Diving equipment


Diving equipment, or underwater diving equipment, is equipment used by underwater divers to make diving activities possible, easier, safer and/or more comfortable. This may be equipment primarily intended for this purpose, or equipment intended for other purposes which is found to be suitable for diving use.
The fundamental item of diving equipment used by divers other than freedivers, is underwater breathing apparatus, such as scuba equipment, and surface-supplied diving equipment, but there are other important items of equipment that make diving safer, more convenient or more efficient. Diving equipment used by recreational scuba divers, also known as scuba gear, is mostly personal equipment carried by the diver, but professional divers, particularly when operating in the surface supplied or saturation mode, use a large amount of support equipment not carried by the diver.
Equipment which is used for underwater work or other activities which is not directly related to the activity of diving, or which has not been designed or modified specifically for underwater use by divers is not considered to be diving equipment.

Classes of underwater breathing apparatus

The diving mode is largely defined by the type of breathing apparatus used.
This is the diving equipment worn by or carried by the diver for personal protection or comfort, or to facilitate the diving aspect of the activity, and may include a selection from:

Underwater breathing apparatus

The underwater environment usually requires a diver to wear thermal, sting and abrasion protection.
This equipment includes buoyancy control equipment and mobility equipment:
Buoyancy control is achieved by ballasting with diving weights and compensating for buoyancy changes during the dive using a buoyancy compensator:
  • Diving weighting system - to counteract the buoyancy of the diving suit and diver to allow descent. Professional divers may use additional weighting to ensure stability when working on the bottom
  • Buoyancy compensator, also known as Buoyancy Control Device, BCD or BC - is usually a back mounted or sleeveless jacket style device which includes an inflatable bladder used to adjust the buoyancy of the diver under water, and provide positive buoyancy at the surface. The buoyancy compensator is usually an integral part of the harness system used to secure the scuba set to the diver. The earlier collar style buoyancy compensator is seldom used any more.
Mobility equipment allows the diver to move through the water and maneuver on the spot:
  • Fins for efficient propulsion
  • Diver Propulsion Vehicle - to increase the range of the diver underwater

    Equipment for dive monitoring and navigation

These are the equipment used for monitoring the course of the dive and following the dive plan when undesirable events are avoided. They include planning and monitoring the dive profile, gas usage and decompression, navigation, and modifying the plan to suit actual circumstances.
  • Depth gauge lets the diver monitor depth, particularly maximum depth and, when used with a watch and Decompression tables, also allows the diver to monitor decompression requirements. Some digital depth gauges also indicate ascent rate which is an important factor in avoiding decompression sickness
  • Pneumofathometer is the surface supplied diving depth gauge which displays the depth of the diver at the surface control panel. It uses hydrostatic back-pressure on a low flow rate open ended air hose to the diver to indicate depth.
  • Diving watch is used with depth gauge for decompression monitoring when using decompression tables. Largely superseded by dive computers, where elapsed time is one of the standard displays, and time of day may also be available.
  • Dive timer is an instrument that displays and records depth and elapsed time during the dive. It is usually possible to extract the information after the dive. This function is often available as "Gauge setting" on dive computers.
  • Diving compass for underwater navigation. This may be a regular magnetic compass, but is often a selectable function of a dive computer, where a miniature magnetometer is used.
  • Submersible pressure gauge, also known as a "contents gauge" is used to monitor the remaining breathing gas supply in scuba cylinders.
  • Dive computer helps the diver to avoid decompression sickness by indicating the decompression stops needed for the dive profile. Most dive computers also indicate depth, time and ascent rate. Some also indicate oxygen toxicity exposure and water temperature, and may provide other functions. A display of cylinder pressure is available on air-integrated computers, either via a direct high pressure hose, or remotely via a pressure transducer and through-water transmission.
  • Distance line, guide line, or "come-home-line" can be used to guide the diver back to the start point and safety in poor visibility.
  • * A cave line is a line laid by a diver while penetrating a cave to ensure that the way out is known. Permanent cave lines are marked with line markers at all junctions, indicating the direction along the line toward the nearest exit.

    Vision and communication

Underwater vision is significantly affected by several factors. Objects are less visible because of lower levels of natural illumination and are blurred by scattering of light between the object and the viewer, also resulting in lower contrast. These effects vary with wavelength of the light, and color and turbidity of the water. The human eye is unable to focus when in direct contact with water, and an air space must be provided. Voice communication requires special equipment, and much recreational diver communication is visual and based on hand signals.
  • Masks allow the diver to see clearly underwater and protect the eyes.
  • * Full face masks protect the face from dirty or cold water and reduce risk by securing the gas supply to the diver's face. If it contains no mouthpiece, the diver can talk, allowing the use of communications equipment.
  • * Half masks cover only the eyes and nose. The diver breathes from a separate mouthpiece on the regulator or rebreather.
  • ** A prescription mask, or glasses which can be mounted inside the mask or helmet to provide clear vision underwater, enhancing the experience and safety for those with vision problems. A prescription mask contains lenses mounted in the scuba mask frame or bonded to the original viewports.
  • Diving helmets are often used for surface-supplied diving. They provide the same benefits as the full face mask but provide a very secure connection of the gas supply to the diver and additionally protect the head.
  • Underwater writing slates and pencils are used to transport pre-dive plans underwater, to record facts while underwater and to aid communication with other divers.
  • Dive lights, which are usually waterproof and pressure rated torches or flashlights, are essential for safety in low visibility or dark environments such as night diving and wreck and cave penetration. They are useful for communication and signalling both underwater and on the surface at night. Divers need artificial light even in shallow and clear water to reveal the red end of the spectrum of light which is absorbed as it travels through water. Underwater video lights can serve the same purpose.
  • Hand-held sonar for a diver can provide a synthetic view using ultrasonic signals emitted and processed by an electronic device and displayed on a screen.
  • Ultrasonic signalling devices which attract the buddies attention by vibration have been marketed and may have some limited utility.