Night Diving

Introduction

In Scotland we are lucky to have such a varied and diverse coastline in which to dive, from the islands and long sea lochs on the west coast, to Orkney’s Scapa Flow and Shetland Islands to the north and the dramatic seascapes and reefs of the east coast and south east corner of Scotland. Nutrients and warmish water flow in, aided by the Gulf Stream and North Atlantic Drift. However, it is this nutrient laden current which also brings in limited underwater visibility. At certain times of the year, the underwater visibility can result in almost night dive conditions at depth, even in the middle of the day!!!

These more “character building” underwater conditions can be a useful and gentle introduction to full night diving conditions. Some might ask; “Why would you want to dive at night, in the pitch dark?” Good question, which I will try to answer. I will also, if I may, suggest how night diving can be done with maximum safety, as well as enjoyment.

Why Night Dive?

The main joy of night diving is that you will often see creatures which only come out to roam and feed at night. For example, in November there is a good chance of seeing the very small Bobtail Squid or Cuttlefish. Norway Lobsters and Common Lobsters are more likely to be on the prowl at night and various fish species may be found “sleeping” under rocks. They hardly move, caught in your diving light beam. If you turn out your diving light, you may see microscopic bio-luminescent creatures giving off a light show, as you move your hands or fins in the water. Your exhaled air bubbles may also cause a light display. It looks like the Milky Way…… underwater! Above all, the colours of the seascape can appear more vivid caught in the beam of your diving light.

Night diving can be exhilarating and exciting experience, however it can be potentially dangerous and should not be undertaken by new and inexperienced divers. Most of us live in towns and cities where we nearly always have good street lighting at night. It may therefore be quite a surprise to realise how dark it really is in the countryside or on the coast. It really is pitch black, especially on a moonless night. Underwater it will be black ink black!!!

Diver experience

Consequently, you need to be a confident, experienced diver, totally familiar with diving techniques, with your equipment and have a considerable number of dives under different conditions logged. You will, of course, be diving with an equally experienced buddy diver. Nevertheless, it is important to have some “self-reliant” skills. For example, you should know, by touch alone, where all your equipment is located; your diving computer, your compass, your air contents gauge, your suit inflation and deflation valves, your alternate air source, your BCD dump valves, etc. You should be confident that your equipment has been well maintained and is in perfect working order. No leaky hoses or dodgy “o” ring seals!!! You should also be carrying at least one fully charged and reliable underwater light, which you will be using through-out the night dive!!

Underwater visibility will be limited to what you can see in your diving light beam, so you need to know exactly where your buddy diver is located at all times. Good, clear and concise hand signal communication with him/her is essential. Obviously, you should keep fairly close to your buddy, but one advantage of night diving is that you will probably be able to see the glow from your buddy’s diving light at quite a distance. This should not be used as an excuse for poor or sloppy “buddy diving”!! However, if you do become “slightly separated!?!?”, you should be able to locate your buddy again, if you have not strayed too far apart, but watch it!! Diving experience and “self-reliant” skills will be an asset in these circumstances to avoid stress or anxiety, as it is very easy to become separated on a night dive.

It is all too easy to become disorientated underwater on a night dive. There is no sun shining down through the water to guide you and there is a very limited view of your surroundings, reef walls, the sloping seabed, etc, so it is for this reason that you should set your compass for the direction of the shore. As you will already be familiar with the dive site, facing the direction of the shore should help re-establish your orientation in the water.

Communication

So, how do we communicate underwater? A specific set of “diving light” signals has been developed over the years and can be found in various diving manuals and publications. This involves waving your diving light around in a manner similar to semaphore. However, I suggest that as most of us do not night dive too often, it would be more appropriate to just use the “normal” hand signals we use during daylight dives. The difference at night is that you use your diving light beam to illuminate your hand signal, whilst being careful NOT to shine your diving light in your buddy’s face!! S/he will not be at all pleased to be dazzled and, of course, it is potentially dangerous, as many modern diving lights emit a very powerful beam which, at close proximity, could damage eyesight!! PLEASE Be Warned!!

It will not have escaped your notice that most diving gear, for some reason I do not understand, is BLACK! Not very helpful in the night diving scenario, so once again, we have a good reason for not straying too far from your buddy as you might not be able to actually see him/her more than a couple of metres away!!

Planning a Night Dive

The Dive site should be well known, with minimal current, a sloping seabed, reef or wall with a known reasonable maximum depth. There should be good road access** if it is a shore site with easy access across the beach area to the water.
Avoid adverse sea and weather conditions. This is meant to be fun!!
Appropriate Expedition positions should be appointed; ie Expedition Leader, Beachmaster, Safety Officer, Dive Leaders, Standby Diver, etc as required.
Full Dive briefing by the Expedition Leader and Records kept.
Entry/exit point(s) should be marked with lights/flashing lights.
Buddy pairs ideal, or maximum of 3 divers together.
PROPER buddy gear checks prior to entry.
Avoid dives deeper than 30 metres.
Avoid dives requiring decompression stops (other than Safety Stop)
Maximum dive duration of 1 hour.

** Good road access required in case of an emergency requiring evacuation to medical facilities or access for “Search & Rescue” assets. Having an incident is bad enough, having it at night, with difficult access, just complicates the issue ten-fold.

The Diver & Personal Diving Gear

As underwater visibility will be limited, more or less, to what can be seen in a torch beam:

Divers must be fully familiar with their own diving gear.
Each diver is already experienced to the target depth.
Brightly coloured diving gear where possible.
Each diver has own emergency independent air supply if possible.
Each diver has a diving light and a backup diving light.
Each diver has a compass AND it is set to point to the shore!!!
Buddy & signals check prior to the start of the dive.

During the dive you should be aware at all times of the location of your buddy. This should be quite easy, as you will see the glare from his/her diving light beside you. However, it is quite easy to become distracted by a critter under a ledge or rock and before you know it, your buddy is a very faint glow in the distance!! Oops!! That “distance” may be only 3 or 4 metres, but it could be enough to be of “concern” or start an incident.

At the end of the diving, it should go without saying, that the Expedition Leader checks that everyone is confirmed out of the water!! Before you leave the dive site and head for home, do a double check that all that black coloured diving equipment has been safely stowed away and not left lying around the ground or the bushes, cunningly disguised in its black finish!! It could otherwise turn out to be a very expensive night dive. Having done all that, have another, absolutely final check around!!!

Additional Facilities

It is highly likely that most night diving in Scotland will take place from late autumn through to early spring, when night falls early in the day. This will invariably mean that the evenings/nights could be rather chilly. It is therefore absolutely essential to provide yourself with food, hot drink and plenty of warm clothing, such as anoraks, changing robes, hats and gloves. Your normally quite acceptably warm dry suit and thermal under garments may not “cut the mustard”, especially if you are standing around between dives. You should also be equipped with an ordinary torch and/or head torch for moving around the pitch-dark diving site. Don’t waste your diving light battery!!!

Night Boat Diving

Boat diving at night opens up a whole new area. However, everything above applies plus making arrangements to enable divers to find their way back to the boat as the dive draws to an end. The boat should be well illuminated both above and below water. If diving from a “liveaboard” or “Day” boat, there should be a tender/inflatable boat to enable diver pickup. However, this tender boat presents a risk of running over unseen surfaced divers!! When divers surface at the end of a boat night dive, it is a good idea to keep your diving light on, until you are picked up. Alternatively, if you are carrying a strobe light, turn it on so that everyone knows where you are!!

Conclusion

We all know that scuba diving is a potentially hazardous sport. However, with proper training and experience the risks are minimised and understood. Night diving presents us with new challenges. The limited visibility, the complete blackness of the water, the feeling of being completely on your own, make it essential that you have some “self- reliant” skills. This, in itself, is a controversial subject for another time and place.

Having said that, night diving can be a thrilling experience and present you with a new aspect of interest, give you a new visual experience, interest and understanding of the creatures we enjoy seeing underwater. Above all, night diving will add to your skills and confidence underwater.

Clydebank Sub Aqua Club

Night Diving