Night & Limited Visibility Diving Flashcards

When conducting a night dive, what is the recommended primary light color for the marker light clipped to your tank valve or BCD?

Answer: White

A white marker light on your tank or BCD helps your buddy and dive leader keep track of your position in the water column.

Which underwater navigation technique is most reliable during a night dive with zero ambient light?

Answer: Compass and kick-count

Compass bearings combined with kick-cycle counting provide a consistent, light-independent way to track distance and direction.

A diver notices bioluminescent organisms glowing in the water during a night dive. What should the diver do to best observe this phenomenon?

Answer: Turn off lights and wave a hand gently through the water

Bioluminescence is best seen by extinguishing artificial lights so the faint natural glow becomes visible when water is disturbed.

What is the PADI recommendation for the minimum number of lights a night diver should carry?

Answer: One primary and one backup light

PADI requires at least one primary light and one backup light so the diver can continue the dive safely if the primary fails.

During limited visibility conditions caused by a silt-out, a diver should first:

Answer: Stop, remain still, and allow particles to settle

Stopping and hovering neutrally buoyant allows fine particles to settle enough to regain some visibility before making a calm exit.

What role does a surface marker buoy (SMB) play in night diving safety?

Answer: It signals the boat or shore support to your surfacing position

Deploying an SMB at the end of a night dive alerts boat traffic and surface support to the diver's location during ascent.

How should divers signal 'I'm okay' to each other using torches during a night dive?

Answer: Move the light in a slow, large circle

A large, slow circular motion with the torch is the standard 'okay' signal for night diving without blinding your buddy.