PADI Divemaster Theory flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Duty of care

The legal and ethical obligation of a Divemaster to act reasonably, within training and standards, to protect divers under supervision. Breach can create liability.

Pre-dive safety check

Buddy verification that air is on, BCD inflates, weights are secure, releases are fastened, and both divers are OK before entry.

Active supervision

Maintaining visual contact, position, and head counts over a group at entry, underwater, and exit, rather than simply being present in the water.

Missing diver first action

Note the last-seen point and time, alert surface support, allow a brief surface search, then start an underwater search from that point.

Divemaster scope limit

A Divemaster may guide certified divers, assist instructors, and conduct Scuba Review, but may not teach or certify open-water students independently.

Certified assistant role

A diver working under an instructor's direct supervision, handling equipment, demonstrations, and station supervision while the instructor retains evaluation responsibility.

Skill demonstration standard

Perform each skill slowly, clearly, and in the taught sequence, neutrally buoyant where appropriate, because students copy observed behaviour rather than spoken instructions.

Mask flood cause

Usually a poor seal from hair, a strap over the hood, or nose exposure; fix the seal before repeating the skill rather than repeating the same failure.

Student stress signals

Rapid shallow breathing, wide eyes, refusal to descend, clamped regulator, or frantic signalling indicate rising stress; slow the pace and re-establish contact.

Instructor evaluation authority

Only the instructor signs off skills and decides pass or fail; assistants observe and report but do not certify or judge student competence.

Pressure per depth

Pressure rises one atmosphere for every 10 metres of seawater, so absolute pressure equals one atmosphere plus depth in metres divided by ten.

Boyle's law

At constant temperature, gas volume is inversely proportional to pressure; a balloon halves at 10 metres and is one-quarter at 30 metres.

Dalton's law

Total pressure of a gas mixture equals the sum of partial pressures, so each gas fraction multiplies with depth and increases nitrogen and oxygen exposure.

Henry's law

Gas dissolved in a liquid is proportional to its partial pressure, explaining nitrogen uptake on descent and controlled release during ascent and safety stops.

Maximum ascent rate

The standard recreational limit is 18 metres per minute, or 60 feet per minute, with a safety stop near 5 metres after deeper or repetitive dives.

Buoyancy principle

An object floats when the weight of water it displaces exceeds its own weight; adding gas to the BCD increases displacement and lift.

Heat loss in water

Water conducts heat roughly 25 times faster than air, so body heat drains quickly and exposure protection plus dive duration planning become safety factors.

Rescue first priority

Recognise the problem, assess the scene, and establish your own buoyancy before acting, so the rescuer does not become a second victim.

Panicked diver approach

Keep your regulator in place, approach from behind or below, establish positive buoyancy for both, and calm the diver before attempting a tow.

Unresponsive diver ascent

Bring the victim up at a controlled rate, establish buoyancy at the surface, check breathing, and begin rescue breathing or CPR with oxygen if trained.

In-water rescue breathing

Use a pocket mask with head-tilt and chin-lift, seal it before removing the regulator, and continue ventilations while towing toward the exit.

Tired diver tow

A steady kick keeping the victim's head above water, using a technique that lets the rescuer watch both the victim and the route to the exit.

Emergency oxygen use

Provide 100 percent oxygen for suspected decompression illness or near-drowning when trained and equipped, and arrange emergency evacuation simultaneously.

Search pattern choice

Expanding square, U-pattern, or circular searches are selected by site shape, visibility, current, and the last-seen point of the missing diver.

Site briefing content

Entry and exit, depth profile, hazards, marine life, buddy and recall signals, and emergency access are covered before every guided dive.

Buoyancy and reef damage

Keeping about a metre of clearance and securing dangling equipment prevents coral contact, sediment clouds, and the most common diver-caused reef injury.

No-touch rule

Do not handle, feed, or ride marine life; touching removes protective mucus, and feeding alters behaviour and can cause injury to animals and divers.

Mooring use

Use fixed moorings where provided and avoid anchoring on coral, since anchor and chain damage is a leading human impact on popular reef sites.

Marine protected area rules

Local regulations may ban fishing, collecting, and touching; check the rules before diving and follow them over personal preference or habit.

Boat diving head count

Count divers before entry and after surfacing, display a surface marker or flag where required, and keep a designated surface support person watching.

Site condition check

Tide, swell, wind, current, and visibility determine suitability; set a conservative turnaround point and abort if conditions exceed the plan.

Leave-no-trace diving

Remove all rubbish, avoid bottom contact, and report environmental damage or injured wildlife to the operator or local authority after the dive.