Night Diving
Explosion of colors of corals and sponges in the beam of underwater light, concentrating on details in a narrow range of light and meeting the active night living beings – this is the motivation of night diving.
Night diving has well increased scale of being more risky and additional risks as: flows, penetration diving, decompression should be excluded. But the main risk in night dives is the underwater psychology, about which we wrote couple of weeks before. Diving site, equipment and underwater skills must be exactly the same as several hours earlier at the same place in the daytime.
Planning A Night Dive
Dive site for the scheduled dive should be familiar from previous immersion in order to facilitate orientation. To mitigate the exposure to darkness dive must begin at dusk, even the bright moon at night is credibility with its reflected light. Requirements to the night diving site:
1. lack of surf or strong flows (stable weather, tides control);
2. sufficient visibility under the water and the absence of
obstacles, such as ropes, cables, trees or caves;
3. lack of surface activity as dredgers or traffic.
4. a reliable and safe entry and exit, without steep slopes, and islands of algae, or the bottomless pit;
Immediately prior to diving you should thoroughly checked your and your partner’s equipment. This also applies to the illuminator, which is needed after immersion for removal of equipment.
Checklist before a night dive
So before we start a more detailed discussion about what to do, or what not to do, let’s just go over a short checklist, which is a must to remember for everyone and in addition to the usual activities and security requirements pay special attention to the following items:
- You know where you go! You must have dived here during daytime
- Do not take alcohol at least 2-3 hours before the dive
- The group must not exceed 3 per.
- Particular attention to your and your partners’ diving equipment
- Only non decompression dive
- Diving where you know where the bottom is – do not dive into the abyss
- Do not swim away a long distance
- If possible, do not exceed a depth of 8-10m (at Sea 15-20m)
- Set compass course correct and check it with partners
- Clarify light signals (light on hands, on chest) and emergency signals
- Use dive lights only under water (do not confuse with the emergency signals)
- Do not dazzle other divers
- Do not touch, do not cover and not to frighten sleeping creatures
- Keep the dive light away from the computer and the compass (magnetic switches).
- Keep the dive course accurate
- Remember the way back to the anchor or to the coast (natural landmarks or compass)
- Keep away from the nets, ropes and other obstacles
- Do not raise the sludge
- If you lost your dive light, do not panic, take the spare light or the chemical one
- If there is no backup dive light contact with the partner
- If you lost your partner: after a short search turn off the light for a second, if still no result, do not panic and calmly start a controlled ascent.
- And finally and again: night dive is not for training and exercises, but to receive impressions
Be ready!
With darkness primitive human fear is approaching, making some divers bring under water powerful lights of 50-100 watt, with which they think they may fight monsters from the television, instead of diving under the water calmly. No! This isn’t the way, so carefully read this article.
Night diving gear can be the same as during the daytime (with some exclusion), it must be complete and fit, studied and experienced.
Safety Gear
The equipment must also be complete and fitted. This refers to the luminous or reflective devices, with the possibility of dive at night, even without the light. At night, it is important not only what you see, but also who will see the diver at a distance from the boat. As with all the dives in the sea requires a set of safety equipment that should have every member of the group.
These include:
1. Reflect able and light collecting strips and inserts in suits.
2. Flash lights
3. Rocket signals
4. Acoustic signals
5. Dive knife – even a little, to be sure, because at night with limited lighting you can be easily entangled in nets or lines, and must be easily and quickly get out.
All equipment must be put as close as possible to the body. Equipment should be well studied.
Dive Lights
To be fully ready, first and the most important part in night dives is the reliable, easily managed dive light with a maximum power of 30 – 50 watt with a sufficient work time, including the time for dressing and road time.
Even reliable lights can be broken or lost, therefore it is necessary to keep a spare light for the team. Particularly it is worth noting comfort of dive light control.
Requirements to the dive light are:
1. waterproof housing, impact resistant, rugged shell, protection from the full discharge of the battery, the battery level alarm;
2. durable, shock-resistant, working perfectly on surface;
3. stable grip with the possibility of attachment to the ring line jacket with a carbine;
4. good controllability even with thick gloves;
5. single-or double-ring seal on the inner diameter of the threads;
6. quick chargeable device that makes the light functional for multiple times, following one after another dive.
What about your partner?
Night diving means that you have enough experience, so that there is no problem with the equipment and skills. Usually, adjusting diving plan you should with the partner with little experience.
The group should not comprise of more than three divers, including not more than one beginner. He/she must understand the special rule: absolute honesty. Beginner should well understand the danger signals of the head of the group, which in this case with manual contact should rectify the problem. This leads to a precise instructions before diving and the beginner should be always in the middle.
Briefing before the diving;
Personal gear, as well as the partner should be examined, manageable with closed eyes and thoroughly tested. Informed diving details (depth, duration, and when to do that). Particular attention is paid to the use of underwater signals at night. Repeat the signals given by a light, such as, «all in», (circular motion lamp) and an alarm. We recommend that you show signs on the backwards to the breast, highlighting their lantern, then the light will be sent from the partner.
Normal planning of emergency situations is different from the day diving because of the following reasons:
1. darkness hinders any rescue action;
2. doctors, a pressure chamber, pharmacy, etc. is more difficult to find at night;
3. prefer own safety (oxygen artificial respiration device, a mobile telephone, the exclusion of risk, fear).
You can go. Dive!
The attraction of the night dives is to see many living organisms, which can be met only at night, and watch sleeping fishes, which we know from the daytime diving. Many of the creatures have different colors at night.
If you need to consider fishes closer cover deflector arm to reduce the luminous flux. The same rules are to protect the environment for daytime diving also.
Finally, all is behind and we are in. This could be the start of the shore, or, if the diving starts of a boat, holding on the rope. Here is a free entry into the darkness requires some habits. Flashlights should be included at all times to facilitate the gathering of the group. With the loss of partner light should be turned off for a second to find him/her with help partners light. This disabling can be done only briefly, the other diver does the same.
At the time of diving may be situations where an agreement when all the lights are switched off simultaneously for a short time. For example, while observing the magnificent play of luminous marine organisms in tropical seas.
The duration of diving should be precisely defined, as to ensure peace on the shore. Not later than the first pale light starts flashing signal or battery level, the whole team should be at the point of exit.
Dangers at the night dives
Dangers lie already at the entrance. Steep slopes, slippery ground, profits, accumulation of islands or shoals of algae can cause problems for divers and their equipment.
However, the main danger is psychological. The most experienced diver fear the night, when suddenly from the darkness, fearful of his movements, the fish encounters with him. The difference is that an experienced diver smile, a newcomer may panic because of stress waiting for shark attacks
Another risk – it is underwater obstacles that may be encountered because of negligence or limited visibility. In this situation only calmness and slow retreat helps. This is the same as if you have sailed in a cave and suddenly came across an upright wall. Periodically monitoring the direction of the compass, find the way back. Check the course at night is most needed, without it turning at a light you can easily lose their bearings.
Another danger are ships. It’s better not to dive in such sites. Even a quiet anchored ship can be dangerous. There are accidents in which a diver is sucks by the cooling pump.
A big risk can be considered the so-called effect «vertigo».
This loss of senses in the field of orientation in space. These include:
1. eye, showing the horizon
2. specific sensors in the muscles, which indicate the direction of application of force
3. body equilibrium, the so-called vestibular apparatus, indicating the direction and change of the situation.
Dived in slightly turbid water, with no visible bottom, you may lose all three of the sensors with the minor problems with the pressure, feeling the sudden dizziness. In severe cases, you can lose orientation when it is not possible to determine where the top and bottom is. Such places the entrance to the water should be avoided. This effect disappears as soon as reaches the surface and see the stars or the boat lights.
Health disorders – alcohol – drugs – drugs
It goes without saying that violations of health and after taking alcohol, receive certain medications and immediately after the meal is not allowed to dive.
Mental problems.
Darkness, especially among beginners, is an easy sense of fear. Increased psychological stress for a diver can cause panic and the erroneous actions. The truth to yourself and especially to the partner – this is a mandatory requirement. When the symptoms of fear (random motion of the lantern, the frequent breath, wide-open eyes) you need to create a bodily contact, and possibly finish the dive. People suffering from claustrophobic (fear of closed spaces), should not dive at nights.
Loss of partner.
In a dense co-navigating and observing light partner, the loss of the latter is reduced to a minimum. However, if one is lost, your dive light must be turned off for a second, to better see the light of the partner. Lights can be switched off only for search and then for appointment appointment. If this search does not result in a short time, emerge.
Problems of orientation.
Night dives should be conducted only on the well-known for the daily water diving site. Reliable orientation marked by the natural orientation or compass must be guaranteed. Do not swim for long distances, if possible, stick to the boat, or place of entry into the water.
Compass course must be pre-determined and stored or recorded on a tablet. It is necessary to take into account the deviation of a compass due to the mass of metal or a magnetic switch.
Loss of orientation;
At night diving, mostly when surfacing, there can be dizziness, which may lead to a complete loss of orientation.
Eyes, we define to the horizon and look for a fixed point. If you close your eyes, you lose information. We are just helpless, especially if you are in motion.