The night dive begins twenty minutes after the sun sets. Not earlier: the transition from the diurnal to the nocturnal reef behaviour that makes the night dive different from the day dive takes the twenty minutes after the last light to complete, and the diver who enters at fifteen minutes after sunset is entering the reef in the transition rather than in the nocturnal state that the night dive is specifically for.
The twenty minutes is the waiting that the night dive requires, and the offshore boat at anchor makes the waiting available in the form that the shore-based night dive does not: the afterdeck, the last of the evening light, the sundowner if the programme and the depth allow it, and the specific quality of the offshore anchorage in the dusk that the waiting produces as its own experience rather than as the delay before the experience.
The equipment check happens on the dive platform in the last light: the torches tested, the backup torch confirmed, the VHF clipped to the BCD, the tank pressure confirmed at the full that the afternoon compressor fill produced. The dive partner system is the same system as the day dive but more specific in its application: in the dark, the dive partner is the person whose torch is visible from the distance the dive plan specifies and who is within that distance for the entire dive, not the dive partner who is visible from across the reef in the ambient light of the day dive.
The briefing before the night dive is the briefing that includes the signal system that the torches communicate: the specific circles and sweeps and holds that mean the same things in the dark as the hand signals mean in the light, in the form that the torch can communicate them.
The Safety at Anchor
The night dive from the Naora anchor has a specific safety architecture that the shore-based night dive and the day-boat night dive do not provide in the same form. The boat is at anchor directly above the dive site: the ascent from the dive ends at the anchor chain that the diver follows to the surface, and the dive platform is five metres from the chain’s surface end.
The surface support is the crew member on the afterdeck with the torch and the VHF: the person who tracks the divers’ torch beams below the surface and who maintains the communication with the vessel’s VHF and with the divers’ VHFs if the surface signal requires a response. Water, oxygen kit, and VHF are always at the platform and ready. The night dive from the Naora anchor is not the unsupported night dive of the shore diver who parks the car at the beach and enters without surface cover. It is the supported night dive of the diver who surfaces twenty metres from the vessel and whose surface cover is watching from the deck.
