GLOSSARY
70 terms every dive center and snorkel operator should know.
Professional Association of Diving Instructors. The largest recreational dive training agency. Issues cert cards recognised by dive operators worldwide.
Scuba Schools International. A major dive training agency whose certifications are widely accepted alongside PADI.
The entry-level certification. Qualifies a diver to dive independently with a buddy, typically to a maximum depth of 18 metres.
The next certification level, adding deeper dives and specialty skills such as navigation and night diving. Common depth limit around 30 metres.
A certification focused on diver safety, problem prevention, and managing dive emergencies. A prerequisite for professional ratings.
The first professional rating. A Divemaster can guide certified divers and assist instructors. Often the guide on a boat trip.
An introductory experience for uncertified people — a short briefing, basic skills, then a guided dive under instructor supervision.
When a student completes classroom and pool training with one operator and finishes open-water dives with another. Referral paperwork transfers the record.
The certification card proving a diver holds a qualification. Operators check the agency, level and number before a dive.
Focused training in a single area — deep, wreck, drift, nitrox, night. Stacks on top of core certifications.
Qualifies a diver to use enriched-air nitrox. Required before an operator fills a diver’s cylinder with anything other than air.
A record of a diver’s completed dives — site, depth, time, conditions. Used to show experience and currency.
Buoyancy Control Device. The inflatable jacket or wing that holds the cylinder and lets a diver control buoyancy. Common rental item.
The assembly that delivers breathable air from the cylinder at ambient pressure. Serviced annually as a rental item.
The part of the regulator that attaches to the cylinder valve and reduces high tank pressure to an intermediate pressure.
The mouthpiece part of the regulator that delivers air on demand as the diver breathes. A free-flowing second stage flags a reg for service.
The backup second stage carried for sharing air in an emergency. Also called an alternate air source.
The pressure vessel holding a diver’s breathing gas. Requires periodic visual and hydrostatic testing to stay in service.
The most common rental cylinder, holding about 80 cubic feet of air at 3,000 psi. The workhorse of most fleets.
The two cylinder-valve fittings. DIN screws into the valve; yoke (A-clamp) clamps over it. Operators stock regs for both.
Neoprene exposure suit that traps a thin water layer for insulation. Rented in various thicknesses (3mm, 5mm, 7mm) by water temperature.
A sealed exposure suit that keeps the diver dry, used in colder water. Requires separate training and specialist rental stock.
A wrist or console device that tracks depth, time and no-decompression status in real time. Often a rental add-on.
Surface Marker Buoy / Delayed SMB. An inflatable float sent up to mark a diver’s position, especially on drift dives.
A belt of lead weights that offsets the buoyancy of the diver and suit. A missing weight belt is a common return issue.
Foot blades that propel a diver. Rented in open-heel (with boots) or full-foot styles.
The sealed lens that gives a diver clear vision underwater. Basic rental item, often bundled with fins and snorkel.
A waterproof light for night dives, wrecks and dark overhangs. A frequent night-dive rental add-on.
The standard half-day boat trip: two dives with a surface interval between, each on a fresh cylinder. The backbone of most schedules.
A dive entered directly from the beach or a shore-entry point, without a boat. Lower cost and simpler logistics.
A dive reached by boat from a dock. Opens up offshore reefs and wrecks beyond swimming range.
A dive where divers ride a current along a reef while the boat follows their surface marker. Requires SMB use and boat coordination.
A dive after dark using torches. Reveals nocturnal marine life and needs extra briefing and light-rental logistics.
A dive along a steep underwater drop-off. Demands careful buoyancy and depth awareness.
The pre-dive safety check a buddy pair runs on each other’s gear before entering the water.
The rest time on the surface between two dives, allowing nitrogen to off-gas before the next descent.
A common boat-entry technique — the diver steps off the platform in one big stride, gear on and regulator in.
Entering the water with a deflated BCD to descend immediately, used to fight surface current or reach a site fast.
A boat-entry technique where the diver rolls backwards off the tube or gunwale, common on small boats.
Two divers who dive together and monitor each other. Buddy pairs are assigned on the manifest before departure.
The interval a diver must wait after diving before flying — commonly 12 hours after a single dive, 18+ after repetitive dives — to avoid decompression sickness.
Decompression Sickness. Illness caused by nitrogen bubbles forming in tissue when a diver ascends too fast or exceeds limits.
A reversible impairment, like mild intoxication, caused by breathing nitrogen at depth. Eases on ascent.
A short pause, typically three minutes at around five metres, near the end of a dive to off-gas nitrogen before surfacing.
The maximum time a diver can stay at a given depth without needing mandatory decompression stops on ascent.
Printed tables used to plan dive depth and time within no-decompression limits, before dive computers became standard.
Recreational Dive Planner. A PADI table or wheel for planning no-decompression dives and surface intervals.
Balancing the pressure in the ears and sinuses during descent to prevent barotrauma. Divers equalise early and often.
The standard diver medical form. A “yes” answer may require physician sign-off before the operator clears the diver.
Divers Alert Network. A dive-safety organisation providing emergency guidance, insurance and research to the diving community.
Breathing gas with a higher oxygen fraction than air, extending no-decompression time at moderate depths. Requires certification.
Surface Air Consumption — how fast a diver uses air. Guides plan dive length and turnaround around the highest consumer.
A guided surface swim with mask, snorkel and fins over a reef or site. No certification required, popular with families.
The introductory scuba experience for uncertified guests, run under close instructor supervision in shallow water.
A pool or sheltered shallow area where beginners learn basic skills before an open-water dive.
A short, supervised first scuba experience — the common name for a taster session that often becomes a Discover Scuba booking.
The mask, snorkel and fins bundle rented for a snorkel tour. Tracked and checked back in like dive kit.
A snorkel outing led by a guide who briefs, positions and supervises guests. Configured as its own trip type with a headcount.
The trip roster — every diver on board with cert level, buddy pair, tank, weight and rental-gear list. Crew work from it at the dock.
The liability release a diver signs before a trip. Captured digitally at booking and archived for insurance.
Confirming a diver holds the qualification a trip requires. Operators capture agency, level and number, then a guide reviews the manifest.
A pre-authorisation hold placed on a diver’s card, usually for rental gear. Released on clean check-in or applied to a documented charge.
The published rules for wind, swell and visibility cancellations — reschedule offers, deposit roll-forward and refund windows.
A short skills-review session for certified divers who’ve been out of the water a while, before they join a regular trip.
The training-record documents transferred when a student finishes open-water dives with a different operator than their course start.
On a schedule, the built-in gap between a diver’s two dives, which shapes trip length and boat turnaround.
A bookable product — 2-tank boat dive, night dive, snorkel tour, Discover Scuba — each with its own price, requirements and departure time.
A diver who booked but didn’t check in by departure. Triggers a follow-up and frees the seat for a walk-up.
A diver or snorkeller who books on the day at the dock rather than online. Rung up on the dock-side POS.
A hold covering rental kit — mask/fins through full BCD-and-reg sets — released automatically once the gear checks back in clean.
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