Alert Diver March 2023

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DAN Southern Africa

Publisher DAN Southern Africa


Nicolene Olckers, Dennis Guichard, Francois Burman, Claudio Di Manao, Audrey Cudel, Frauke Tillmans, Kyle Kray, Liz Louw, Charl Marias, Brittnee Engelbrecht, Leanne Walmsley, Keri Muller, Christine Tamburri, Maryka Pace, Grant Dong, Jim Gunderson, Liam Brennan, Alex van der Hoven, Petar Denoble, Mike Barron, Gareth Lock, Miko Locci, DAN Medical Team


Morné Christou, Nicolene Olckers, Dr Frans Cronje

Cover photography

Carel van den Colff The Klipdish (Rock Fish) are stunning little fishes with various species in and around Cape Town and False Bay Some can be aggressive at times, but they are mostly very curious Several species have stunning eyes, while others are shy and seldom seen This one wanted to be seen and photographed This is a Speckled Klipfish it’s Latin name Clinus Venustris I shot this image with my Canon EOS 700D camera in a Sea&Sea RDX640 housing and used the Sea&Sea YS D1 strobes to light the scene


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Alert Diver Philosophy

Theviewsexpressedbycontributorsarenotnecessarilythoseadvocatedbythe publisherorDANSouthernAfrica Whileeveryeffortismadetoensuretheaccuracyof informationandreports,thepublisherandDANSouthernAfricadonotacceptany responsibilitywhatsoeverforanyerrors,omissions,oranyeffectsresultingtherefrom TothebestofthepublisherandDANSouthernAfrica’sknowledge,contributorshave notindulgedinplagiarism Althoughtheutmostisdonetoavoidsuchoccurrences,the publisherandDANSouthernAfricawillnotbeheldresponsibleforthecontributors’or writers’indulgenceinplagiarism Nopartofthispublicationmaybeusedor reproducedinanyformwithoutthewrittenpermissionofDANSouthernAfrica E&OE

6 10 12 20 23 Perspectives New Annual Diving Report Demo Divers Dive Resort Safety Special Forces Diver 27 32 42 44 50 The Inhaca Ocean Alliance Freediving Instruction Blue Ocean Dive Resort For The Love Of The Ocean Scuba Nudi Clothing & Apparel 54 58 66 70 74 Decompression, Stage & Bailout Cylinders Lights Film Action What Dive Computers Don't Know -Part 2 Scuba Cylinder Rundown Terrific Freedive Mode 80 84 90 96 102 After The Accident Analysing Decompression Sickness Risk Breathing & Buoyancy Control The Benefits of Being Bald Diving Etiquette 110 114 122 128 132 From The Medical Line Peter Bennett Researcher Profile The RADD Program Medical Grade Oxygen The Story We Get Told 138 142 146 147 148 Kaboom! The Big Oxygen Safety Issue Group Fitness At The Pool Member Review Calling The Hotline Parting Shot Cover Image CONTENTS

Safe Diving Starts With You


All divers should realise that they are ultimately responsible for their safety Divers Alert Network is here to support you Still, DAN cannot make up for what divers are unwilling to do in caring for their safety, such as proper equipment maintenance

DAN provides several programs that help divers take responsibility for protecting themselves while diving, whether they're at home or travelling Wherever you go, DAN will be there as your dive safety organisation – but when it comes to safety, it's up to you first and foremost


Preparedness is critical to effectively managing emergencies. An EAP customised for each dive site is essential; you must craft one before diving Though DAN does not create EAPs for you, our teams are available to consult and advise with planning for unpredictable scenarios anywhere in the world

DAN has a wealth of experience helping divers manage sudden and unexpected emergencies; however, careful preparation on your part can immensely improve our ability to assist To quote renowned DAN medic Marty McCafferty: "If it took three planes, two boats, and a donkey to get there, it's going to take the same to get you out" Before you embark on your trip, get to know the medical resources close to your destination and any possible methods of accessing appropriate medical care

If you'd like to learn more about emergency planning, read the following Blog Posts

Emergency Planning: Why Do We Need It?

Emergency Planning: What Makes A Good Plan?

Emergency Planning: Practicing The Plan


Proper training is essential to ensure a positive outcome in an emergency DAN offers various first-aid and emergency oxygen courses to give divers the confidence needed as first responders Don't let yourself be left helpless in an accident or medical emergency - take the initiative and acquire the necessary skills to help To do so, you can sign up for online elearning modules or in-person DAN first aid classes Find a DAN instructor at https://wwwdansaorg/find-a-dan-instructor

DAN has made many safety products available, including various first aid and oxygen kits in differing sizes and configurations It is important to be aware of these lifesaving essentials when diving, even if it is not your responsibility to purchase them

If your dive operator does not have the right items available or refuses to display them for inspection, don't hesitate to modify your plans. Remember that you could be hampered significantly if you do not have the necessary emergency first aid equipment


As a DAN member, you benefit from evacuation coverage and the opportunity to purchase dive accident and emergency benefits Obtaining coverage should be a priority rather than an afterthought ahead of your dive journey To safeguard yourself against potential expenses related to medical emergencies, it is essential to read what your DAN membership plan covers and identify any gaps that may need to be filled with supplemental coverage DAN can recommend travel insurance per trip or annually to help fill any remaining gaps

Your health and fitness are of utmost importance regarding dive safety The number of reports concerning strokes and heart attacks is on the rise In the past, a quarter to a third of all fatalities in diving resulted from cardiovascular issues, which has likely increased in recent years DAN strives to advance research on keeping dives safe and accident-free and is constantly studying fitness requirements for divers Yet, it's up to each diver to maintain a fitness level suitable for their specific situation Not only do you need to be physically prepared for expected conditions, but you also need to be able to handle unpredictable situations, such as strong currents or long surface swims

Divers must stay vigilant regarding their health, continuously assessing if any factors may prohibit them from diving and addressing these issues at the yearly physical

Many divers are back diving in the ocean after the global pandemic If you're rejoining them after an extensive gap or disconnection from diving, remember that your skills may have

deteriorated during this period of absence. Thus, it is advisable to recognise your limitations and choose a suitable dive spot, depending on your competence. If you've been away from diving for months, do not go for a site famous for its fierce currents Returning to diving after an extended break isn't like riding a bike – you can't just pick up where you left off Examine your gear; if it needs to be serviced or tested before use, you may first require some retraining or practice time in shallow water

Divers Alert Network is dedicated to providing dive safety and medical emergency assistance for all divers We also strive to give divers confidence through our initiatives, aiming to empower the global diving community

You can take advantage of the resources available to ensure dive safety, such as those offered by DAN, your local dive operator, and your community of divers Taking the initiative and ensuring you are prepared ensures that you and your fellow divers can safely enjoy the underwater world DAN will be there for you if you are ever in need We are devoted to ensuring you have the best opportunities to dive safely through training, educational materials, rescue, and first aid equipment Our goal is that all dives should be incident and accident-free



The newest edition of DAN’s Annual Diving Report is now available While the release of the 2020 report was delayed, it offers fascinating insights, statistics, and case summaries of recreational dive incidents and fatalities that occurred in 2018

As in previous years, the report covers breath-hold diving incidents, DAN’s injury monitoring program, and the geographical distribution of incidents and has special sections covering equipment failures, the role of training and education, and implications of divers’ cardiovascular health and fitness.

The case studies provided in this report give insights into divers’ behaviours and highlight the importance of safe diving practices. Readers can learn more about the data collection process, review expert analysis of various situations and hazards, and better understand triggers, mechanisms of injuries, disabling injuries, and causes of death. Read the 2020 Annual Diving Report at

Pros Choose DAN


Dive Safety Alert Diver DIVERS ALERT NETWORK
Richie Kohler, Professional diver, shipwreck researcher, and film-maker, explains why he chooses DAN.

Most people know the historical significance of D-Day, the infamous day when Allied forces landed on the shores of western Europe on June 6, 1944

Many have heard stories and even seen films of the brave men carrying rifles who fearlessly charged out of the gates of amphibious landing craft and onto the beaches of Normandy, France, running directly into an onslaught of enemy machine guns and mortar fire

Few people know the story of the men who went into these enemy waters before them Armed with nothing but a mask, fins, and a knife, these divers were tasked with destroying the countless enemy obstacles entrenched in the shallows that would prevent Allied watercraft laden with infantry from ever reaching the sand

One of those divers, George Morgan, was only 17 years old Having graduated from the US




UDT men welcome the Marines to Japan © NATIONAL NAVY SEAL MUSEUM

Navy's experimental Underwater Demolition Team (UDT) program just days before, Morgan found himself thrust amid the chaos and churning ocean surf of Omaha Beach

The task seemed impossible: Clear angled metal beams, steel tetrahedrons, and concrete posts from 16 predetermined landing zones Some zones were longer than football fields And because of tides, weather, and the Allied watercraft speeding in fast behind them, the UDT divers barely had a half-hour to complete their mission

Completely defenceless and fully exposed to the enemy, Morgan and the other UDT divers scrambled amid the horrific landscape and gruesome carnage They dodged endless incoming rounds and explosions as they deployed demolitions to clear the beach zones so their brothers in arms could attempt to land.

Thirteen of the 16 zones were successfully cleared. The foot soldiers who survived the landing would go on to secure the beachhead and the first significant victory of the Allied forces' push into Europe.

Only 48 percent of the UDT divers at Omaha

Beach that day survived the grisly invasion, yet they still completed their impossible mission There would be no rest for Morgan and his fellow divers, however Immediately following the battle, they were shipped out to the Pacific to continue the fight D-Day was just their first introduction to the war!

"Everybody did what they had to do," said Morgan, now 95, reflecting on the events of that day and the days that followed After Normandy, he saw direct combat in numerous major operations in the Pacific theatre, from the sands of Iwo Jima to the deadly reefs of Okinawa and the dark jungles of Borneo

The combat application of the UDT in the war effort was specific and dynamic Conducting underwater reconnaissance was a primary objective The UDT divers went into enemy territory ahead of the main Allied amphibious landing forces, taking depth measurements and notating terrain features vital information that often determined Allied watercrafts' avenues of approach They searched for enemy mines and underwater obstacles, destroying them with intricate explosives they expertly handled

Scouting ahead to uncover enemy shoreline emplacements, the UDT divers were often the

A kamikaze attacks a U S warship off Okinawa, Japan © NATIONAL ARCHIVE George Morgan in uniform, 1945 © COURTESY GEORGE MORGAN

first to encounter enemy forces. In the rare instances when they discovered hostile-free environments, they would sometimes put up signs letting Allied forces know the UDT had been there first and that the area was safe for landing While humorous at face value, the signals were well received

The esprit de corps among the UDT divers, Marines, and Navy sailors was strong and built on mutual respect and care for one another The UDT divers risked their lives to prepare a safe landing for ground forces, and they knew what those equally brave men would have to face once they landed on the shore

Between waves of landing ground forces, UDT divers would volunteer to remove the dead bodies of Allied soldiers from the water by either retrieving them or weighing them down in impromptu burials at sea to keep the morale strong and not hamper the spirits of replacement soldiers when it was their turn to enter the fray When Navy ships went down, UDT divers acted as rescue swimmers, retrieving wounded and injured sailors from the water and pulling them to safety

Why are the incredible stories of UDT divers like Morgan unknown to most? As prototype warriors in an emerging field, the utmost secrecy was necessary for the men to operate successfully During World War II, the UDT's commanding officer issued a media blackout

After the war, the UDT divers evolved into what is known today as the US Navy SEALs These professed and proven "quiet professionals" still perform the same kinds of secretive missions as their UDT predecessors The tradition of secrecy has kept the UDT's exploits essentially outside the public's awareness

Andrew Dubbins, an award-winning journalist from Los Angeles, California, interviewed Morgan over an extended period to better understand the UDT's history "Morgan and his fellow frogmen came long before our modern age of high-tech warfare, exemplifying pure strength, endurance, resourcefulness, and

A kamikaze attacks a U S warship off Okinawa, Japan © NATIONAL ARCHIVE


courage," Dubbins said "The SEALs were able to draw from and build on the experiences and pioneering techniques of the World War II frogmen."

UDT divers truly were pioneers in their fieldcraft. Their training became even more innovative as a direct result of their experiences. In the icy waters of the Pacific, one UDT diver discovered that he could prevent his mask from fogging up by spitting into it. Wetsuits had yet to be invented, so demo divers like Morgan wore long johns thickly coated in grease over their swim trunks to provide insulation against the cold water

Underwater demolition was particularly challenging work. Varying by design and mission specifications, a single UDT diver could sometimes be responsible for carrying up to 60 pounds of explosives. The divers would try to create neutral buoyancy to the waxed canvas bags that held the explosive material Still, the loads were often too heavy or too inflated, making them extremely difficult to manage in the water.

The use of scuba did not have a practical combat application for the UDT The brand-new regulator technology of the time, known as the Aqua-Lung, was still in its infancy. While the demo divers had some use for this device, it was not as dependable or as efficient as a well-trained skin diver. It also wasn't readily available, and the UDT already had enough trouble sourcing rubber dive masks with tempered glass and swim fins with reinforced foot straps from the few U S sporting goods stores that carried them.

Both military and recreational divers today receive training about the safety hazards of the activity before venturing off on their own. As the first divers of their kind, however, the UDT divers had no predecessors who could adequately warn them of the fundamental dangers they would face with diving. They commonly suffered from upper respiratory and ear infections, painful muscle cramps, and hypothermia from overexposure to the cold water They were not immune to painful encounters with marine life, such as sharks and barracudas or abrasive contact with the toxins from coral reef polyps


D-Day Underwater DemolitionTeamOne

A forerunner to the Navy special operations force known as the SEALs, Naval Combat Demolition Units helped clear the way for the initial invasion force on D-Day.

Dive Safety Alert Diver DIVERS ALERT NETWORK


Barotraumas were common because UDT divers often had to execute rapid descents without proper equalization Morgan surfaced after one dive with blood pouring out of his nose and ears after being unable to equalize and having to dive to depth regardless of the sinus pressure and pain he felt

As the war raged on, the threats and dangers to UDT divers increased. As the enemy quickly became aware of the UDT's existence and purpose, they attacked them with vigor as the demo divers attempted to conduct their missions Sniper and machine gun bullets whizzed over the heads of UDT divers at the surface They hid from the incoming fire beneath the waves, holding their breath as long as they could and watching the bullets stop a few feet underwater and trickle down to them like fish food being dropped in an aquarium Even so, the inherent dangers of diving were the least of their worries

Staying underwater for protection was useless against enemy shells, which created colossal shock waves when they exploded at depth Any diver in proximity to a blast

would suffer a concussion, incur damage to internal organs, or be killed outright. One particular shell explosion launched Morgan 20 feet in the air, rupturing a disk in his back, dislocating a limb, and lodging shrapnel in his body

The enemy dangers became unimaginable as the Navy drew closer to the Japanese homeland Kamikaze fighter planes laden with explosives smashed themselves into the decks of Navy ships, and the UDT divers operated anti-aircraft quad guns in attempts to shoot them down

The kamikaze planes had their underwater counterparts: the human-operated small suicide submarines called Kaiten The Japanese equivalent to the UDT, the fukuryu (dragon divers) swam underneath Navy ships. It stabbed upward at the hulls with pole charges Underwater combat was not a Hollywood screen spectacle for the UDT divers but a frightening reality threatening the frogmen's lives daily

"Will I live to see the sunrise?" was an intrusive and inescapable question that lingered in Morgan's mind


"You're surrounded by death," Morgan told Dubbins during one of their many talks "My thinking during the war, especially when we were overseas, was, is this going to be my last day, my last week? You don't know"

The story of the UDT holds value to anyone who has ever donned a mask and fins and swum beneath the ocean waves. The courage and tenacity of the demo divers invite us to emulate the same principles in daily life. It also provides a sense of gratitude, not just for the equipment that divers have at their disposal today but also for the world we can dive in, thanks to the personal sacrifices of these divers.

"Morgan has told me several times that he doesn't enjoy rehashing these painful war stories and finds our conversations difficult. I told him it's important to share his story so that future generations never forget." Dubbins said. "But I often wonder if I'm doing the right thing, probing an old man's most difficult memories. Then again, if I don't ask the questions now, they may never be answered."

Read more about Morgan's personal journey as a UDT diver and Dubbins' experience writing about it in his new book, Into Enemy Waters

UDT divers return from a successful demolition mission off Saipan © NATIONAL NAVY SEAL MUSEUM
This 1957 black and white propaganda film MN 8328 is by the U.S. Naval Photographic Center for its Sea Power for Security series. Dive Safety Alert Diver DIVERS ALERT NETWORK
U.S. Navy Frogmen UnderwaterDemolitionTeams



Planning a dive vacation and all the associated details can be frustrating The logistics of obtaining gear, arranging transportation to and from dive sites, and booking a place to stay that can accommodate your needs requires patience and attention to detail All-inclusive dive resorts offer relief from much of this vacation orchestration, providing concierge services and prearrangements for every conceivable facet of your stay

When selecting a dive resort, read the fine print on what the resort offers. More specifically, look for what the resort does not include so you won’t encounter surprises upon arrival. Read reviews of the resort on travel websites or scuba diving message boards, but remember that negative feedback is much more common than positive comments and is sometimes questionably credible Perform due diligence, and reach out to the resort’s customer service team with any questions; they should be forthcoming with information and happy to assist you

The dive opportunities at resorts vary by geographical location and season Some resorts feature house reefs, which are dive locations in the immediate vicinity to the resort While the close proximity is enticing and will allow you to dive more frequently, you may find the sites crowded or lacking in variety When selecting your resort, consider projected visibility, water temperature, and other general dive conditions

Many dive resorts provide transportation to offshore locations, which can give you the experiences you desire but alternatively take up more of your time Some offshore locations have dive restrictions, such as paid entry permits with a set number of visitors allowed daily

Staying at a dive resort can help you avoid some of the stress of trip planning and allow you to relax and enjoy your vacation However, taking precautions would be best and not entirely offloading your sense of personal responsibility on the medical or first-aid abilities of the resort Being mindful of safe travel and diving fundamentals will allow you to make the most of your all-inclusive dive resort stay

Regardless of the resort you select, practising the fundamentals of safe diving while on location is essential Have an emergency action plan in place, and recognize any limitations of the resort regarding medical care and

recompression chamber access in the event of a dive emergency. Remember to perform predive function checks on your gear, and know how much breathing gas you have and its exact composition before you start each dive

Retain your situational awareness when diving with strangers While the dive resort’s local guides are experienced and know the area, other visiting divers may become caught up in the excitement of their trip and exhibit negligence or disregard for safe diving practices

All-inclusive dive resorts offer a fantastic experience but don’t leave everything to chance Retaining your responsibility in emergency planning and diving safely will improve your ability to relax and enhance your overall peace of mind

There can be no higher accolade in diving than to be one of the very elite who can call themselves a Special Forces Diver. Who they are and what they do widely shrouded in secrecy; it’s the humbling pinnacle of diving. As far back as I can remember, I have held the illusionary romanticism of military frogmen in aspirational revere as an impressionable young boy.

These military dive courses have an incredibly high failure rate compared to recreational dive training. Just because you want to be one of them isn’t enough to ensure you might be. However, that desire might be the quintessential factor that drives you through the long challenge of becoming one.

Special Forces, by default of their mandate within military organisational structures, typically don’t operate within the borders of the country they serve. Their function is to serve the security interests of their country in far-flung lands performing covert operations


This article is reviewed and approved by the South African Special Forces Association with respect and gratitude. www recce co za Denn s Gu chard s a mu ti-agency qual fied Scuba Instructor Trainer & a DAN Master Dive Pro member He is a qualified D ver Med c and Saturation L fe Support Technician, freelancing as a hyperbaric technologist at the Netcare St Augustine’s Hospital Hyperbaric Medicine and Wound Care Unit, Durban, South Afr ca

under a directive from the highest levels of Government They perform their tasks under high stress, requiring extensive physical and mental endurance The 4 Special Forces Regiment seaborne Operators have a longstanding history of successful clandestine function around the southern African coastline that is feared and respected

As one of the world’s most revered military diver training courses, you cannot just volunteer to be a South African Special Forces Diver The entry pre-requisite is successfully completing the gruelling 18-month Special Forces Operator training course, which is itself notoriously difficult to achieve

Originally located on Salisbury Island in the Durban harbour, special forces seaborne operations fell under the auspices of the thennamed 1 Reconnaissance Commando. As the need for specialist seaborne operations grew, so did the requirement for a secluded specialist training and operational base.

4 Reconnaissance Commando was thus officially commissioned on an isolated peninsular near Langebaan, north of Cape

Town, in July 1978 Their function was to provide ‘specialist amphibious, surface, and underwater capabilities for reconnaissance and offensive purposes’

1 Special Forces Regiment was secluded on the Bluff in Durban It was originally the Special Forces school home centre for the Operator candidates training cycle The Regiment also retained a full operational function in specialist urban counter-terrorism tactics 5 Special Forces Regiment, based in Phalaborwa, specialises in landborne operations The Special Forces operational HQ is based in Pretoria The Special Forces School is now based north of Pretoria after Durban’s 1 Special Forces Regiment was disbanded in 1996

Hopeful Operator candidates are filtered out very quickly if they cannot contend with the incredibly gruelling physical and endurance demands of training They require an aboveaverage IQ, as well as suitable psychological strength Initially, the Operator course pass rate was barely 5%, although as the initial preselection filtering process improved over time, the percentage of candidates successfully completing the ultimate goal also improved

The Special Forces Operator course includes an introductory ‘Water Orientation’ training phase, ensuring basic competency in seaborne operations This also includes small boat training, where any candidate’s aptitude for water work is first identified

4 Special Forces Regiment unit emblem 4 Special Forces Regiment unit emblem

It is said that Special Forces soldiers are like postage stamps as they can be delivered by land, sea, or air, no matter the weather Some who complete the full Operators training cycle might be hand-selected to attend further specialist training in seaborne operations

Training as a Special Forces seaborne specialist is an intense 6-month additional commitment consisting of various building blocks The nowqualified Operator, if nominated, will commence with the ‘Combat Swimming’ course, which includes general seamanship, sea survival, and open water swimming This is followed by a ‘Coxswain’ course introducing the operational application of Special Forces craft, including cooperation training with the SA Navy vessels Only after successfully completing the above will the member be allowed to attend the ‘Special Forces Attack Diver’ Course They really are the elite of the elite

Basic watermanship training can require completing 50m underwater swims in one breath, passing the infamous drown-proofing test, and long-distance ocean swims with fins at night demonstrating endurance and navigational competency

As well as timed 32km ocean swims with fins within 75 minutes, and 5km runs in under 20 minutes But fitness alone is not enough Any Special Forces Diver has phenomenal strength of mind in hand with incredible vigour and endurance, can work in isolated high-stress situations for long periods, and is equally a good team player

Most countries have their own version of seaborne Special Forces units and are equally held in the highest respect They are trained to the highest level of competency utilising all manner of underwater apparatus, including 100% oxygen rebreathers and underwater propulsion vehicles They are masters at underwater reconnaissance and demolition, moving and working as ghosts of the deep

To most of us regular humble humans, these elite Special Forces Divers are mysterious enigmas, like shadows in the dark, whoever and wherever they are serving their countries It is fascinating to get even any insight into their secluded world We can only be grateful they exist, in awe of all that they are and all that they have and continue to achieve

01 Special Forces diver propulsion vehicles




"The Municipal Council has just asked me to start a sports development programme for the children on Inhaca Island" That Is how our conversation started

Nyara (aged 6), our first little ocean warrior Protégé discovering the treasures of life underwater - Photo by Liz Louw

Me a South African Biokineticist and Freediving Instructor with a passion for children and community work, and a Mozambiquan Sports Professor serving a term on the Maputo Municipal Council We were seated next to each other on Qatar's Doha - Johannesburg flight leg on our way home from Portugal Serendipity had set things in motion for the start of something great

"Since they live on an island, surrounded by the ocean, why don't we get them into the water?"

That was my obvious response Being a born water woman and ocean lover, what started as a seemingly normal, polite conversation turned into an animated, in-depth discussion of the how's and why's of starting a youth-focused swimming/diving programme on the picturesque Inhaca island of Southern Mozambique.

We considered the opportunities that such a project would have for the children. We also contemplated its benefits to the community, the local economy and the surrounding marine environment. We discussed the importance of water safety and environmental awareness. We

elaborated on the possibilities for further education and career opportunities in swimming, diving, lifesaving and marine ecology We had nine hours to construct a plan and use them while still in the air

At the end of our discussion and the flight, the councillor leaned forward and asked, "Do you believe in serendipity?" I nodded The promise of creating such a project pulled on some tender heartstrings of mine Aside from being an opportunity to combine all the fields I love –sport, the ocean, community upliftment and childhood development – I had been nursing a deep wound for nearly a decade

In 2011, I discovered the wonders of Sodwana Bay, only to return in 2012 to personally witness the plummet in whale shark sightings I learnt that the neighbouring Mozambiquan government had signed a fishing treaty with China, allowing them free reign in the Southern East African waters And the whale sharks had paid the price

Like a knife twist in the heart, this fact had stayed with me for nearly a decade When I found myself seated next to a man who had a foot in the Capital City's governance and being presented with an opportunity to both educate

Some Inhaca youth find afternoon entertainment between an old concrete ruin and the surrounding ocean Photo: Shani Shepherd/Ocean Echo Scuba The view from the abandoned Pestana hotel with Portuguese Island in the distance Once a frequented destination for cruise ships, now nearly forgotten Photo credits: Liz Louw

and raise the country's future leaders, it was like being a small voice, like a child's voice, perhaps; a mere drop in the ocean; but still, a chance to make a difference. And a chance in just the right little piece of paradise.

Nestled just within the entry to Maputo Bay, only a 2-hour ferry ride from the Capital City, Inhaca harbours a mind-blowing environmental feast with pristine beaches, coral reefs, mangroves, seagrass beds where secret dugongs still graze and lush tropical forests Due to its lush biodiversity, representing all the biomes of Mozambique's vast coastline, researchers have been visiting Inhaca for decades The Eduardo Mondlane University operates from the Marine Biology Station of Inhaca, known as EMBI (Estação de Biologia Marítima de Inhaca in Portuguese)

After a pandemic and a pregnancy, we relocated to Mozambique, busy navigating the legal aspects of setting up life and a sports development project in this beautiful but equally challenging paradise

After searching for a suitable organization to partner with to gain the project go-ahead from

the Maputo Council, we came across the Sentinel Ocean Alliance – fellow Capetonians already successfully implementing their TurnThe-Tide Ocean Immersion programme with the youth of Hout Bay. We reached out to them while discussing how to reach more communities along the Southern African coast. They enthusiastically agreed to partner with us and assist us in setting up a similar programme for the children of Inhaca Island. And so the Inhaca Ocean Alliance was born.

Our programme is just beginning, and getting the wheels turning has been a long struggle When this article comes out, we will have just completed our Instructor training course from the course directors at Sentinel Ocean Alliance We will be gearing up to start the programme for the children in the new school term

While the Maputo Municipality is on board with permissions for the project commencement, the budget for establishing and running such a project is beyond their Sports portfolio's budget We need external funding to provide salaries for our Turn the Tide instructors and to afford our project's running costs and future expenses

of life on Inhaca
Fishing and boats are a way

If you would like to show your support or donate, please get in touch with Liz Louw by sending her an email to request the banking detail: lizfreediving@gmailcom

Please follow us on Facebook at Inhaca Ocean Alliance to get in touch or email lizfreediving@gmailcom directly to find ways that you can be involved Visit us on the beautiful Inhaca Island!

Sentinel Ocean Alliance is a registered Public Benefit Organisation with Section 18A tax-exempt status It can issue tax receipts for donations, with which you can claim a tax deduction

Liz Louw is a PADI Freedive instructor, experienced Biokineticist, passionate mother of Ari and lover of all the Oceans She is based in Southern Mozambique and teaches freediving to those interested in this diving discipline

making its way through the blue One of the amazingly diverse marine
to be found around Inhaca Island
loggerhead turtle



The growing global interest in freediving and breath-hold diving has created the need to develop structured and endorsed courses for Instructors This has also opened new opportunities to develop courses for Freedive Instructors to grow and train other professional freediving instructors We asked PADI Freediver Instructor Trainer Charl Marais what went into the new PADI Distinctive Specialty of Freediver Staff Instructor course

Images By Nicolene Olckers

Scuba diving offers a specific course for people who intend to assist scuba course directors (CD) in Instructor Development training. This is a mandatory course before a PADI Professional can help a Scuba course director during an Instructor Development Course (IDC) The Staff Instructors Course aims to develop the assistant to serve as a mentor, counsellor, and trainer Someone capable of mentally, psychologically and physically working with Instructor Candidates on an IDC During this time, the staff instructor (SI) candidate is groomed to assist in developing professional dive instructors The Scuba SI course is a bridge from training divers to training instructors, and it encompasses greater responsibility and takes a dive into the IDC

In freediving, the more advanced instructors are used as certified assistants on a Freediver Instructor course The minimum requirement for the PADI Freediver curriculum to act as an accredited assistant has the PADI Advanced Freediver Instructor certification This standard allows the instructor to be capable of freediving deep, having taught deep freediving courses and allows for a substantially experienced assistant It also allows the PADI Freediver Instructor-Trainer (FD-IT) to utilise an experienced professional to assist during a course

"I wanted to allow my assistants to develop a bit more This course is not a prerequisite to assisting on an FD-ITC There is a definitive difference between training a student to dive and preparing an instructor candidate to teach diving I wanted more for my FD-ITC assistants; thus, the course was designed," said Charl, "I designed the PADI Distinctive Speciality of Freediver Staff Instructor (FD-SI) because I wanted the mental and emotional growth offered to the Scuba staff instructors I wanted more for my staff; I wanted them to stand out in a classroom and take charge confidently I enjoyed the 'above and beyond' the programme offered as this course allows the certified assistant to be coached and groomed

Freedivers ascending from depth
Charl Marais on the surface during a fun dive excursion with other freedivers

into a counsellor, mentor and coach for instructor candidates I wanted them to be competent in all these aspects and experienced in dealing with instructor-level candidates since there is a large gap between the mentality of a student and that of an instructor candidate The development and training are also very different"


Organising and Preparing Candidates for the FD Instructor Training Course

Independently upskill and mentor candidates in preparation (before) for the FD-ITC

Assist with conducting FD-ITC training segments with PADI Freediver InstructorTrainer present and in control

Evaluate and critique instructor candidate knowledge development, confined and open water teaching presentations with Freediver Instructor-Trainer present and in control

Provide counselling and remedial training for FD instructor candidates

Observe the orientation and closing sessions of the FD-ITC Instructor Examinations


As with the Scuba Staff Instructor course standards, Charl ensured adherence in developing the freediver version As a result, the Distinctive FD-SI course follows the same principles, values, objectives and outlines as the Scuba SI course It aligns with PADI's values and philosophy

The course presentations, knowledge reviews, manuals, exams and workshops were based on the above, but also on tried and tested standard teaching tools to avoid potential challenges when training freediving instructors


Pre-assessment of Dive theory, skill evaluation, and a knowledge development presentation The SI Candidate must have an 80% pass rate on skill demonstrations, briefings, exams and presentations

Attending various course presentations

Writing and passing a standards exam for the Distinctive FD-SI

Higher level physiology, safety and physics training

Evaluation Training where the SI candidate can evaluate student teaching presentations and is offered feedback and critique

Finally, when prerequisites have been met, the SI candidate has to audit a full FD-ITC by staffing the course as an Advanced Instructor and conducting one of the seven instructor development presentations

A diver preparing to enter the water
Using the freediving rule of one up, one down, divers on the surface will watch their buddies progress underwater A freediver swimming in a clearing surrounded by the kelp forest


This course does not focus on developing a freediver into a PADI Instructor. Instead, it focuses on assisting the development of a PADI Advanced Freediver Instructor in developing their professional conduct when working with candidates undertaking instructor training. "We also focus on mental, personal, psychological and knowledge development," said Charl.

The PADI Distinctive Freediver Staff Instructor is an elite, distinctive speciality. They are responsible for influencing the development of the next generation of PADI Freediver instructors To apply for this course, the candidate needs to be a PADI Advanced Freediver instructor who has experience teaching PADI Advanced Freediver courses and has assisted with PADI Master Freediver development


The course involves an in-depth study of teaching, collaborating with and supporting other candidates who want to teach freediving. A freediving Staff Instructor has to relearn the Instructor

course in a supporting role – identifying areas where they can support Freediving Instructor Candidates. "It has taught me to engage with my students and candidates on a much more personal level, recognising that certain people experience different challenges/difficulties on course as well as overcome them differently", says Brittnee Engelbrecht. "What is nice about an IT course is that all candidates have the desire to learn and improve their skills – so a lot of the time, when a problem is encountered, there is a joint/communal effort to effectively problem solve – which has taught me different ways of teaching and problem solving on my own courses "

To become a staff instructor, you must engage with the material, complete several presentations, and complete the Staff Instructor examination You must also revise the other Freediver examinations to enhance and recap Freediver, Advanced Freediver and Master Freediver theories. The final step of the journey was to audit an Instructor Trainer Course

D i v i n g I n t o F r e e d i v i n g I n s t r u c t i o n



"I would like to continue teaching Freediving courses in and around Cape Town I joined Charl in a business aptly named Apnea Addicts Freediving We intend to continue training instructors in South Africa and around the world – which he has already started with a trip to the Maldives in 2022 I want to continue my personal development and reach a 40m constant weight freedive. We need to keep growing; the only way to do that is to continue learning."


"Being a freediving instructor is very different from being a freediver Yes, the passion, endurance and training remain But the focus turns from yourself to whoever your student is. It is a selfless passion, as any teacher will confirm The satisfaction of seeing physical, mental and emotional growth within a person is far beyond self-satisfaction. I advise any freediver wanting to teach and instruct others never to withhold the opportunity

of experience from yourself Every dive and every encounter is an opportunity to grow in your capacity and what you can offer others."

Freediver Staff Instructor, Brittnee Engelbrecht - studied Education at Stellenbosch University. She has always loved working with children and thought of becoming a teacher. After a few practice sessions in the classroom, she discovered open space suited her better – it offered an engaging curriculum to share her knowledge. She found that becoming a freediving Instructor fulfilled the teaching aspect of her degree She free dives because there is no other place she can go to where the feeling of being both in and out of control is blended uniquely. Each dive is both ominous and wonderful Although survival is very likely, it is not guaranteed! Whether diving into the ocean and seeing creation in its rawest form or being in the pit of the quarry with no shadow, knowing there is light to cover the expanse of darkness, freediving has been her personal journey of self-discovery. It has helped her to help others conquer their fears.

D i v i n g I n t o F r e e d i v i n g I n s t r u c t i o n



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Situated in the Sleepy little hollow of Umkomaas, Blue Ocean Dive Resort has become one of the premium dive centers, diving Aliwal Shoal

This little on-land-liveaboard offers 27 en-suite rooms for double, single, family or twin occupancy

Started in 2014, Blue Ocean Dive Resort now boasts three boats and a state-of-the-art, oneof-a-kind dive center Our membrane system allows us not to charge for Nitrox in any dive prices All packages include breakfast, cylinder hire, weight hire, and air/nitrox fills

We dive on Aliwal Shoal, a fossilized sandstone reef system that used to be the coastline around 500 million years ago The reef is around 3km offshore, and the diversity of life is as follows




"The Agulhas current moves warmer ocean water from the Indian Ocean along the Eastern Coast of South Africa. Then, it pushes nutrient-rich water from the ocean's depths towards reefs like Aliwal Shoal This, in turn, allows marine life to flourish" - Bio on the Go

We boast several species of sharks, of which most are seen all year round Dolphins, Turtles, eels and Rays are also perineal Amongst these treats, we see the whale migration, and Humpback Whales travel north from around Mid-May to Mid-August and back south from around the beginning of September into November

Ragged Tooth Sharks reach our reef during the South African winter months Starting in May, we can see the males eagerly awaiting the arrival of the females for mating season This visit lasts well into November, and they start disappearing by December

The motto here is that you arrive as a client and leave as a friend, which rings true when you see the return guests (friends) we get to see again


"If you want to dive the world-class reef of Aliwal Shoal, stay at a fun dive resort, and experience the amazing happening of the Sardine Run, Blue Ocean Dive Resort is the place to go Nicki and Gary are the most lovely people to run the place, and the whole team works in a very professional and welcoming way I had an amazing Sardine Run experience with them and will definitely come again Keep up the great work!" wrote Timo D on their TripAdvisor page

Kimbostoo added, "A great spot to stay at whilst diving when diving Aliwal Shoal The accommodation was exactly what is requiredrooms are simple but very pleasant The restaurant and terrace are a big bonus-great

food and a real chill-out area. The diving aspect was also well organized, divemaster and skipper were great. All in all - a professional and very pleasant setup. A great base from which to experience an Aliwal Shoal dive excursion Highly recommend"


Blue Ocean Dive Resort

@Blueoceandive1 /blueoceandiveresort @BlueOceanDiveResortUmkomaas
bookings@blueoceandive co za



It’s the new mindfulness practice, the trail running of the sea, a great adventure and a way to escape the noise Slowly breathing in and out, calmly holding your breath and sinking along a tropical reef in the Red Sea or into the Kelp forest in Cape Town brings an instant calm Endorphins fire, and I am filled with a benign sense of joy after my dive How often can you find that these days?

TEXT & PHOTOS BY KERI MULLER Why do I freedive? For the silence in my head, the shimmering liquid light and the sense of being alone in a wild world Soft Coral Gardening - Red Sea - Keri Muller

I’m a snorkeller at heart with little interest in going deep on the line or swimming through caves. I prefer to swim around in the shallows, somewhere between 2 to 6 meters deep, where the light still carries the full rainbow colour spectrum The forest canopy splices sunshine making it dance and weave on sea urchins and starfish floors, creating an endless show In this space, I play on one breath and fiddle with my camera settings to recreate what I see

The Cape coastline is fickle; the swell and raging South Easterly wind determine where one can dive Generally, it means the Atlantic side of the Peninsula, but when the Northwesterly blows, it clears up False Bay Standard freediving requirements in Cape Town differ from the rest of the world Shore entries can be tricky off rocks, you’ll have to get used to the kelp tickling your body, and you’ll often be confronted by the average visibility of about 3 to 4 meters A good day ranges from 6 to 10 meters in contrast to the average of 20 meters in tropical waters

With this in mind, I book a holiday to the Red Sea Using the relaxed little town of Dahab as our base, we check into a quirky apartment on the beach in the neighbourhood of Asalah, an old part of town with a reef right on our doorstep The streets are dusty, and the buildings crowd around narrow lanes leading down to the sea We’re a quick 15-minute walk to the main tourist area and several beautiful dive sites

Diving in the Red Sea differs from my everyday underwater world in the Kelp forests The one similarity is that you can access plenty of dive sites from land, which is a significant plus The biggest shock is adjusting to the warm temperatures and the constant visibility into the big blue without the ‘protection’ of the Kelp forest Sometimes you can’t dive for days in Cape Town, but in the Red Sea, none of that applies

Blue Hole - Red Sea - Keri Muller Blue Hole - Red Sea - Keri Muller Ras Mohammed - Red Sea - Keri Muller Blue Hole - Red Sea - Keri Muller

Plopping into the water for the first time after a rather long flight resulted in endless squeals of delight from myself and my buddy Neither of us could believe what we saw and quickly lapsed into a slightly delirious state of joy The soft palette of pastel corals created a gentle topography reminding me of gelato ice cream with an array of toppings in the form of brightly coloured reef fish I loved these reefs around the town extending out from the land in a flat shelf and then dropping you straight down into the blue

Freediving, like scuba diving, in the Red Sea is strictly regulated as there are fatal accidents yearly in this diving mecca Without a freediving guide and certification, you may not go out on a boat You can’t even rent a weight belt as it immediately makes the dive school liable. When we see the multitudes of people learning to scuba and freedive everywhere, we start to understand the necessity of these strict rules. If you want to learn to freedive, I’d highly recommend spending a holiday in Dahab on the Red Sea; there are many schools and easily accessible reefs to practise your skills.

Freediving has become hugely popular in Cape

Town, helped by the world-famous film, ‘My Octopus Teacher’ Multiple WhatsApp groups ping away, sharing ocean conditions and linking up with buddies all over the Western Cape daily Freediving courses are booked three months in advance, and freediving gear sales have gone through the roof If you haven’t seen it, watch it now

Around Cape Town, you can start snorkelling in a tidal pool and slowly gain confidence before heading into the sea I love this ocean activity, compared to scuba diving, because it has shallow barriers to entry All you need is a mask and snorkel to get started, and if you like it, move on to buying fins and a weight belt Wetsuits are optional, but in temperatures ranging from 12 to 20 degrees in Cape Town, you’ll probably want one unless you’re particularly prone to self-flagellation, as I was for a few years If it is something you like, then do a course You will enjoy the course much more if you are comfortable in the water and using a mask

The ocean has always been a safe space for me It’s where I go to soothe my anxiety or, more recently, to mend a broken heart Most days, I dive for the sheer joy of it and out of curiosity for what I might see

Disco Time - Castle Rock MPA - Keri Muller Kelp Forest - Castle Rock MPA - Keri Muller Kelp Forest - Castle Rock - MPA - Keri Muller
Evening In The Kelp Forest - Castle
- MPA -
Diving Amongst The Kelp To Scout Out The Perfect Shot - Castle Rock - MPA - Keri Muller
Fish Adventures - Castle Rock - MPA - Keri Muller
Keri Muller Helen Walne

Freediving sounds a little scary to most; I recommend thinking of it as adventurous snorkelling as I do. Don’t let the thoughts of holding your breath for minutes and diving to great depths put you off The simple reason being it’s not about that at all


Cape Town, South Africa

The majority of freedive sites in Cape Town are accessible from the shore They are located on the False Bay side of the Peninsula close to the ocean Wikitravel has a meticulously puttogether list of sites along the Cape Coastline Monitor the weather and keep an eye on the swell As mentioned above, diving in Cape Town can be tricky, and conditions can change quickly Contact one of the companies below if you’d like to hire a guide or equipment or do a course I’d recommend hiring a guide to start, many of the shore entries aren’t obvious, and you will need a car to reach them A guide will also ensure that you stay safe if you are unfamiliar with diving in Cape Town


https://wikitravelorg/en/Diving the Cape Pen insula and False Bay

This resource is a huge help With loads of information, and was created by an avid diver and underwater explorer, Mr Peter Southwood

Cape Town Freedivers: www capetownfreediving com

Argonaut Science: www argonautscience com

Pisces Divers: www piscesdivers co za


I’ve only spent ten days here, so I am not an expert We found the dive sites easy to access from land and plenty of internet resources

giving instructions on where they are. We brought all our gear, but you can hire equipment if certified. We engaged a freediving guide to take us to the more remote reefs by boat near Dahab and another guide in Sharm el Sheik who took us to dive in Ras Mohammed National Park, an absolute highlight Day trips can be arranged where they will pick you up with a taxi driver and show you where the sites are, saving you time and confusion You will also have the contact number of knowledgeable taxi drivers for future trips Like anywhere in the world, get there early For example, we arrived at the world-famous Blue Hole at 7 am and had it to ourselves for 2 hours The same applied at Shark reef in Ras Mohammed National Park

Dahab – Catherine www blueoceanfreedivers com

Ras Mohammed – Antonella www freedivingworld

Seal Dancing In Front Of My Camera Lens - Keri Muller



Currently, their catalogue showcases t-shirts with bright and colourful nudibranch designs, each displaying the unique patterns and hues of these sea slugs The t-shirts are made from high-quality, breathable materials, perfect for active people who love diving, swimming, or just enjoying the ocean The response from customers has been overwhelmingly positive, and the brand is quickly gaining a reputation for its unique designs and comfortable wearability

Scuba Nudi is a proudly South African scuba apparel brand created by a mother-son duo, Leanne and Joshua Walmley They own Absolutely Scuba diving centre in Mossel Bay, South Africa The concept for the clothing range was born from their fascination with the iridescent beauty of Nudibranchs, colourful sea slugs commonly seen by scuba divers worldwide.

They will expand their product line to include hoodies, beach footwear and UV rash vests. The brand aims to become a one-stop shop for diverse scuba-themed clothing for men, women, and children. The duo are also considering collaborations with other ocean conservation organisations to raise awareness and support for protecting the ocean and its inhabitants.

As a truly South African brand, Scuba Nudi is proud to contribute to the local economy and promote South African talent and creativity The brand's founders believe that showcasing the beauty of Nudibranchs and other sea creatures can inspire people to appreciate and protect the ocean in South Africa and globally

They are a brand with a purpose, celebrating the beauty and wonder of the ocean and its inhabitants The brand's founders are committed to creating high-quality, comfortable clothing that promotes ocean conservation, and their goal is to inspire others to appreciate and protect the ocean With their unique designs, comfortable clothing, and commitment to ocean conservation, Scuba Nudi is sure to become a popular brand among scuba enthusiasts and ocean lovers in South Africa and worldwide


Leanne Walmsley

Tel: +27 84 879 6288

Email: boss@scubanudicom



Diving equipment often goes by different names, depending on the training agency or the part of the world where you were trained: What some divers call a dive light, for example, others might call a dive torch These names are synonymous, and the worst that can happen by interchanging them is that it might give away where you were trained (and possibly provoke minor jesting) or lead to minor misunderstandings However, actual harm is very unlikely

On the other hand, sometimes, terms that seem to be synonyms refer to entirely different devices For instance, a spool and a reel might seem similar but are not: Reels do contain spools, but spools – as such – are functionally different from reels. Hence, the term you use has a direct bearing on its method of operation and application. Interchangeable use may, therefore, not be innocuous and may even result in injuries

In some cases, a piece of equipment has multiple uses Divers might describe the same object as a decompression cylinder, a stage cylinder, or a bailout cylinder Although the device may be identical, its application and the training required to use it safely may differ vastly

So, divers need to know the difference between simple synonyms and particular technical use of terms when referring to a piece of diving equipment


Technical divers may use decompression cylinders, stage cylinders, and bailout cylinders during complex dives involving a variety of gas mixes and applications Depending on the dive they are planning, these cylinders are typically carried in addition to the primary configuration

Gas planning with cylinders is crucial to ensure a diver has an adequate breathing-gas supply to execute their dive safely

such as doubles, side mounts, or rebreathers. Special contingency gas planning is necessary when diving with such cylinders to ensure that, in case of a catastrophic failure, all divers can return to the surface safely

The size of the cylinder may vary with its use Twelve-litre aluminium cylinders are popular, but often cylinders are used that are half that size Ten-litre cylinders may also be used as decompression or bailout applications Because steel cylinders are negatively buoyant, aluminium ones are generally preferred Regardless of the size, however, the rigging is typically similar, with slight variations from diver to diver to meet their individual needs


Decompression cylinders: As the name suggests, decompression cylinders contain gas that divers use during staged decompression dives, which include stops at various depths for predetermined lengths of time before surfacing to allow for efficient off-gassing Decompression gas typically contains more than 40 percent oxygen A diver may carry more than one decompression mix on longer, deeper dives

In non-overhead environments, divers typically carry decompression cylinders throughout the dive and breathe from them after reaching a safe depth for the mix’s maximum operating depth (MOD) Divers try to avoid dropping these cylinders when diving in open water so they can ascend at any point during the dive if an emergency arises

In overhead environments such as caves, most divers leave their decompression cylinders at the beginning of the dive for use when they reach the exit This practice is acceptable because there is typically only one way in and out

Stage cylinders: Stage cylinders allow divers to increase penetration distance in an overhead environment, such as a cave, wreck, or mine

Divers breathe from cylinders that they place at predetermined intervals along their path Some divers drop these cylinders based on pressure, while others drop them based on time While making their way out, divers pick up the cylinders and use them Regardless of the divers’ gas management method, all team members must agree on a procedure before commencing the dive

Note that environmental conditions may affect a chosen procedure, such as carrying a stage cylinder further into high-flow cave systems so that gas is more readily available in case it is needed quickly

Bailout cylinders: Rebreather divers use bailout cylinders in case a catastrophic loop failure requires a switch to open circuit. Divers must be mindful of the bailout cylinder gas’s MOD, because they must be able to breathe it at the dive’s maximum planned depth.

Unlike stage cylinders, divers carry bailout cylinders throughout the dive to immediately access breathing gas if a rebreather failure occurs. Some dive plans for overhead environments include placing additional bailout cylinders at predetermined distances.

A diver must always have sufficient gas attached to them for the transport time needed to travel safely to their next previously dropped cylinder. The best practice is for each diver to carry enough bailout gas to perform a self-rescue and get back to the surface safely on their own.


Divers need extra training to carry additional breathing gas. Whether decompression, stage, or bailout cylinders, each requires additional training Divers may take further training courses on decompression procedures, wreck penetration, or cave diving to expand their skills and knowledge Even though these cylinders may look the same in size and rigging, each has a unique function within a given dive plan It is important to note that divers may carry more than one type of cylinder on any given dive, such as having both stage and decompression cylinders on an open-circuit cave dive

Divers are encouraged to abide by their training agency’s recommendations and stay within the scope of their training This helps ensure that every dive is as safe as possible Divers should strive to understand the terminology and use it appropriately Doing so helps decrease confusion, which ultimately increases a team’s safety

Decompression cylinders, stage cylinders, and bailout cylinders are different pieces of equipment Correctly referring to each type will ensure everyone knows their intended use

Rebreather divers carry bailout cylinders if a catastrophic loop failure requires them to switch to open circuit



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To truly capture all the beautiful creatures that intrigue us, underwater photographers and videographers prefer impressive lighting solutions

As one descends deeper underwater, the colours disappear, making it difficult to record the vibrant colour of the underwater corals, creatures, and other inhabitants This is where the use of strobes and or video lights play an essential role in underwater photography and videography

It is possible to take photos or video underwater using the available natural light, that is, if you want to intensify the mood or be dramatic using shades of grey Some photographers specialise in this type of imaging However, suppose you are aiming for the finer details in all their full, glorious colour (and not keen on spending hours on postproduction colour correcting) In that case, you will need strobes or lights!



The selection and use of strobes & video lights in underwater photography

Maryka Pace works fu l-time n the diving industry at Dive Action, Cape Town She assists photographers w th their needs for underwater photography equipment Underwater photographer John Vowles with his Nauticam set-up Photo by Harry Stone


Recycle Time: the minimum time needed for the strobe to 'power up' between flashes

Guide Number: the power of the strobe; the higher the guide number, the more powerful the strobe

Beam Angle: the angle at which the light spreads, normally measured in degrees


CRI Rating: the Colour Rendering Index has a scale of 0 – 100. At zero, all colours look the same, and at 100, you will show the true colour of an item

Lumens: the more lumens, the brighter the light

Battery Life: most lights will indicate the run time/burn time on the different power settings


CRI Rating: the Colour Rendering Index has a scale of 0

100 At zero, all colours look the same, and at 100, you will show the true colour of an item

Lumens: the more lumens, the brighter the light

Battery Life: most lights will indicate the run time/burn time on the different power settings


There are pros and cons to using one or two strobes or video lights.


The Pros

Contrast: You will have more contrast, and one light will allow the shadows and texture to stand out more and be distinguished from the background.

Directional lighting and the use of a 'snoot': A 'snoot' is a tool that fits over a strobe or light. This is much like a 'lens hood'. This allows the photographer to control the light beam's direction and radius. Using a 'snoot' is particularly effective when you only have one strobe or light or want to light up a specific creature in your image. This technique is often used in blackwater and macro photography.

Price: You will need to check your bank balance and consider your budget.

The Cons

Beam Angle: The angle of the beam of one strobe or light is not ordinarily broad for wide-angle subjects such as wreck or reef settings. It can be tricky to get the light in the correct position.

Backup: Having two is always better than one It is unlikely that both strobes or lights will fail simultaneously, so you can at least make some plan to get that shot


The Pros

Increased cover: The light and angle of two strobes or lights are likely to cover the wide-angle subject easily and evenly

Backup: You will have a backup if one of the strobe or lights stops working for some reason

The Cons

Expense: Obviously, buying two strobes or lights is more expensive than buying one

Not all of us aspiring underwater photographers have the means to buy two lights at once Make no mistake, one strobe or light is a great place to start Buying one good, large & powerful strobe is a good start Instead of replacing an underperforming light or mixing and matching lights, save and budget for a second light Having two different lights can make lighting your images underwater a complicated affair It is somewhat like buying your own dive gear and buying the best you can afford


Apart from providing natural colour correcting, lighting also minimises backscatter Your strobe or light positioning will depend upon your subject This can vary significantly from doing macro photography to framing that vast wreck you are diving on


Strobes and video lights work on the same principles regarding positioning For One Strobe Or Light

The positioning is very similar whether your subject is a macro or wideangle.

Generally, you will position the strobe or video light above your housing either to the left or the right side. This will depend on the direction of light desired. You can use this to play around with your subject shadow creating a special effect image.

To attach and position the light, you must use a combination of either double ball arms or float arms. These arms will attach to the housing or the mounting tray, to each other and finally to the light itself using purposemade clamps.

When shooting macro, you will face the strobe or light forward and slightly down at an angle you want over the subject. The light should preferably be positioned behind the port, more or less above the housing body, close enough not to create a camera shadow at the bottom of your image. When doing wide-angle images, you will move the light up and extend the arm as far as possible from your lens facing the light forward and slightly upward to prevent backscatter in your image

For Two Strobes Or Lights Shooting Wide-Angle

It is best to have the strobes or lights positioned on either side of the housing in line with the back of the dome port.

For Two Strobes Or Lights Shooting Macro

When opting for macro photography, the best is to have the strobes or lights brought forward and in line with the macro port Preferably angle the strobes or lights slightly inwards

The bigger the subject, the further the strobes or lights will be stretched

The smaller and the closer the subject, the closer and tighter the strobes or lights will be to the macro port

Strobe and video light positioning is not an exact science. Still, it is important

Dive Safety Tips When You Practice Your Underwater Photography

Remember your buoyancy – maintaining good and neutral buoyancy will protect you and the reef environment Grabbing onto the reef is not a good habit Also, take note of what you do with your finned feet

The underwater environment is sacred – If you cannot get the shot without endangering life, don't take it

Monitor your air consumption and dive time between shots Don't get so immersed in getting that perfect image that you run out of or low on air

And worse having to do and extend safety stops

Dive safe and have fun learning new underwater lighting techniques

Good lights are VITAL in underwater photography There is a whole array of colours to capture! On land, you battle to see these unique colours in proximity to each other Conversely, underwater it is like taking a dance down the catwalk! Grab your camera and the strobes or light(s) and experiment!

Strobes and powerful video lights prove their worth once you experience their results!

Photo by Callum Evans


BYDENNISGUICHARD Dennis Guichard is a mult -agency qualified Scuba Instructor Trainer & a DAN ‘Master Dive Pro’ member He is a qualified Diver Medic and Saturation Life Support Technician, freelancing as a hyperbaric technologist at the Netcare St Augustine’s Hospital Hyperbaric Medicine and Wound Care Un t, Durban, South Afr ca

A typical blood donation is about half a litre (500mL), and normal adults have 56 litres of blood in their bodies As such, donors give up about 10% of their total blood volume per donation It takes about 24 hours for the body to replace the donated blood plasma and about 46 weeks to replace the donated red cells However, blood iron levels may not reach pre-donation until eight weeks after donation Although blood volume will return to normal quickly, a lower red blood cell count may contribute to fatigue and dehydration Such conditions increase one's risk of a diving accident or possible DCS As defined by the UHMS, medical standards for divers should not dive for at least 48 to 72 hours after blood donation. DAN routinely recommends 72 hours.

Guidelines for a return to diving after DCS tend to depend mainly on the type of bend a diver experienced and the actions that might've led to that It is believed that if you get DCS in a particular location of your body that you may be susceptible to repeat hits in the same location This however probably depends on whether you change your dive habits and/or just keep doing the same things the same way that got you bent in the first place DAN guidance for a layoff from diving might be required to include anything between two to six weeks with mild DCS Anything up to 6months layoff might be prescribed if more severe DCS symptoms were experienced Divers may experience lingering symptoms from tissue damage or inflammation. A dive doctor's medical clearance is always recommended.

Elevated levels of carbon dioxide can occur in our bodies due to the effects of breathing increased gas density at depth, over-exercising, skip-breathing, or excessive breathing resistance from equipment. This can cause dilation of the blood vessels, which may increase perfusion during a dive, increasing nitrogen loading. Carbon dioxide is carried to the lungs and dissolved in our blood plasma. It has a gas tension which also contributes to tissue supersaturation in decompression Carbon dioxide has a very high narcotic potential, 20 times more than nitrogen, also adding to the narcotic effects of nitrogen at depth It is essential to breathe efficiently on scuba and avoid the deep water when breathing compressed air

Recommendations are that we should not dive deeper than 30m on air This is because the exertion of breathing enhanced gas density (beyond 5g/L) at that depth triggers a risk of carbon dioxide build-up in the body Therefore, 40m is considered the absolute maximum safe limit for diving on air because of gas density (6g/L at this depth) and the severe risk of carbon dioxide accumulation due to the effort of breathing that increased gas density Similarly, if increased exertion is experienced, the maximum depth should be reduced Carbon dioxide has an anaesthetic effect under pressure and may even lead to deep water blackouts. The very reason why deep technical divers add helium to their breathing mixture is to reduce the gas density being breathed and also to minimise DCS risk.


It is frequently suggested that females might have a higher incidence of DCS than men, mainly due to a larger body mass index (which is an amusing misconception looking about on any beach anywhere) There is no conclusive evidence to show that women divers have any higher susceptibility to DCS than males In fact, I am pretty confident that female DCS susceptibility is less than men's due to their typically lower tidal volumes (ie nitrogen exposure) and usually more conservative diving habits Fluid retention during menstruation and being on the contraceptive pill have not been proven to increase the susceptibility to DCS The DDRC in Plymouth, England, has done extensive research on 'women in diving', and you can read much more on the subject by visiting their website.


Cigarette smoke contains some 50 times the carbon monoxide (CO) content considered to be a safe air purity standard Blood flow to the brain increases by up to 400% when exposed to CO The ramifications of this on CNS oxygen toxicity and DCS are concerning Such an increase in blood flow would impact nitrogen perfusion, absorption, and cerebral DCS risk on an otherwise ordinarily safe dive Cigarette smoke inhalation affects pulmonary bubble mechanics that may hinder the effective elimination of inert gas and predispose to DCS As silent bubbles accumulate in the lung filters quite extensively in the initial 45-60 minutes after a dive, it would probably be prudent to avoid that desperate cigarette for a good hour or so after surfacing from any dive.

Swimming is invaluable for enhancing your cardiovascular fitness by getting into a swimming pool and swimming lengths with your mask and fins on Fitness is essential for optimal cardiovascular functionality, minimising the risk of DCS-stress, and reducing post-dive fatigue Also, for minimising the risk of clinical DCS and for managing in-water stress You can build up a basic level of diving fitness by just diving often It is valuable to exercise your diving-specific muscles with your own scuba equipment Still, nothing beats working on your swimming and cardiovascular fitness to increase your enjoyment of being underwater on scuba To minimise your risk of DCS and enhance your ability to manage stress in the water, invest some swim time at your local gym to be the best diver you can be.

COVID-19 is here to stay It's become a part of us all It invades every cell of our bodies and takes residence there asymptomatically It has been shown to be harbouring in the bacterial microbiomes of people's large colons for well over a year or more Many people worldwide suffer from lingering fatigue, brain fog, and other symptoms from long-covid Long-covid is shown likely to be caused by amyloid micro clots forming on the endothelial surface of our blood vessels The virus may also cause damage to the lung alveoli by causing cells to fuse We don't know yet what impact SARSCOVID-19 might have on scuba diving in the longer term. There may be an impact on how inert gas perfuses into and out of tissues, and DCS risk might be elevated.


A 'PFO' or a hole in the heart that does not close completely after birth may become a problem for divers later in life Up to 25% of the population is believed to have a PFO However, only 5% are likely to have one considered detrimental enough to scuba diving Under some conditions, i e , when you equalise your ears or cough underwater, the blood pressure in the heart's right atrium can increase slightly over the left Nitrogen-enriched blood can shunt from the right to left side of the heart atria allowing microbubbles to pass directly back into the arterial circulation The majority of divers we treat in the chamber are indeed rather suffering with a PFOinduced bend of this nature. These types of bends can often be severe, causing neurological insult often with lower limb paralysis.


Dive computer algorithms are based on benchmarking of average risk and do not consider us individually We are each quite remarkable and unique, of course We all have different heights, weights, and BMI scores We have different levels of cardiovascular efficiency Our blood health varies with different levels of the various biomarkers Our cardiovascular health varies depending on lifestyle and genetic predispositions It is known that some people naturally generate high venous gas bubble scores on the same dive that others don't Even individually, we can generate microbubbles on a dive today that our bodies might not do tomorrow, due to biological variables from day to day. We are each very unique and individual.




The 12-litre aluminium cylinder is by far the most popular, but this does not necessarily mean it is the right one for you

Cylinders come in various sizes and materials, and you can set them up in multiple configurations Choosing the right cylinder for your dive is vital for your enjoyment and safety

Checking the air pressure in your tank is always prudent before diving


The standard aluminium 12 L is an economical cylinder that offers an appropriate amount of breathing gas for most divers Younger or smaller divers, however, may struggle with the size and weight of an aluminium 12 L and instead be more comfortable with a shorter cylinder, such as an aluminium 10 L Divers who quickly consume gas may benefit from a larger-capacity cylinder, such as an aluminium 15 L, to extend their bottom time

When choosing an appropriate cylinder size, consider factors such as the cylinder’s weight, gas consumption rate, anticipated dive profile, personal comfort, and how much gas your buddy may need if you need to share air in an emergency If the largest aluminium cylinders don’t provide adequate gas, consider switching to steel cylinders or a setup that allows you to carry multiple cylinders


Understanding the differences between steel and aluminium cylinders is essential for choosing the right material for your needs Steel cylinders come in various capacities matching those of aluminium cylinders

Whether full or empty, steel cylinders tend to be negatively buoyant underwater Aluminium cylinders often start negatively buoyant but eventually become positively buoyant as a diver consumes the breathing gas Although steel cylinders are more negatively buoyant underwater, they have thinner walls than aluminium ones and often weigh about the same, if not less, on land than comparable aluminium cylinders This buoyancy difference means divers using steel cylinders do not need as much lead to achieve proper weighting

The final and perhaps most important consideration is that steel is much more vulnerable to rusting than aluminium Even small amounts of water in a steel cylinder can

cause significant rusting and pitting, which can permanently damage the cylinder Minor oxidation may occur if moisture gets into an aluminium cylinder, but it is unlikely to cause significant damage Annual visual inspections are crucial for detecting corrosion before it becomes significant and leads to irreversible damage


The single-cylinder configuration we learned to dive with is sufficient for most dive conditions You can add another cylinder to your setup if you wish to have redundancy or extra breathing gas You can consider a mini bailout bottle with an integrated regulator Still, their limited gas volume and the possible lack of an appropriate submersible pressure gauge (SPG) restrict their usefulness. A 12-litre pony bottle is another option. You can strap it to the cylinder on your back or clip it to your buoyancy compensator’s D-rings. With their own first stage, second stage, and SPG, these pony bottles provide a completely redundant system with more breathing gas should the diver encounter an issue.

For more information on small bailout cylinders, see Jill Heinerth’s article “Air and a Spare”


Back-mounted doubles may be a good alternative if you want a setup where the cylinders are more secure and provide more gas than a single-tank-and-pony configuration

This back-mounted configuration consists of two cylinders with left- and right-handed valves interconnected by a manifold Each cylinder will have its own first and second stage, a BCD or drysuit inflator hose, and an SPG as necessary The benefit of this setup is that you have a completely redundant system that rests on your back, similar to carrying a single cylinder Suppose a regulator or cylinder has a catastrophic failure In that case, the diver can isolate the issue by closing the appropriate valve while still having access to the other cylinder as a gas reserve

A sidemount configuration may be appropriate if you struggle to carry a heavy set of doubles or find it difficult to squeeze through narrow restrictions in caves or wrecks With sidemount, you fasten cylinders along your flanks through bungees and bolt snaps

Checking the air pressure in your tank is always prudent before diving

This flexible configuration allows you to quickly identify and resolve any issues because the regulators and valves are easily visible and accessible, unlike with doubles, where valves are located behind the head. Because each cylinder is separate, you need to occasionally swap regulators to maintain a similar pressure in each cylinder. The cylinder positions and flexible attachments can make it challenging to perform a giant stride entry or handle cylinders on a boat, especially in rough conditions.

As with all your dive gear, choosing the cylinder material, size, and configuration best suited for the diving you plan to do is essential to your dive safety and enjoyment. If you have any questions, do not hesitate to contact the experts at your local dive shop, who can work with you to customise a setup that works for you



Shearwater Teric - The Watch That Transforms You Photo by Nicolene Olckers Shearwater Teric - Dive Mode - Freedive Photo by Nicolene Olckers

You are a Freediver Take a look at your personal gear It differs from what you would use as a scuba diver: simple designs or ergonomically shaped ones to improve underwater dynamics The experienced freediver will most likely opt to have a lowvolume mask, making for easier equalising using less air and effort to equalise their mask Most freedivers also opt for the most basic snorkel, no snorkel and no mask

The same can be said of choosing a dive computer Having a dive computer will make your freediving safer and more enjoyable and help you track and improve your performance


There are a few basic considerations when selecting a dive computer. Competitive divers will most likely opt for a watch-style computer that is small, dynamic, and consistently and accurately records their dives. It should at least be able to display your max depth, dive time and surface interval time, right?

Charl Marais, Freediving Instructor Trainer, had this to say. "I don't like fancy gadgets. The computer should work and not just stop

working or malfunction suddenly For me, reliability is key" He also preferred simplicity and insisted manufacturers/suppliers should provide proper service delivery in the diver's country Charl mentioned the more essential features include the recording and display of surface interval times and bottom time The computer should, at minimum, have one depth alarm and include a timer/stopwatch and chronograph Using the timer/stopwatch and various alarm settings will let the diver know precisely where they are during their dive

Timers or stopwatch features are often used by instructors when training students Competitive freedivers often use timer and alarm features to know when to kick, when to do mouth-fill equalise and when to prepare to turn and head back to the surface

Brittnee Engelbrecht, Freediver Staff Instructor at Apnea Addicts in Cape Town, said she uses her computer's stopwatch feature to time her students' dives This enables her to know how long they have been under and when she should dive to the safety depth to check on them as they return to the surface Or to know when she should dive down to fetch them when they overstay their dive time

Shearwater Teric - Multiple Diving Modes Photo by Nicolene Olckers


The research on decompression sickness (DCS) has also improved developments in dive computers Although DCS is most often only attributed to scuba divers, it can also be a risk to freedivers

As the freediver descends to depth, the partial pressure of nitrogen in their lungs increases and is absorbed in their blood and muscle tissues Suppose the excess nitrogen is not given time to dissolve from their system while at the surface; they, too, run the risk of DCS.

Taking proper surface intervals and planning is critical to safer freediving. Dives deeper than 50 meters should be limited to one deep dive daily. Should the diver repetitively dive to shallower depths and not spend enough time on the surface to outgas - freediving instructors and fun divers take note – he will risk developing DCS.

DCS can be caused by many factors, whether they are age, physical fitness, dehydration, physical injury, or body type. As a general rule, the surface interval should be twice that of the dive time when diving shallower than 30 meters. To calculate the surface interval time for diving deeper than 30 meters, the maximum depth is divided by 5.


Being able to analyse aspects of their dive with a dive computer makes comparing dive time and speed can be highly beneficial to

ensure that the diver's breath-hold is being used as effectively as possible

Some dive computers currently on the market also have configurable sampling/logging rates and ascent/descent indicators suitable for freediving. The dive logging system and sampling rates will enable you to break down each dive section separately to see where improvements can be made.

Setting the sample rate of your dive computer to 1s allows a diver to record every second of the dive accurately. The ability to retrace your dive by downloading the data from your dive computer can set you free to concentrate on and develop your freediving performance in much finer detail.

Having a dive computer is essential to make freediving as safe as possible to extend your depth and time and monitor your progress during and after. You don't necessarily have to buy a new one; you can check if the dive centre in your area provides rentals.

i h i
Full Colour. High Resolution. AMOLED. Dive Safety Alert Diver DIVERS ALERT NETWORK Shearwater Teric TheWatchThatTransformsYou W A T C H V I D E O



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We all want every dive to be incident- and accident-free, but unfortunately, that is not always the reality. Accidents happen; when they do, few people are lucky enough to walk away entirely unscathed physically, mentally, or emotionally

Being involved in a traumatic event can take a toll on everyone: dive professionals or rescue divers who perform a rescue, lay providers who help with CPR and first aid, and dive buddies or bystanders People might recover from an event with time and have minimal long-term effects For some, the trauma fades to memory but can still bring up strong but transitory feelings, thoughts, and reactions when they recall it

A severe, prolonged, or life-threatening incident can cause some people to have effects that can last for months or years When particular symptoms last for at least a month, clinicians may diagnose post-traumatic stress disorder

(PTSD). According to the National Center for PTSD, about one-half of all U.S. adults will experience at least one traumatic event, and about 6 percent will develop PTSD.

Whether the trauma causes transitory feelings and thoughts or a diagnosed case of PTSD, there are two general ways of helping deal with it: informal and formal

Informal methods include going out to lunch or grabbing a cup of coffee with a dive buddy, family member, or someone involved in the event and talking with them about the incident These conversations often help someone process the event and may be all they need to resolve the effects If you are the listener, it can help if you avoid interrupting or offering examples from your own experiences When the time is right, you might acknowledge their distress with statements such as, “It’s really tough to go through something like that” or “This is such a tough time for you ”

By Jim Gunderson and Liam Brennan Photos by Stephen Frink EDUCATION
Divers who are involved in critical incidents may experience psychological impacts Individuals who potentially put themselves in harm’s way may be doing so both physically and mentally
are not immune to the psychological effects of critical incidents
trained and certified practitioners should administer emergency oxygen and psychological first aid to individuals in need Like physical rescues, psychological first aid is a dynamic and adaptive strategy for giving someone the care they need within the context of their situation

The most critical thing to remember is that how we derive support from others can be vastly different. Do your best to be the listener that the individual needs.

Self-care is crucial It is OK to be not OK, and acknowledging that is the first step toward getting better Eating healthy, well-balanced meals, staying hydrated, and exercising can go a long way for many people Getting ample rest is helpful; some people might benefit from developing or maintaining at least one purposeful activity each day, such as a hobby Reducing caffeine, alcohol, and other nonprescription substances may also be beneficial

Sometimes people need a more formal structure of individual or group counselling with a licensed clinician or therapist Standard counselling can be for one or two sessions or continue long-term

Psychological first aid (PFA) is an intermediate step in some instances Like standard first aid, PFA provides an initial intervention to reduce immediate distress and determine the need for further care Several programs are available, such as the RAPID model, developed by George S Everly Jr, PhD, at Johns Hopkins University, or Critical Incident Stress Management (CISM), created by the University of Maryland’s Jeffrey T Mitchell, PhD

The RAPID model (reflective listening, assessment of needs, prioritization, intervention, and disposition) enables crisis responders, even those without mental health training, to aid in administering PFA It focuses on completing the following five steps when engaging with an affected individual:

Build a rapport with the individual through reflective listening

Assess the individual’s cognitive, emotional, behavioural, physiological, and spiritual reactions to determine the degree of the incident’s effect

Prioritize the most affected individuals

Conduct the intervention process for those in need.

Review the individual’s disposition and the intervention’s overall effectiveness.

Another crucial component is understanding that when a lay provider cannot manage and mitigate the concerning reactions, connecting the individual with a higher level of care is imperative

CISM is a small group session facilitated by a trained clinician and a cohort In a dive setting, the affiliate could be a dive professional who lends their expertise to the event At the same time, the CISM expert manages the debriefing process The main goal is to provide some PFA that empowers those involved in an incident by enhancing resistance to stressful situations, building resiliency, and facilitating recovery

The CISM session should be a small group of people involved in the critical incident and not currently engaged in response efforts All participants should be psychologically ready for the debriefing rather than tired The session happens 24 to 72 hours after the incident and when all the surrounding work, including cleanup and documentation, is complete

Regardless of what method you experience to

deal with the effects of being involved with or witnessing a traumatic incident, reaching out for help is a critical step There is no shame in asking for help and communicating your needs following a traumatic event It will assist you in dealing with psychological trauma and returning to normal activities, including diving

Pros Choose DAN


Tec Clark, Associate Director, Scuba Diving Nova Southeastern University, explains why he chooses DAN.

Dive Safety Alert Diver DIVERS ALERT NETWORK

Few things are more exciting than the long boat ride to the far reefs north of Sodwana Bay. The sight of the seemingly endless primary dune coastline from out on the backline delights the cockles of one’s heart. There’s just something about the high-pitched drone of the boat engines and the fresh seawater spray aroma that rejuvenates the soul as nothing else can.

Named after marine geologist Dr Peter Ramsey, Ramsey’s Reef is located about 12 kilometres from Jesser Point at Sodwana Bay. It’s a reef that is rarely dived but ranks as one of the most beautiful and a personal favourite at Sodwana. Home to thousands of species of juvenile fish, mind-blowing swim-throughs, endless coral, and many larger pelagics, it’s a dive not to be missed.

Being the analytical data nerd that I am, one of my recent dive profiles gave me an ideal opportunity to showcase the level of tissue saturation and decompression stress risk profiling that is easily possible to do


Developed and reviewed with gratitude to Dr Lyubisa Matity at the Gozo General Hospita Hyperbaric & Tissue Viabi ity Unit Bespoke

tissue mapping to ensure
in subsea and hyperbaric

By accessing the tissue data off my Shearwater Peregrine dive computer, I can run that through an Excel-based algorithm analysis tool I’ve developed to visually model tissue saturation and desaturation in accordance with either the Bühlmann ZH-L16C or ZH-L16A algorithm

Below you can see what my tissue loads would look like diving on either air or EANx36 The substantial benefits of both EANx32 and EANx36 are easily demonstrated with reduced saturation loads and resulting in reduced DCS risk compared to air diving

Different tissues absorb and eliminate inert gas according to their defined half-life times The two graphs below represent the sixteen hypothetical tissue types assumed in the Bühlmann ZH-L16 based decompression algorithm These sixteen tissue saturation curves are displayed below for the two comparable gas mixtures simulated, ie, air versus EANx36

In terms of decompression sickness risk, we are interested in knowing the peak surfacing gradient factor (GF) in the leading tissue Tissues 5 & 6 are running ‘hot’ on the air dive, and tissue four is doing the same on the reduced-nitrogen-load EANx36 dive

The most saturated tissue is where bubbles might form and define the nature of any potential DCS injury But DCS risk is also heavily influenced by the peak desaturation gradient and the extent of time our tissues carry that excess load We refer to this as the ‘Integral Tissue Super-Saturation’ value (ISS) measured in bar minutes

By running various ‘what-if’ scenarios through my spreadsheet, we can quickly review the impacts that different lengths of safety stop times and breathing mixes have on tissue saturation and desaturation loads (refer to Table 1) The benefit of extended safety stops is easily demonstrated

We can also plot out the Integral Super-saturation across each of the sixteen Bühlmann tissues (refer to Table 2) to see which leading tissue presents the most significant risk for bubble formation. The heat maps visualise which tissues are running ‘hot’ and carrying the most significant desaturation loads over time

The valuable difference between diving EANx36 over air on this dive is also seen in the total off-gassing times - only 112 minutes on EANx36 rather than 241 minutes on air from in-gassing all that extra nitrogen through the air dive An analysis spreadsheet tool of this nature is invaluable because it empowers us to evaluate the impacts of our diving behaviourisms and breathing gas choices I always do 5-minute safety stops as a part of my strategy to minimise DCS risk and post-dive fatigue

Safety is paramount, and information is King

Dennis Guichard is a multi-agency qualified Scuba Instructor Trainer & a DAN ‘Master Dive Pro’ member. He is a qualified Diver Medic and Saturation Life Support Technician, freelancing as a hyperbaric technologist at the Netcare St Augustine’s Hospital Hyperbaric Medicine and Wound Care Unit, Durban, South Africa.

Developed and reviewed with gratitude to Dr Lyubisa Matity at the Gozo General Hospital Hyperbaric & Tissue Viability Unit.

Pros Choose DAN TrustedWhenItMattersMost

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Ivana Inglesina & Victoria Cole, PADI® Platinum Course Directors, Pro Dive Vibes, Curacao, explain why they choose DAN.



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'As a child, I was fascinated by how marine creatures held their position in the water. The Nautilus is the one creature that captivated my curiosity and inspired my direction more than any other

Hanging motionless in any depth of water and the inspiration for the design of the submarine with multiple air chambers within its shell to hold perfect buoyancy, it is truly a grand master of the art of buoyancy

Buoyancy is the ultimate foundational skill in a diver's repertoire, whether a beginner or an explorer It is the base on which all other skills are laid With good buoyancy, a problem does not become an emergency; it remains a problem to be solved calmly under control

The secret to mastery of buoyancy is control of breathing, which also gives many additional advantages to the skill set of a safe diver Calming one's breathing can dissipate stress and provide a sense of well-being and control Once the breathing is calmed, the heart rate will calm too, and any situation can be thought through, processed and solved

Always 'Stop, Breathe, Think and then Act'

Breath control is used in martial arts to control energy flow, prenatal training, and childbirth At a more superficial, everyday level, pausing to take several slow deep breaths can resolve physical or psychological stress in many scenarios found in daily life

How, you may ask does that relate to buoyancy control? Well, of course, the breath moves a significant quantity of gas volume to or from the diver, and if the breathing pattern is incorrect, it can impact buoyancy significantly; if the pattern is correct, then it can fine-tune the control to the perfection of my friend the Nautilus Phil Short, Dive Industry Consultant and Dive Safety Officer and Training Director IANTD UK

For those of you who watched Jacques Cousteau's adventures featured in the "Silent World" documentary dating back to 1956, the first generations of underwater explorers ventured deep equipped with three moderatesized cylinders harnessed to the back, CG45 air regulators the size of an alarm clock, a shatterproof glass mask over the eyes and nose, a weight belt and rubber foot fins It was a twenty-five-kilogram apparatus that relied on the human lungs' most powerful yet sensitive ballasting system Also, at the end of the last century, some may recall that their first diving lessons were performed using lung control only before integrating a buoyancy control device at a later stage

Nowadays, the importance of breathing properly while diving is often introduced primarily as a safeguard for new divers to avoid a lung over-expansion injury during an uncontrolled ascent, the golden rule is "never hold your breath!" Beyond the concerns over uncontrolled buoyancy, holding one's breath or skipping breaths can also lead to a build of CO2 and other hypercapnia issues On the flip side, breathing continuously might also lead to hyperventilation issues Therefore proper ventilation is essential from a physiological perspective to ensure efficient gas exchange in all tissues by using the tidal volume of the lungs during the immersion The more uncontrolled tidal volume breathing is, the less redundancy will exist in the form of inspiratory and expiratory reserve volumes, including precise buoyancy adjustment

Propulsion can compensate for lack of buoyancy control Its effect is similar to throwing a paper plane in the air; it will forcefully glide until it loses speed and crashes The awareness of the impact of such adjustments cannot be fully experienced while propelling oneself through the water but rather in static mode In contrast, a controlled descent or ascent can be initiated solely using the inspiratory and expiratory lung reserve

rather than wasting gas fiddling constantly with a wing or drysuit inflator valve.

Building awareness of breathing cycles by taking normal breaths in a slow rhythm and adding minor adjustments when required is the key to fine-tuning buoyancy control. However, the total lung capacity has limitations and is impacted by external factors such as buoyancy and ballast weight distribution.

Buoyancy distribution varies based on one's gas volume management strategy for adding or removing gas from various parts of equipment throughout the dive, specifically the BCD or wing, counter-lungs and drysuits. One size does not fit all; in addition to the amount of gas involved, the proper sizing of each piece of equipment relative to the individual's morphology determines their capacity to efficiently distribute the gas volume to where and when it needs to be.

It is common among beginners to believe that being over-weighted will prevent one from shooting to the surface It's the same as for the lungs Minimising the required gas volume in the equipment by correct weighting facilitates buoyancy management ensuring that the right amount of gas flows in and out However, the amount of gas required to compensate for the excess weight can become unmanageable and most likely disturb the diver's normal breathing pattern and the time required to vent gas, causing them to surface too fast

Some of the ballast weight we carry as divers is an integral part of our configuration, such as the backplate, regulator, and valves and cannot be modified during the dive However, other variables prompt action: Many of us filled our early diving logs conscientiously ticking equipment boxes and writing down how many kilos of weight we were carrying while ignoring other major components The list is long, but each component matters Are

we planning to dive high or low-pressure steel cylinders? What is the cylinder's weight? What is the weight change between a full and empty aluminium cylinder? Are you diving in freshwater, salt water, or the Red Sea? Weight-wise, what is the impact of removing some undergarment layers after switching to a heated system? The list of possible combinations is endless, so one needs to know how to make a proper assessment when visiting a new environment or after making changes in one's overall configuration. Any change requires a weight check, which is not time-consuming when entering and preparing to exit the water. Once again, buoyancy relies mainly on lung capacity and starts with draining the gas from all equipment parts.

After filling your lungs to approximately 80% of their volume, you should float above the surface, float at the surface with your lungs 50% full, and start sinking after exhaling down to 20% capacity. However, repeating this check before exiting the water with almost empty cylinders (even more with aluminium or low-pressure steel cylinders) is also wise to ensure one can maintain your buoyancy comfortably at a safety or decompression stop when your tanks have minimal gas Building experience to master static neutral buoyancy and controlled ascent/descent does not require much depth Practising in the shallows is potentially safer and more challenging as this is where significant pressure changes occur

Maintaining your target depth is a safeguard against (no) decompression obligations

Managing neutral buoyancy in static or dynamic mode supports the ability of a team to stay together, communicate and react in an emergency


Building environment awareness is a key driver to buoyancy and breathing management choices when diving, for instance, close to a reef, when exhaling in overhead environments (percolation generated by exhaled gas swelling to a ceiling can lead eventually to poor visibility), or when anticipating the impact of salinity changes when entering a halocline.

As a virtuous cycle, buoyancy mastery triggers control. Control leads to comfort, comfort to calm, calm to control, focus and gas saving to maximise the time spent underwater and make the best out of the moment.

As undersea pioneer Jacques Cousteau once explained, "At night, I had often had visions of flying by extending my arms as wings. Now I flew without wings. Delivered from gravity and buoyancy, I flew around in space." Zero gravity is natural to the Nautilus and part of space's natural law. Underwater, weightlessness is a skill to be learned before it can become second nature. It's an achievement. For your House of Cards structure to stand firm, you must start by building a solid foundation. Once a diver masters the ability to hold their position in the water column, they can evolve comfortably and safely in a multidimensional space and position themselves where they want and need to be as part of a team and as part of an environment


Audrey Cudel is a cave explorer and technical diving instructor specialising in sidemount and cave diving training in Europe and Mexico She is also renowned in the industry for her underwater photography portraying deep technical and cave divers Her work has appeared in various magazines such as Wetnotes, Octopus, Plongeur International, Perfect Diver, Times of Malta, and SDI/TDI and DAN (Divers Alert Network) publications



Have you ever wondered if there is a simple way to improve your diving experience? The good news is that there is: being bald! My name is Alex, and I'm bald. So, let me tell you why this is a good thing!

Then, while diving, hair can also cause many frustrations. Hair can often get in the way of putting on your face mask before and after getting wet. Whether you just did a mask removal and replacement, and now your mask is tangled in your hair, or you've got that leak that won't go away because of one strand of hair stuck in the mask seal – hair can be a real nuisance Maybe you're tired of having to tie up your hair or squeeze and pull your hair through that tight hoodie for a cold dive What about after an ocean dive? The saltwater causes your hair to get tangled, and without a shower and conditioner, it might just stay that way Then there is the business of shaving that moustache off, or your mask won't seal properly These are just some of the issues you can say goodbye to once you start living the bald life

Once you say goodbye to hair, every mask strap is comfortable Your hair never gets in the way during a mask clearing The post-dive shower and dry-off take 5 minutes or less If a bald person ever showers for over 5 minutes, they are just wasting water

Let's not start with how easy it is to put on the tightest hoodie; it just glides over your scalp When I did my scuba instructor certification, I had to remind myself that others might not have my huge advantage I had to remind myself on numerous occasions to include hair issues and how to deal with them while diving, something which, for years, I had completely forgotten about

Seeing students' reactions underwater when I pretend to pull my 'hair' back when I put my mask back on after a removal and replacement demonstration never gets old Not to mention the confused faces of those who weren't paying attention during the briefing, seeing their bald instructor stroking his scalp underwater

I wasn't always as bald and beautiful as I am today. I was born in 1996, and for 15 years, I had a full head of constantly messy and curly hair. I had a small bald patch on the back of my head when I was younger, which we presumed was a birthmark or something similar It was only when the bald patch got larger and was joined by another bald patch on the top of my head that I realised something was askew After a quick visit to the dermatologist, alopecia was diagnosed without any other symptoms

Alopecia is an immuno-disorder whereby your immune system mistakenly attacks your hair follicles, causing them to become inflamed, resulting in ultimate hair loss Each person has a different overall response, and hair loss can come and go throughout your life, but there is no known cure There are various treatment options and ways to manage hair loss with varying amounts of success for different treatments and people I did try just about everything, and, no, there is no magic wand guaranteed to bring your hair back

Depending on the amount and type of hair loss, you may have a different diagnosis This was a daunting diagnosis, and at the age of 16, I had progressively lost every hair on my body, including my eyebrows and eyelashes I had gone from Alopecia Areata to Alopecia Universalis At that time, it was not a source of pleasure It was more like needing to climb through a hole - nothing severe or lifethreatening, but definitely a hole! I will never forget walking back to class after Mr Warwick Taylor, a teacher I will never forget (since he was my game changer), proceeded to shave off all my hair after pulling me out of class because we had to do something about the situation I had been covering massive bald patches with hair that was busy falling out-dreading the avalanche of hair on my pillow every morning and the constantly blocked drain in the shower Holding on was worse

than letting go, and the time had come for me to do the latter

The beginning of losing hair can be slightly stressful Things do tend to change quite quickly People may start treating you somewhat differently because you have no hair I mean, NO hair I still remember meeting a Reach for the Dream member on a flight back home from Port Elizabeth who thought I had cancer and insisted I contact them as soon as possible I am not going to lie to you; it was tempting I had been in dire straits – holding onto whatever I had left Then, after I was bald as a coot, I stopped worrying about it

In later years, I had the pleasure of many joyous discoveries, some of which I mentioned earlier Little did I know that my 'loss' would become my superpower. After I had just let it go, my life improved, but that took a while. At 17, I realised my baldness had many advantages. It was not a disability. It can be for good or evil; it's up to you. With that realisation my attitude changed, and if you can relate to my story, I encourage yours to do the same.

What changes in diving, you may ask?

Very little Your life is way easier in many ways, but there are one or two things to remember For instance, if you are prescribed medication, you'll need to ensure it's conducive to diving by mentioning it to your dive doctor or contacting DAN to check

Be careful of the sun A cap and buff will become your best friend Use sunscreen Beware the cap tan When your eyelashes are gone or short, a pair of close-fitting sunglasses can make all the difference in keeping sand out of your eyes on a windy beach Always wear a hoodie to protect you against the sun and prevent you from getting cold since you have no more insulation on your head A buff works well underwater and in water too warm for a hoodie

Your nails might become a bit weird because, well, nails are basically hair as well This does not affect everyone, but you may need to be aware of it

In the long run, the main side effect of having little or no hair will remove many more problems than it gives I haven't bought shampoo or conditioner in over ten years Slightly more moisturiser, though, which brings me to my last tip Keep that scalp moisturised!

It is important to note the positive effect diving had at that time and to this day It allows you to experience the world uniquely with guaranteed company since you never dive alone A safe space where it does not matter what you look like; if you dive, you are always part of a team We all look the same underwater, anyway The inclusiveness of diving may ultimately be better than the best medication (and not just for those who lost all their hair) It's always important to stay active and involved in an inclusive and caring dive community It allowed me to rediscover myself and become who I am today I discovered my passion for diving and, ultimately, teaching others to dive Something I have completely fallen in love with and have enjoyed for the past three years as an instructor and ten years as a recreational diver

My diving journey began with a search for adventure Diving restored and rebuilt my confidence: a gift from the diving community gave me for which I will always be grateful Anyone with a rare medical condition, which may or may not have a social impact on their life, should consider diving as a sport It has the surprising and unexpected ability to free you to be who you were always meant to be Just remember to take it slow at first and always see a diving doctor before you begin your adventures into the underwater world to ensure there are no complications for you to be aware of as a diver Then take it step by step as you learn to dive, including an environment/centre that will allow you to do so Small things may apply to you and you alone, which you may only learn about once you start diving The importance of always wearing a hoodie, even in pool sessions, to avoid intense sunburns on my scalp was one of the lessons I had to learn very quickly

The last piece of advice is to have as much fun as possible. Diving and interacting with an accepting diving community is one of the best places to simply be yourself, whether it's a place to escape from reality for a while, or a chance to regain your confidence; diving tends to offer you precisely what you need.

To those living with alopecia who may be having a tough time, be bald, be beautiful, and be yourself. Don't let baldness disable you; let it empower you! No one in this world is like you, and it's about time you realise it.

On Facebook: @alexvdhoven

Instagram: @alexvdhoven

Alex van der Hoven is a full-time Scuba Instructor based at 7th Heaven Scuba in Gauteng, South Africa.

Pros Choose DAN


Dive Safety Alert Diver DIVERS ALERT NETWORK
Michael Clarke, Group Director, Watersport & Marine Division, Sandals and Beaches Resorts, PADI® Course Director, explains why he chooses DAN




"I've seen things you people wouldn't believe… Divers' nerves on fire off the shoulder of Shark Reef… I watched canister light beams glitter in the dark near the Labyrinths of Thistlegorm. All these moments will be lost in time, like cameras off the side of the boat – unless we talk about it?" - Roy Batty - if he had been a diver

Humans do not behave instinctively in the way birds or ants do People need to be trained to collaborate effectively as a group They need role models and leadership The same is true for scuba diving Yet, somehow, we are expected to function effectively together as a group, or with a dive buddy we hardly know, and to do so in a highly complex environment

I have also been intrigued by the spontaneous Brownian-like motion of a group of scuba divers commencing a dive: just like gas molecules, they eventually seem to try and fill all the available space The phenomenon is remarkably predictable, almost like a law of science It usually starts off well enough, with the divers descending, generally, in a straight line However, eventually, they almost always end up in a ball It may be entertaining to watch with easy open water diving However, when diving in a canyon or inside a shipwreck, this can quickly become dangerous So, what should divers do to prevent this from happening?


I'll be the first to admit that there is a certain similarity between a dive briefing and adding sugar to coffee Within less than a minute, it dissolves! This is where the skill of a divemaster or leader comes in: Their ability to engage the divers so that they stay together and listen from beginning to end without the attention wandering off defines them as true professionals versus just another dive tour guide

One of the Golden Rules I've learned from experience is to put the least experienced divers closest to the dive guide, leaving the more experienced ones further down in the queue

Another simple intervention is to assign numbers to buddy teams Once given a number, people - including divers - tend to order themselves automatically without needing further intervention


A common mental (albeit unconscious) mistake is thinking that a group of divers are one big buddy team That is a very wrong notion with potentially disastrous effects For starters, it erodes one of the most fundamental principles of diving safety – the buddy pair system in which divers are conditioned to look out for each other's wellbeing underwater! It's not monogamy but the safe practicality we are promoting! Divers should be actively encouraged to look out for their buddies irrespective of gender or experience In another issue on Diving etiquette: The Buddy, we get into this in greater detail


Once buddy allocations and numbering have been assigned, it is far more likely for a line to be formed with divers diving side-by-side (like the animals entering Noah's Ark) As they steadily fin in their pairs and explore the reef wall, the divemaster (DM) can also better point out something interesting, like a particular clownfish family Then, as the divers go by in their pairs, each successive team points it out to the next as the procession progresses The instructors or more experienced divers who choose to dive at a slightly deeper level (for instance, if they decide not to have bubbles blowing into their face all the time), may do so This type of diving is pure bliss and any divemaster's dream Yes, this is Paradise

Here is an example of the opposite, undesirable, scenario: The DM spots the clownfish. All the divers rush to see what they are pointing at. And it's bubbles and fins everywhere. Suppose the clownfish aren't already scared off by the onslaught of divers darting towards them, the underwater jacuzzi of bubbles will undoubtedly make them more challenging for others to see. On top of that, the flailing fin collection will likely dislodge someone's facemasks or regulators. Nobody will enjoy this.


1 –

Don't overtake the buddy team in front of you

In the same way, you wouldn't jump the queue in a supermarket, don't overtake the divers in front of you. Stay in your lane. There may be exceptions, such as when the current is strong, or the diver in front of you suddenly stops to take a picture Still, usually this overtaking is the result of finning too fast The problem is easily remedied, fin more slowly It's not rocket science

2 – Respect safety distances

Bearing in mind that conditions such as currents and visibility may influence the rules we are sharing here, for the most part, and with good to excellent visibility, keeping the distance of about one diver's length between buddy pairs avoids crowding, getting your mask dislodged by fins, unnecessary disturbance of silt, and aggregation of bubbles that make the scenery invisible or make the water murky There are special techniques to avoid unnecessarily dislodging silt, but unless you're very thoughtful about it; use a special finning technique; or dive on a rebreather, a certain amount of silt will inevitably decrease viz a little as the line progresses

Less experienced divers tend to be quite heavy on their air supply, so allowing them to swim closer to the DM makes good sense. It sets a better pace for the group.

3 – Don't monopolise

Getting back to the discussion of diving in a line, let me mention one truly irritating behaviour I see occasionally. Let's say a group of divers are fortunate enough to discover a lovely nudibranch; the stage is set for a dive from hell unless the divers keep the line and don't linger unduly. Everyone deserves a chance to see it.

This brings me to photographers! It is wise for photographers to position themselves towards the end of the line. Hiring a private guide is often even better, and -- yes -- I know it incurs extra costs. However, the reduction in frustration will likely make up for it. Photographers also often eventually fall so far behind that they even become separated from the group, so there is yet another reason why having your own tour guide may be a good idea If this is impossible, well, then stick to the rules, but don't let your camera take the place of following the divers in front of you

4 –

Be on time

Even reasonably minor delays during the initial part of a dive can influence the entire dynamic of the rest of a dive Note that I'm not advocating people jumping off willy-nilly and hitting each other on the head with their dive cylinders However, a carefully counted down: "one two three go" can work wonders in getting everybody in the water simultaneously, allow for a quick head count and allow the dive to commence the dive before any prevailing currents start to splay the group over the size of a football field Put in the extra effort to make yourself visible to the DM, and you will have done them a great favour


5 – Watch your buddy

I realise we've gone on a bit about this issue. Still, successful buddy diving is not only fundamental to diving safety but also to diving enjoyment As humans, we live in a twodimensional world – for the most part: we look left and right but very seldom the up and down! In addition, although divers focus mainly on the bottom to avoid hazards, the reality is that the most dangerous things are usually close to the surface, such as other divers and the dive boat propellors A steady, smooth descent is the objective, with buddy pairs looking out for each other What is to be avoided, as far as possible, is one or two divers having buoyancy or year equalising issues, being delayed during their decent, and the DM -- upon arriving at the bottom to make sure that everybody is still together -- going to one of the former buddy pairs, asking them about their missing buddy, and getting a blank or wide-eyed expression in response Please behave accordingly

6 – Thou shalt not harass

One of the mantras of scuba diving is "take only pictures, leave only bubbles" Sadly, it is not uncommon to find divers coalescing around a single sea creature, such as a moray eel or reef shark, and scaring it into oblivion Divers holding onto turtles don't realise that this may lead to drowning them Overly aggressive approaches toward sea creatures are not only potentially dangerous but harmful for the sea creatures as well Also, by being negligent in this way, they may very well be denying the divers behind them the opportunity of sharing in the enjoyment

7 – Shakers, horns, and other noisemakers

In the past, the DM's and other dive leaders have used 'Shakers', underwater 'hooters', and other noisemakers to try and attract divers' attention

These are fallen out of fashion, not only because of the harm they might inflict on the divers but also because of the havoc they cause to the sea life. Unfortunately, not everybody is up to speed on this, so if you have one of these devices, use it responsibly at modest noise levels unless there is a true emergency Otherwise, believe it or not, just talk! When buddy pairs dive that I tune with each other, it's very easy to hear the other person talk (or, if necessary, scream!) through the regulator


– Surface where and when you are supposed to surface

No one will ever blame a diver for surfacing far from the planned exit point, or sooner than planned, if they ran low on air or got caught by a strong current However, reckless disregard of prior arrangements or surfacing far away from the entry point is often the first step in the sequence of events leading to a missing diver situation

9 – Waiting for the deco guy

Be thoughtful in planning your dives so that you do not have to spend obligatory decompression while everybody is waiting for you on the dive boat? Many divers prefer to stay near the boat, in the shallows, waiting for their turn to board and minimising the time on the boat (especially if they are prone to motion sickness) But don't deliberately build in a prolonged deco-stop that will keep the other divers waiting for you Also, even if you are very light on air, don't be inconsiderate and leave your fellow divers developing motion sickness on board as you slowly wait for your dive gauge to reach 50 bar Note that this does not apply in safety situations where the unforeseen delay in the wreck requires a slightly longer stop However, while a five-minute stop is acceptable, spending half an hour is not, especially if the sea is choppy

10 – Be kind

As a customer on a dive boat, you have many opportunities to be thoughtful towards others and kind to your DM DM's, no matter how seasoned they may be, still have your safety nagging in their head If they know they can count on you to be thoughtful and communicate with them if there are any problems, you're one less diver they need to worry about Remember, they are in charge, which also comes with a certain amount of liability for your safety So be considerate, communicative, and courteous


DAN Member since 1997, Claudio Di Manao is a PADI and IANTD diving instructor He's the author of a series of books and novels about diving, including Shamandura Generation, an exhilarating portrait of Sharm el Sheikh's diving community He collaborates with magazines, radios and newspapers, talking and writing about diving safety, marine life and travels



Yourgatewaytodivesafetyservices&worldwidedive coverageatlowannualrates!



Q | My son is on the autism spectrum and wants to learn scuba diving. Will his autism be a problem?

Everyone with autism is unique and must be evaluated independently There will never be an all-inclusive recommendation

First, all decisions must be made by you, properly trained dive instructors, and the physicians who are most closely involved in his behavioural and physical care Each case depends on the person’s level of function and comorbidities For some individuals, scuba diving comes naturally, and they handle it well with the proper accommodations and qualified instructors The risks are too high for others, and diving should not be considered

In making an informed decision, you must consider the following: Does he have any sensory imbalances?

These can cause hyperreactivity to stimuli that can be aggravated underwater as well as panic and subsequent life-threatening injuries

Can he make prompt decisions and monitor gauges, depth, air consumption, and buoyancy? Research indicates that many people on the autism spectrum have some cognitive impairment, which can affect decision-making

Repetitive behaviour such as tics or rocking may present difficulties with basic underwater skills such as buoyancy control, which could lead to injury Some people on the autism spectrum have challenges with muscle tone and coordination

Finally, it would be best to consider his awareness of cues and his ability to understand the need to equalise his ears frequently


This is not an all-inclusive list. You may review this information with groups specialising in autism spectrum disorder.

If he is cleared to dive, investigate organisations that specialise in scuba diving for people with disabilities Depending on your son’s level of functioning, an adaptive scuba instructor may be a resource to consider

Q | Would a diagnosis of hypermobile EhlersDanlos syndrome affect my ability to dive?

Diagnosis of hypermobile Ehlers-Danlos syndrome (EDS) is considered a relative contraindication to diving, meaning that depending on the nature and severity of this highly variable condition, diving may or may not be recommended

EDS is an inherited disorder that affects the connective tissues of the body It has several classifications based on symptom presentation and location, including hypermobility (or overly flexible joints), which is associated with a

collagen defect affecting connective tissues’ ability to support muscles, organs, and other tissues.

The industry standard is for a diver to be able to put on all equipment, enter the water, swim, be able to self-rescue or rescue a buddy if required, exit the water, and remove all equipment without assistance These activities involve movements of your major joints and back They could provoke common complications from this condition, such as joint dislocations or subluxations Joint dislocation while diving can place you in a dangerous situation

Some symptoms of hypermobile EDS are joint pain (including costochondritis in the chest) and bruising; these symptoms mimic decompression sickness and may make it difficult for a physician to diagnose you should you have a problem while diving correctly

The condition is associated with Raynaud’s disease, so the risk of spontaneous pneumothorax must be considered Additionally, cardiovascular concerns can

include valve dysfunction and vascular aneurysms that should be followed regularly by imaging

Other issues include skin fragility, bleeding problems, jaw dysfunction, globe (eye) rupture, kyphoscoliosis (a restrictive lung disease), gastrointestinal issues (including bowel rupture), and loss of consciousness (orthostatic hypotension or postural orthostatic tachycardia syndrome)

Discuss these issues with your physician team before diving, and encourage them to consult DAN

able to return to diving if you are otherwise healthy and fit for the rigours of the sport These ports are typically filled with fluid and, therefore, non-compressible at depth, so diving should not be a concern However, several manufacturers make the ports, so we recommend asking your oncologist to check with your device’s manufacturer for pressure ratings or depth restrictions

If your doctors have released you for full, unrestricted activity, you should be able to return to diving without complication Given that it has been some time since you were last in the water, we recommend completing a graded exercise program and a refresher course to help you get ready to dive safely

Q | I am evaluating a patient with Tourette syndrome who wants clearance to scuba dive He has significant motor tics, so I need guidance or resources to discuss with the family

Tourette syndrome is a neurological disorder that is a relative contraindication to diving The nature and severity of the motor tics need to be considered along with any associated conditions Even a simple tic such as coughing, throat clearing, or grunting that may involuntarily occur during ascent may obstruct air flow and increase a diver’s risk of pulmonary barotrauma Also, consider whether the diver can hold and maintain a regulator in his mouth for the dive duration

Q | I am a certified open-water diver and a cancer survivor. I finished chemotherapy five months ago, and the cancer has been dormant for several months. To facilitate repeat chemotherapy, surgeons installed a port just under the skin in the upper chest area below the clavicle. What concerns or limitations should I consider before returning to diving?

Concerning your port, if everything has healed and there are no complications, you should be

Ben Strelnick, NREMT, W-EMT Anne Strysniewicz, AEMT, DMT

Intense and violent motor tics may cause injury to the diver or others or affect gear or situational awareness while underwater, potentially leading to a dangerous situation This can be especially problematic during an emergency ascent or challenging sea conditions. Stress, excitement, and anxiety have been reported to worsen the severity of tics.

Have an honest, detailed conversation with the dive candidate and their support system, including their family, dive supervisors, and physician team. Discuss the realistic expectations of diving and whether their current medical status allows them to dive safely.

You have already identified significant motor tics that would be of concern. The industry standard is for a diver to safely put on all equipment, enter the water, swim, self-rescue or rescue a buddy if required, exit the water, and remove all equipment without assistance.

For more information about adaptive diving, contact DiveHeart (diveheartorg) or the Handicapped Scuba Association (hsascubacom) They may have additional insight or experience working with divers with this condition

Most divers know Peter Brian Bennett, PhD, DSc, as the founder of Divers Alert Network, through which he brought significant changes in how we understand and enact dive safety He became the international force for recreational dive safety and provided major support for research in recreational diving Dive physicians today continue to reference the book Physiology and Medicine of Diving, which Bennett co-edited with the late David Elliott, PhD

Bennett earned his bachelor’s degree in chemistry and biology from the University of London in 1951 While working for the Royal Navy Physiological Laboratory, he completed a doctorate in physiology and biochemistry at the University of Southampton in 1964 He moved to the US in 1972 to be a professor of anesthesiology at Duke University Medical Center, where he eventually became the senior director of the FG Hall Laboratory for Environmental Research, Duke’s hyperbaric chamber facility




Photos From The Peter Bennett Archives Peter Bennett monitors divers in the Duke Hyperbaric Center chamber during a record 2,250-foot trimix dive in 1981
on dive physiology research
DAN founder Peter Bennett had a profound influence

While at the Royal Navy Physiological Laboratory and Duke University, Bennett planned and conducted a long list of dive research projects that included almost everything relevant to dive physiology. He studied nitrogen narcosis, oxygen toxicity, decompression illness, safe ascent rates, highpressure nervous syndrome (HPNS), and mixed-gas diving, among many other topics.

Few researchers have furthered the understanding of the human body under pressure as profoundly as Bennett did in his lifetime. After his death on Aug. 9, 2022, Alert Diver asked some of his former colleagues to share their memories of the man who changed the world’s view on diver safety.

Richard Moon, MD, a professor of anesthesiology at Duke University, remembers starting his career in hyperbaric medicine under Bennett’s mentorship.

“I first met Peter Bennett in 1973, when I visited Duke to learn about opportunities in undersea medicine I felt as if I already knew him, having read his textbook When I met him in person, Bennett was working on HPNS mechanisms, which manifested as tremors, unsteadiness, and what became known as ‘microsleep’ - falling into a slumber when not specifically engaged Bennett was gracious, interesting, and very encouraging

“In 1979, I decided to come to Duke as a pulmonary fellow, hoping to join a research team working on underwater physiology By that time, Bennett was the F G Hall Laboratory director He and his collaborators had obtained funding from the National Institutes of Health to explore human physiology during deep diving The plan was to do a series of experimental dives at Duke with a maximum depth of 2,000 feet of seawater (fsw) or more they ultimately attained a record-breaking 2,250 fsw

“Bennett led the formation of a team of investigators, all working on deep diving’s physiological effects. His contribution to the science was developing a method of reducing HPNS by introducing a narcotic gas (5 to 10 percent nitrogen) into the helium-oxygen atmosphere. This method led to significantly improved performance, as did much of his life’s work.

“With diver performance enhanced, John Salzano, PhD, and Enrico Camporesi, MD, trained the divers to insert arterial catheters and perform blood gas analysis during exercise under these extreme conditions. I had the honour of working with them and Bret Stolp, MD, PhD, during those investigations.

“Bennett’s skills as a leader and mentor and the ease with which he dealt with people provided the basis for his exceptional accomplishments. He was always highly encouraging of junior investigators around the world and was a great friend and supporter.”

Alessandro Marroni, MD, president of DAN Europe and founding member of International DAN, was a colleague and friend of Bennett’s for many years.

“I first met Peter Bennett in person in 1976 in Aberdeen, Scotland, at the Human Factor in North Sea Operational Diving symposium He presented his deep-diving studies, which were already very extensive, and his work was widely known even before the 1981 record dive at Duke At that time, I was the medical director of dive activities of the Italian National Oil Company I was responsible for the saturation diving operations at Forties Oil Field in the North Sea It was natural for me to approach Bennett and ask for his advice about the safety and efficiency of such operations

In 1975 Bennett receives the first Undersea and Hyperbaric Medical Society Oceaneering International Award for services to commercial diving research Bennett performs the “ball-bearing test” of fine motor control while breathing an argon-oxygen mixture at the Royal Navy Physiological Laboratory in 1963

“I had just started an organization in Italy called International Diving Assistance to help recreational divers during emergencies when I heard of Bennett starting DAN in the U.S. as the Diving Accident Network. I wrote to Bennett to ask about his interest in international cooperation. It took a couple of years and several exchanges by airmail and fax, but he was in favour of the idea and generously agreed for us and two other diver helplines in Japan and Australia to also use the DAN name. That was the start of what became International DAN, and DAN Southern Africa soon joined DAN Asia-Pacific, DAN Japan, and DAN Europe. I remember drafting the International DAN charter at the bar of the Washington Duke Inn with Chris Wachholz and Bennett’s oversight like it was yesterday.

“My collaboration with Bennett soon expanded to joint research projects about dive safety and medicine. For many years afterwards, until he retired, there was hardly a week when we did not exchange an email or talk on the phone. Our correspondence continued, although at a slower pace, after his retirement

“His scientific stature is undisputed, and we will always remember him as a giant in underwater physiology, medicine, and dive safety The way I most like to remember him, aside from his undoubted reputation, is for his human qualities, integrity, generous sharing of his vision, and relentless passion for pursuing it ”

Ulrich van Laak, MD, DAN Europe’s area medical director for Germany, Austria, and Hungary, remembers Bennett’s groundbreaking research in saturation diving and the early stages of International DAN

“For many years, Peter was the brains behind a large saturation diving project in Geesthacht, Germany, which I was fortunate to witness firsthand He took divers who were doing welding work to nearly 2,000 feet on

trimix in the German Underwater Simulator (GUSI) and brought them back without HPNS by decompressing them over several weeks.

“We always invited Bennett to teach during our annual course for German Navy dive medical officers. We even aligned that course with the experiments in Geesthacht to ensure we would have Bennett as faculty to talk about saturation diving. In one of these courses in the early 1980s, I remember him talking about the Divers Accident Network that he had just founded. We were enthusiastic about his ideas to optimize international dive accident management and networking, especially since the military (not only in Germany) had been forced to partially withdraw from assisting recreational divers. All of us were happy to support this dive safety network in its early stages.

“In many ways, the feasibility workshop for an international DAN which brought worldwide delegates to Durham, North Carolina, in 1989 was the foundation for today’s understanding of dive safety ”

Dan Orr, former DAN president and CEO, worked with Bennett in DAN’s early years.

“Before DAN, instructors in the field had to develop a complex emergency assistance plan for managing dive emergencies, which sometimes included developing a relationship with a local hyperbaric chamber When DAN started, everyone in recreational diving had a way to contact a knowledgeable dive medical professional who could provide critical emergency assistance when divers needed help the most

“In the early years, DAN reached out to the recreational diving community to identify who was influential in different regions These individuals became DAN volunteer alert instructors or volunteer associate coordinators Bennett invited me to take on both roles to actively support and promote DAN in my part


Peter Bennett ReachingOutAward

First awarded in 1989, DEMA's Reaching Out Award recognizes those individuals that have had a positive impact on recreational diving by reaching out to help grow the industry. Recipients are inducted into DEMA's Hall of Fame.

Dive Safety Alert Diver DIVERS ALERT NETWORK

of the country, and I would eventually be DAN’s first training coordinator

“I remember a quote that stuck in my head and speaks to the kind of person Bennett was: ‘I hire the right people for the right role and let them do their jobs If you put me in a position where I have to tell you what to do, I’ve obviously made the wrong choice So just do your job, and we’ll both be happy!’

“During the 23 years that I worked at DAN, Bennett’s mentorship and encouragement helped me grow beyond the role of training coordinator to assume greater responsibilities, and I adopted his management philosophy He had the unique ability to identify and use the inherent skills of each person who worked for DAN while energising them to do their best for the members and dive community we served.

“He was undoubtedly a tough taskmaster, with strong beliefs and even stronger convictions. His eyes were firmly fixed on the greater good regardless of what others thought. As a result, all of us at DAN never lost sight of the fact that if we did not do our best, there could be dire

consequences for our members and divers in the field.”

Renée Duncan, communications coordinator for the Undersea and Hyperbaric Medical Society (UHMS), worked with Bennett at DAN and later at UHMS.

“My introduction to Peter Bennett was when I worked at Underwater USA in the late 1980s and early 1990s, and he received the first Prince Tomohito of Mikasa International Marine Award for his contributions to diving and hyperbaric medicine This recognition came from his esteemed colleague in Japan, Yoshihiro Mano, MD, PhD From this initial gesture, a great friendship that continues today grew between the dive and hyperbaric medical associations of the U S and Japan

“In 1993, Bennett hired me to work in his communications department at DAN Our numbers both member and employee counts swelled over the 15 years I was there I recall a rigorous interview process with the home office staff and then with Bennett at the Duke hyperbaric chamber

“That job was the start of busy, challenging, and happy years at DAN under Bennett’s tutelage, and I recall my time there as some of the most influential days in my professional life I later left DAN to take care of family matters, and when I was ready to resume work,

The first edition of Peter Bennett’s Physiology and Medicine of Diving was published in London in 1969 Two divers go to 1,500 feet during a record deep dive in 1970 at the Royal Navy Physiological Laboratory

I applied to UHMS Bennett had taken charge there, and I once again stepped into the orbit of this great scientist and entrepreneur I’ve never looked back”

Frans Cronje, MBChB(UP), MSc, founder and former president of DAN Southern Africa, recognizes Bennett’s profound lifetime achievements and contributions to dive science.

“Peter Bennett was a remarkable man in every way He described himself as ‘affably belligerent’ While it is certainly true that he did not suffer fools, he nurtured and defended his friends, colleagues, and staff with equal vigour Apart from our professional ties, Peter was always a dear, loyal, and supportive friend He once described me as a ‘catalyst’ a sobriquet I treasure to this day

“Peter richly deserves recognition for the many selfless investments he has made to our scientific discipline, in establishing and leading several organizations (particularly DAN and UHMS), and for his influence on countless lives and careers”

pot” in 1983
The staff at the German Underwater Simulator (GUSI) diving facility pose in front of the large “wet

Over the last decade or more, there has been an enormous increase in efforts to protect the oceans and their inhabitants. We have become more aware of plastic pollution and the gross overfishing of ocean resources worldwide. In South Africa, we now have 42 declared Marine Protected Areas, some of which are as far afield as the Prince Edward Islands in the Southern Ocean. The need to grow our understanding of the ocean's ecosystems and inhabitants has become a priority not only to those passionate marine scientists but, more often, citizen scientists who happen to be spending time in the ocean daily. Yet we still know more about the moon than what's happening in the ocean.

Cape RADD – Cape Research and Diver Development is the brainchild of Mike Barron and Dylan Irion. The company is based on their previous work experiences at other worldwide marine research and conservation organisations As Cape RADD, they wanted to create something with tangible take-home skills and knowledge focussing around early






Cape Marine Research and Diver Development A group of snorkellers preparing to dive for science

career marine scientists looking to gain handson experience and apply their SCUBA diving skills uniquely and purposefully. "We intentionally created a Field course program, a more structured and academically beneficial course rather than a volunteer internship style Which is, perhaps, a little more relaxed and opportunistic in the day-to-day experiences", explained Mike

After 12-18 months of researching the needs, writing course material and location reconnaissance, they based themselves in Simons Town, Cape Town Not only was this a perfect destination for marine research, with a thriving diving community and access to the relatively sheltered and incredibly biodiverse waters of False Bay There seemed to be a gap between a local marine research station and field scientists' training facility

"It was only later that we realised we needed to be better at communicating about the science and the plight of the local marine ecosystems that we decided to start our outreach programs and Eco-tourism focussed experiences", said Mike, "their idea was to educate and inspire the local community and to further promote the area as such a special, vibrant and important area of environmental importance on the international stage as well"

"We wanted to include the community in our work, so we created our snorkel/SCUBA for a science experience whereby recreational divers could get involved and learn about the Kelp forest ecosystem in more detail whilst directly contributing to local marine research and conservation by assisting our team of marine biologists in collecting shark photo ID data" This has turned out to be a flagship project with growing popularity

The goals of Cape RADD are twofold Firstly, it creates a platform for marine research and conservation in the scientific field

By collaborating with local and international scientists, they offer a comprehensive training facility for the next generation of marine field scientists and divers.

The second goal is to create educational materials and experiences to increase awareness and interest of recreational divers in the kelp forest ecosystem "We believe this will inspire and promote protection through community buy-in and local 'ownership' This is done through our scientific communication outreach and eco-tourism program"


Cape RADD has many projects which they are currently working on From gathering data on endemic benthic shark population to monitoring kelp forest health through kelp grazer density and distribution surveys Our general focus is on measuring the biodiversity of the local marine ecosystems and providing baseline monitoring datasets for historical records These will provide a reference point for changing variables over time and space

They also collaborate with various local and international Universities on projects from monitoring microplastic density in False Bay to public perceptions of sharks and the benefits of 'Citizen Science' as contributors to conservation using social science aspects Other projects include shark behaviour and movement, beach profiles, sand erosion/dumping, and macroinvertebrate monitoring surveys


Cape RADD offers different programs that people can get involved with, depending on their level of interest, time and budget The SCUBA or Snorkel for science is a short 2-3 hour program that introduces guests to the

Looking for shysharks in low visibility underwater will require a torch Diving in the Kelp Forest
Diver collecting data in a predetermined area underwater A reef scene in blue Cape water is a rare sight
An octopus caught displaying its full splendour

area as a biodiversity hotspot and their work Participants are explained how they can assist in spotting and identifying endemic shyshark species during the dives, contributing towards the primary dataset for population estimates

They are guided by trained marine biologists who offer insights into the intricacies of the kelp forest and point out things otherwise the untrained eye may not notice All whilst having lots of fun in the water

The Marine Biology Field course offers a more intense program, which is 2-4 weeks of developing new skills and knowledge that give a much deeper insight into field biologists' necessary skills and challenges This involves scientific diving and freediving workshops, measuring biodiversity and GIS mapping lectures, and lots of involvement in other research projects such as kelp density and distribution, fish and shark surveys, and much more. This course focuses on early-career scientists and students or keen conservationists who want to learn more about marine science. The SCUBA diver who wants to use their diving skills to assist with research and build a deeper foundation of understanding of marine ecosystems is more than welcome to sign up for this program as well.

"We also have a hybrid program which offers insight into the marine conservation work with Cape RADD alongside training people to SCUBA dive from open water beginners to professional instructor level with our sister company Impact Divers This is an excellent way to develop your diving skills and certification and gain some insight into the marine conservation side of the industry at the same time", explained Mike


As soon as you take the focus away from just the SCUBA diving and towards other tasks in the water such as sampling, data collection or photography work, it increases the risk of distracting divers from the basic safety precautions

"We must be very aware of this and ensure safety comes first Our team are very experienced in what they do, from in-depth safety and dive objective briefings to wellplanned and executed dive plans and extra eyes in the water", insists Mike He also reiterated that they dive to industry standards and never do dives that guests or students are not qualified to do "We also have DAN cover and well-trained first aid staff should the worst happen"

Looking for shysharks in low visibility underwater will require a torch Diving in the Kelp Forest


Mike Barron is a United Kingdom-born Marine Biologist "I am originally from the UK but haven't lived there for over 12 years I studied at Bangor University in North Wales before heading to Mosselbay to study Great White sharks", said Mike He completed his Master's degree by research through the University of Pretoria, studying White Shark Deterrent Behaviour while based in Mossel Bay He spent a brief 2-year spell working in Australia, on the Great Barrier Reef and the Ningaloo Reef on the West coast, as a marine biologist and Dive guide with Whale Sharks He is also a qualified scuba instructor and commercial diver

Cape urchins underwater




DAN introduced the first standardized emergency oxygen course for divers as lay providers in 1991. More people trained in oxygen delivery means that providers in dive locations worldwide need to have emergency oxygen units available Obtaining oxygen refills, however, is an ongoing problem, because procuring medical-grade oxygen requires a prescription

Oxygen has other dive-related uses Technical and rebreather divers require enriched-gas mixtures up to pure oxygen and often use partial-pressure techniques to make nitrox, heliox, and trimix In some applications, most commonly for commercial divers, surface decompression occurs in a hyperbaric chamber, with the divers breathing pure oxygen to complete their decompression obligation These applications are not medical, but they require pure, breathing-gas-quality oxygen

What is pure oxygen, what is breathing oxygen, and how can you obtain oxygen for nonmedical use? The South African Bureau of Standards

(SABS) in its standard SANS 532-2009 (a new revision is due later this year), provides a specification for oxygen and classifies oxygen in gas form into four grades: medical oxygen, aviation and industrial grades (99 5% pure), and food grade (99 0%) Aviation grade needs to meet the highest specifications of all grades but is also the most expensive due to the analytical requirements

Medical oxygen should only be dispensed by a medical prescription; there is no restriction on aviation grade

The same process produces almost all pure oxygen gas, and the primary differences are simply the requirements for analysis certificates An acceptable, safe and available alternative to medical oxygen is aviation grade oxygen , which is perfectly acceptable for all breathing-oxygen applications, but medical applications administered by or under the supervision of a physician require compliance with the SANS 532 medical oxygen standard

01 Oxygen in gas form is classified into four grades of significantly different levels of purity Only two of these four grades meet the requirements for breathing-gas applications
Photo by Stephen Frink

Some industry gas supply companies will be unwilling to fill your cylinders and offer only the option of renting theirs. While it might seem financially motivated, they might believe they can control their equipment’s cleanliness and might doubt the cleanliness of yours. Compressing oxygen is not without its dangers, some of which are related to contamination inside the cylinder and valve

Purely from a statutory point of view, only aviation oxygen can be used to fill breathing oxygen cylinders, and not the other way around You will need to do your own shopping for prices and availability, but aviation oxygen is the highest quality oxygen for dive-related activities, including technical mixes, emergency oxygen by the layperson, and rebreather cylinder refills

Oxygen is oxygen, and if the purity exceeds 99 percent, it is safe for use where pure oxygen is required The critical consideration is if you need breathing gas, in which case only medical and aviation grades meet our (South African) requirements




Respondtoadiveincidentfasterwith DANemergencyresponsegear.


Gareth Lock - The Human Diver

Bio: Gareth Lock has been involved in highrisk work since 1989. He spent 25 years in the Royal Air Force in various front-line operational, research and development, and systems engineering roles, giving him a unique perspective. In 2005, he started his dive training with GUE and is now an advanced trimix diver (Tech 2) and JJ-CCR Normoxic trimix diver. In 2016, he formed The Human Diver intending to bring his operational, human factors, and systems thinking to dive safety. Since then, he has trained more than 500 people face-to-face around the globe, taught nearly 2,000 people via online programmes, sold more than 4,000 copies of his book Under Pressure: Diving Deeper with Human Factors, and produced "If Only…," a documentary about a fatal dive told through the lens of Human Factors and a Just Culture.

Hearing stories is how we learn. Over the millennia, we have learned to know what is right or wrong, good or bad, or a successful outcome or one of failure, through the telling of stories Good stories tell a narrative, and great stories elicit an emotional response The more emotion we feel, the more 'sticky' the story is to our memory Improving your memory isn't just about recall; it is also about how the memory was encoded, making the information easier to find when needed Finding the lesson of a story at the right time is critical in diving Answering questions during the exam at the end of your diving course is helpful to test recall However, how well does the score on a test correspond to successfully recalling the knowledge when you actually need it?

"We only know what we know when we need to know it " – Dave Snowden

Our knowledge is incredibly contextual, and how and when we use it is triggered by the cues and clues we see, hear, feel, taste and smell Once we have sensed these cues, we match them to previous experiences and execute an action

Sometimes these patterns are not what we expect, and we make a 'bad decision'. We only know whether a decision is flawed by its consequences, making it a bit like writing the test before taking the course. If we 'knew' it was bad, we wouldn't do it. The more experience we have, the more mental models we have, which allows us to make the 'best' decision. We are 'satisficing' – it is good enough for the situation we are in – Captain Sullenberger landing on the Hudson River is a classic example of this, given the limited options and time he had. To learn from an event, we must understand the context; otherwise, our knowledge is essentially a piece of the jigsaw puzzle that doesn't fit.

For example, does it matter that divers follow a guide into a wreck and start to explore it? They know the guide is experienced, has dived these wrecks before, and everything looks OK. There isn't a perceived risk because there is no percolation of rust particles, and the divers have good finning techniques to ensure the silt doesn't get stirred up. But what if this isn't the case?

The environment remains the same, and there still isn't a line laid by the guide so that they can find their way back out, but in this case, the divers kick up the silt, and the visibility is reduced to zero in some places – all unknown to the guide The divers never learnt great siltlimiting finning techniques, as they have no consequence in open water Now, however, they are stuck in a wreck without a line and with zero visibility In hindsight, it is obvious to see the knowledge failure in THAT situation Context is king!

Ultimately, we want to make 'good' decisions –find that part of the wreck or reef we've heard about, or that elusive fish or nudibranch to take a photo of, or explore a new section of a cave Diving involves many variables If everything was guaranteed and certain, it wouldn't be as exciting or enjoyable!

Photo by Jenny Lord

However, uncertainties also mean things may go wrong. Learning from mistakes is a powerful training tool. However, we can't afford to make every possible mistake ourselves – partly because we don't have the time and partly because we might not survive them! Therefore, sharing near-miss stories, i.e., stories with a rich context and vividly depict the events' conditions, increase the likelihood that they will be 'sticky'. Then we can pull the relevant, important information when we need it on a dive. So, while learning from your own mistakes is not without merit, learning from others is much better!

These context-rich stories are sometimes known as 'second stories'. First, stories are told from the perspective of proximal causes; those causes are closest in time and space to the event Still, most adverse events have their genesis further back in time This long gestation period means multiple, different causal roots, all coming together at just the wrong time/space for an incident or accident to happen These second stories explain the conflicts and tensions that exist: time pressures, money pressures, incomplete diver instruction, poorly designed equipment poorly maintained or serviced equ excessive noise, sea-sickness, changes, visibility & current changes these factors provide a context describes the difference between wha happen and what did happen On occasions, some of these conditions w been present There was a su outcome, and as such, we don't recog significance of that information unless an effective post-dive debrief to re what went well and why, what improvement, and how

Apart from individual learning, we ca stories with other divers in the comm agencies like Divers Alert Network, o media like the Human Factors in Di Group, to help others learn. Howe every diver has a learning attitude towards

near-misses and adverse events. Instead of focusing on learning, they focus on blaming and what was done wrong (the first story) without taking the time to understand the second story. The only way we can change this is through role-modelling by leaders in the community. This doesn't have to be done by leaders with a title, but by leaders who are willing to make a change in the industry, who are eager and have the courage to talk about being human, making mistakes, and explaining the context. The explanation is not 'an excuse'. Instead, it is about explaining the 'local rationality' – how it made sense for someone to do what they did at the time, given THEIR knowledge, skills, resources, and constraints. Not those of the observer…the observer's story always seems more evident because the dots can be joined at leisure Still, it is usually incomplete, omits the context and subjective experience of those involved and is therefore frequently biased or unrealistic

Be curious, not judgemental, because if you are, you might discover the story that really happened, not just the one you were told

Gareth Lock - The Human Diver



Yourgatewaytodivesafetyservices&worldwidedive coverageatlowannualrates!




The date was 13 September 2019 For Mirko Locci, a qualified Rescue diver, it was a typical day of diving and helping out at the local dive centre in S’Oru e Mari on the Quatese coast, Sardinia He offered to refill the oxygen cylinders that divers would use with rebreathers (Closed Circuit Rebreathers are mainly used by technical, cave and specialist divers and require special training) He was familiar with the process at the centre and knew the equipment he had to use While filling the last of five of the cylinders, there was a loud and sudden explosion Mirko was engulfed in flames “After the explosion, I thought I had died As I walked out of the building, I looked around and remembered thinking it was okay”, he said The equipment room that housed the compressors or breathing gas filling equipment had remained intact When the bystanders asked if he was all right, he replied: “I’m a little scorched, but I am fine” Little did he know

Air compressors refill cylinders for divers with breathable air, and operators need appropriate training to use the equipment At the time of the explosion, the machines were not being used as the air bank had adequate air to fill the cylinders Mirko used a booster pump, also known as a pressure multiplier, to fill the Oxygen specific cylinders This is used to compress oxygen for special breathing gas for divers using not only normal air, such as with closed circuit rebreathers This piece of equipment failed, resulting in the explosion and subsequent oxygen fire

Mirko suffered first, second and third-degree burns to 40% of his body in the resulting fire Once outside, people rushed to him, and he realised that he needed to cool down his burnt skin He acquired a nearby garden hose, connected it to the water supply, and poured cold water over himself The fire and emergency

Mirko (Left) with American diver Elton Davies on his dives in False Bay Mirko Locci in the hospital a few days after the accident
The day of the burn accident cooling the burns with fresh running waater Healing up after several skin grafts and transplants
In hospital the day after the accident
Back home taking a careful walk doing his exercises

services arrived within minutes, and he was rushed to the nearby hospital After stabilising and assessing his injuries, he was transported to a specialist burns facility He was treated there for the next two months

The worst burns were to his legs and feet, and he needed skin grafts and transplants The transplants were successful, and he returned home after only one and a half months in the hospital Over the next year, he received physiotherapy and had to develop new habits to care for his burnt skin “The transplanted skin is not as elastic as normal skin and requires regular stretching and the regular application of moisturising lotion I was fortunate to have the best medical treatment,” said Mirko

On 22 January 2023, we met Mirko while he was visiting South Africa and joined him on a few fantastic dives in False Bay He is a current DAN Europe member He advises that operators ensure their equipment is in peak condition when providing oxygen fills He also learned that the equipment he used during his accident needed special and regular maintenance

Here the exploded booster pump is visible

A refreshing dip at your local swimming pool can be appealing in the heat of the summer

But the pool is more than just a great place to cool off and socialize - it also offers excellent opportunities to get active and improve your fitness

Many pools offer group fitness activities to help you get your heart pumping Group fitness classes can improve motivation, provide accountability and push participants to a greater level of fitness Plus, group fitness activities are an excellent way to expand your social network Let’s dive deeper into three different group fitness activities that may be available at your local pool


A Masters swim team is a group of adults, 18 years and older, who get together to swim laps

The swimmers’ ability levels range from beginner to elite - the only prerequisite for becoming a Masters swimmer is knowing how to swim



DAN recommends that d vers avoid strenuous exercise for 24 hours after diving This avoids increasing the chances of decompress on sickness During your annual physical exam or following any changes in your health status, consult your physician to ensure you have medical c earance to d ve

Belonging to a Masters team is typically an inexpensive venture. You might pay a drop-in rate or a one-time or monthly fee, either fixed or based on the number of workouts you attend per week

If you want to take your Masters swimming to the next level, Masters competitions are available To find a Masters team in your area, visit usmsorg


When some people hear water aerobics, they think of exercises geared toward a geriatric population But you can find water boot camp classes and underwater cycling at many pools More and more people are realiSing the benefits of aquatic activity benefits divers have known about for quite some time

The foundation of water aerobics’ effectiveness is the fact that water is roughly 800 times denser than air The water’s density creates resistance that works our muscles; meanwhile, the water’s buoyancy helps reduce the impact on the body’s joints

Pools may offer a variety of water aerobics classes; some may be intended for therapeutic purposes, while others might incorporate highintensity interval training (HIIT) Most classes will include exercises designed to elevate your heart rate

Many water aerobics programs involve time in both the shallow and deep ends of the pool Participants in deep-water classes wear a flotation belt to keep them above the surface at all times Shallow-water classes don’t use these belts, as participants are able to stand on the bottom Both deep- and shallow-water classes use an array of equipment, including dumbbells, kickboards, webbed gloves, resistance bands and more

To participate in any type of water aerobics class, you should be comfortable with floating. You don’t necessarily need to know how to swim to participate in water aerobics.

Contact your local pool or visit their website for more information about their water aerobics programs


Take your breath-hold diving skills to the next level by joining your local underwater hockey team

As you might imagine, underwater hockey involves two opposing teams, sticks and a puck It’s played with six players on each team at a time on swimming pool bottoms, typically at 7 to 9 feet deep A 10-foot-wide goal sits on the bottom at each end of the pool Players wear a mask, snorkel and fins as well as a water polo cap, a mouth guard and a protective glove on their striking hand Using curved 10- to 12inch sticks, players endeavour to outscore their opponents by striking the 3-pound rubbercoated puck, attempting to send it into the opposing team’s goal

Since all contact with the puck happens on the pool bottom, players constantly rotate between diving down to play and surfacing to get a breath

Regulation matches feature two short but intense 15-minute halves Matches and tournaments take place all over the US and the world For more information about your local underwater hockey team, visit usauwhorg

No matter what aquatic activities you enjoy, a pool near you likely offers something of interest to you this summer Use your membership not only to get that refreshing splash but also to improve your dive fitness


Advertise In Alert Diver

active divers and travel enthusiasts through DAN’s quarterly publication. Advertising Alert Diver https://www dansa org/alert-diver-advertising



I phoned DAN a couple of weeks ago as I had a general medical concern the day before going for a fun dive I was put in contact with a medical doctor who could assist me in making a well-informed decision relating to the dive the next day Thank you for being there and giving me the needed facts to make the right decisions!



All diving emergencies

Non-diving medical emergencies

Diving medical information, such as fitness to dive, medication, and travel medical advice and enquiries

Travel notifications and advice

Diving medical examiner contact details

International medical centres or doctors who want to confirm DAN memberships


The caller and/or patient’s name and contact number

The nature of the emergency

The patient’s DAN membership number, if applicable or known

The patient’s medical aid information, if the incident occurred within South Africa

The patient’s travel insurance information, if applicable



Is an air ambulance or a helicopter available?



How urgently does the patient need advanced life support and should they be moved to intensive care?



If the caller is not at the scene, at least one local contact number should be provided in order to reach the person that is in need of assistance, or those who are in charge of their care.


DAN makes a conference call to one of the on-call diving medical officers (DMOs) when an emergency call is received and the nature of the event has been established The DMO will provide specialist diving medical advice regarding how and what should be done immediately and will also make decisions concerning the further management of each case, depending on the situation.


Aeromedical resources, such as helicopters and air ambulances, cannot be dispatched unless authorised by the DMO. It may take longer to activate an air ambulance than it would take to mobilise emergency medical services via a ground ambulance Several factors, aside from costs, will determine aeromedical evacuation

What are the optimal logistical considerations for efficiently and safely moving the patient to a place where they can receive medical assessment and appropriate medical care, with appropriate medical support, during the transfer?


Are these appropriate for a helicopter or a fixed-wing air ambulance? Are these open, particularly at night? What are the customs or immigration requirements? What are the implications of getting the patient to the landing zone or airport, or the crew to the patient?

The DAN hotline provides emergency medical assistance to injured divers. We encourage you to call early, even when you are uncertain, rather than wait until the situation has become critical as the opportunity to assist becomes more restricted


Parting Shot

My photos are generally taken in water depths between 2 to 5m to utilise natural lighting I don't use strobes or anything like that My dive buddy Helen Walne - and I am terrible at taking photos of each other. We are not of the women swimming with large mammal types. We are more adventurous snorkelers who potter about in the Kelp. I really like the accessibility of snorkelling One just needs a mask It's so much less intimidating than diving and even freediving It is a great way to get comfortable in the ocean and start freediving The image was taken in the Castle Rock Conservancy, inside one of the Marine Protected Areas in False Bay. I use a Canon R camera with a 16mm lens in an Ikelite housing. – Kerri Muller, Underwater Fine Art Photographer based in Cape Town, South Africa Follow her on Instagram - @kerimuller

Your gateway to dive safety services & worldwide dive coverage.

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Articles inside

Kaboom! The Big Oxygen Safety Issue

pages 138-139, 141-142

The Story We Get Told Vs. What Really Happened

pages 132-134, 136

Do I Need Medical-Grade Oxygen

pages 128-130

The RADD Program

pages 122-124, 126-127

Peter Bennett Reaching Out Award

pages 114, 116, 118-121

Diving Etiquette

pages 102-103, 106-108

The Benefits of Being Bald

pages 96-100

Breathing & Buoyancy Control

pages 90-91, 93-94

Analysing Decompression Sickness Risk

pages 84-87

After The Accident

pages 80-82

Terrific Freedive Mode

pages 74-78

Scuba Cylinder Rundown

pages 70-73

What Dive Computers Don't Know - Part 2

pages 66-69

Decompression, Stage & Bailout Cylinders

pages 54-56

For The Love Of The Sea

pages 44-49

Freediving Instruction

pages 32-35, 38, 40

The Inhaca Ocean Alliance

pages 27-30

Special Forces Diver

pages 23-25

Dive Resort Safety

pages 20-21, 23

Demo Divers

pages 12-15, 17-18

New Annual Diving Report

page 10
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