To the novice diver, the thought of a night dive can conjure terrifying images of drifting in complete darkness with huge monsters lurking outside the light beam. Night diving is not like this; it is an exhilarating form of sport diving. After one night dive, most divers come back for more!
Why Dive at Night
Many fish are nocturnal, only coming out at night. The day time fish are usually quieter at night and can be approached much closer.
The water columns filters out most colour in the first few metres, leaving some dive sites a bit colourless. However, on a night dive, artificial light brings back these colours in a spectacular display.
Navigation on a Night Dive
Navigation requires careful attention on a night dive, though the need to travel large distances is lessened. It is good practice to dive a site visited during daylight as the seascape may look familiar. This includes the entry and exits points.
Most interesting fish life can be found at the end of the torch (flashlight) beam. An hour can be spent exploring a ten metre square that would be passed over during the day. A large, slow circle within sight of the exit point safety light is a good dive plan. For an interesting spot in the distance, a compass can be used to navigate.
Buddy System on a Night Dive
The buddy system is important during a night dive as it’s easy to lose someone in the dark. If a diver is feeling anxious, a buddy line (a short line between two divers) can be used to reduce the chance of divers separating.
Things to do on a Night Dive
There are some interesting exercises for night diving. First off, turn off all sources of artificial light. This is best done by covering the torch beam with a hand or holding it against the body to stop all light. Turning off a torch underwater should be avoided as the action can compromise the seal. With no artificial light the true beauty of a night dive can be seen.
If it’s a moonlit night the light dancing on the ruffled surface above gives a spectacular sight. Depending on the marine environment, a hand waved through the water may leave streams of tiny, bluish lights dancing off the fingers. This is phosphorescence and is caused by tiny plankton type organisms giving off a bioluminescence when disturbed. This phenomenon can sometimes be seen streaming off diver’s fins.
Hand Signals on a Night Dive
Normal hand signals are difficult to use at night. The golden rule is to never shine a light in another diver’s face.
There are some signals to use with a torch. To attract a buddy’s attention, wave the torch light back and forth in the horizontal just in front of them. To signal “something wrong”, wave the torch up and down.
Saying “OK” is waving the torch in a circle. This also applies on the surface.
For other hand signals, or if using a sign language, the torch beam should be pointed at the hand to illuminate the signal.
The local dive shop is the place to start night diving. Most shops offer courses covering the skills of night diving.
For a pure thrill, there is something exciting about descending into the dark sea, the stars overhead with the thought of friends sitting in the bar or curled up in bed. This is what night diving is all about!
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