SCUBA Diving Acronyms: Know The Common Ones & What They Mean

You will inevitably come across acronyms when you are around a diving school. You might have even heard some of them before. But what do they actually mean? In the list below you can find some of the most commonly used scuba diving acronyms:

ADT – Actual Dive Time
When we calculate our dive time using the RDP we refer to the ADT as the actual time the diver spends underwater.

AOW – Advanced Open Water
After a diver completes their OW, they often opt to continue on to their AOW, which takes them to 30 meters maximum depth.

BCD – Buoyancy Control Device
The BCD, also referred to as the “jacket” keeps the diver positively buoyant on the surface and neutrally buoyant underwater. Mastering buoyancy takes practice!

BWRAF – BCD, Weights, Releases, Air, Final OK
The pre-dive safety check involves five steps. Divers complete this in a buddy team. They check each others equipment functionality and diver readiness before entering the water. To remember this we often use the phrase “Bruce Willis Rules All Films”.

CESA – Controlled Emergency Swimming Ascent
This is an emergency skill practiced during the OW course. If the diver has run out of air and they do not have their buddy, they need to swim up slowly.

DIN – Deutsche Industrie Norm
This is a valve system that requires the regulator to be directly screwed into the tank valve as opposed to clamped on, which is the case with the yoke system.

DMT/DMC – Divemaster Trainee / Divemaster Candidate
This is the first level of professional diving. Divers train for up to 8 weeks to complete their divemaster program.

DSD – Discover Scuba Diving
More commonly known as a try dive, during a DSD divers can go diving under the close supervision of an instructor without having to complete a course and obtain a license to dive first.

DSMB – Delayed Surface Marker Buoy
As divers ascend to shallower water, the DSMB is inflated underwater and shot up to the surface to warn boats of divers coming up.

EANx – Enriched Air Nitrox (percentage of O2)
Normally divers use air, which is 21% O2 and 79% N2. Nitrogen limits bottom time and divers can train to dive with higher percentages of oxygen to extend their NDL.

EFR – Emergency First Response
As part of the Rescue course, divers also take a basic first aid course referred to as the EFR course.

IDC – Instructor Development Course
After you have completed your Divemaster program, you can train to become an instructor by completing the IDC.

LPI – Low Pressure Inflator
To inflate their BCD, divers connect a low pressure hose from the tank, which inflates the BCD by the simple press of a button.

MOD – Maximum Operating Depth
The deepest depth the diver can go to based on their gas mix, normally this is only used when diving on EANx among recreational divers.

NDL – No Decompression Limit
The time limit a diver has to adhere to at a certain depth in terms of Nitrogen absorption. In recreational diving we do not plan decompression stops.

OW – Open Water
The first level diving certification where a diver can dive with a buddy and no professional supervision. Maximum depth is 18m.

PADI – Professional Association of Diving Instructors
The most widely recognised training agency for recreational divers.

RDP – Recreational Dive Planner
This is a table used by divers to plan their maximum depth and dive time according to their Nitrogen loading.

RNT – Residual Nitrogen Time
How much Nitrogen remains in the body on repetitive dives depends on the previous dive’s depth and duration. This time needs to be subtracted from the next dive to stay within no decompression limits.

SCUBA – Self Contained Underwater Breathing Apparatus
This is the full set of equipment used by divers to explore the underwater world.

SD – Scuba Diver
A diving certification where professional supervision is still required and the maximum depth is limited to 12m.

SI – Surface Interval
How much time the diver spends in between dives. The longer they wait the less RNT is left to accommodate for on repetitive dives.

SPG – Submersible Pressure Gauge
The gauge that tells the diver the remaining pressure in their tank. This is monitored closely to avoid running out of air.

SSI – Scuba Schools International
Another large and popular recreational dive training agency.

Come across any other popularly used scuba diving acronyms not in this list? Let us know and we’ll add them here.

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