At night everything looks completely different, even sites that you have dived at before dozens of times will look new. When we dive during sunlight hours we will observe the whole area that we can see, if the visibility is 20 metres then we can get a very good idea of the layout of the site, and with a little practice we should be able to navigate ourselves around without too much effort. However at night we can only see as much as our torch beam will allow us. Looking at the same rock from two different angles will change your perspective entirely which leads to navigation problems. Here are 9 tips that could help you get more out of your night dives and keep you safer at the same time.
Tip 1) Dive Earlier
When I have previously taken customers on night dives they are normally surprised that I ask them to show up so early. Usually I plan to jump in at sun set, so we will have around 10 to 15 minutes of ‘dusk’ light before it goes completely dark. This comes with several advantages: It is easier to kit up, do pre-dive safety checks and enter the water while there is still light. You also get to watch the reef life shift from diurnal (day) to nocturnal (night) over the course of the dive. Many animals hunt at dusk as they use the last remaining light of the sun, and take the opportunity that many day dwellers are still active.
Tip 2) Learning the New Signals
Because it is dark while night diving (hopefully) it is harder to communicate. You and your buddy should review any signals, or come up with new ones, during the pre-dive briefing. Consider changing two handed signals so that it can be done with one hand, so the other hand illuminates the signal. Also your lights can work as very effective signalling devices, although light signals are generally kept basic, they are very effective at getting each other’s attention. The basic light signals are circling of the torch beam, which means OK, Slowly moving from side to side, which means minor problem such as equalising troubles, and rapidly moving the light beam form side to side means emergency, such as out of air.
Tip 3) Stay Close to your Entry Point, and Stay Shallow
Generally night dives should be kept shallow, so you have plenty of bottom time to really look around. If you stay close to your entry point then you will less likely to get lost, which means you can focus more on finding the weird and wonderful creatures that inhabit the reef by night.
Tip 4) Brighter is not Always Better
Think about the kind of creatures that live on the reef at night, they probably have pretty good night vision. If you swim through with a torch as powerful as the sun then you will make the nocturnal creatures swim off and hide. As a new night diver you may feel a little nervous, and the extra lumens will help reduce those nerves, but as you get more experience you will get more comfortable and find that smaller torches allow you to see more of the night life.
Tip 5) Be Careful where you Point your Torch
Nocturnal creatures have eyes that are very sensitive to bright lights. If you shine in their eyes with a 300 lumen torch then you will either temporarily or permanently damage its eyesight. If you blind it, even just for a second, then you lead it open to predation. Remember as divers we are there to passively observe, not to play god and decide who gets eaten and who doesn’t. This is also true for other divers, if you want your buddy to enjoy the dive as well then avoid blinding them.
Tip 6) Leave a Trail
Just like the classic fairy tale by the Brother Grim where Hansel and Gretel left a trail of white pebbles so they could find the way out of the forest where they were abandoned, night divers should mark their entry and exit points so they can find their way out of the water. If shore diving this could mean placing a bright marker light at your entry point, if diving from a boat then leave a light on the boat so you can find it easily again after you have surfaced. It is not just for helping you navigate during the dive, if you are in a remote area then there may be no other lights around. The last thing you want to ruin your dive is getting lost at sea…
Tip 7) Dive Familiar Sites
If you know the site well before then you have a far better chance of navigating your way around. You can uses compasses and maps at night, but it is hard. You should be able to rely on natural navigation for night diving, and use you compass as a backup if you get lost.
Tip 8) Be Fully Equipped
You will need a primary torch for each diver, and preferably a backup each (or at least one between buddy team). These should have wrist lanyards, as most dive lights are negatively buoyant and may be gone forever if dropped. Your backup will generally be smaller and weaker than your primary. It should be small enough to stow away and not dangle around, but powerful enough to allow you to see properly. Your backup torch is like your alternate air source, it should be checked before every dive, but only used in the event of an emergency. If anyone needs to switch to a backup light during a dive then the dive should be aborted.
Tip 9) Dive Slowly
This rule applies for all diving but at night it may be even more relevant. The night reef can be a difficult place to live, so to help air survival many creatures have evolved elaborate camouflage patterns to help protect themselves. If you swim too fast you will not see much, and your dive will be a boring one. If you really take your time and go slow you will have a better chance of finding things like Octopus or Scorpionfish.
‘9 Tips for Night Diving’ was written by Mike
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