Pink sea fan
UKDIVING
Crystal jelly by night
PHOTO: DAN BOLT
Night diving in the UK is one of the most underrated experiences we offer, and it genuinely transforms sites you think you know. Here’ s how I’ d frame it for members.
Main considerations
Planning matters more at night than it does in daylight, so the discipline has to be sharper. Every diver needs a primary torch and a backup- a failed light on a night dive isn’ t an inconvenience, it’ s a dive-ending event, and you don’ t want to be relying on a buddy’ s spare in cold water. Get into the habit of a light-signal briefing before you enter: the slow circular‘ OK’, the rapid sideto-side for attention or a problem. Hand signals don’ t work at night unless lit up( carefully so you don’ t blind your buddy).
Navigation is the big one. In UK conditions your visual references disappear the moment you’ re off the shotline or away from the wall, so compass work and a good sense of your site pay off. On quarry dives, following a fixed line or a known contour is far more relaxing than mid-water into the dark. Task-loading also climbs – buoyancy, gas, buddy, light, navigation all demand attention at once – so trim the ambition and don’ t treat a night dive as the time to try a new bit of kit or push depth.
Cold and exposure need respect too, particularly on the winter quarry dives. You’ re often kitting up in the dark, in a freezing car park, and your extremities chill faster when you can’ t move around much. Thermal protection, a plan for entry and exit points you can actually find again, and marker lights or a strobe on the shotline or exit make a real difference. Buddy contact needs to be closer than in daylight- it’ s surprisingly easy to lose someone who’ s only a few metres off, so agree on how you’ ll stay in visual touch with each other’ s torches. And a small point that matters: let someone on the surface know your plan and expected exit time, and make sure your surface marker and torch are visible for the boat cover and / or Dive Manager. A glow stick( in normal speak, or‘ cyalume’ in Sophie R speak) attached to the top of an SMB or DSMB can help visibility, or buddy pairs with different colours can also ID pairs to the surface cover.
What you actually get to see
This is the payoff. Marine life behaves completely differently after dark. Nocturnal hunters come out – you’ ll see much more active crustacean behaviour, with lobsters and crabs out in the open rather than tucked away, and octopus are far bolder at night. Fish that bolt in daylight often sit still, almost trance-like, letting you approach within touching distance. Your torch beam pick colours out of the gloom that UK divers rarely appreciate, because in daylight everything’ s filtered to green and blue.
Colony of brittle stars at St Abbs
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