Recreational diving formally started with Jacques-Yves Cousteau, and when he invented the aqualung in 1943 it was a massive breakthrough in the science of diving. In 1954 Hugh Bradner brought us the wetsuit. These two leaps in SCUBA engineering inspired the trend of equipment manufacturing that has led to the recreational systems we use today.
At the same time diving education was growing at a staggering pace, with the first formal training organisation forming in 1959 which was called the National Association of Underwater Instructors (NAUI), which was formed as non-profit organisation. It comes as no surprise that very soon organisations such as PADI and SSI would rise in a commercial scene and soon overtake NAUI’s market share.
This rapid development of the diving industry has kept focus on getting individuals to the point where they hold a certification which allows them to dive down to 40m with a buddy. By keeping this depth limit organisations and manufacturers of diving equipment have been able to make diver training reasonably fast with a small theoretical requirement.
Now that recreational diving has been going at full steam for the past 50 years there are many different technologies and disciplines that have formed. Each of these have their benefits and might even suit your style of diving.
The single cylinder used with a BCD (Buoyancy Compensating Device) has taken the world by storm. Every dive resort and dive center offers diving in this discipline. While roughly 1500 PADI dive professionals (Divemaster & Instructor) are trained every month to spread this discipline, it’s likely to be around for many more years to come.
The single cylinder back mount style of diving is the perfect way of introducing individuals to recreational diving, the reason for this being the simplicity of the setup. All you need to go exploring is a cylinder, regulator, BCD and site specific snorkelling equipment.
This discipline however is very limiting when it comes to bottom time and depth. With only a single cylinder it’s difficult diving below 40m or even attempting longer than 30 minute dives to depths below 30m. The reason for this being lack of gas required for decompression.
Overall, this is a brilliant way to start SCUBA, however if you’re going to take this activity seriously and plan to do frequent dives on deeper wrecks and reefs you may want to look in to one of the other disciplines.
Twin sets are made up of two normal cylinders combined with a manifold and tank bands. The driving force behind twins has been to achieve longer bottom times at greater depth. There are a few discomforts that come with twin cylinders since they are very cumbersome and heavy, however they have advantages that cannot be ignored.
The primary advantage of these sets is that they generally double your gas allowance. This is very beneficial when diving with Nitrox as it can often more than double your bottom time. The true advantage however only shows itself when you couple twin cylinders with advanced Nitrox and Trimix decompression techniques.
Twin set diving is the ultimate way to explore new dive sites which lay at depth. It is currently the most rugged discipline and the go to configuration for divers exploring new sites. The reason for this being that it has a much better safety record and much lower initial buy in cost over rebreathers at moment.
Sidemount diving has been around since the 60s where it was very popular among cave and wreck divers in the UK. However in the past 20 years many commercial rigs have come on to the market. These include the Armadillo, the Razor and the Hollis SMS range. Since these systems have made the discipline main stream there’s no surprise that training organisations have written up specialty programs in both recreational and technical diving.
Sidemount diving is a technique where divers attach cylinders to the each side of their body instead of mounting the cylinders on a back plate. The benefits are very clear and the rapid growth of the discipline makes sense when you consider that it will increase flexibility, accessibility, safety, comfort and especially your redundancy of gas.
Rebreathers are basically gas recyclers. What they do is a two stage process where firstly they remove CO2 and secondly add Oxygen.
When a diver exhales, this gas is channelled through a scrubber (a device generally filled with a granular substance called sodium lime), this then absorbs an excess CO2 from the exhaled breath.
The rebreather will also go through one more crucial step before the diver gets their next breath of gas, this is of course the replenishment of oxygen. Rebreathers will constantly monitor the oxygen content in the “loop” with 3 or more oxygen sensors. Once oxygen drops below the required partial pressure set by the diver, the rebreather will replenish the loop with more oxygen using a solenoid valve.
Rebreathers are therefore the most efficient discipline. They allow divers to use only the gas they metabolise. This has massive benefits, especially when divers need expensive gasses containing helium, because rebreathers have almost no waste of gas your costs per dive decrease dramatically.
Furthermore rebreathers offer divers a chance to explore the ocean silently. Marine life behaves much differently with the absence of bubbles, thus giving underwater photographers much closer interaction when using this discipline!