PADI Night & Limited Visibility Diving 5 — Questions and Answers
Question 1: What is the best strategy for maintaining buddy contact in extremely limited visibility (less than 1 meter)?
- Use a buddy line or tether between divers (Correct answer)
- Maintain constant voice contact through the regulator
- Each diver follows a separate compass heading that converges at the exit
- One diver holds the other's tank valve at all times
Correct 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.
Question 2: How does nitrogen narcosis risk compare between night and day dives at the same depth?
- Night dives carry greater narcosis risk due to darkness amplifying disorientation
- Night dives carry lower narcosis risk because divers move more slowly
- Nitrogen narcosis is depth-dependent only and is unaffected by ambient lighting (Correct answer)
- Cold water at night prevents narcosis by reducing nitrogen solubility
Correct 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.
Question 3: A night diver wants to photograph bioluminescent plankton. Which camera setting approach is most appropriate?
- Use maximum strobe power for the brightest shots
- Shoot with strobes disabled, high ISO, and a slow shutter speed (Correct answer)
- Aim the primary torch at the subject during exposure
- Use a red filter over the lens to enhance contrast
Correct 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.
Question 4: Which surface condition should cause a dive team to CANCEL a planned night dive?
- Light onshore breeze with 1-foot chop
- Dense fog reducing shore visibility to under 50 feet (Correct answer)
- A partial moon with some cloud cover
- Air temperature 10°F below water temperature
Correct 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.
Question 5: What physiological change makes breathing work feel slightly harder during cold-water night dives, affecting air consumption?
- Cold water increases blood viscosity, reducing oxygen delivery
- Cold temperatures increase air density and regulator breathing resistance
- Darkness causes shallow breathing from anxiety, reducing efficiency
- Both increased regulator resistance and anxiety-related breathing changes (Correct answer)
Correct 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.
Question 6: Why should night divers avoid touching or collecting bioluminescent organisms they encounter?
- Handling stops the bioluminescence permanently in that area
- Contact can injure fragile organisms and may expose the diver to toxins (Correct answer)
- The glow indicates the organism is diseased and contagious
- Touching triggers an alarm response that attracts predators
Correct 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.
Question 7: Which pre-dive equipment check is uniquely emphasized in the PADI Night Diver Specialty course?
- Verifying weight belt buckle orientation
- Testing all dive lights for full charge and function before entering the water (Correct answer)
- Confirming wetsuit zipper is fully sealed
- Checking SPG for accurate depth reading
Correct 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.
PADI Night & Limited Visibility Diving 5
What is the best strategy for maintaining buddy contact in extremely limited visibility (less than 1 meter)?