Underwater Skills & Safety Procedures Flashcards

When performing a controlled emergency swimming ascent (CESA), a diver should:

Answer: Ascend slowly while continuously exhaling and making an 'ahh' sound

During a CESA, the diver must continuously exhale to prevent lung overexpansion as air expands with decreasing pressure.

What is the primary purpose of the 'stop, think, breathe, act' sequence when a diver encounters a problem underwater?

Answer: To prevent panic and allow rational decision-making

This sequence helps prevent panic, which is a leading factor in diving fatalities, by forcing deliberate thought before action.

A diver notices their buddy is not responding to signals and appears rigid underwater. The first action should be:

Answer: Check for consciousness by tapping and observing

Assessing the buddy's responsiveness is the first step before initiating any rescue or ascent procedure.

When sharing air using an alternate air source, the donor diver should:

Answer: Stay close to the receiver and ascend together controlling rate

Both divers must ascend together at a controlled rate while staying close to maintain the air-sharing connection.

Which condition is most likely to cause a diver to experience mask squeeze?

Answer: Failing to exhale through the nose during descent

During descent, increased pressure creates a vacuum inside the mask unless the diver equalizes by exhaling a small amount of air through the nose.

What does the term 'negative entry' refer to in diving?

Answer: Entering the water with a fully deflated BCD to descend quickly

A negative entry involves entering the water with the BCD deflated to achieve rapid descent, used in conditions with strong surface currents.

The recommended hand signal for 'I am out of air' is:

Answer: Hand moving across the throat in a slashing motion

The throat-slash signal universally indicates an out-of-air emergency and requests an alternate air source.

During a safety stop at 15 feet (5 meters), a diver's computer shows they have exceeded their no-decompression limit. The diver should:

Answer: Extend the safety stop until the computer clears the obligation

If a diver inadvertently exceeds NDL limits, extending the safety stop allows additional nitrogen off-gassing before surfacing.

What is the purpose of the pre-dive buddy check (often remembered as BWRAF)?

Answer: To verify all equipment is functioning and both divers are prepared

The BWRAF buddy check (BCD, Weights, Releases, Air, Final check) ensures all equipment is properly configured before entering the water.

A diver experiencing nitrogen narcosis at depth is most likely to exhibit which behavior?

Answer: Impaired judgment and euphoria similar to alcohol intoxication

Nitrogen narcosis impairs cognitive function and can cause euphoria, poor decision-making, and loss of coordination at depth.

When ascending from a dive, the maximum recommended ascent rate according to most training agencies is:

Answer: 30 feet (9 meters) per minute or slower

Most agencies, including NAUI, recommend ascending no faster than 30 feet (9 meters) per minute to allow adequate nitrogen elimination.

A diver who surfaces far from the boat in a current should:

Answer: Inflate SMB, conserve energy, and signal for pickup

Inflating an SMB (surface marker buoy) makes the diver visible while conserving energy is essential in a current.

What is the correct response if a diver's regulator free-flows while underwater?

Answer: Breathe from the side of the mouthpiece and ascend in a controlled manner

Breathing from the side of the mouthpiece controls the flow rate while the diver safely ascends to have the regulator serviced.

Which factor primarily determines a diver's susceptibility to decompression sickness on a given dive?

Answer: The amount of nitrogen absorbed based on depth and time

DCS risk is driven by the amount of nitrogen absorbed, which is directly determined by dive depth and duration.

When performing an underwater search pattern, the 'U-pattern' is most appropriate for:

Answer: Searching a large open area with good visibility

The U-pattern (or lawn-mower pattern) covers large open areas efficiently when visibility allows divers to maintain consistent swim lanes.

A diver finds an unconscious diver underwater with the regulator out of the mouth. The rescuer should first:

Answer: Replace the regulator or hold the victim's mouth closed and ascend

Replacing the regulator or sealing the airway prevents water ingestion during the controlled ascent to the surface.

What does it mean when a diver gives the 'OK' signal at the surface using one hand making a circle on top of the head?

Answer: I am OK

The surface OK signal — hand forming a circle on top of the head — communicates to the boat or shore that the diver is fine.

Which gas law explains why a balloon inflated underwater will expand as it is brought to the surface?

Answer: Boyle's Law

Boyle's Law states that at constant temperature, gas volume is inversely proportional to pressure — as pressure decreases on ascent, volume increases.

A diver with a dry suit experiences a suit inflation malfunction causing uncontrolled ascent. The correct response is:

Answer: Dump air from the BCD and activate the dry suit exhaust valve

Simultaneously dumping BCD air and using the dry suit exhaust valve helps control buoyancy during a runaway ascent.

What is the minimum recommended surface interval before flying after recreational scuba diving?

Answer: 18 hours

NAUI and most agencies recommend waiting at least 18 hours after multiple dives before flying to allow adequate nitrogen off-gassing.