Night & Limited Visibility Diving Flashcards
7 cards from real PADI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Night & Limited Visibility Diving flashcards as text
What is the best strategy for maintaining buddy contact in extremely limited visibility (less than 1 meter)?
Answer: Use a buddy line or tether between divers
A short buddy line (1–2 meters) physically connects the two divers, ensuring they cannot become separated even when visibility is zero.
How does nitrogen narcosis risk compare between night and day dives at the same depth?
Answer: Nitrogen narcosis is depth-dependent only and is unaffected by ambient lighting
Nitrogen narcosis is driven purely by partial pressure of nitrogen at depth, not by light conditions, though darkness can compound the diver's perception of impairment.
A night diver wants to photograph bioluminescent plankton. Which camera setting approach is most appropriate?
Answer: Shoot with strobes disabled, high ISO, and a slow shutter speed
Capturing bioluminescence requires a long exposure in total darkness — strobes would overpower the faint natural glow, and high ISO captures it without artificial light.
Which surface condition should cause a dive team to CANCEL a planned night dive?
Answer: Dense fog reducing shore visibility to under 50 feet
Dense fog prevents surface support and boat traffic from seeing divers at the surface, creating a serious collision and rescue risk that outweighs the dive.
What physiological change makes breathing work feel slightly harder during cold-water night dives, affecting air consumption?
Answer: Both increased regulator resistance and anxiety-related breathing changes
Cold air is denser, increasing regulator work of breathing, while the psychological stress of darkness often causes divers to breathe less efficiently — both raise air consumption.
Why should night divers avoid touching or collecting bioluminescent organisms they encounter?
Answer: Contact can injure fragile organisms and may expose the diver to toxins
Many bioluminescent creatures such as jellyfish, fire worms, and certain corals are delicate or possess defensive stinging and toxic chemicals that can harm divers.
Which pre-dive equipment check is uniquely emphasized in the PADI Night Diver Specialty course?
Answer: Testing all dive lights for full charge and function before entering the water
Light reliability is life-critical at night, so PADI requires verifying that primary and backup lights are fully charged and functioning before every night dive.