At a time when the oceans and seas are sick, where fish swallow plastic, where entire islands of waste are formed, scuba diving is not only a sport, but it is also a form of reconciliation with nature, a possibility of wonder that raises awareness of the strengths and weaknesses of our civilization…Scuba diving ranks 11th in the world for sports.

But why dive? Scuba Diving in Phuket offers the discovery of the underwater world; a new world which already brings a very great feeling of freedom; first and foremost of what sticks to the earth, the earthly attraction. This freedom of movement is extended by that of the wonder that touches us. As on Earth, the seabed has very varied ecosystems and climate. Thus, we see that the sea is not only a vast blue, but that it contains the thousand colors of animals and plants never seen before, if not in aquariums: the light and the reflection of the sun are different, in the algae are hiding small inhabitants, the bottom of rocks or sands sometimes have surprising shapes … we are invited into a universe where beauty reigns.

The diving  is practiced in a professional or as a hobby, and is to stay underwater while breathing with scuba gear, or more rarely a hookah. The specific equipment generally consists of a wetsuit, a mask, flippers, a ballast worn on a belt or integrated in a stabilizing vest, and a diving bottle generally containing compressed air around of 200  bars . The gas is brought to the diver via a regulator.

Measuring instruments allow the guides to control the dive: a manometer and a dive computer. Previously, a depth gauge, a time measurement instrument and decompression tables were used. Professional dives are carried out by the military or in different branches of industry in the marine environment, for the exploration and exploitation of this environment. The main purpose of recreational diving is to discover the underwater world. Fishing is prohibited for divers equipped with diving suits, so it is reserved for snorkelers. In addition, the collection of objects is regulated.

Some of the diving equipments

Open-circuit

Open-circuit uses the breathing gas only once for respiration. The gas inhaled from the scuba equipment is released to the environment, or sometimes into another item of equipment for a special purpose, usually to increase buoyancy of a lifting device (buoyancy compensator, inflatable surface marker buoy or small lifting bag). The breathing gas is generally provided from a high-pressure diving cylinder through a scuba regulator. By always providing the appropriate breathing gas at ambient pressure, demand valve regulators ensure the diver can inhale and exhale naturally and without excessive effort irrespective of the depth, as and when needed.

Rebreather

Less common are the closed circuit (CCR) and semi-closed (SCR) rebreathers which process all or part of each exhaled breath for re-use by removing the carbon(iv)oxide and replacing the oxygen used by the diver. Rebreathers release few or no gas bubbles into the water and use lesser stored gas volume for an equivalent depth and time because exhaled oxygen is recovered.  This has advantages for research, military, photography, and other applications.

In a closed-circuit, decompression can be much reduced as a result; divers can stay down longer or require less time to decompress. Planning decompression requirements requires a more conservative approach for a Semi-Circuit Rebreather than for a Closed Circuit Rebreather

Gas mixtures

 The most commonly used mixture is nitrox, commonly known as Enriched Air Nitrox (EAN). Due to increased risk of oxygen toxicity when using Nitrox, a resultant gas from the combination of oxygen, nitrogen helium can be used. This resultant mixture is called trimix.

Diver mobility

The diver’s personal mobility is enhanced by swinfins and also diver propulsion vehicles in some cases. Fins have a large blade area and use the more powerful leg muscles thus are much more efficient for propulsion and manoeuvering thrust than arm and hand movements but needs skill for control.

Buoyancy control and trim

To dive safely, divers must control their rate of descent and ascent in the water and be able to maintain a constant depth in mid-water. Equipment such as diving weighing system diving suits (wet, dry or semi suits are used depending on the water temperature) and buoyancy compensators can be used to adjust the overall buoyancy. When divers want to remain at constant depth, they try to achieve neutral buoyancy. This minimizes the effort of swimming to maintain depth and therefore reduces gas consumption.

Underwater vision

People with myopic effect can see better underwater without a mask than normal-sighted people. Diving masks and helmets can solve this problem. Divers who need corrective lenses to see clearly outside the water would normally need the same prescription while wearing a mask.

Masks tend to fog when warm humid exhaled air condenses on the cold inside of the faceplate. To prevent fogging many divers spit into the dry mask before use, spread the saliva around the inside of the glass and rinse it out with a little water. The saliva residue allows condensation to wet the glass and form a continuous film, rather than tiny droplets. There are several commercial products that can be used as an alternative to saliva, some of which are more effective and last longer, but there is a risk of getting the anti-fog agent in the eyes.

Artificial light is useful to provide light in the darkness, to restore contrast at close range, and to restore natural colour lost to absorption.