Join us in this week's article as we embark on a captivating journey through the history and remarkable evolution of scuba diving.
The development of scuba diving is closely linked with the advancement of diving equipment. By the start of the 20th century, two primary types of underwater breathing apparatus had been pioneered. The first was open-circuit surface supplied equipment, where the diver's exhaled gas is released directly into the water. The second was a closed-circuit breathing apparatus, which filters the diver's exhaled breathing gas to remove carbon dioxide, recirculates it and adds fresh gas to replenish oxygen levels. The closed-circuit system was more suitable for scuba diving at that time, as there were no reliable, portable, and affordable high-pressure gas storage containers. However, with the availability of high-pressure cylinders in the mid-20th century, two scuba diving systems emerged: open-circuit scuba and closed-circuit scuba systems.
“Rebreathers” are an alternate term used to refer to closed-circuit scuba systems. Diving engineer Henry Fleuss designed and built the first commercially practical scuba rebreather in 1878. His self-contained breathing apparatus comprised a rubber mask connected to a breathing bag. This apparatus utilised an estimated 50%–60% oxygen provided from a copper tank, while carbon dioxide was eliminated by passing it through a bundle of rope yarn soaked in a solution of caustic potash.
The invention of SCUBA
Throughout the 1930s and World War II, the British, Italians, and Germans dedicated efforts to developing and extensively employing oxygen rebreathers for the initial utilisation by frogmen (a frogman, also referred to as a commando frogman, is an individual who undergoes training in scuba diving or swimming underwater with tactical objectives, encompassing military duties and, in certain European nations, police operations. This personnel are alternatively recognized by more formal designations such as combat diver, combatant diver, or combat swimmer).
In the United States, Major Christian J. Lambertsen invented a free-swimming oxygen rebreather. In 1952, he secured a patent for a modified version of his apparatus, which he named SCUBA, an acronym representing "Self-Contained Underwater Breathing Apparatus." This term eventually became the common English expression for autonomous diving equipment and the activity associated with it.
While a functional demand regulator system had been invented in 1864 by Auguste Denayrouze and Benoît Rouquayrol, it was the open-circuit scuba system developed in 1925 by Yves Le Prieur in France that marked a significant advancement. However, Le Prieur's system was a manually adjusted free-flow system with limited endurance, rendering it impractical for extensive use.
It was not until 1942, amidst the German occupation of France, that Jacques-Yves Cousteau and Émile Gagnan successfully designed the first safe and effective open-circuit scuba system known as the Aqua-Lung.
This innovative twin-hose system combined an improved demand regulator with high-pressure air tanks. The Aqua-Lung was officially patented in 1945. To market his regulator in English-speaking countries, Cousteau registered the trademark Aqua-Lung, which was initially licensed to the U.S. Divers company, and later in 1948 to Siebe Gorman of England.
Progress in Buoyancy Control Devices
In the early days, scuba sets typically featured a basic harness consisting of shoulder straps and a waist belt. Many of these harnesses lacked a backplate, causing the cylinders to directly rest against the diver's back. Moreover, early scuba divers ventured underwater without the assistance of a buoyancy aid. In case of an emergency, they had no choice but to discard their weight. However, in the 1960s, adjustable buoyancy life jackets (ABLJ) were introduced, offering a solution to compensate for buoyancy loss caused by neoprene wetsuit compression at depth. These life jackets also functioned as flotation devices to keep an unconscious diver in a face-up position at the surface.
ScubaPro introduced the stabiliser jacket in 1971, which is categorised as a buoyancy control device or buoyancy compensator. Another configuration of a scuba harness, known as a backplate and wing, incorporates a buoyancy compensation bladder called a "wing" positioned behind the diver. The wing is placed between the backplate and the cylinder(s). This setup gained popularity among cave divers engaged in lengthy or deep dives, as it allows them to carry multiple extra cylinders while keeping the front and sides clear for conveniently attaching other equipment.
The Use of Nitrox and the Emergence of Modern Rebreathers
In the 1950s, the United States Navy (USN) established procedures for military use of what is now known as nitrox. Oxygen-enriched air diving procedures were introduced by Morgan Wells of NOAA in 1970. NOAA published scientific nitrox diving procedures in their Diving Manual in 1979. The International Association of Nitrox Divers (IAND) began teaching nitrox for recreational diving in 1985, despite initial resistance from some agencies. Today, the use of nitrox has become common in recreational diving, with multiple gas mixtures being used in technical diving to reduce decompression time. However, nitrogen narcosis sets depth limitations when breathing nitrox. Helium was investigated by the U.S. Navy in 1924, and after successful experiments, cave divers began using trimix to enable deeper dives.
Rebreather diving saw a resurgence of interest in the late 1980s due to the challenges of deeper and longer dives. Oxygen sensing cells, available since the late 1980s, allowed for accurate monitoring and maintenance of breathable gas mixtures in the loop at any depth. Semi-closed circuit rebreathers entered the recreational scuba market in the mid-1990s, followed by closed circuit rebreathers around the turn of the millennium. Rebreathers are currently manufactured for military, technical, and recreational scuba markets.
Growth of Recreational Scuba Diving
Recreational scuba diving emerged from activities like snorkelling and underwater hunting. Initially, breath-hold time limited underwater excursions. However, the invention of the aqualung, along with the introduction of the wetsuit revolutionised recreational diving. In the 1950s and early 1960s, scuba diving was primarily accessible to those who could afford or make their own equipment and undergo intensive training.
As the sport gained popularity, manufacturers recognized the market potential, leading to the development of user-friendly, affordable, and reliable equipment. Advancements such as buoyancy compensators, improved diving regulators, wetsuits, dry suits, and dive computers further enhanced safety, comfort, and convenience. Additionally, less rigorous training programs encouraged more individuals to learn scuba diving.
Initially, professional diving organisations and navies provided exclusive training to their personnel using their specific equipment.
The first recreational scuba diving school was established in France for training on the Cousteau and Gagnan twin-hose scuba. The first school to teach single-hose scuba was founded in Melbourne, Australia, in 1953. Civilian training expanded with the establishment of schools such as the Scripps Institution of Oceanography in the United States, the British Underwater Centre in the UK, and the Los Angeles County-based Underwater Instructor Certification Course.
Amateur teaching within club environments characterised early instruction, exemplified by organisations like the Scottish Sub Aqua Club, the British Sub Aqua Club, Los Angeles County, and the YMCA. Professional instruction began in 1959 with the formation of the non-profit NAUI, which later split to form the for-profit PADI in 1966. Other organisations, such as NASDS and SSI, also introduced dive centre-based training programs.
Scuba diving has become a popular leisure activity, and dive shops are present in many diving destinations, offering services like air fills, equipment sales, rentals, repairs, and training. While tropical and subtropical regions attract holiday divers who train and dive during vacations but rarely dive locally, technical diving and the use of rebreathers are increasing, especially in areas known for deep wreck diving. Recreational diving depths are typically limited by training agencies to a maximum of 30 to 40 metres due to safety concerns such as oxygen toxicity and nitrogen narcosis.
The diving industry has undergone significant advancements from its early days of cumbersome equipment and limited exploration opportunities. Currently, it is entering a new era of evolution driven by technological breakthroughs and a heightened awareness of environmental issues. Consequently, scuba diving professionals are embracing state-of-the-art tools and shouldering increased responsibilities compared to the past.