PADI Night & Limited Visibility Diving 3 — Questions and Answers
Question 1: Which aquatic behavior is MOST commonly observed by night divers that is rarely seen during the day?
- Coral spawning and invertebrate feeding activity (Correct answer)
- Fish schooling in tight defensive formations
- Increased jellyfish migration to depth
- Sea turtles resting on the surface
Correct answer: Coral spawning and invertebrate feeding activity
Many invertebrates — such as octopuses, lobsters, and corals — become active at night for feeding, making nocturnal dives rich with unique behavior.
Question 2: A diver enters the water at night and cannot see the bottom. What is the safest descent method?
- Free descent as fast as possible to reduce surface time
- Descend along a reference line while equalizing frequently (Correct answer)
- Jump in and fin toward the glow of the reef
- Descend feet-first without a reference using compass only
Correct answer: Descend along a reference line while equalizing frequently
Using a descent line provides orientation, rate control, and a physical reference that compensates for the lack of visual depth cues.
Question 3: What condition is a night diver MOST at risk of experiencing due to the absence of natural light?
- Nitrogen narcosis at shallow depths
- Loss of spatial orientation and vertigo (Correct answer)
- Accelerated oxygen toxicity
- Increased decompression sickness risk
Correct answer: Loss of spatial orientation and vertigo
Without visual reference points, divers can lose their sense of up and down, leading to disorientation — a major night-diving hazard.
Question 4: In limited visibility, a diver's torch illuminates a cloud of particles and they cannot see their buddy. What is the correct immediate action?
- Ascend alone to the surface and wait
- Stop, signal with light, and listen for buddy's bubbles (Correct answer)
- Swim in a widening circle for up to 3 minutes
- Inflate BCD and rise to the surface quickly
Correct answer: Stop, signal with light, and listen for buddy's bubbles
PADI's lost-buddy procedure starts with stopping, looking, and listening — using light signals and listening for exhaust bubbles to relocate the buddy.
Question 5: Why is it important to allow time for night vision (dark adaptation) before a night dive?
- It allows the diver to see underwater without a torch
- It improves peripheral vision at the surface so hazards are spotted (Correct answer)
- It reduces the chance of mask squeeze
- It speeds up descent by making the water look darker
Correct answer: It improves peripheral vision at the surface so hazards are spotted
Dark-adapted eyes can detect dim lights and movement at the surface, helping divers spot boat traffic, entry points, and their exit safely.
Question 6: What torch-signaling method indicates 'something is wrong' or 'come here' during a night dive?
- Large slow circle
- Rapid side-to-side waving (Correct answer)
- Pointing the light upward
- Steady beam held still
Correct answer: Rapid side-to-side waving
Rapidly waving the light back and forth is the universal underwater distress or attention signal used during night diving.
Question 7: During a night dive briefing, the dive leader instructs divers never to shine their torch into another diver's eyes. Why?
- It can cause permanent retinal damage at close range
- It destroys the diver's dark adaptation and causes temporary blindness (Correct answer)
- It drains the battery faster than expected
- It causes the mask to fog instantly
Correct answer: It destroys the diver's dark adaptation and causes temporary blindness
Shining a bright light directly into a diver's eyes destroys their night adaptation and can leave them temporarily unable to see in the dark.
PADI Night & Limited Visibility Diving 3
Which aquatic behavior is MOST commonly observed by night divers that is rarely seen during the day?