Glossary of Scuba Diving Terms (D)

Understanding That Strange Scuba Language

Welcome to our glossary of scuba diving terms. Diving, like many sports, has its own language. Our scuba glossary is for anyone interested in understanding the scuba diving definitions, scuba diving terms or scuba slang found in this strange scuba communication that divers use.

Our glossary of scuba diving terms is easy to use. Just click on the letter that corresponds to the first letter of the word that you are looking for. All the words that begin with that letter will be displayed.

We will be constantly updating our glossary of scuba diving terms. If you think we have missed a term or you can not find the scuba diving information you are looking for, please let us know. We will add it and the best definition we can find to our glossary of scuba diving terms.

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D

Divers Alert Network (D.A.N.) is nonprofit organization that provides dive emergency advice and assistance. They also provide information about diving injuries. DAN promotes diving-related medical research and education, collects injury statistics, and offers dive safety services to its members and the diving community.

The total pressure exerted by a mixture of gases is equal to the sum of the pressures of each of the gases making up the mixture. Each gas is acting as if it alone was present and occupied the total volume.

A line used as a fixed reference to aid in an accurate survey of an area.

Returning to conditions of normal atmospheric pressure in a controlled environment such as a recompression chamber.

Any dive that exceeds the recreational, no-decompression limit. This type of diving requires a decompression schedule of stops before reaching the surface.

DCI is a term to include all bubble-related injuries arising from decompression. This term includes both decompression sickness and arterial gas embolism.

DCS is a potentially dangerous medical problem resulting from nitrogen leaving the body when ambient pressure is lowered. If the nitrogen leaves the body too quickly, bubbles can form in the tissues and bloodstream of a diver's body. DCS can be divided into two Types. Type I shows musculoskeletal and/or skin manifestations only. Type II shows neurologic, cardiac, and/or pulmonary manifestations.

A scheduled stop in a diver's ascent to allow nitrogen to pass from body tissue back into the bloodstream at a safe rate. This is also known as off-gassing. When a decompression stop is not mandatory, it is called a safety stop.

A recreational dive at a depth of 60-130 ft. (18-40 meters).

Marker buoy deployed just before ascent. It is inflated underwater and released to indicate where a diver will surface.

Dive Equipment and Marketing Association. DEMA is a non-profit organization of equipment manufacturers, training agencies, dive media, travel companies and dive retailers that seeks to promote scuba diving and snorkeling to the general public.

See second stage

An analog or digital instrument uses ambient pressure to show a diver their current depth below the surface.

Traveling from the surface to depth.

A line suspended from a boat, float or buoy that allows divers to control their descents and ascents. This control line also provides guidance to the bottom in poor visibility or strong currents. An ascent line helps divers to make safety or emergency decompression stops at 10-15 ft. (3-5 meters).

A dividing membrane or thin partition. The thin muscle separating the chest cavity from the abdominal cavity is the diaphragm. The rubber (or other material) separating the demand chamber in a regulator from the surrounding water is also called a diaphragm.

Deutsches Institut fur Normung. A screw-thread fitting for attaching a regulator first stage to a compatible pillar valve on a scuba tank. A DIN fitting allows for a higher working pressure than a yoke-type or A-clamp fitting. DIN fittings are most common among European diver.

A commercially run diving business that offers training classes, equipment sales and rental and organizes guided trips to local dive sites.

A digital device that constantly measures depth and time, based on a pre-programmed algorithm. A dive computer calculates tissue nitrogen loading and elimination in several theoretical compartments and provides a continuous readout of the dive profile. This gives a diver a range of information, including depth, elapsed time and duration of the dive at current depth before decompression becomes mandatory and a warning if the rate of ascent is too fast.

An instrument panel that can contain a tank contents gauge, depth gauge and a compass. A dive console can also consist of a dive computer and compass.

May be either a red rectangle with a white diagonal stripe or a blue and white double tailed pennant. Flags are used to warn watercraft to stay away because there are divers below.

An employee of a dive center or dive school who guides qualified divers around local dive sites.

A diver in a buddy team that is designated (by agreement) to be the pacesetter and decision-maker on the dive.

Specially designed underwater light used for night, cave or wreck diving.

A plan for a proposed dive. This plan should include the depth, dive duration, intended goals, entry point, exit point, underwater signals and back-up or contingency plan.

A printed table of dive times for specific depths. Dive tables are used to help divers avoid DCS. Most dive tables are based on Haldanian theory for nitrogen loading and off-gassing.

The duration of a dive. Dive time starts when the diver leaves the surface and ends when they start their ascent to the surface.

A diver who is qualified to act as a dive guide, assist dive instructors and oversee the preparation of dives for paying dive customers. This is considered to be the first level of professional diving.

An organization offering diving instruction and diving activities on an amateur basis. In Europe, the term can refer to a dive center that offers dive training on a commercial level.

A center that offers dive instruction on a commercial basis.

A propulsion vehicle that is either ridden or clung on to by a diver to minimize swimming effort underwater. These vehicles are used in exploring large dive sites.

A dive where the diver is propelled along a route by underwater currents.

A D shaped ring in metal or plastic that is use to attach equipment to your BCD while diving.

A falling away of the seabed, such as a reef wall or rock shelf that descends steeply.

A water-tight exposure suit that keeps the diver's body warm by providing insulation with a layer of air. A dry suit offers a high degree of thermal protection in waters that are too cold for comfortable wetsuit protection, usually below 65'F.

A one-way valve that releases air from an inflatable device.