Diving is a gear-dependent activity. Scuba diving equipment allows the diver to adapt to the underwater world and makes him a part of it. Diving can be done almost anywhere where there is water. The equipment used varies depending on the diving environment as well as the diver’s preferences. A diver should buy his equipment based on three factors: the comfort of the gear, the fit of the gear and appropriateness for the type of diving planned. Equipment also depends on the temperature of the water, with cold-water scuba gear differing subtly from warm water scuba gear.
Warm Water Diving
With warm, clear water, there is usually a need for only minimal to moderate exposure protection. Scuba equipment for warm water is generally lightweight and comprises the most streamlined scuba components. This scuba gear is ideal for diving in water that has a temperature of 24°C/75°F or warmer.
Cold Water Diving
Cold water diving requires more protective gear compared to warm water diving, so as to provide maximum exposure protection and manoeuvrability. A typical setup for cold water diving includes a full wetsuit and a scuba unit with a Buoyancy Controlled Device (BCD). This type of scuba diving gear is meant for diving in water that is 15°C/60°C to 24°C/75°F.
The most important equipment used by a scuba diver is called scuba, the self-contained underwater breathing apparatus that is transported by the diver and allows him to breathe underwater. Recreational diving is done using a half mask covering the diver’s eyes and nose, and a mouthpiece to supply air from the demand valve.
Open circuit scuba do not have a provision for using the breathing gas more than once. The gas inhaled from the equipment is exhaled to the environment, or sometimes into another item, usually to increase the buoyancy of a lifting device such as a buoyancy compensator or lifting bag.
Closed circuit and semi-closed rebreathers are less commonly used, and unlike open circuit sets, process all or part of the exhaled air by removing the carbon dioxide and replacing the oxygen used and make the air suitable for reuse.
Fins and propulsion vehicles enhance the mobility of the diver. Fins are efficient for propulsion and manoeuvring due to their large blade area and use of the powerful leg muscles. Streamlining the dive gear reduces the drag and improves mobility.
Divers need to control the rate of ascent and descent in the water to dive safely and to maintain a constant depth. Equipment such as diving weighting systems, diving suits and buoyancy compensators are used to adjust overall buoyancy. Diving suits account for buoyancy changes by decreasing in volume as the diver descends and increasing in volume as the diver ascends. Buoyancy compensators allow easy and fine adjustments in the diver's overall volume by adjusting the volume of air in the bladder and therefore buoyancy.
Weight systems are provided to divers to offset the tendency to float underwater, ensuring a gentle descent underwater.
Diving masks prevents hypermetropia by protecting the eye from the refracted rays of the sun underwater. Providing an air space in front of the diver’s eyes does this. It helps the diver’s eyes to see clearly underwater.
Colour vision is affected by the turbidity of the water, thereby reducing contrast. This problem is solved by using artificial lights that provide light in the darkness and restore natural colour lost to absorption. They are used to look into cracks and crevices while exploring underwater, and also for diving at night.
This garment, usually made of foamed neoprene, provides thermal insulation, abrasion resistance and buoyancy. Wetsuits also help increase the flexibility, freedom of movement and stroke rotation of the diver. A close fit and a couple of zips help the suit to remain waterproof.
Dry suits provide insulation to the diver while immersed in water. Dry suits cover nearly the whole body with the exception of hands, head and sometimes the feet. A dry suit is used when the water temperature is below 15°C or for extended immersion in water above 15°C. It provides proper insulation by preventing entry of water, thereby making it better suited for long cold water dives.
A dive watch is used to measure the amount of time under water (dive time). This helps the diver keep track of time so that he/she does not run out of air to breathe.
A depth gauge is provided to divers to measure to monitor the dive depth. The importance of the depth gauge is that it allows divers to not exceed the depth limit beyond which problems caused by water pressure arise, thus helping the divers remain safe.
Dive knives are a handy tool as well as a safety device for divers because they help the divers to cut loose from entanglements in nets or lines.
Dive flags mark the position of the divers to boats to keep them away from the region so as to prevent accidents from taking place. It also indicates the position of the diver to safety personnel, in case of an emergency. The markers also allow easy and accurate control of ascent rate, stop depth and safer decompression.
To make the experience of diving more fun, accessories like a scuba gear bag to carry all of the divers’ dive equipment to the dive site, underwater slates and lanyards can also be carried. Other items like whistles and signal tubes are used as signalling devices to catch the attention of other divers or a dive boat from a distance in case of emergencies.