The Pros and Cons of Night Diving December 2, 2019 by lukesheppard

As scuba divers, we can dive pretty much anywhere around the globe that there’s water and thanks to modern technology and a few O-Rings in our dive torches we can now dive when-ever we like. Back in the Jaques Cousteau era of diving, they had rubbish dive lights or some kind of magnesium flare but it’s only been in the last 10 years or so when dive lights have really excelled. 100 lumens used to be a pretty powerful dive light but now we’re in the thousands of lumens from a pretty cheap torch so we can see a lot better in the dark underwater.

A majority of our dives take place during daylight hours for a few reasons; one there’s usually daylight during the day so you can see what you’re doing and the entire reef to navigate, it’s warmer and easier to dry yourself and your kit off in the sun. 

Personally, I love a good night dive and we don’t get to do enough of them. There are 24 hours in each day that you get to spend exploring our wonderful world and we waste around 7 hours of that sleeping so we only have 17hrs to go diving each day. I find a night dive is a more personal kind of dive where I feel more solo, but I’ll go into more later. Night dives tend to be a bit more serene than a normal dive you don’t get all of the normal distractions you get during the day and the freedivers don’t tend to come out at night.

the pros and cons of Night Diving.

The Night Shift

Much like us, marine life has its own bedtime too and when the bright and colourful day shift clocks out and hides in the reef somewhere the night shift comes out. The reef literally changes shape with new weird and wonderful life creeping out and doing its thing. You’ll find plenty of photophobic stuff that usually steers clear of bright lights and even a few things you recognise, but acting very differently. Either Parrotfish snoozing inside the reef in their own little snot bubble, look it up it’s gross, in which case avert you torch, don’t shine you light on them or they’ll wake up and won’t get back to sleep, or you may see something that’s usually sedate during the day out hunting for its dinner or just some fish that you can only ever see at night to tick off your bucket list.

Some marine life has adapted to us scuba divers too, one of the most annoying though is Lionfish, and all of the Red Sea night divers probably know all about this already. Lionfish are these spiky boys who are voracious hunters spreading around the Red Sea and now the East Coast of the Americas. These guys hunt around Dawn and Dusk and they’ve learnt that when scuba divers are around, stick close to them. Scuba divers can produce light and they tend to shine them at tasty fish which both highlights them so the Lionfish can see them and it blinds the tasty fish so they can’t see the lionfish coming. Swimming around a Red Sea reef you’ll be pestered by Lionfish following you around for an easy meal, wouldn’t be so bad if those spikes weren’t full of venom…

Focused

With only the beam of your torch and a small amount of ambient light from the surface, night diving shuts out a lot of the excess background so you can purely focus on what’s right in front of you with no little distractions out of the corner of your eyes. This can be quite disconcerting for some divers because you really can’t see or hear things coming, so if you have a particularly powerful imagination, shining your torch into the blackness of the water and see nothing reflects back at you can freak you out thinking about what might be out there, or just behind you.

I find I get much closer to the reef during a night dive because most of the big stuff is either rare or impossible to find so you get to focus more on the tiny macro stuff doing their thing in the little nooks and crannies of the reef. Shine your torchlight at a reef and you’ll see tiny eyes shining back at you and if you look hard enough you’ll see the shrimp or fish attached to them. Without the big picture to distract you the reef at night makes you look at all of the tiny stuff filtering food out of the water or scurrying around looking for food, so take your time to look at the little bits for once and see what they’re doing.

It’s Dark and Cold

It’s obviously dark at night and this can screw around with your sense of direction. If you don’t have a compass on you then it can be quite tricky to keep your bearings and navigate a dive site because you can’t really use landmarks anymore. You can usually still see if your torch fails because the ambient light is enough for our eyes but you are hard to see for everybody else, so if you get lost or separated you will be very hard to see, especially in that black wetsuit. Bring a backup torch because even a tiny pocket torch will help you be found on the surface if you’re near a boat. Losing your buddy is quite hard on a night dive because their torch beam is easy to see from a way away and your torch is quite a handy way of communicating too.

Without or sun the earth would be a pretty cold desolate place so it does get noticeably colder in the water when the sun goes down. Mid-afternoon is lovely because the sun has been warming the water up all day, but, after that, the water temperature drops a few degrees and you will notice that in your rash vest and board shorts so wrap up for a night dive and don’t forget to adjust your weights. 

Safety

When I was working abroad at this one place we used to run night dives at about 3 to 4am in the morning, which meant a rubbish night’s sleep and a rude awakening when you had to get everything set up in the dark before you jump into the chilly water. ‘Why is it that we only do night dives in the early morning hours?’ I asked and the blunt response was that quite frankly if there’s an incident, by the time we get you out of the water and into the boat, crossed the cove to the local town and to the airport, the airport will have opened for the day so we could get you to the nearest hospital with a chamber to fix you. 

In remote locations, you have to take things like this into account. Sure you can go diving but the chamber might shut at night or over weekends. Also with the night shift coming out, you can’t always see what’s around you so if you’re a bit of a flailer and your hands are all over the place you might slap something, best case scenario it’s your buddy, worst case scenario it’s the pointy end of a stonefish… 

Bioluminescence

Stuff glows in the dark underwater. One of my best experiences was hitting a patch of bioluminescent plankton underwater. Turn off your dive light for the best experience and these tiny planktons glow green when the water around them is disturbed so the water sparkles as you move through it. So you can basically make plankton angels in the water on your safety stop. It’s trippy until you remember that you’re not on LSD and it’s just nature being awesome.

If you have a blue light or something that makes a light near the UV range of the spectrum, you can see some bioluminescence in most underwater life. Many marine species have invisible patterns all over them that you can only see under certain wavelengths of light. We’re still not 100% sure why they have these patterns but if you do have the right torch and filter these patterns glow light they’re under a black light. The specific wavelength of some blue light basically makes the proteins in these patterns glow so it turns the reef into a blacklight party.

Blinding

Another con is the other divers on the dive with you. Our eyes are pretty special and do function quite well in low light so I tend to use a low power setting on a torch but when someone cruises past you and shines their 3k lumen torch in your face to see if you’re part of their group you’re done for about 5 minutes while your eyes readjust. If you’re in the water, don’t shine your torch at anyone else. If you need to read your gauges then remember to shut your eyes first before you shine your torch on them. The reflective glass and white face will dazzle you and again, you’re useless for a few minutes. Most gauges glow in the dark so just shine your torch on them for a couple of seconds and then look at them. You’ll realise why the backlight on your computer looks so weak during the day on a night dive, it’s actually quite bright at night so you don’t want to waste battery power going any brighter…