehistory, from the mythological monsters described by seafaring people, to the science fiction of Jules Verne and the modern underwater adventures in Hollywood films. Breath-hold diving, dangerous though it can be, has been used to collect pearls, sponges and valuable commodities from the sea floor for many generations.

Advances in underwater exploration began nearly three centuries ago using diving bells and large cumbersome sealed suits using pumped air from the surface. Only very recently advances in technology and mechanics have allowed people to visit this domain safely for exploration using comfortable, self-contained air delivery systems.

Though air-assisted underwater exploration has been around since the 1700’s, underwater exploration was out of reach for the average person, and recreational scuba diving was an unthinkable luxury. Great advances in the engineering of valves and compressed air tanks in the 1930’s produced the first systems that we would call “scuba”: the Self-Contained Underwater Breathing Apparatus. These early scuba tanks were clunky, inefficient systems that spouted air constantly into the diver’s face. Between 1942 and 1946, Jacques-Yves Cousteau (a French naval lieutenant) and Emile Gagnan (an engineer) developed the Aqua Lung; a device which used pressure valves to deliver properly pressurized air only when the diver breathed in. Over the next two decades experimental dives with the Aqua Lung proved its reliability and in the 1960’s “sport diving” was born.

NAUI, the National Association of Underwater Instructors, was formed in 1960 to regulate and teach safe scuba diving to enthusiasts of this new sport. PADI, the Professional Association of Diving Instructors, was formed in 1967.

In the 1970’s, scuba equipment continued to evolve and the typical scuba system was enhanced by buoyancy compensation vests, better valves and submersible pressure gauges. Through the 1980’s and 1990’s, scuba as a recreational sport became a multi-billion dollar industry with its popularity prompting even more innovation in the design and the engineering of better, safer, lighter, more comfortable equipment.

Today, scuba diving is accessible to almost anyone with only a modest investment in equipment. Anywhere you want to dive you can usually find a dive shop near-at-hand to rent tanks, go on a guided dive with a master diver, take a chartered boat or just strap on the tanks and swim out from the shore.

Scuba Diving Types

As a scuba diver, you have many kinds of diving that you can participate in. Most divers choose diving “open water” which includes an ocean, sea or lake. Wreck diving is a dive that is specifically targeted at visiting a sunken vessel. Cave diving is an exhilarating experience for divers who are careful and who are not claustrophobic! Rescue diving is a specialized dive for paramedic or rescue operations and is usually attempted only by trained emergency personnel. Deep diving is a risky, but attemptable, pursuit given the proper training. Divers go below 100 feet. Night diving using underwater torches is simply amazing and every certified scuba diving enthusiast should try it at least once. Some scuba divers do not consider rivers to be “open”, since the range of movement is limited to the banks of the river, so “river diving” is sometimes considered a separate kind of diving.