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Stop – Breathe – Think – Act

research by Syntia

The Scuba Diving Notebook

Octopus in its house in Playa Chica y Barranco del Quíquere (Puerto del Carmen)

“Weightless, levitating in the middle of the ocean, scaffolded in buoyancy compensator, left with no other option but to enjoy vibrancy and the rhythm of underwater life between volcanic ashes, shipwrecks and reefs.

It started on 16th of December in 2022, and wouldn’t be as much perfect without my dive instructor team and Calero Dive Center! The dive equipment is high quality, facilities are modern and the team is welcoming and professional! I decided to continue dive training and getting certified in three diving specialties. Thank you Ariel, Amie, Remi, Sergio, Cris and the entire team! 

After returning from my first diving trip I documented general diving guidelines that I was introduced with before starting the training, and it made me realize how good and safe dive equipment has developed to have this freedom of taking full control in dives.”

Accepting responsibility

Following through the guidance the most important is to maintain these rules and minimize the risk associated with scuba diving. However, inability to make good judgments and common sense due to the lack of knowledge, skills and experience opens higher risks associated with all diving activities.

Therefore I am ultimately responsible for my safety during all diving activities. Failure to comply with responsibilities increase the risk of serious injuries or death. Accidents can happen even when all safety guidelines are followed. Divers should obtain personal dive accident insurance and plan for emergencies.

Dive Competency

Always dive within limits of training, certification, experience, comfort and ability.

By reaching bottoms at the swimming pool have you ever imagined what diving is like? Slowly descending, normalizing your breathing and equalizing under the surface while unnoticeably increasing pressure of air in your lungs.

With more pressure the air gas is compressing and its volume decreases. Our lungs and other cavities that are filled with air get squeezed down to a smaller volume, nevertheless compensating it with compressed air from the tank.

However the buoyant force, always opposing the gravity, is caused by the gravity. Fluid pressure increases in depth because of the gravitational weight of the fluid above, and with more pressure on any object in water loses some weight.

When the object displaces an amount of water equal to its own weight, the buoyant force acting on it becomes equal to gravity and the object will float.

Buoyant or upward effective force of the water becomes positive with any increase in water density. To leave the surface the diver reduces volume by releasing air, so that the buoyant force is less than the gravitational downward force and the diver descends.

Once I started learning the laws of floatation I forgot about the laws of gravity and broke my wetsuit while running to the boat.. Watch out!

The light absorbs where different wavelengths of light penetrate in different depths. The light is converted to heat, and the longest wavelengths with the lowest energy are absorbed first. However the temperature of 15 to 20 deg remains up to 4 bars during the coolest months on the coast of Lanzarote.

Colors transform when diving to different depths, but with good visibility only intensity variates in recreational diving. Yellow fins, red hair, pink torch, green stripe on a Nitrox tank – there are so many details to keep an eye on for the detail. The red channel is loosening first, then orange, yellow, green. And finally blue is absorbed at around 200 feet.

Refraction accounts for light bending as it does not continue passing through water in a straight line, where the diffusion makes the light beams scatter through. These characteristics of light occur on the calmest days with good visibility.

Having an extra light source places the colors back into the visible spectrum that is important for exploring the marine as well as photography and videography.

Once I started noticing the difference in visual details, color and sound I knew that I’m diving comfortably.

Maintain appropriate diver health

Beware of physical fitness, physical health and mental awareness to dive.

As we use our fins, it works out our quad muscles, hamstrings, calves, ankles, hip flexors, core, and shoulders. Most of the body muscle groups are active during the diving, and yet you do not feel tired unless diving against a strong current.

Remember, any object in water has a loose weight- weightlessness exercise lowers the bar for those with injuries or knee buckling. Diving adds resistance to all the body parts as well as strength and endurance- it introduces resistance training that increases intensity with depth.

During the first two weeks of diving I lost some weight that resulted in changing the wetsuit size which made diving more comfortable in cooler temperatures without losing heat while we propel our body forwards and explore the dive site.

Overcoming resistance or and moving forwards isn’t always easy due to the currents. The dive must be planned in a way that the current would help divers return to our starting point.

With respect to buoyancy control and managing the currents the underwater camera on the dive training is prohibited. Having a firsthand knowledge on your diving skills and experience on different dive sites will teach you and give the knowledge that can be only fulfilled in practice. Being comfortable with your dive skills has a profound impact on your underwater photography.

Stop – Breathe – Think – Act – Rule nr 1

Various surveys indicate that more than half of all divers have experienced at least one panic or near-panic episode that causes divers to behave irrationally and can lead to some dangerous or even fatal incidents.

Stop any necessary action and breathe, it will allow you to gain control. You will start being aware of your surroundings, overcome the fear and realize what’s outside of your comfort zone.

The most common issues that may lead to panic are either diver-equipment related, e.g. buoyancy control or uncontrolled ascend, or diving conditions.

Most of the diving risks are mitigated by prior training, planning the dives and diving your plan. Other issues are solved underwater and takes one step at the time prioritized early. Separation from a dive buddy, poor visibility, lack of adequate dive planning, limited overhead dive environment such as ice dives, caves, wreck penetration. Diving conditions can be challenging but solvable with a clear mind and diving buddy. Always look after yourself and your diving partner!

When starting a dive training the best way of learning from experienced divers is observing them and reflecting. Communication is the first sign of your diving buddies health and well-being.

Utilize a dive plan

Plan my dive and dive my plan. Listen to and follow dive briefings.

Getting to know the dive site and its diverse marine life starts from planning the dive. Depending on diving conditions divers should be knowledgeable of taking care of each other during an emergency. Planning the dives covers what will be the duration of dive, gas supply, maximum depth, bottom times, time on the surface, diving conditions and surroundings of the diving site.

For multiple repetitive dives during the day, deepest dive must be done in prior and each subsequent dive shallower than the previous dive. Surface interval might increase depending on the nitrogen exposure time. Maximum dive depth must be aligned to the divers with least training abilities.

Coral reefs provide habitat for a large variety of marine life, including various sponges, clams, crabs, oysters, octopus, sea stars, sea urchins, and many species of fish. Knowledge about the diving site and the navigation will help the divers overcome obstacles and be more relaxed in their discoveries.

The coffee breaks between the dives are the rescue for the divers. It allocates time to analyze the dives, criticize and correct the diving skills, fixing the hair and preparing for the next dive.

On my latest diving trip while having a severe migraine between the dives I was able to recover in 1.5h surface time only with a glass of water. By limiting the movement my surface air consumption (SAC) decreased for 5l with an average depth of 15m as I stayed shallower from the rest of the group and not forced myself diving deeper.

Re-evaluating the return to specific depth and bottom times is essential if the diver doesn’t feel well after any symptoms of i.e. the bends, nitrogen or carbon dioxide toxicity have subsided.

Dive planning eventually starts with the dive computer to keep you in control of your diving limits and comparison of diving history over the time.

A dive computer records and provides all data from a dive in real-time, taking depth and time information and applying it to a decompression model to track the dissolved nitrogen in your body.

Diving computer continuously tells how much dive time you safely have remaining, the actual and maximum depth, bottom times and indicates about the safety stops and no-decompression diving limits. All the necessary details from diving are registered in your logbook, diving computer is your second buddy.

Not only the health check but the buddy check must be coordinated for you and your diving equipment to be all set for your next dive.

Be a responsible dive partner

Remain with my dive partner from start to finish of my dive. Know our plan to reunite if separated underwater.

Air consumption depends on the diver’s capacity of lungs and physical appearance, diving experience, lifestyle and level of training that impact their breathing habits.

Sharing the air underwater might not be a problem if one of the diver’s air consumption is much higher, however it limits the overall diving duration for both. In order to extend the dives longer for both divers they must have a similar air consumption rate.

During the dive training divers normally don’t ask about gauge pressure or bottom time to their instructors, neither do the divers when diving in a group with one SMB and air tank. However it shouldn’t be neglected, because the diver might be aware of the conditions of the site that impact their breathing patterns or simply confirm that they’re on enough air.

Entering the water with a closed tank is not a good buddy check! Scanning the least important kit for safety measures- camera, drysuit, torch, fins, harnesses, mask and other accessories- might sum up in expense, but even the most experienced divers will leave the air tank closed and with a tied up regulator, balancing their buoyancy negatively.

Getting slightly cold underwater may seem insignificant. However ignoring signals of your body in prolonged exposure to extreme temperatures can lead to serious health problems, such as hypothermia, hyperthermia and heat stroke.

Hypothermia is the condition in which the body loses heat faster than it can produce, dropping the temperature required for normal metabolism and body functions. With the conduction the heat is getting transferred directly between two surfaces from the warmer to cooler balancing the temperature. Solids are better conductors than liquids and gasses.

Convection is a second type of heat exchange between liquids and gasses and is an ongoing process- cooler water flows to the areas in which temperature rises higher. The diver’s body heats the water around, and it flows away to be replaced with cooler water again.

A diver begins losing heat via conduction- the rate of loss depends on the type of exposure protection. The convective heat loss drops the temperature with the movement of water around. In fact, convective heat loss is much more significant than the conductive, and it can be 1000 times greater than that in air. Another factor is breathing. The air we inhale is around the ambient water temperature, and our body warms it counting for about a quarter of our body’s heat loss in the form of exhaled warm air. As the diver goes deeper, the density of the breathing gas increases with the volume decreasing and the heat loss from exhaling increases even more. Whenever your buddy signals about getting cold is probably the right time for ascending to shallower depths or returning to the boat.

Responsible diver cares about their partner and the other divers. In my first dive I feared losing the ground, but my dive buddy stayed at my arms’ reach supporting me at any time and increasing my confidence. Taking care and listening to your partner makes diving a positive experience!

Inspect my dive equipment

Before each dive, I will inspect my equipment and make sure everything is working properly.

I will confirm my cylinder valve is completely open. When using blended gas (i.e., Enriched Air Nitrox) – I shall analyze my gas and know its limitations. I will establish proper weighting, know how to release my weights, and verify my buoyancy compensator (BC) and inflator are connected and functioning properly. I will secure my submersible pressure/depth gauge and/or dive computer where it is easily accessible, and know how to use each.

Buoyancy is what controls divers movement underwater- a good buoyancy control will make you better at managing your air and give you a better position and control of your diving.

The type of cylinder affects diver’s buoyancy- aluminum tanks are more buoyant than steel and require more weight for about 2 kg to compensate for your base weighting.

Although a full steel tank is negatively buoyant more than its empty, aluminum cylinders also become more buoyant by consuming the air, but it changes from negatively to positively buoyant, floating and not sinking underwater. During a buoyancy check it is recommended to use a near-empty cylinders and add more weights to compensate.

Air cylinders are not mistaken with Nitrox- Nitrox tanks are clearly labeled with identification marks usually printed in yellow and green with the word Enriched Air Nitrox printed continuously on it in bold green or yellow letters. The type of gas is getting confirmed by an Oxygen analyzer reading the oxygen concentration levels- oxygen rate above 21% is considered as Nitrox with more than 21 and less than 100% of oxygen mix in the gas.

When a gas leak is coming from the valve of your cylinder, close it and double check the filter not to be loose and DIN threaded valve, wherein to screw the regulator into the tank valve. All the equipment must undergo the standard procedure of inspection and testing once a year. A small leak of gas from the cylinder has a minor significance, especially when it’s your instructor’s. Unless you reach the same level of air consumption don’t get over annoying and overreacting about the sand in a valve. Be careful about your belongings and always double check all the equipment yourself.

If you’ve lost your mask after the dive, look at your eyes, shoulders or ask your buddy to make fun of it. Look in the pockets of your buoyancy jacket – eventually you will find more trash in depths of the ocean and carrying a separate bag for cleaning is more sustainable and safe.

Don’t pick up the open metal cans with bare hands to avoid cutting yourself and bleeding unless you are planning to feed the sharks. Be reaching towards anything that is unrecognizable, it might be as well as hidden shark or any other endangered species that impose the risk of attack for its own safety in response.

Diver awareness

Monitor my cylinder pressure; making sure to surface with reserve gas and never run out of gas.
Monitor my depth and time, respect no decompression limits, perform controlled ascents, safety stops, and monitor my dive partner.

Always trust your cylinder gauge to measure your cylinder pressure and your diving computer to align with the time and depth. Monitoring your maximum operating depth, bottom time and no deco limits is calculated automatically. Deep diving opens more possibilities and risks diving deeper in diving sites, and calculating the time limits and safety margin along the way will make you aware about not exceeding those limits.

Deep diving limits are based not only on numbers but your comfort, experience level and skills. 

These limits are standardized and have been established for the safety of the diving community based on Doppler ultrasound research.

Open Water Divers are allowed to dive as deep as 18 meters. It is the entry level limit for gaining more experience and skills before going further in training in recreational diving. Diving below 18 meters requires preparation and more sophisticated diving equipment along with supervision of diving professionals. Diving below recreational limits 30 meters the effects of pressure multiply requiring more careful planning and monitoring.

The process of dive planning ensures that every diver in the team will fit their own objective, skill  level, abilities, comfort and safety factor. Exploring a new diving site, research of marine life, locating reefs or shipwrecks, navigation training, clean-up or a fun dive- there are so many objectives to work on.

By calculating the breathing gas consumption diver knows how much breathing gas will remain at a certain depth, but it also depends on diving conditions and cylinder size.

Surface Air Consumption (SAC) can be calculated by multiplying your total air consumption in bars with the volume of the cylinder, a gas in your container (AC x V), and dividing it with the dive duration in minutes times the absolute pressure at depth (t x P).

For instance, if the diver uses a 10 bar with 12l cylinder at average depth of 15m for 10min, the surface air consumption will be 10×12 / 2.5×10 = 120 / 25 = 4.8 l/min. This expression is only for the SAC rate at the surface, it must be converted at depth with absolute pressure in bars. While remaining at 15m the air consumption rate would be 4.8×2.5=12 l/min, and at max 40m 4.8×5=24 l/min that is doubled. 

Making a safety stop at 5m for a minimum of 3 minutes during every ascent will reduce the amount of nitrogen dissolved in a diver’s body which reduces his risk of decompression sickness.

During a dive, a diver’s body absorbs nitrogen gas which compresses due to water pressure following Boyle’s Law, and saturates body tissues. During a dive, a diver’s body absorbs nitrogen gas which compresses due to water pressure following Boyle’s Law, and saturates body tissues. During ascent, bubbles increase in size and are released by tissues into the veins. It travels to the lungs, where they are offgassed through breathing. Faster ascent rates are thought to have an impact on decompression stress by not allowing sufficient gas bubbles to be offgassed through breathing.

DCI is one of the greatest concerns associated with fast ascents. When bubbles arise or become trapped in tissues or vessels they begin to cause traumatic injury to the body, which is known as decompression sickness. Air can enter the arterial circulation and result in an arterial gas embolism (AGE), which can cause a rapid onset of stroke-like symptoms. At worst it may result in bursting structures in lungs known as alveoli.

The greatest pressure change is near the surface. Never exceed an ascent rate of 9 meters per a minute. A slow ascent requires good buoyancy control and a method of monitoring the ascent rate such as a dive computer or timing device and depth gauge. Nitrogen in a diver’s body expands most quickly during the final ascent, and allowing additional time to eliminate it with safety and deep diving stops will further reduce the risk of decompression sickness.

A partial pressure is a concentration of a particular gas in a diver’s mixture of breathing gasses. Central nervous system oxygen toxicity becomes more substantial for recreational divers reaching a partial pressure ppO2 above 1.6 level of oxygen that is the maximum limit. 

Depending on a mixture breathing ppO2 is increasing linear with concentration of FO2 and depth, therefore EAN32 is recommended nitrox mixture to keep within ppO2 and depth limits between 30 and 40 m maximum.

Maintain proficient scuba skills

I understand scuba skills and knowledge are perishable.

If it has been more than six months since my last dive, I understand the importance of taking a Scuba Skills Update course. I will maintain proper buoyancy throughout my dive, ascend slowly, and breathe properly to avoid overexpansion injuries.

Recreational divers can take advantage of the latest diving technologies. Closed circuit, electronic rebreathers are similar to the Primary Life Support Systems or a subsystem which is a device connected to an astronaut or cosmonaut’s space suit allowing extra vehicular activity with maximum freedom, independent of a spacecraft’s life support system. Diver, similar to an astronaut, is completely reliant on rebreathers as part of the Delivery System for environmental underwater life support.

The regulator provides the diver with a sufficient amount of gas at ambient pressure. Air consumption increases in the direct proportion to the depth and pressure according to Boyle’s law. Air consumption increases excessively by erratic movement or vigorous activity, therefore divers must have a good physical condition. It becomes significant when carrying a limited gas supply at depth. A diver at two bar absolute pressure 10 meters depth uses twice as much air as the diver on the surface, and at four bars 30 meters depth as four times as much.

Because of the greatest pressure increase at the first 10 meters the most effort happens while descending towards negative buoyancy at shallower depths- divers must relax and align their breathing pattern balanced with deep inhalation and even exhalation.

Since the amount of gas contaminants increases with greater air consumption in depth, it explains why a contaminated gas that is not toxic at the surface may be at depth. Carbon dioxide contamination may derive if the compressor is not in a well ventilated area, or its filters haven’t been changed regularly. The most common factor of carbon dioxide toxicity is irregular breathing and contamination of the air supply with exhaled gasses. Breathing patterns can affect an overexertion, wrong size wetsuit that cause inadequate thermal protection, poor physical condition or deep diving without prior training, or malfunction of some low quality regulators that can’t provide sufficient air.

Divers should slowly ascend from all dives to avoid decompression sickness and arterial gas embolism. Mastering a slow ascent requires good buoyancy control. Good buoyancy skills will allow you to breathe easily at depth and maintain low air consumption during the dive. For instance, a 12l cylinder with 200 bars will last 60 minutes when the average air consumption remains 15 liters per minute at surface or increasing depth, when multiplying this rate with the number of absolute pressure.

Respect the environment

Be aware of currents, waves, visibility, temperature, weather, boat traffic, slippery,
uneven and unstable surfaces, overhead environments, entanglements, and hazardous marine life.

I understand boats are unsteady surfaces and will always use one hand to stabilize myself. I understand the importance of taking an orientation dive with a local professional when diving in unfamiliar environments. I will obey all diving and applicable regulations, statutes and codes.

The underestimated skill underwater is a observance. During the first dive attention on breathing and buoyancy control may take the course off the site. The dive planning is essential taking necessary risk evaluation and organizing dive groups according the objective, proficiency and equipment.

Underwater eco or a regular recreational dives wherever a scuba dive takes place, the purpose of removing trash in the ocean from more touristic sites is unavoidable.

Carried by ocean currents and broken down by waves and sunlight, the plastic accumulate large garbage patches with ocean gyres and rotating currents. The debris not only spreads across the surface of the water but also reach the bottom of the ocean, harming the marine ecology and ecosystem.

Do not pick up sharp packaging materials such as metal cans with bare hands. Remember that most of the dives require to have a diving certification and experience, and the clean-up kit such as trash collection bag and diving accessories.

The floor of the ocean reveals not only trash but the hidden treasures- flatfish, weever fish camouflaged in the sand, different species of Rays as well as empty shark beds. Stingrays aren’t aggressive and have only been known to perform attacks on divers when provoked such as being stood upon or wading across shallow waters.