Scuba diving (diving). Practical advice
A unique sport – scuba diving – opens up to you a whole universe in which you are a guest. The stunning and unfamiliar world of scuba diving is an unforgettable experience of a lifetime, an encounter with the inhabitants of the sea and the extraordinary beauty of the underwater world. This article is devoted to basic technical recommendations for mastering scuba diving and will be useful for those who are beginning to master the basics of scuba diving.
Diving is a sport in which an athlete dives with a scuba diver, an apparatus that supports the possibility of human activity under water by providing him with the necessary air mixture for breathing.
Underwater exercises for the diver
Before a basic dive a beginner diver needs to know and be able to perform some of the techniques required in this sport.
Here are the most important of them:
Foot down diving with a scuba diver – (if there are problems with the alignment of breathing, it is recommended to dive feet first).
After fully emptying the buoyancy compensator, the diver exhales after first equalizing the pressure at the water surface and dives slowly, breathing normally and making regular breathing equalizations.
Head-down diving
Experienced and dexterous divers who have no problems with pressure equalization can dive from the swimmer’s position: after venting from the buoyancy compensator, the upper body should be bent at a right angle and dive in the same manner as with a snorkel.
The legs are jerked to an upright position above water. The net weight of the legs above the surface of the water presses on the diver, plunging him into the water. Once the flippers are fully submerged, you can start paddling with them.
Partially and fully filling the mask with water, removing the mask, and swimming without a mask
If the mask strap tears or slides upward under water after jumping into the water, the mask may separate from the face. To prepare the diver for this situation, various stages of filling the mask with water and blowing it out are simulated, up to and including swimming without a mask.
Partially filling and blowing the mask with water
First, by gently lifting the mask’s wraparound, just enough water is introduced to the mask to avoid covering the eyes. The diver should breathe in and out through his mouth. When there is enough water in the mask, it can be removed by simply pressing the mask’s upper sealing lip with one or both hands while exhaling through the nose.
By the time the exhalation begins, the diver looks down to raise the head to an upright position while exhaling through the nose. The air flowing into the mask will displace the water. If there is still water, simply inhale from the air regulator and remove the water by exhaling through the nose again while pressing the top edge of the mask.
Completely filling the mask with water and blowing out
During this exercise, as described above, the mask sealing rim is lifted completely until the mask fills with water. Those who wear contact lenses should close their eyes during this exercise to prevent the lenses from being washed away by the water.
Water entering the mask may cause some people to feel depressed and unable to breathe. Concentrating on calm, even breathing (mouth in and mouth out, or mouth in and nose out) will help you deal with this feeling.
Take off your mask completely and swim without a mask
Holding the breathing regulator in your mouth, underwater remove your mask while continuing to breathe calmly. Then, in contact with your partner, swim for 1 minute. If you squint your eyes hard, you can see your surroundings and orient yourself in general.
This exercise is mandatory for certification in almost all international sport diving organizations.
Take out and put the breathing regulator back in your mouth
If it may become necessary to take the breathing regulator out of the mouth under water, e.g. for alternate breathing, the diver must be able to remove any water that has penetrated into the regulator before beginning to breathe.
Warning. During all exercises in which the breathing regulator is not in the mouth, the airway must be kept open so that lung injury from overpressure does not occur during ascent. This is due to the constant release of small bubbles while the regulator is not in the mouth.
Removing water from the breathing regulator can be done in two different ways.
- You should inhale before taking the regulator out, and when you put it back in your mouth, simply exhale into the regulator to remove the water that has penetrated there.
- If there is no air available to blow out the regulator when you exhale, you should briefly press the air shower, displacing the infiltrated water. You can plug the mouthpiece with the tip of your tongue to avoid inhaling splashing water when you turn on the air shower.
Return the breathing regulator to your mouth by tilting your entire body to the side where the regulator is located, usually to the right. If the breathing regulator is behind you, it moves forward because of its own weight.
At the same time, move your hand from that side of your body backward and then in a circular motion forward. In most cases, the combination of body tilt and the circular motion of the arm will cause the medium pressure hose to catch on your hand.
If this does not happen, you should grasp the bottom of the cylinder with one hand and lift it up while your other hand simultaneously tries to grip the second step behind your head along the medium pressure hose.
Breathing from an alternative source
Stationary
After breathing in and out of their own breath regulator, the partner is signaled “Out of air” and “Give me air”. If the partner does not immediately respond to these signals, the diver takes the partner’s alternate breath source himself.
The correct response from the partner would be to instantly remove the alternate breathing source and pass the second stage to the partner, holding on to the medium pressure hose.
In this way, a diver who is out of air can turn on the air shower himself and take the breathing regulator in his mouth as he feels most comfortable. With his free hand, the diver holds on to his partner’s vest.
Tip
If you pull your head back with the mask full of water to blow the air out, water will enter your paranasal sinuses through your nose. This discomfort can be avoided by tilting your head down as you begin to blow through your nose and slowly lifting it up.
If your mask has a purge valve, keep your head tilted forward. Water that has entered the mask will flow out through the lowest point of the mask. After breathing calmly through the breathing regulator, exhale calmly and in a controlled manner through the nose to expel the water.
On the Move
In the stationary position, partners signal “OK” to each other and float away together, with the “no air” partner close to the donor. It is preferable to set up the alternate breathing system so that there is enough space for a medium pressure hose so that both divers can easily swim next to each other.
Lifting with breathing from an alternate source
In a stationary position, one diver switches to a partner’s alternate air source. Both divers are on the same level and facing each other. In this position, each grasps the right forearm of their partner at elbow level and signals each other to “OK” and signal for ascent.
Thus, during surfacing, the left hand is free for the inflator and everyone can control their buoyancy.
If the ascent rate is observed and breathing is normal, an ascent to the surface of the water is performed. There, the alternate breathing source is replaced with your own breathing regulator or tube without lifting your head out of the water.
Alternate breathing – stationary and in motion
Contamination of infectious diseases by the use of one breathing regulator by two divers alternately is almost impossible, but it cannot be completely ruled out. Therefore, you should perform this exercise only with familiar partners or for training purposes only imitate it.
In alternate breathing, it is necessary that both partners pass the breathing regulator to each other in a constant rhythm. When doing this, the donor takes his mouthpiece out of his mouth and passes it to his partner by holding the medium-pressure hose at the partner’s signal “Air out”.
At the same time, both partners take hold of the straps with their free hand and hold each other. Once the regulator is out of the mouth, the airway should remain open by letting out small bubbles, i.e. light exhalation.
The donor takes the second stage in his hand or places the mouthpiece in his mouth while holding on to his partner’s wrist. He then blows out the second stage with an exhalation or removes infiltrated water with an air shower and takes two breaths. After the second breath, he takes the regulator with the mouthpiece out of his mouth and can take two breaths himself.
This rhythm is exchanged between partners, with the donor holding the breathing regulator by the medium pressure hose at all times. In this way, the second partner can use the air shower.
Simulated Alternating Breathing
As explained above, here the donor does not take his regulator out of his mouth, while his partner takes his regulator out of his mouth for two breaths.
The partner takes the second step from the donor, takes two breaths through his own regulator, and returns the second step to his partner.
Alternating Breath Ascent
Once both divers have found the right rhythm for alternate breathing, they give each other the “OK” signal followed by the “Ascend” signal.
To avoid barotrauma to the lungs during the entire ascent, you should exhale air in doses when the regulator is not in your mouth. Everyone is responsible for their own buoyancy.
Breathing from a permeable lung machine
This exercise prepares the diver for the possibility that a defect in the breathing regulator or a sudden increase in air supply due to icing on the regulator may occur underwater.
The head should be tilted down and turned to the right. At the same time, one bite prong of the mouthpiece should be taken out of the mouth with the thumb and pulled slightly to the side, while the rest of the mouthpiece remains in the mouth.
By lightly pressing the air shower, you should simulate the release of air from the regulator. The air being discharged goes mostly around the neck and ear of the head tilted forward, leaving enough air for normal breathing.
Take off and put back on the scuba
Should it happen that the diver becomes entangled in ropes or nets underwater, the diver must be able to take it off and put it back on.
After emptying the buoyancy compensator, kneel down in a place on the bottom where you will not harm animal or plant life. You should start by unbuckling the harness on your belly.
Take care! Do not unbuckle the belt by mistake! After unbuckling the belly strap, unfasten or loosen the shoulder straps. Remove the shoulder belt from your left hand and use it to hold the right shoulder belt. With your right hand, grasp the bottom of the tank from behind and pull the tank forward through your right hand. Place it vertically in front of you or pull it over your hip.
Put it on in reverse order. Once the shoulder strap is on the right arm, grasp the bottom of the cylinder with your right hand and put it on your back while bending forward. While your right hand holds the cylinder and buoyancy compensator on your back, insert your left hand into the corresponding opening of the buoyancy compensator.
Once all available clasps and straps are secured, the partner is signaled “OK”.
Take off and put back on the weights
Unbuckle the weight belt and hold it closely in front of you. To put on the lead belt, lean forward and lift the belt first to your hamstrings and then to your back. After ensuring that no breathing regulator or alternate air source hoses are under the belt and that the belt is not kinked, fasten the quick-release buckle.
Make sure that the open end of the belt is secured by hand, otherwise the lead weights may slip.
If packets of weights are used, they are placed in the holders provided and secured securely.
Removing the Inflator Coupling
If any damage to the inflator is found due to infiltration of sand or mud, on rare occasions the inflator button can become jammed in the pressed position and the buoyancy compensator will fill without stopping.
The bleed valve should be opened immediately to avoid a rapid ascent and associated injuries. Quickly disconnecting the coupling from the inflator will immediately interrupt the air supply to the buoyancy compensator.
Filling the compensator by mouth inflation device
If one of the above-mentioned injuries occurs, you can dive with a mouth blower. Hold the inflator in your left hand with the mouthpiece facing you. Inhale while holding the breathing regulator in your right hand and take the regulator out of your mouth.
Exhale into the buoyancy compensator at a volume that leaves enough air to blow through the regulator. If you inadvertently exhale too much, you can blow out the regulator with an air shower.
Alternate between the breathing regulator and the mouthpiece until neutral buoyancy is achieved.
Using the Breathing Valve
In order for the diver to confidently use not only the functions of the conventional inflator inlet and outlet valves, but also the integrated rapid air release valves, various exercises can be conducted. These should be arranged at the beginning of the first dive to avoid injury from unintentional falls.
Example. In shallow fashion, the diver gets to the bottom, where he is held by a partner while the buoyancy compensator fills up. When the partner releases the diver, the partner simultaneously exhales completely and opens the bleeder valve.
Warning! If you don’t exhale, the overpressure may injure your lungs if you ascend quickly to the water surface. Ideally, an experienced diver, in spite of almost full vest, ascends to a maximum of 1 m.
Emergency Ascent
Should the unthinkable happen and the partners lose each other and the air reserve suddenly runs out, the diver can use the remaining air in his lungs and the medium pressure hoses to rise to the surface from a maximum depth of 12 meters.
By ascending upwards, another breath becomes possible in most cases. The exhaled air is released gradually during a slow ascent, so that only the excess air comes out and the lungs remain full.
Most sport diving organizations conduct this exercise in such a way that the breathing regulator remains in the mouth, some take it out and hold it in their hand so that if there is a sudden lack of air during the simulation, it can be put back in the mouth.
While surfacing, the right hand should be held above the head and moved upward, rotating slowly to change the angle of view. On the surface of the water, the buoyancy compensator is inflated by mouth. During this surfacing, the instructor should have constant physical contact with the student to ensure safety.
Buoyancy compensation, stationary and in motion
The diver with outstretched legs is positioned on the bottom, with the right hand resting on the bottom and the left hand on the inflator.
Air is then slowly and gently blown into the buoyancy compensator in small portions. After each portion of air, the diver takes a normal inhale and exhale.
The compensator is perfectly filled if the diver, breathing in and out normally, is able to balance on the fin tips without the rest of the body touching the bottom, and the diver does not float.
When breathing in, the body rises slightly and when breathing out, it sinks again.
From this position, the diver starts moving, maintaining a constant distance from the bottom, making a coarse change in buoyancy through the compensator and an exact change through breathing.
Alternatively, you can perform this exercise also while standing or sitting on the bottom, the jacket should be filled with small portions of air until steaming close to the bottom with normal breathing is achieved.
Rescuing an unconscious scuba diver
This exercise simulates an accident in which a partner is unconscious or has already lost consciousness. The most important thing in such a situation is the rescuer’s own safety. Unreasonable actions and exceeding the ascent rate will only lead to your own injury, they will not help the injured diver.
If the partner does not respond, you need to make physical contact by grabbing his hand or arm, while simultaneously asking with a sign the question, “Is everything okay?” If the partner does not respond to this either, the rescuer should take a position to the side or behind the victim to avoid being attacked if the partner suddenly regains consciousness.
Your own buoyancy compensator should be emptied. Then, reaching over the victim’s shoulder with your left hand, grasp the victim’s inflator. Two fingers of the right hand should support the partner’s chin and extend the neck. At the same time, the regulator in the mouth should be secured with the other fingers.
The victim’s buoyancy compensator is then filled so that the rescuer and his partner can ascend with one compensator without exceeding the ascent rate.
The victim’s head is supported during the entire exercise. An ejection force should be provided for both the casualty and the rescuer. This is done by filling the buoyancy compensator and dropping weights.
First and foremost, a quick transport to shore or to a boat, only there on a rigid base can cardiac recovery be performed!
If the shore or a boat cannot be reached quickly, in case of respiratory arrest, the injured diver should be given artificial lung ventilation directly in the water during transport. The effectiveness of this method, however, is very questionable, since indirect cardiac massage cannot be performed.
It is recommended that you attend a special diving safety and rescue course to learn the necessary skills.
If artificial respiration in the water is necessary, it is recommended to proceed as follows.
Remove the regulator from the mouth of the partner lying on his back and determine if he is breathing: is there a sound of breathing? Can breathing be felt and/or are breathing movements visible?
If there is no breathing, after checking the airway for foreign bodies and their probable extraction, start mouth-to-nose, mouth-to-mouth or mouth-to-mask artificial ventilation.
Two to three breaths are taken first and continue CPR every 5 s during transport.
The rescuer is at the side of the victim during transport and, if necessary, removes him and his equipment on his way to the shore or boat.
Use Rautek’s rescue grip or a grasp under the arms to pull the victim to the shore or into the boat, where indirect heart massage with simultaneous artificial respiration is possible on a hard surface.
Navigation with a compass
To find a particular point at a dive site, such as a sunken ship, the set bearing on the compass is set so that the notch points forward in the direction of the target.
After diving and compensating for buoyancy at the desired depth, the compass should be held with both hands outstretched forward. The diver positions himself so that the compass heading coincides with the desired direction and swims away with his partner.
The imaginary bearing line starts at the compass dial and continues to the tips of the fins.
Ideally, a diver without a compass easily touches the heading partner’s hand at an angle from the compass.
Thus, on night dives or poor visibility, the partner can illuminate the compass. The lantern should be at such a distance from the compass that electromagnetic deviation is avoided.
Here were listed the basic skills without mastering which a potential diver should not make dives. Knowing these basic rules will avoid injuries and accidents underwater.