Underwater diving, is a sport. It is a human activity which refers to the practice of descending below the water's surface to interact with the environment. Immersion into the water and then exposing onself to the high ambient pressure often has physiological effects. These effects impose a limit upon the depths and duration that are possible in ambient pressure diving. Humans are usually not physiologically and anatomically well adapted to the environmental conditions of diving. To make it easy for humans, different type of equipment has been developed to extend the depth and duration of human dives, and for allowing different types of work to be done. There are different modes in which the sport of diving is practiced. These are:
(i) Freediving: Freediving is a very common mode of diving. It makes the use of external breathing devices, and relies on the ability of divers to hold their breath until they reach the surface again. The technique ranges from simple breath-hold diving to competitive apnea dives.
(ii) Scuba diving: It refers to diving with a self-contained underwater breathing apparatus. This apparatus is of a kind which is completely independent of surface supply. Scuba gives the diver mobility and horizontal range far beyond the reach of an umbilical hose which is attached to the surface-supplied diving equipment (SSDE). Scuba divers are employed in the armed forces covert operations commonly known as frogmen, combat divers or attack swimmers.
(iii) Surface-supplied diving: An alternative to self-contained breathing systems is to supply breathing gases from the surface with the help of a hose. When combined with a communication cable, a pneumofathometer hose and a safety line it is known as diver's umbilical. It may also include a hot water hose for heating, video cable and breathing gas reclaim line.
(iv) Atmospheric pressure diving: Atmospheric pressure diving is one which is done with the help of Submersibles and rigid atmospheric diving suits (ADS). It is usually practiced in a dry environment at normal atmospheric pressure.
(v) Unmanned diving: Unmanned diving refers to a form of diving that is practiced without the operations of a human being. This is practiced with the help of Autonomous underwater vehicles (AUVs) and remotely operated underwater vehicles (ROVs). AUVs are robots that travel underwater without requiring any kind of human assistance. These can be deployed at greater depths and in more dangerous environments because the danger to human life is not involved.
By: Anuja Arora