Alert Diver March 2024

REBREATHERS

PART 1

Editor

DAN Southern Africa

Publisher

DAN Southern Africa

Contributors

Nicolene Olckers, Dennis Guichard, Francois Burman, Georgina Jones, Adam Sokolski, Tim Blömeke, Kyle Kray, Maryka Pace, Mark Powell, Jim Chimiak, Juan ValdiviaValdivia, Madeline Coombs, Frauke Tillmans, Jessica B Adams, Audrey Cudel, Gareth Lock, Guy Thomas, Ken Findlay

Team

Morné Christou, Nicolene Olckers, Dr Frans Cronje

Cover Photograph

By Nicolene Olckers Underwater Photographer Raoul Coscia’s happy face during a dive at Rocky Bank, False Bay It was his first dive after having shoulder surgery The image was made with a Canon EOS 5D MKIV fitted with a Canon 1635mm lens set at 16mm The camera was housed in an Ikelite 200DL housing with an 8-inch dome port and two DS 160 strobes Settings: ISO 200, 16-35mm@16mm, F71, 1/160sec, Manual mode

Contact

Website www dansa org

Advertising mail@dansorg

General mail@dansaorg

Phone +27-11-266-4900

Diving Emergencies +27-82-810-6010

@dansouthernafrica @divesafety /DANSAorg

Alert Diver Philosophy

Theviewsexpressedbycontributorsarenotnecessarilythoseadvocatedbythe publisherorDANSouthernAfrica Whileeveryeffortismadetoensurethe accuracyofinformationandreports,thepublisherandDANSouthernAfricado notacceptanyresponsibilitywhatsoeverforanyerrors,omissions,oranyeffects resultingtherefrom TothebestofthepublisherandDANSouthernAfrica’s knowledge,contributorshavenotindulgedinplagiarism Althoughtheutmostis donetoavoidsuchoccurrences,thepublisherandDANSouthernAfricawillnot beheldresponsibleforthecontributors’orwriters’indulgenceinplagiarism No partofthispublicationmaybeusedorreproducedinanyformwithoutthe writtenpermissionofDANSouthernAfrica E&OE

@dan sa org

ProsChooseDAN

TrustedWhenItMattersMost

Maurtius Valente Bell, Dive Safety Officer, California Academy of Sciences, explains why he chooses DAN.

DIVE INSTRUCTORS

DIVE SLATE | PERSPECTIVES

TEXT BY MORNÉ CHRISTOU

THE SIGNIFICANCE OF SKILLED EDUCATORS OF DIVERS CAN NOT BE OVERSTATED. Upon reading this issue of Alert Diver, you will come across several stories that emphasize the significant and lasting value of Skilled Educators of Divers (SEoD). For example, one instructor's teachings on safe diving practices proved life-saving for their students years later Another SEoD offered guidance and support to a new diver who had a negative experience, ultimately preventing them from giving up on the sport entirely

SEoDs serve as positive examples, displaying a suitable level of assurance and motivation They possess a keen sense of responsibility As such, rather than being careless or indifferent, they adapt thoughtfully and deliberately to the unique requirements of their students and surroundings Every dive is considered as a distinct event Thereby, they identify potentially risky circumstances and offer aid pre-emptively to their divers rather than waiting to react to mishaps

SEoDs engage in purposeful behaviour, understanding the impact this may have on others' perceptions of divers and diving as a whole They are conscientious of the importance of self-discipline and adherence to rules and protocols while also being cognisant of potential hazards and how to prevent them

It is imperative for an instructor to understand that every diver has the potential to promote a culture of safety while diving. The time spent with a SEoD can significantly impact one's attitude towards safety. At DAN, we have long acknowledged the importance of capable instructors who strongly emphasise safety in their students. That is why we continuously strive to provide various programs, tools, and resources to empower SEoDs in their roles.

THE IMPORTANCE OF EMERGENCY OXYGEN

Per our stated purpose, DAN remains dedicated to promoting safe diving by providing education This includes offering first aid, safety, and medical training to divers, dive professionals, and health care providers In fact, at the DEMA Show in 1991, DAN unveiled the first universal oxygen first aid program to ensure that oxygen and trained personnel are readily available on all dive boats and sites It is, therefore, a critical step for every dive instructor to obtain certification in emergency oxygen administration as well as the qualification to teach it to their students

Dive professionals serve as the backbone of dive safety They are the initial promoters and essential contributors towards achieving this goal While DAN is readily available to assist with making transport arrangements for an injured diver or cover the expenses of hyperbaric treatment, the provision of emergency oxygen is a crucial first aid intervention in ensuring prompt and necessary care for any injured divers

In our ongoing pursuit of this vision, we provide the diving community with affordable, dependable and user-friendly oxygen kits for sale

THE IMPORTANCE OF DAN’s STUDENT MEMBERSHIP PROGRAM

Many qualified divers may be familiar with DAN’s dive accident membership benefits However, it is especially important for diving students to know that DAN offers student dive accident membership benefits at no cost to students and instructors. This coverage is specifically designed for entrylevel training and can protect against injuries that may occur during instruction. As such, dive instructors are strongly encouraged to take advantage of this complimentary program for their students' safety.

In the event of dive-related injuries, it is crucial for the injured diver to have immediate access to proper medical care DAN facilitates access and cover for divingrelated accidents and injuries, including transport, the assistance of specialised doctors and hyperbaric chamber treatments Depending on the severity and location of the injury, the financial burden of a diving accident can be catastrophic To address this, DAN provides dive accident membership benefits to prevent this

As an advocate for dive safety, DAN recognises the significance of providing membership benefits for diving accidents as a vital outreach to the renewing recreational

diving community If you are a dive professional, enrolling your students in this program provides both them and you with valuable peace of mind while reducing your liability

THE IMPORTANCE OF EMERGENCY PLANNING

Students should rely on a competent instructor to prioritise safe diving protocols Throughout their training, whether at an entry-level or advanced stage, students should be reminded consistently to maintain their proficiency and have a wellprepared emergency plan in place

We urge dive professionals to advise their students that they can easily access an expert in dive medicine in an emergency by simply making a phone call Additionally, we highly recommend that the DAN emergency hotline be included in all discussions about emergency planning, particularly when diving in remote locations.

PROPONENTS OF SAFETY

Ensuring safety is of the utmost importance when diving Promoting and supporting DAN contributes significantly to the overall safety of divers When DAN Southern Africa first emerged as a membership organisation in 1997, many of its current benefits were not available Thanks to our members standing behind us has allowed the benefits to expand just because our members shared the belief in DAN's mission of promoting and preserving diver safety

Even before we could offer emergency oxygen training, remote evacuation assistance, and dive accident membership benefits, DAN provided an avenue for divers to contribute to a worthy cause that would soon have a significant and lasting impact on dive safety Our commitment to diving safety continues unabated Your support provides for its benefit, and we thank you all for this.

A READER RECENTLY BROUGHT TO OUR attention that multiple Alert Diver contributors credited a dive instructor with providing training that saved their lives over the years Upon researching this connection, we discovered a previously unrecognised factor in the career development of many dive industry leaders and scuba pioneers, including a DAN Rolex Diver of the Year, a Women Divers Hall of Fame member, accomplished underwater scientists and researchers, cave explorers, public safety divers, Navy SEALs, service members across the U.S. armed forces, and dive team members in three-letter government agencies. In speaking with divers from each of these esteemed groups, we confirmed one thing they all had in common: Larry Brown was their scuba instructor.

|

© JOHN

| © JOHN

LARRY BROWN SMILE AND BE HAPPY

DIVE SLATE

TEXT BY KYLE KRAY

Hometown: Perry, Florida Age: 75

Years Diving: 62

Why I’m a DAN Member: DAN’s oxygen and CPR courses for dive emergencies, decompression theory seminars, and accident and fatality information provide tremendous educational value to students and instructors

LARRY BROWN SHARES A LIGHTHEARTED MOMENT WITH STUDENTS DURING CLASS IN 1982

LARRY BROWN SHARES A LIGHTHEARTED MOMENT WITH STUDENTS DURING CLASS IN 1982

ROTTET/TECHNICIAN

ROTTET/TECHNICIAN

STUDENTS PRACTICE BUDDY BREATHING AND EQUIPMENT EXCHANGE WHILE MAINTAINING FORWARD MOTION AND TRIM | MAINTAINING FORWARD MOTION AND TRIM | © JOHN ROTTET/TECHNICIAN © JOHN ROTTET/TECHNICIAN

STUDENTS PRACTICE BUDDY BREATHING AND EQUIPMENT EXCHANGE WHILE

Why did you become a dive instructor, and where did you teach?

Diving was always a spiritual experience for me that I wanted to share with others When I was 17 I told my father I wanted to be a teacher Dad only had a 10th-grade education, but he taught me more about education than anyone He said to me, “Larry, if you can’t love every student like they’re your own kid, no matter how big of a jackass they are, you’ve got no business teaching” It inspired me

After separation from the Navy in 1971, I enrolled at Bringham Young University and taught scuba as a part-time faculty member I started teaching as a sophomore and continued while completing my undergraduate and graduate degrees After I moved back to the East Coast to be closer to my parents, I started teaching scuba at North Carolina State University in 1976 and taught there full-time until I began phased retirement in 2019.

Why are so many of your students successful in the dive industry?

Each student decides for themselves what they want to become. It is something that is already growing inside them that I cannot take credit for. My job was to ensure that my volunteer assistants and I nourished that seed The strength of the North Carolina State Scuba Program has always been our volunteer assistants, both current and former students, who return to assist with the next class of divers Our volunteers have always been givers, not takers they are the stick that churns the butter If anyone is responsible for the success of a student who went through the program while I was teaching, it’s them There have been hundreds of volunteers over the decades to whom I am deeply indebted, and I love them as if they were my own children

All the divers we talked to said your scuba classes were some of the most rigorous dive instruction they had ever received.

They also said it was the most rewarding and that what you taught was applicable in life and diving. Achieving high standards gives students lifelong confidence and helps them learn they can do more than they thought possible If you don’t have high standards for your students or you ask for less than their best, you rob them of reaching their full potential Education often suffers because we water down things for the weakest students instead of taking the time and making the effort to bring them up to a higher level Students need the selfsatisfaction of earning and learning what they can achieve

Life, like diving, is about learning how to thrive under pressure and developing an attitude of gratitude smiling and being happy regardless of the circumstances Adversity can help us learn things that we may not learn otherwise It is important to learn that no matter how stressed we get, we can train our minds to be slow and relaxed, use good technique, and, therefore, be able to handle most hardships.

What was one of the best teaching tools you implemented during your 50 years of instruction?

I realised early on that explaining and then demonstrating a skill was insufficient for students to understand how to perform it fully, so I started demonstrating skills on 8mm film as a visual aid

My assistants and I eventually started using TiVo to record students performing a skill and then would compare that with a video of my demonstration as the model With instructor assistance, this technique allowed students to receive immediate feedback on their skills It also allowed them to visualise and self-critique their performance two critical elements in skills development and implementation

What is the best advice you can give to any diver?

Many divers feel the need to be guided instead of achieving the knowledge and skills necessary to dive and explore the underwater world safely Don’t be too trusting of others, including me, and be willing to question any information, standards, training procedures, skills, or research.

Don’t automatically assume that the way you’re doing things is the best and safest way just because someone you hold in high esteem believes that it is. Try to critique and evaluate ideas and concepts for yourself to ensure they represent the best and safest way If they don’t, then have the courage to go through appropriate channels and make changes

SCUBANAUTS

DIVE SLATE

DEVELOPING THE NEXT GENERATION OF SCIENTIFIC DIVERS

TEXT BY KYLE KRAY | PHOTOS BY STEPHEN FRINK

FOR OVER 20 YEARS, the nonprofit marine science education program known as SCUBAnauts International (SNI) has introduced young people ages 12 to 18 to informal science education through underwater exploration. While many youth organisations exist in the dive industry, this group’s scientific rather than recreational nature and strong diving safety foundation give SNI a unique identity

With a focus on marine research and undersea conservation projects, full-fledged members known as Nauts can positively impact the environment with hands-on experience while active citizenship and community service empower them to become future leaders

Nauts follow an exciting pathway of personal development, learning team-building skills and the importance of leadership through participation in real-world underwater marine research activities with institutions such as NASA and the Mote Marine

Laboratory. Scientists guide all SNI missions and provide training for mission success.

Through research diving and one-on-one interaction with mentors, Nauts master the dive skills necessary to be safe in the water. They foster their passion for the undersea world with knowledge and experiences that will stay with them for the rest of their lives.

SAFETY IS PRIORITY

Since its inception, SNI’s focus has been to provide youth with a safe learning environment, so leaders spend a lot of time teaching them safe dive techniques All the physical dynamics involved in safe scuba diving must become second nature for Nauts to use scientific tools underwater while observing and recording data without becoming task-loaded

To qualify as American Academy of Underwater Sciences (AAUS) scientific divers, all members participate in rigorous training upon first joining They must also

renew their status each year through participation in a swim test, scuba skills and diver rescue evaluations, and CPR and diving first aid training

“At the start of 2023, we trained 51 teens and their parents through the full DAN Diving First Aid for Professional Divers course,” said Katie Cooper, SNI’s chief operating officer and dive safety officer “Another 32 participated in our off-year challenge, where we asked them to complete hands-on practice of key skills while their formal certification is still valid This training is one of the first requirements for new families with our organisation, and each year it sets the stage for the safety culture of our organisation.”

In addition to required safety qualifications and ongoing skills training, SNI has its own dive control board. Volunteer dive safety experts from government, educational, and private agencies and institutions constitute the board, which ensures that all Naut dive missions comply with AAUS research dive standards and practices

Becoming a scientific diver takes dedication, but the positive impact on young divers’ personal character development is worth the time and effort The critical thinking skills and emergency first aid techniques they learn in adolescence follow them into adulthood and wherever their dive careers take them Many Nauts plan to study marine sciences

or dive research and receive scholarships for college tuition or internship programs from SNI’s partner scientific organisations

“About 70 percent of our alumni pursue careers in a STEM [science, technology, engineering, and mathematics] field, and 60 percent report they are still active divers after graduating the program,” Cooper said

“Many of them earn advanced, nitrox, and rescue diver certifications through their tenure in the program, and they often graduate high school with more than 100 lifetime dives”

GETTING STARTED

To get started, all youth need is an interest in the ocean, diving, passion, and a willingness to participate actively. Local or regional meetings are held monthly and open to visitors. A parent or adult accompanies every Naut in the classroom and while diving, allowing them to strengthen their relationships by connecting over a shared interest and experience

SNI continues to increase opportunities for young explorers and future leaders in the dive industry by establishing new chapters nationally and internationally If there is no SCUBAnauts gathering in your area, email NewChapter@SCUBAnautsIntlorg for more information about the safety and certification requirements for establishing your local chapter

ProsChooseDAN

TrustedWhenItMattersMost

Michael AW, Underwater Photographer, Director, Board Member, Ocean Geographic, explains why he chooses DAN.

WITH WILDFIRES RAGING IN CANADA, ITALY, GREECE, THE US, and elsewhere, divers and dive operators have called DAN Medical Services and DAN Safety Services with concerns about whether the smoke from wildfires may contaminate breathing gas

When similar concerns were raised in 2018, DAN sent a team to investigate the impact on air quality in and around 17 dive shops ranging from San Diego, California, to Eugene, Oregon, all exposed to wildfire smoke. The findings did not identify any apparent increased risk to divers.

Analyzing both environmental air and compressed air, DAN’s team measured concentrations of carbon monoxide (CO), carbon dioxide (CO2), and particulate matter in the air near the dive shops and the fires and in recently filled scuba cylinders

WILDFIRES AND BREATHING-GAS CONTAMINATION

What the team found was reassuring: When analysing the air outside, even when smoke was present and particulate levels were unacceptably high, the handheld monitor did not show elevated environmental levels of CO or CO2

Next, the team evaluated cylinders In most cases they found that dive store owners were using filters that included a catalyst called hopcalite, which causes CO to convert to CO2 in the presence of gases containing oxygen (such as air) As an additional safeguard, these owners were not filling cylinders on extremely smoky days Some operators filled their storage banks on clear days to continue filling cylinders even when the air quality index was unacceptably high Most of the dive operators had adapted their practices to ensure safe air and safe diving for their clients, and their level of safety awareness is commendable

In conclusion, visible smoke in surrounding areas, even when the human nose can detect it, should not compromise air quality in scuba cylinders Dive operators should appropriately maintain their compressor and filtration systems, utilise filters fitted with CO removal agents, preferably draw air from inside their buildings, and heed basic safety practices regarding nearby fires

Concerned divers should ask the fill station if it uses CO removal agents, and they can smell their air before diving to ensure there is no residual particulate matter.

DAN EMERGENCY HOTLINE

DIVE SLATE | TRAVEL SMARTER

WHEN YOU NEED IT MOST, DAN will be here to help. We coordinate emergency evacuations and cover the costs for our members up to R900,000 per person. Every DAN member is entitled to these emergency services and travel, medical, legal, and personal assistance.

When you travel more than 100 kilometres from home and need assistance whether it helps with a prescription, translation services, or a medical evacuation, all you must do is call the DAN Emergency Hotline at +27-82-810-6010 We’ll arrange the help you need

For a life-threatening emergency, first, contact local emergency medical services (EMS) or get the injured person to the nearest medical facility Ensuring the person is stable and a medical professional assesses their condition is critical After contacting EMS, call DAN at +27-82-810-6010 for additional assistance or a consultation with the local medical provider

When you call the DAN Emergency Hotline, you will be asked for your name, location, and callback number. If you are a DAN member, please also provide your DAN member number. DAN medics may make an immediate recommendation or ask to call you back after making arrangements. They may reach out to their provider network for the best possible assistance.

If the call drops, we will immediately call you back at the phone number you provided If you don’t hear from us in minutes, try calling back

The DAN Emergency Hotline receives thousands of calls per year DAN medics are on call 24 hours a day, 365 days a year, to assist divers and medical personnel in managing dive emergencies These dedicated medical professionals answer the call no matter where they are or what they are doing

ProsChooseDAN

TrustedWhenItMattersMost

Stephen Frink, Underwater Photographer President, Waterhouse Tours, Publisher, Alert Diver® Magazine, explains why he chooses DAN.

DIVERS ALERT NETWORK has published a reference document to promote medical fitness to dive throughout divers’ lives Intended to be used by divers, dive professionals, and doctors, the document establishes a schedule for medical questionnaires and physical evaluations based on age and other relevant factors The information is presented in table and flowchart format for quick reference and ease of use.

Everyone’s health status changes over time. DAN collects an enormous amount of data on who gets hurt while diving, and the schedule leverages that data to reduce the number of preventable injuries and deaths that befall divers every year.

Take the initiative to dive safely for as long as possible by exploring this resource at https://wwwdansaorg/blog/2021/04/14/guid elines-for-lifelong-medical-fitness-to-dive

GUIDELINES

THEBOSSOFWRECKDIVING

LOCAL DIVING

THE BOSS OF WRECK DIVING IN CAPE TOWN

TEXT&PHOTOSBYNICOLENEOLCKERS

PHOTO BY: NICOLENE OLCKERS

PHOTO BY: NICOLENE OLCKERS

Diving on sites around the Cape Peninsula and False Bay in South Africa, the chances of diving on a sunken wreck are unique and often very adventurous. Several wrecks, such as the ones in Smitswinkel Bay, were scuttled (purposely sunk) as underwater artificial reefs. Others became sunken treasure and shored wreckage because of big, rough seas and sometimes hard-hitting storms along the coastline The harsh rocky coastline and merciless Cape storms have claimed several ships and lives in Duiker Point

THE DIVE SITE

Although intrepid hikers often explore the visible wreckage by hiking the trails from Llandudno or Hout Bay, divers who wish to explore the wrecks underwater should and can only access it by boat The hiking trail entails some severe bouldering and rock hopping A study of the tide tables is advised, and those brave enough should remember to carry enough drinking water in extreme heat It is also important to note

that the dive site has been situated within the Table Mountain National Park Marine Protected Area since 2004, and a permit to dive here is required by law.

The Bos400 and SS Oakburn wrecks lie in 22-25meter deep water on a rocky reef in the Karbonkelberg area between Hout Bay and Llandudno, in the western cape, South Africa The interesting fact about the site is that the BOS lies almost on top of the Oakburn

The SS Oakburn was a British steamer sailing from New York to Sydney Despite sounding its foghorn repeatedly, it ran hard aground in dense fog on May 27, 1906 The force of the impact was significant, and the ship began to break up immediately The cargo of railway tracks, sewing machines, musical instruments, glassware, oil and paper were scattered along the shore Although most of the crew and passengers were rescued, tragically, two lives were lost in the event

PARTS OF THE GIGANTIC STURCTURES OF THE BOSS400 .PHOTO BY: NICOLENE OLCKERS

PARTS OF THE GIGANTIC STURCTURES OF THE BOSS400 .PHOTO BY: NICOLENE OLCKERS

On 27 June 1994, the Russian tugboat Tigr towed the BOS400 to Europe when the tow rope broke. The gale force of North Westerly wind and rough sea pushed the BOS to shore, and it washed up on the rocks of Duiker Point. Despite several attempts by Tigr and her crew to refloat the huge crane barge, it remained grounded. Over time, the wreckage broke up and sank into the water. Most of the wreckage is scattered underwater down a slope to 20m, where the steel mingles with the wood wreck and cargo of the Oakburn

PLANNING YOUR DIVE

The best time of year to get in at this dive site is during the summer months from November through February This time of year offers the best visibility, often exceeding 20 meters of clear blue water Despite the tropical-looking water, temperatures will plummet as low as 7 degrees Celsius Adequate insulation, such as a dry suit or a double-layer wetsuit, should keep most divers relatively warm for the duration of the

dive Gloves and a hood are recommended

This site is excellent for adventurers with diverse diving experiences, from free divers to advanced scuba enthusiasts. The depth range and sometimes calm conditions are ideal for introductory to advanced wreck dives, including wreck penetration.

Divers can access the cavernous stern section of the BOS relatively quickly, and some of the steel superstructure underwater makes for exciting images

FAUNA AND FLORA

During a recent dive, the team encountered vibrant marine life As nature slowly claims the artificial structures, it has become home to hundreds of West Coast rock lobsters and gently swaying Kelp taking hold on the outer plates The kelp provides a haven for juvenile fish and the occasional playful seal At the same time, dark shy sharks, colourful rock suckers and brown crabs can also be seen amongst the flowing kelp fronds

FROM INSIDE THE WRECK PHOTO : NICOLENE OLCKERS

FROM INSIDE THE WRECK PHOTO : NICOLENE OLCKERS

SOUTHERNAFRICANSEASLUGS

LOCAL DIVING

A COMPREHENSIVE GUIDE AUTHORED BY THE WORLD EXPERT IN THE FIELD

TEXTBYGEORGINAJONES

AAWHITE-FRONTEDRAINBOWDORIDGONIOBRANCHUSSP2 WHITE-FRONTEDRAINBOWDORIDGONIOBRANCHUSSP2 PPHOTO:DUNCANPRITCHARD HOTO:DUNCANPRITCHARD

PHOTO: TIM BOETIGGER

PHOTO: TIM BOETIGGER

The story of the making of ‘Southern African Sea Slugs’ began in a California rockpool when Terry Gosliner, then 15, saw his first nudibranch. He was hooked and set out on a career in invertebrate zoology, particularly sea slugs. So dedicated has he been that he has, out of the around 3,000 scientifically described sea slug species globally, himself described 1,000 species. His first post was as head of malacology (the study of snails and slugs) at Iziko (then the South African Museum) in Cape Town, and his first published book, in 1987, was a field guide to the sea slugs of Southern Africa

Fast forward to 2018, when a project called SeaKeys was underway It aimed to unlock a basic biological understanding of South African marine species, and part of that included getting world experts to come out to South Africa and help identify species and share their knowledge with locals Terry was, of course, asked to give a nudibranch workshop His plan for the workshop was to invite area specialists, whether divers,

underwater photographers, or academics, from around the region. At the end of the seminar, he explained that he wanted to use all the group's observations of the size and behaviour of the sea slug species in their areas to produce an update of his 1987 book.

This approach to making a field guide makes its contents much more wideranging and considerably more accurate, particularly in terms of distribution, than a guide produced by the observations of only a few people

And so the data collection began It involved the observations of 80 photographers and thousands of photographs, all of which had to be identified, arranged into species, and then described It was a rather major undertaking

The guide includes all 868 sea slugs from around southern Africa Several neverbefore-known species are shown, along with previously unknown egg ribbons (sea slugs

AN UNUSUAL COLOUR VARIANT OF AN UNUSUAL COLOUR VARIANT OF THE SPECTACLED RAINBOW DORID, THE SPECTACLED RAINBOW DORID, GONIOBRANCHUS ANNULATUS. GONIOBRANCHUS ANNULATUS.

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With 26 main authors and contributions from many other divers and photographers, this is the definitive guide to sea slugs for the Southern African coastline, includes all species known from the temperate, storm-lashed waters in the west, to the warm, tropical coral reefs in the east.

produce species-specific egg ribbons that can be useful in distinguishing between species). One species, photographed by a volunteer at the Two Oceans Aquarium, had not been seen since it was scientifically described in 1927. Other more unfortunate observations provided evidence of what eats nudibranchs: they were photographed being eaten by sea spiders, other sea slugs and an anemone Dedicated beachcombers and rock poolers, particularly in the Eastern Cape, provided observations of range extensions The guide has been formatted with ease of identification in mind: the inside front cover has a series of line drawings showing different body shapes with relevant page numbers The whole book is colourcoded according to which group of sea slugs is being covered, the colours coming from an evolutionary schematic that shows the relationships between the groups As well as nudibranchs, the groups include bubble snails, sidegill slugs, umbrella snails, sea hares, sea butterflies and sea angels, headshield slugs, sap-sucking slugs and

air-breathing sea slugs. A motley crew! But in the guide, each group has been assigned a colour marked on the header and down the side of each page, making it easy to find a particular group. Within the nudibranchs, the biggest group, there are also colour codes for each biological family.

Each major group begins with an overall description of the group characteristics, and each species is listed with a quick-find distribution icon showing which coast it has been seen on -- blue for the West Coast, green for the South and red for the warmer East Coast The depth of the icon colour indicates the depth at which the species has been seen

Since the guide, though written using current academic classification, is intended for recreational users, each species has been given a common name In some cases, the names existed; in others, they were formulated according to species diagnostics The scientific name is shown alongside the

THE FIRST KNOWN OBSERVATION OF EGG-LAYING IN THE ELONGATED THE FIRST KNOWN OBSERVATION OF EGG-LAYING IN THE ELONGATED PANTECHNICON DORID (CERATOSOMA TENUE). PHOTO: SARAH KEYSER PANTECHNICON DORID (CERATOSOMA TENUE). PHOTO: SARAH KEYSER

common name for scientific use and ease of comparison with other guides

Images for each species show as many variants as are known for the species from the region In cases where the photos submitted were too problematic to be printed, they have been reproduced in watercolour Where known, the guide details what environment the animals prefer, what they eat, what eats them and what their egg ribbons look like

There's also a section at the end of the book for egg ribbons, arranged by egg ribbon shape In the species descriptions, a final entry details anything of interest about the species that may be known: who the species was named for or what it is called in texts and any other snippets

Perhaps it will inspire a new generation of rock poolers and underwater enthusiasts to discover more about these fascinating animals

IN THE PHOTO BELOW ARE THE WORKSHOP PARTICIPANTS WHERE THE IDEA FOR THE BOOK BEGAN

Back Row Left-Right: Peter Southwood, Brian Sellick, Colin Ogden, Bill Liltved, Guido Zsilavecz, Terry Gosliner, Carel van der Colff

Front row Left-Right: Jessica Toms, Jenny Strömvoll, Kate Jonker, Maddy Ogden, Georgina Jones, Evania Snyman, Valda Fraser

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y a e s da So o s , a d ou d e to te you about my favourite diving spots in Zanzibar. I am a diving instructor and underwater photographer specialising in macro photography. Over the last 15 years, I have done over 2000 dives in Zanzibar The choice of dive sites below is my subjective selection based on what I like the most: lots of macro life, easy but exciting dives, and good places for underwater photography.

A Few Words of Introduction Zanzibar, an island off the coast of Tanzania, is known not only for its beautiful beaches and rich cultural heritage but also for its fascinating underwater world that stretches beneath the surface of the water. The waters of Zanzibar are rich in colourful coral reefs, a variety of fish species, and abundant macro life.

Zanzibar offers many diving spots accessible to divers of all levels of experience. The best dive sites are in the north, around Nungwi, and in the northeast, near Mnemba Atoll, a protected area and the most renowned place for diving and snorkelling.

TRUMPET FISH AT MNEMBA

TRUMPET FISH AT MNEMBA

MORAY EEL INSIDE THE PLATE CORAL OF KICHAFI REEF

MORAY EEL INSIDE THE PLATE CORAL OF KICHAFI REEF

TUMBATU ISLAND (NUNGWI)

A long reef with beautiful, healthy, hard and soft corals There is a lot of macro life: nudibranchs, shrimps, eels and crabs The dives are shallow and easy It is an excellent spot for underwater photographers I found there, among many others, a beautiful Cyerce Nigra sea slug, something I thought was only possible in the Philippines There are a few dive sites at Tumbatu Island but my favourite is MWANA WA MWANA

SHANES REEF (NUNGWI)

Pieces of reef scattered on the sandy bottom The corals may not be the most beautiful, but the site contains fascinating creatures: Rhinopias, seahorses, frogfish, nudibranchs, octopuses, etc It's a very cool spot for all divers Occasionally, there may be a current that makes photography challenging

KICHAFI (NUNGWI)

A beautiful reef with healthy hard and soft corals There are moray eels and nudibranchs that pose beautifully for the photos The reef consists of two parts: the first is an extensive section of plate coral, and after crossing over the sand, you reach the second part, a gently sloping reef At the beginning of the second part, a large rock provides shelter for a school of glass fish, leaf fish and moray eels

KICHWANI (MNEMBA ATOLL)

A moderately steep reef with soft and hard corals. The place is, unfortunately, quite crowded, but it is my favourite Mnemba dive site for underwater photography. You can find a lot of macro life, like nudibranchs, moray eels, leaf fish, and shrimps, including Mantis Shrimps. Not long ago, we found a beautiful Bornella anguilla slug that looks a bit like a dragon.

SANDBANKS (MNEMBA ATOLL)

Gently sloping reef with many soft and hard corals. Large schools of fish are often encountered a pleasant and beautiful spot for relaxing dives. There is a big chance to find a giant frogfish

SMALL WALL (MNEMBA ATOLL)

As the name suggests, it's a wall neither too big nor too small It is a good place for a deep dive as the wall goes down to about 30 meters You can encounter big schools of fish, especially when there's a current On the reef you can also find a lot of nudibranch, leaf fish and moray eels

PIPIEFISH HIDING IN THE SOFT CORAL. PHOTO TAKEN ON SHANES REEF IN NUNGWI.

PIPIEFISH HIDING IN THE SOFT CORAL. PHOTO TAKEN ON SHANES REEF IN NUNGWI.

CYERCE NIGRA SEA SLUG. ONE OF THE MOST BEAUTIFIL CREATURES. PHOTO TAKEN AT TUMBATU ISLAND

CYERCE NIGRA SEA SLUG. ONE OF THE MOST BEAUTIFIL CREATURES. PHOTO TAKEN AT TUMBATU ISLAND

SCHOOL OF BUTTERFLY FISH AT KICHWANI AT MNEMBA

SCHOOL OF BUTTERFLY FISH AT KICHWANI AT MNEMBA

Whether you are a novice or an experienced diver, Zanzibar's underwater world offers something for everyone. From colourful coral gardens to encounters with fascinating marine life, the island invites divers to explore the magic beneath the surface and return with beautiful memories.

PART 2

GEAR|TEXTBYMARYKAPACE|DIVEACTIONCAPETOWN

Welcome to part 2 of Underwater Photography

Choose Your Weapon! Choosing the right camera for your underwater photographic and filming needs can be daunting when you aren’t sure what camera will best suit you and your needs. Part 2 of this article will discuss DSLR & Cinema cameras and give examples of each.

Cameras DSLR

DSLR cameras are mainly used by intermediate to advanced photographers; however, if you are a beginner, don’t let that scare you off; you will never know if it works for you unless you try The acronym DSLR means ‘digital single-lens reflex camera’ This type of camera uses mirrors and prisms to create an optical viewfinder, unlike mirrorless cameras with an electronic viewfinder With a mirrorless camera, the light moves in a ‘straight’ line from the lens to the image sensor Once the information from the image sensor has been processed, it will be displayed on a small screen, the EVF (electronic viewfinder) With DSLR cameras, the light enters the lens and moves straight until it reaches the primary reflex mirror It is then directed up and around, ending at both the image sensor and the optical viewfinder simultaneously Due to the bigger sensors being used in DSLR cameras, they can produce sharper and clearer images with better resolution

Look at the Nikon D7200 (see photos above and below) Although an older model, it still performs amazingly well in low light The Nikon D7200 boasts a 242MP APS-C CMOS Sensor, 51 autofocus points, 1080p/60p & 1080p/24p, and 1110 shots of battery life

NIKOND7200CAMERA

PROS & CONS OF MIRRORLESS CAMERAS

Pros: Interchangeable lenses, excellent battery life, great in low light

Cons: Big and heavy, older technology

NAUTICAMNA-D7200HOUSINGFORTHENIKOND7200CAMERA

THE PHOTO ABOVE WAS TAKEN OF AN AMERICAN CROCODILE WITH A NIKON D7200 CAMERA

THE PHOTO ABOVE WAS TAKEN OF AN AMERICAN CROCODILE WITH A NIKON D7200 CAMERA

WITH A TOKINA 10-17MM FISHEYE LENS IN A NAUTICAM HOUSING | HILMAR LÜCKHOFF

WITH A TOKINA 10-17MM FISHEYE LENS IN A NAUTICAM HOUSING | HILMAR LÜCKHOFF

THE PHOTO ABOVE WAS TAKEN OF ORIENTAL SWEETLIPS FISH WITH A NIKON D7200 CAMERA

THE PHOTO ABOVE WAS TAKEN OF ORIENTAL SWEETLIPS FISH WITH A NIKON D7200 CAMERA WITH A TOKINA 10-17MM FISHEYE LENS IN A NAUTICAM HOUSING | HILMAR LÜCKHOFF WITH A TOKINA 10-17MM FISHEYE LENS A NAUTICAM HOUSING | HILMAR LÜCKHOFF

BioHilmar Lückhoff

My diving experience started 25 years ago and exposed me quite early to the wonders of the Red Sea, gradually expanding to Southeast Asia and accelerating at a stunning rate when DSLR cameras became the norm in underwater photography An Olympus in an Ikelite housing and strobes was my first proper camera gear with a steep learning curve, leading to the Nikon 7100 and now D7200 in a Nauticam housing, which I have no wish to alter Over the past ten years, it has become a passion of mine, taking me, amongst others, to the spectacular wide-angle opportunities of Raja Ampat and the exciting macro sphere of muck diving in Lembeh My latest thrill was blackwater diving in Anilao, the nudibranch capital, which was challenging and intoxicating I enjoy visualising the scenes again during editing, and the knowledge gained in identifying reef creatures, constantly amazed at the incredible biodiversity of our underwater world The artistry of underwater photography is certainly addictive, but I equally enjoy trails and trekking with a camera on my chest When at home, I find myself trying to master a bonsai collection I shoot with a Nikon D7200, Tokina 10-17mm fisheye lens, Nikon 105mm macro, Nikon 60mm macro for blackwater, and +7 Diopter for supermacro in a Nauticam housing with float arms for slightly negative buoyancy. Inon Z240 strobes and Backscatter Mini Flash 2 + optical snoot as strobes and snooting device. A 45-degree standard viewfinder, almost essential for macro photography.

HILMAR LÜCKHOFF DIVING WITH HIS NAUTICAM NA-D7200 CAMERA SYSTEM

HILMAR LÜCKHOFF DIVING WITH HIS NAUTICAM NA-D7200 CAMERA SYSTEM

Cameras Cinema

Here, we enter the world of professional cinematographers The first camera that springs to mind is the RED DSMC 1/2/3 (Digital Stills and Motion Capture) range of cinema cameras These cameras are modular cameras with a wide range of lens mounts that can be added to the camera They do not have a viewfinder or rear screen fixed to the body; both are extras and would need to be plugged into the camera's body externally Cinema cameras are interchangeable lens cameras with large sensors and an extensive dynamic range that offers resolutions of 4k and above Ideally, you will want your cinema camera to be approved on the Netflix-allowed camera list

The example I will use for the cinema cameras is the RED Komodo 6K. The Komodo has a 199 MP Super 35mm Global Shutter CMOS sensor, a dynamic range of 16+ stops and frame rates of 40fps at 6k 17:9 The Komodo 6K is on the approved cinema camera Netflix list, along with all the RED cameras apart from the RED One camera

REDKOMODO6KCAMERA

Cameras Cinema

NAUTICAMNA-KOMODOHOUSINGFORTHEREDKOMODO6KCAMERA

PROS & CONS OF MIRRORLESS CAMERAS

Pros: Interchangeable lenses, a wider choice of frame rates, codecs, bit rates, bit depths and colour sampling

Cons: Price

THE PHOTO ABOVE WAS TAKEN WITH A RED KOMODO 6K CAMERA IN A NAUTICAM HOUSING

PJ KOTZE

THE PHOTO ABOVE WAS TAKEN WITH A RED KOMODO 6K CAMERA IN A NAUTICAM HOUSING

PJ KOTZE

THE PHOTO ABOVE WAS TAKEN WITH A RED KOMODO 6K CAMERA IN A NAUTICAM HOUSING | PJ KOTZE

THE PHOTO ABOVE WAS TAKEN WITH A RED KOMODO 6K CAMERA IN A NAUTICAM HOUSING | PJ KOTZE

Bio PJ Kotze

I’ve always had a deep affinity for water and the ocean I consider it a privilege to spend time in or on the ocean and document ocean-based stories and subjects, combining my love of cinema and storytelling with my passion for diving and the ocean through my production company, Bonanza Films and as an underwater camera assistant and DOP

After working in the world of documentary and broadcast for many years, I was fortunate to start working as a camera assistant to the master underwater cinematographer Roger Horrocks, which provided me the opportunity to learn and work on expanding my skill set with regards to rebreather and technical diving, field craft and importantly natural history storytelling I have been fortunate to work in various capacities on Netflix, BBC, and Discovery channel productions

One of the most important lessons I have learned in the demanding field of underwater natural history filmmaking is to use the best gear at one’s disposal, which is why I own and operate a RED Komodo 6K camera in a Nauticam housing. The Komodo’s small form factor makes it ideal for travel and allows me to switch from using it underwater to rigging it for topside use. Considering the effort and logistics it often takes to initiate an underwater shoot, I want to capture footage at the highest quality and resolution possible,

Bio PJ Kotze

and the RED Komodo’s 16-bit R3D 6K files combined with Nauticam’s beautiful optics provide that for me in a small and manageable package Having used various underwater housings over the years, none come close to the quality, durability and dependability offered by Nauticam, and I am grateful to the team at Dive Action for their excellent continued after-market service and Nauticam support in South Africa

I hope my work plays a small part in making people more aware of the ocean's wonders and the importance of protecting it.

Website: www.pjkotze.com

Instagram: @pj kotze cine

PJ KOTZE IS DIVING WITH HIS NAUTICAM NA-KOMODO CAMERA SYSTEM.

PJ KOTZE IS DIVING WITH HIS NAUTICAM NA-KOMODO CAMERA SYSTEM.

PJ Kotze - Ulwandle Trailer 4K

I hope you have enjoyed the two part series of the different types of cameras that can be used underwater to capture all your special moments!

Once you have decided on stills or video, I am sure you will find an option suitable for your skill set and need with the five types of cameras I have covered (Action, Compact, Mirrorless, DSLR & Cinema). If you are still stuck or need more information… call me!

About the Author: Maryka Pace has worked full-time in the diving industry at Dive Action, Cape Town, for the last ten years. She is part of the Nauticam SA team and assists underwater photographers with their underwater photography equipment.

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Caribbean Region, Sandals and Beaches Resorts, PADI® IDC Staff Instructor, explains why he chooses DAN.

HOW TO USE A DOUBLE ENDED BOLT SNAP

GEAR

TEXT BY TIM BLÖMEKE

The double-ended bolt-snap carabiner (or double-ender, in the lingo) is one of the tools in diving that you never knew you needed until you actually needed one. It has this characteristic in common with your DAN membership benefits, which is why we thought it might make an excellent gift for your your dive buddy.

Like most things, double enders come in various shapes and sizes, but the most important feature is the material: 316 marine-grade stainless steel Some cheap versions (often sold packaged with spools) are made of brass While seemingly fine at first, they usually corrode over time to the point of becoming stuck and unusable Stainless steel is what you want

Tech divers typically keep one double ender attached to every reel or spool they carry, and one extra that has its permanent place of residence on the right shoulder D-ring of the harness Some sidemount divers carry even more (close to their own body weight,

it seems, in some cases) and use them to attach a multitude of equipment parts to their gear – the butt pouch, drained cylinders, pretty much anything you might come up with. Recreational divers usually want at least one, as part of their diver surface marker buoy (DSMB) and spool assembly.

Before the DSMB is deployed, one end of the carabiner keeps the spool and buoy together (preventing the spool from unravelling and saving you from the mockery of your buddies) In contrast, the other end attaches the spool and DSMB to whatever you keep your spool and DSMB attached to – a D-ring on the harness or a bungee loop inside your drysuit pouch

When the DSMB is deployed, the double ender has the important task of locking the spool and keeping the line at a fixed length so that the spool hangs at a fixed distance (your current stop depth) from the surface This way, you won’t have to look at your

computer all the time to ensure you maintain the proper depth – you get tactile feedback about your depth from the spool bouncing just underneath your hand.

AN ESSENTIAL TOOL – NOT JUST FOR TECH

Double enders are also an essential tool for any line work that you might do as a wreck or cave diver, and the extra double ender (besides acting as a spare for any of the above tasks) comes in handy for clipping off your GoPro or other small camera that you might be carrying

As with all tools, there is a skill to using them In case of the bolt snap, you will want to learn how to clip them off one-handed: The thumb operates the gate lever, your three outside fingers hold the double ender

by the shaft, and the index finger is extended to locate the D-ring by touch This leaves your other hand free to keep your light steady and your eyes free to pay attention to your buddy or teammates. There are more tricks – how to clip them to a spool from the outside so they don’t open by themselves, and a whole list of techniques for line work in overhead (i.e., wreck and cave) diving.

ABOUT THE AUTHOR

Tim Blömeke teaches technical and recreational diving in Taiwan and the Philippines He is also a freelance writer and translator, as well as a member of the editorial team of Alert Diver You can contact him via his blog page or on Instagram for questions, comments, and inquiries

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Many of the pieces of equipment used by technical divers look different to the equipment used by recreational divers. However, most of the time, the basic principles are the same. The most significant exception to this is when technical divers use rebreathers rather than open circuit (OC). The advantages of switching to a rebreather are obvious for technical divers, but what about recreational divers? Several manufacturers have launched rebreathers aimed specifically at the recreational market, and Rebreather Forum 30 in 2012 explicitly covered this topic One of the consensus statements from the conference was;

The Forum recognises and endorses the industry and training agency initiative to characterise “recreational” and “technical” streams of sport rebreather diver training These groups will have different operational, training and equipment needs

REBREATHERS PART 1 GEAR

TEXT BY MARK POWELL

Are rebreathers suitable for recreational divers?

With the recent announcement of RF 40, it’s a great time to revisit this topic and see if it makes sense for recreational divers to switch to rebreathers

A rebreather is simply a way to reuse the gas breathed out by the diver in conjunction with a method of removing the carbon dioxide produced by the diver The main advantage of a rebreather is that it is much more efficient on gas usage When breathing normal air at the surface, we use up about 4% of the gas we breathe in the form of oxygen needed for metabolism and breathe out the rest of the oxygen and all the nitrogen

This means that 96% of the gas we breathe escapes with each breath At depth, this is made even worse by the fact that we are breathing gas under much higher pressure and so each breath contains a much higher amount of air At 40m, we are breathing five times the amount of air with each breath compared to the surface and at 90m we are breathing ten times the amount that we would be on the surface.

With every breath, this gas escapes from our second stage and bubbles to the surface. This is inefficient as the body still only needs the same amount of oxygen but we are wasting ten times as much gas with each breath in order to obtain it This is one of the reasons why for open circuit divers gas planning and breathing rate is so critical

The limiting factor for an open circuit dive to 90m is almost certainly going to be the amount of gas that needs to be carried for the dive A rebreather avoids this problem by re-using the gas breathed out by the diver, as most of the gas isn’t being wasted, the diver doesn’t need to carry as much gas in order to do the same dive

THE TECHNICAL ADVANTAGES OF A REBREATHER

A rebreather works by catching this exhaled breath and instead of allowing it to escape it

reuses it in the next breath The small fraction of oxygen that was used up by the body is replaced with additional oxygen that the rebreather injects into the breathing loop This means that rather than wasting most of each breath, we reuse all of the gas

By reusing our gas, this provides three key benefits to the technical diver

1 – GAS DURATION

Firstly, we don’t need to use anywhere near as much gas as an open circuit diver The amount of oxygen required by the body is roughly the same at any depth and so our oxygen will last the same at 100m as it will at 20m The balance of the gas in the breathing loop, known as the diluent, is reused rather than wasted and so again we use the same amount at 100m as at 20m This vastly decreases the amount of gas we will need to complete the dive and rather than twin 20L cylinders, we can use two 3L cylinders

On an open circuit, we breathe much more at depth due to the effect of pressure, so as we go deeper and deeper, we have to take larger and larger cylinders. Despite taking these large cylinders, they will still be used up very quickly, so the amount of available gas becomes the most critical part of our dive planning.

On a rebreather, our gas supply is used up at the same rate irrespective of depth so the amount of gas we are carrying is no longer the limiting factor This means that running out of gas on a rebreather is much less of a concern than for an open circuit diver Instead, the critical factors become the amount of decompression we are incurring, the duration of our carbon dioxide absorbent and our risk of oxygen toxicity

2 – GAS COSTS

One of the biggest factors that comes into the decision to switch to a rebreather is costs This has two aspects: the costs of the rebreather, including buying and maintaining it, set against the cost of open

circuit diving One of the biggest disadvantages of open circuit trimix diving is the cost of the gas A twinset of trimix can cost anything from €30 for a relatively weak mix for use in 40m to over €200 for a mix suitable for diving deeper than 100m

This makes each trimix dive an expensive proposition On the other hand, a rebreather uses much smaller cylinders because the gas is reused rather than wasted As a result, we use much less, and the gas costs are much lower We might only be spending €10-€20 for the same mixtures discussed above As a result, there is a significant gas saving when compared to open circuit diving This can look very attractive when you are spending considerable amounts on each open circuit fill

However, this must be set against the costs of the rebreather Depending on the model, a rebreather will likely cost between four and eight thousand euros. If you go for an older second-hand model then you might get one for less than this. In addition to the initial cost of the rebreather you will need to factor in training on the rebreather which is likely to add on another thousand euros. In addition, there will undoubtedly be additional costs to add on extra equipment to the basic rebreather. As a result, it is not uncommon for the initial start-up costs on a rebreather to be between 6 and 10 thousand euros Obviously, you will need to do a lot of trimix diving in order to save enough to justify this initial outlay

The majority of divers do not do enough diving to clearly justify buying a rebreather based on savings in gas costs Unless you are doing 20 or more trimix dives a year then it is not cost effective

3 – GAS LOGISTICS

The third advantage that improved gas usage provides is in simplifying gas logistics during longer dive trips Open circuit divers may use twin 12L, 15L or even 18L cylinders on each trimix dive In addition, they may be

using up to 4 stage cylinders for decompression gas for each dive This requires lots of additional helium and oxygen each day, and filling these large back gas cylinders and decompression cylinders each day is expensive, time-consuming and laborious

The fact that a rebreather uses smaller cylinders makes the logistics of filing much easier The amounts of gas needed are much smaller when filling a 3L cylinder rather than twin 12s so it becomes feasible to take enough gas with you for even a week's diving This contrasts with the situation when using an open circuit where significant amounts of helium and oxygen will be required as the majority will be breathed out and wasted

This can make a big difference if you don’t have a local dive shop that can fill Trimix If you have to drive 80 km there and back to drop off a twinset for a trimix fill and then do the same thing the next day to pick it up, then the logistics of this can be significant. Similarly, if you are diving somewhere without easy access to a dive centre that can fill trimix, taking your own gas simplifies the planning and logistics.

Of course, this assumes that the rebreather will always work as intended Just in case there are any problems with the rebreather, we also need to carry open circuit gas to get us safely to the surface In this case, we would need a bailout cylinder that we could start using at the maximum depth and would then need sufficient bailout to get to the surface completing all our decompression

Unlike the open circuit diver, the rebreather diver will not use their stages unless there is an emergency but will still need to carry them However, on an open circuit the diver will use the decompression stages on each dive and so they will need to be filled each day

4 – DECOMPRESSION OBLIGATION

The other advantage of a rebreather is that it can reduce the decompression obligation when compared to the same dive on an open circuit For a diver using a twinset and a stage cylinder, they may plan their gas to have the optimum mix on the bottom, ie the highest oxygen percentage subject to physiological constraints (PO2 ≤ 14 ATA) in order to reduce the amount of inert gas absorbed by the body

They will also make a choice of the decompression gas carried in the stage cylinder with a view to ensuring that they get rid of the inert gas as fast as possible during the decompression However, the choice of each of these gases will always be a compromise The bottom gas will be chosen to be as rich as possible but with some margin for error in case the dive is a little deeper than expected

If the diver ascends from the planned maximum depth, then the mix is no longer the optimum mix. Equally, the decompression mix will only be the most effective mix at the depth at which the diver switches to it. Prior to the switch, the diver could have switched to a leaner mix and at the later stops there will always be a richer mix that would have provided faster off gassing

A rebreather avoids these problems by constantly adjusting the gas mix being breathed to ensure the minimum amount of inert gas is being breathed The rebreather (or the diver in the case of a manually operated rebreather) adds oxygen to ensure that the minimum amount of inert gas is being breathed

At depth, the diver can ensure that the breathing loop of the rebreather contains the maximum amount of oxygen, subject to physiological constraints and hence the minimum amount of inert gas This will reduce the rate of ongassing

As the diver ascends and completes his decompression stop, the diver can ensure that the mixture again contains the maximum amount of oxygen which will accelerate the offgassing and reduce the required decompression In this way, the rebreather is constantly providing the best gas for the depth the diver is at

To simulate this on an open circuit a diver would have to switch to a new breathing gas mix every meter of the ascent in order to constantly have access to the best possible decompression gas For this reason, a rebreather is sometimes unofficially called a best mix generator

We can see that for the technical diver, rebreathers offer several significant advantages over open circuit diving In Part 2 we will exam whether recreational divers can enjoy the same benefits as their technical diving counterparts

ABOUT THE AUTHOR

Mark had his first experience of diving at the age of 10 when he did a try-dive in a local pool. He was hooked from that point onwards. He learnt to dive in 1987 and has been diving ever since. Mark became an instructor in 1994 and has been actively instructing since then. In 2002, Mark set up Dive-Tech, a dedicated technical diving facility, with the intention of providing the highest quality technical diving training Dive-Tech provides technical training at all levels up to and including CCR Advanced Mixed Gas Instructor Trainer Mark is a TDI/SDI Instructor Trainer and a member of TDI/SDI’s Global Training Advisor Panel He also represents TDI/SDI on a number of international standards groups He is a regular contributor to a number of diving magazines, the author of “Deco for Divers,” and “Technical Diving: An Introduction,” and a regular speaker at diving conferences around the world

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THE RAPID GROWTH OF FREEDIVING in the

US brings a positive light to a sport that is mentally healthy and physically inspiring but has little tolerance for error Shallow-water blackout and respiratory barotrauma are the most feared consequences of freediving, but they can be minimised with training and good safety practices

Serious consequences have been linked to freedives that lacked the basic one-up-onedown rule, bypassed the buddy system, and pushed limits without proper safety measures But not knowing your blind spots is perhaps as dangerous as not knowing how to freedive Risk assessment implies assessing the scene and anticipating problems before starting the freediving session It involves ensuring safety measures are in place in case of an unexpected event

That assessment includes having a written emergency action plan (EAP) for any freediving event, whether competitive or complex recreational. An EAP specific for your dive site and scenario is crucial and clearly delineates what to do in an emergency. The following are basic items to consider when doing a thorough mental risk assessment and building an EAP for freediving.

CERTIFICATION

Make sure all participants are certified freedivers A freediving certification teaches the basic safety standards to follow and provides prevention tips No checklist replaces successfully completing a certification course with a qualified instructor in person

DIVE SITE INSPECTION

A thorough inspection of a freediving site considers potential marine life hazards, water currents, sea state, and water visibility It is a safe practice for all participants to use a lanyard attached to the vertical line when visibility is poor Remember to inspect the access to water (eg, rocks, boats, walkways, etc) to prevent out-of-water trauma or falls

IDENTIFY CLOSEST MEDICAL FACILITIES

Smartphones have made it much easier to map the fastest route to the closest medical facility, but don’t skip identifying the nearest appropriate location to treat freediving emergencies before you dive This precaution can save a life Do this each time you plan a freediving session, whether the dive site is new or well-known

EVACUATION METHODS

Have a designated person who’s responsible for being the evacuation driver of your preplanned method of transportation in case of an emergency Predetermine a safe evacuation route to take to the nearest medical facility

COMMUNICATION

Ensure you have an adequate cellular signal for your phone at a dive site, which can be an issue in remote areas Plan to have alternative communication methods to contact emergency services using a marine radio, satellite phone, or personal locator beacon.

EMERGENCY OXYGEN AND FIRST AID SKILLS

While it is not mandatory for new freedivers to have first aid certification, we highly recommend taking a basic life support certification course before taking your first freediving course Better yet, take a freediving-specific first aid course, if available Having a DAN oxygen unit with you and available for every freediving session can save a life

BRIEFINGS

Before every session, take at least five minutes for a dry briefing to discuss what you will do with your freediving buddies Establish basic life support roles, identify safety teams, and assign buddy pairs Ensure all freedivers present understand the underwater safety framework of how the buoy and line are set up, how lanyards are attached and disconnected, and the presence of any underwater lights

An in-water briefing is mandatory to communicate to your safety buddy the planned depth, dive time, and discipline you are about to perform Also, make clear the depth at which you want to be met if you desire a depth safety Conduct this briefing for each dive and every diver

KNOW YOUR LIMITS

Know your breath-hold limits and those of your buddies The risk grading of each dive and each dive session depends on who is diving that day

DEBRIEFING

If an incident occurs, discuss with the team what happened to prevent future mistakes and learn specific risks from a dive site, underwater manoeuvre, or diver

OTHER CONSIDERATIONS

Rehearse underwater and surface rescue techniques when possible The “time of immersion” is perhaps the most important factor influencing the outcome of a neardrowning victim. Thus, the rescue phase with rapid in-water action is critical for the victim’s survival and outcome.

Sometimes, the wisest decision is to reassess your health and decide not to dive until

alone, and never hyperventilate before your dive

While freediving is growing exponentially in the US, it is still a small community It is our duty to raise awareness about trends over time This means asking not only if a freediver has had incidents in the recent past but also how severe Being open about any recent history of freediving incidents, such as blackout or barotrauma, can mean the difference between doing a safe dive or perpetuating a repetitive bodily injury

The current collective knowledge of freediving safety comes from scientists and medical experts involved in freediving research as well as the elite athletes who participate in the sport and understand the intricate journey a human goes through to gain deeper depths on breath-hold safely We know some but not all of the risk factors for freediving incidents

There is much we seek to understand, such as if there are any accumulative negative effects of chronic breath-holding on the human body or whether shallow recreational freediving is safer or more risky than deep competitive freediving, which features safety lanyard connections and

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PREPARED DIVER

EDUCATION

By Audrey Cudel

'Situation awareness (SA) is the ability to perceive data from the environment around us, make sense of that data to create information, and then look to see how this information and previous experiences will help us predict the future more accurately. If we think about these three steps – perceive, process, project – we can see what SA is and how to improve it.

Perceive – this is based around our sensory systems, especially our eyes, as they hugely influence what we believe to be the real world There are so many visual illusions out there which highlight this To improve our SA, we need to know where to 'look' for data, eg, increase the frequency we look at critical information like depth, bottom time or decompression overhead, site location, exits etc This is where effective dive briefings can help

Process – this is based around making sense of what we have perceived Previous experiences inform this process If we haven't seen

something before or seen the outcome, we shouldn't be surprised when we don't understand what we are sensing. Therefore, to build SA, we need to develop experience in various environments.

Project – this is based on our previous experiences but isn't about what it means now but what will happen in the future. Again, this is where experience is so important. However, this experience doesn't have to be direct; you can learn from others' stories and accounts

More mistakes are made because of inadequate SA and 'good decisions' than good SA and' poor decisions', hence the need for effective SA You can't pay MORE attention, but you can make sure you point it in the right direction'

Play chess? Observing current moves and anticipating the coming moves is the key to mastering the game This is a good analogy for Situational Awareness (SA): a tactical short-term cognitive process

In diving, SA is the process of perceiving environmental elements and events underwater, assessing their significance, and projecting their future effects as an asset, a risk, or peripheral consideration. Since SA is a foundation for successful decision-making, a lack of it leads to human error, one of the primary causal factors in diving accidents. Most of a diver's time underwater is split between training and non-training dives Training dives aim to develop new skills to reinforce and gradually move through each level of our House of Card's pyramid Situation Awareness takes place at the very top of this pyramid: Only a diver with solid foundations (breathing, buoyancy, trim, propulsion, team awareness) has the free mental capacity to turn their attention to their surroundings Once these foundations have been acquired during initial training, further training becomes more safetyoriented and aims at building dependable responses to several what-if scenarios: what if one runs out of gas, what if one has an equipment failure, what if the team gets

separated, what if one misses a decompression stop, what if there is a loss of visibility, and so on. The trained responses to all these potential situations are the output of a mental model based on the collective experience developed by the diving community over the decades. The underpinnings of this model were first described in the booklet "Basic Cave Diving: A Blueprint for Survival" (1979) by legendary cave explorer Sheck Exley: developing knowledge, future responses, and training based on past human errors and accident analysis

The value of this long-term model is to prevent divers from being overwhelmed by information Instead of coming up with a solution to a problem under time pressure, a diver can rely on a set of trained responses: one situation equals one action The downside, however, is that these responses need to be drilled repetitively to become automatisms Some training agencies reinforce this by requiring their divers to

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undergo a formal reevaluation process at regular intervals. Where this is not the case, many instructors will still advise their students to dedicate a few minutes to doing safety drills at the end of every dive.

Non-training dives are an opportunity for divers to build experience, which is a prerequisite for proper SA processing and projection However, while many divers are proud of the number of logged dives they have accumulated, this number doesn't necessarily reflect a diver's actual experience: a thousand dives in the same lake near your home town doesn't give you the skills to dive a wreck in the North Atlantic Genuine experience is built by diving frequently and repeatedly in a variety of environments, each of them with different hazards and challenges such as entry and exit, currents, temperature, visibility, depth, etc The more varied and profound a diver's experience, the more likely this diver will be able to relate their perceptions to a known scenario and quickly select the proper response

However, repetitive experience by itself does not lead to an accurate reading of a situation. By way of illustration, in his Allegory of the Cave, the ancient Greek philosopher Plato describes a group of people who have lived all their lives chained to the wall of a cave. The people watch shadows projected on the wall from objects passing in front of a fire behind them and give names to these shadows The shadows are the prisoners' reality, but they are not accurate representations of the real world –they represent the fragment of reality that we can generally perceive through our senses

The same objects under the sun represent actual reality, which we can only perceive through reason Without education, even extensive experience leads to a distorted perception of reality Applied to a diver's Situation Awareness, distorted perception caused by a lack of education leads to distortions in processing and projection, with potentially hazardous outcomes

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Two factors can jeopardise a diver's SA, foundational and contextual. Foundational distortion relates to the prisoners in Plato's allegory. Despite the repeated experience, the lack of education keeps a diver in a state of wrong perception and fear of experiencing anything else. Diving a single tank of air to sixty meters and beyond with unplanned decompression is an example. In some areas, this might be perceived as a 'normal' dive permitted by local regulations without any recognition, interpretation, or evaluation of the risks involved Not understanding the actual hazards leads to faulty projections and bad decisions

Contextual distortion describes temporary effects where situational factors like stress, mental workload, fatigue, or complexity may affect a diver's state of mind and lead to human errors and accidents The benefit of diving as a team (as defined in a previous article in the 'House of Cards' series) is to mitigate individual contextual distortion by adding redundancy to the analysis of the

situation – i.e., extra brains. Beyond personal SA, it is therefore vital to develop a shared SA within the dive team. Moreover, different people vary in their ability to acquire SA, and providing the same training will not result in the same SA across other individuals with a different sensibility and sense-making capabilities. The degree to which each team member possesses the SA required to meet their responsibilities in the dive plan determines the success or failure of the mission To plan a dive optimally, it is necessary to identify each team member's strengths and weaknesses and assign roles accordingly

A post-dive debrief is essential for developing a shared understanding and improving the team's collective Situation Awareness In the debrief, each team member contributes their interpretation of various situations during the dive and the subsequent decision-making processes and analyses the dive's ultimate success or lack thereof

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Situation Awareness is the apex of our House of Cards of diving foundations – the ace card In military aviation, the 'Ace Factor' describes the ability to keep track of everything in an immediate environment during airborne combat While diving is a more pacifist endeavour in most cases, the divers' Situational Awareness, both as individuals and as a team, makes the difference between looking and visualising, reactive and proactive, and between being a victim and being a survivor To quote Sheck Exley, "Survival depends on being able to suppress anxiety and replace it with calm, clear, quick and correct reasoning"

ABOUT THE AUTHOR

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

Situational Awareness

The Ace in the House of Cards

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STEP AWAY FROM THE COMPUTER

DIVE FITNESS

TEXT BY JESSICA ADAMS, PH.D

Sitting all day is literally killing you It’s true: The longer you sit, the shorter you live Prolonged sitting jeopardizes your health by increasing risk of cancer, diabetes, obesity and cardiovascular disease A hallmark of excessive sitting is a combination of long, weak back and gluteal muscles and short, tight pectorals, abs, hip flexors and quadriceps. Then there’s the sore back, the “spare tyre” around the midsection and the diminished brain activity (in the prefrontal cortex). It is quite ironic that all this sitting is frequently done in the name of productivity (at work) and relaxation (watching television).

Prior to quitting your desk job in the name of good health, try these simple steps to increase your daily physical activity

Physical activity is not the same as exercise; these are regular movement breaks that can be incorporated throughout your day without changing out of your work clothes or needing to hit the showers

It’s pretty simple to combat the effects of sitting if you take the initiative to simply get up. You’ve probably already heard about some methods of increasing your daily steps: taking the stairs, parking farther away and walking to talk to a colleague rather than sending an email. Just taking a moment to stand will “turn on” areas of your brain. These are excellent habits, and you can complement them by incorporating the following stretching and strengthening activities at regular intervals throughout your day

SHOULDER ROLL & RETRACT EXERCISE 1

Consider your posture as you read this article, drive your car or sit (or slump) at your workstation. Most daily activities occur in front of us, which yields tight anterior (front) musculature and lax posterior (back) musculature, particularly in the shoulder area. Years of poor posture can even lead to kyphosis (humpback) over time.

Incorporating shoulder rolls and retractions can combat some of the ill effects of poor posture This will increase your shoulder mobility by stretching the chest muscles and strengthening the back muscles It will also promote easier zipping and unzipping of your wetsuit, donning of your BCD and recovery of your hoses

2

1 Elevate your shoulders toward your ears as high as possible (shrug your shoulders)

Begin seated or, ideally, standing Maintain good posture throughout

3

4

5

Rotate posteriorly (around toward the back) with a circular motion

With shoulders still back, rotate downward

Retract your scapula (squeeze your shoulder blades together), and hold for 10 seconds, actively engaging your rhomboids

TIP

Some people reflexively hold their breath during this static contraction, which is not healthy Always breathe continuously to avoid a spike in blood pressure

LUNGING HIP-FLEXOR STRETCH (WITH STAIR)

EXERCISE 2

A lunging hip stretch is an excellent activity since it serves to simultaneously strengthen and stretch This hip stretch targets your hip flexors, which actually shorten from prolonged sitting It also strengthens your hip and knee extensor muscles

1

2

3

Locate a bottom stair or a single stair in a safe area

Facing away from the stair, take a giant step forward

Place one foot on the stair behind you Place the sole of your foot on the stair

4

5

Bend your front knee, slowly lowering your body into the stretch

Hold for a five count, then repeat

TIP

Make sure your back stays in an upright position so you feel the stretch in the front of the crease of your hip

CHALLENGE

Once you are comfortable, progress to placing the top of your foot on the stair; this will be a less stable position but will provide a greater stretch.

HIP THRUSTERS EXERCISE 3

Hip thrusters are the opposite of the deadly desk-sitting position. This activity simultaneously strengthens your back and stretches the front of your body.

1. Lean your upper back against the front of the chair

Start sitting on the floor in front of a chair. (Make sure the chair is in a stable position against a wall or desk, especially if it is on wheels)

2 Your feet should be closer than shoulder width apart, with the soles of your feet on the floor

4

3 Lift your butt off the ground so your shoulders, hips and knees are in alignment

TIPS

Ideally your belly should be flat like a table

NOTE

To avoid an increased risk of decompression sickness, DAN recommends that divers avoid strenuous exercise for 24 hours after making a dive During your annual physical exam or following any changes in your health status, consult your physician to ensure you have medical clearance to dive

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CARPEL TUNNEL SURGERY AND DIVING

FROM THE MEDICAL LINE

DAN MEDICS & RESEARCHERS ANSWER YOUR DIVE MEDICINE QUESTIONS

Q | When can I return to diving after carpal tunnel surgery?

You need to be completely healed following surgery, which will require time, depending on the severity of the carpal tunnel syndrome and the surgical procedure utilised. Everyone heals differently. Your surgeon will monitor the healing process through follow-up appointments and can estimate your progress

You may also need physical therapy to return your hand to full function Diving is equipment-intensive, and any strength, dexterity, or fine motor control deficits could cause a safety concern for you and your dive group You must be able to operate all your equipment such as gauges, buckles, weights, and valves without restrictions or limitations

Wearing a drysuit or wetsuit will compress the area around your wrist This compression can irritate any surgical site that is not completely healed

An operation involving nerves and tendons does not generally impose any restrictions

on diving once you are fully healed and released by your physician for unrestricted activity. Ideally, you should have no motor or sensory deficit, even during rigorous activity or normal wristband or wetsuit wear. Mild and stable sensory deficits may occasionally persist and require a physician’s clearance before diving.

After any surgery, there is a theoretical concern of an increased risk of bubble formation where there has been some disruption of blood supply that leaves increased or decreased vascularity There have been no studies to prove or disprove this theory

If you are cleared to dive, we recommend noting any neurological deficits and disclosing them to your dive buddy, dive operator, and anyone else who may need to decide on proper assessment and treatment recommendations following a dive injury Confusing a symptom with a preexisting condition when it is a symptom of a new condition could delay or lead to incorrect treatments

Jevon Monaghan, EMT-P

Q | After doing three dives with a somewhat dry throat, I developed uvulitis. It was quite severe, making it difficult to swallow. Is there research on this condition in diving? My main concern is that swelling may impair an airway.

There is no specific research on uvulitis in diving A handful of anecdotal cases exist online of divers who experienced a sore throat or swelling of the uvula after repetitive diving Any condition that affects the airway warrants prompt medical attention

Causes for airway issues range from benign to serious, including allergies, dehydration, medications, infections, and genetic factors While diving should not be the sole cause, it can facilitate some of the causes associated with uvulitis, such as potential exposure to allergens or infectious agents. Continuously breathing dry gases can worsen the situation.

In addition to breathing concerns, you may have difficulty with equalisation. Consulting an ear, nose, and throat physician may be warranted if the condition recurs, and it’s imperative for any condition with concern about your airway

If you notice a sore throat after divin f i from diving until you are evalua treated and your symptoms have re prevent exacerbating the cond transmitting it to others if infectious

Shannon Sunset, NCPT, AEMT

Q | I recently had a UroLift procedu return to diving?

An enlarged prostate, or benign hyperplasia (BPH), is more common age, affecting approximately 500 men worldwide This condition ca bothersome urinary symptoms The

is a minimally invasive procedure to get enlarged tissue out of the way and alleviate BPH symptoms Lifting and pinning back enlarged prostate tissue stops it from blocking the urethra and obstructing urine flow

UroLift implants are made of solid materials and will not likely be problematic while diving, barring complications

Antidepressants, antihistamines, bronchodilators, anticholinergics, and sympathomimetics, however, may worsen BPH symptoms These medications can tighten prostate and bladder neck muscles, causing difficulty with urination, which can pose a diagnostic challenge because the inability to urinate can be a symptom of serious decompression sickness (DCS)

Any additional medication following this procedure may bring additional considerations. The recommendation with any procedure is to be cleared by your treating physician for full and unrestricted activity before returning to diving after healing.

Leandra Lynn, NREMT

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Part of the magic of diving is of course the utter silence we get to enjoy whilst being underwaterWell other than the raucous crackling noise of active reefs of course and the often-frustrating noise of bubbles escaping our diving regulators Silence is absolutely golden, but we don’t necessarily want it to be permanent do we

Inner ear barotrauma (IEBt) and inner ear DCS (IEDCS) are a concern that seems to be occurring more and more often worldwide. IEBt can certainly lead to long-term deafness if not recognised and treated adequately. And so, this seemed like a great topic to highlight.

Although the physiology and pathophysiology of IEBt and IEDCS are distinctly different, both conditions may manifest similarly, presenting as symptoms of either cochlear (ie, hearing loss and/or tinnitus) and or vestibular (ie, vertigo and/or nausea and vomiting) involvement

INNER EAR DECOMPRESSION SICKNESS

RECOGNISING INNER EAR DCS WHEN AND IF IT OCCURS EDUCATION

TEXT BY DENNIS GUICHARD

Dennis Guichard is a multi-agency qualified Scuba Instructor Trainer & a DAN ‘Master Dive Pro’ member He is a qualified Offshore Diver Medic, Saturation Life Support Technician, and an UHMS Hyperbaric Technologist

Differentiating between the two conditions (IEBt vs IEDCS) can be immensely more difficult than you might imagine Although there can often be good clues in the history of the dive events in question, as well as in the presentation and evolving of symptoms And getting that diagnosis right is critical because, although the signs and symptoms can be near identical, the treatments are diametrically different

It is critical with IEDCS to get the diver patient into a chamber as quickly as possible The window for successful treatment of IEDCS is incredibly short and diminishes quickly Ideally we’ll have the patient in a chamber within an hour of presentation of symptoms If we can commence treatment early then there is often a great chance for full resolution of the injury.

IEBt on the other hand absolutely doesn’t require chamber treatment, as doing so can further exasperate that barotrauma.

Barotrauma of course just means an injury (trauma) caused directly by changes relating to pressure (baro). An Inner Ear Barotrauma injury is often sudden and immediate, but not necessarily painful, contrary to what we might expect

The barotrauma can be caused during the descent phase of the dive (an ear squeeze) through inadequate equalisation or from a blocked eustachian tube due to having a cold Or it could also be caused by overequalisation or descending too deep too quickly and then trying to force equalisation too late As the ear drum or inner ear oval window ruptures you might feel a dizzy disorientation, perhaps with ringing (tinnitus) in your ear and also a wave of nausea potentially washing over you

Similarly, you could rupture your ears on the ascent too if you experienced a reverse block

on the way back to the surface But again, this often manifests in a similar manner and you would usually be fully aware of the event

To add difficulty to the confusion we can also often get something known as ‘oxygen ear’ When we dive on Nitrox or breathe oxygen in an emergency the oxygen-rich gas can fill our middle ear spaces Our tissues metabolise that oxygen and in effect create a ‘squeeze’ from the relative negative pressure drop That can feel like fullness within the ears, create mild discomfort, induce temporary hearing loss, and distort diagnosis of IEDCS and/or IEBt

The correct terminology for Inner Ear DCS is Vestibulocochlear DCS, although it is most commonly referred to as the former It can present with much of the same symptoms as IEBt but it is not necessarily an immediate presentation (although it also can be). IEDCS is also often pain free with the only symptoms being the vertigo and nausea. And this is what often makes it so difficult to differentiate between IEDCS and IEBt.

IEDCS can resultantly often be missed, or misdiagnosed, as the ‘old literature’ rather associated it with mixed gas technical diving It was assumed to be rare in recreational sports diving, which has proven to not be true

In sports diving about 83% of IEDCS seem to occur within 1-hour of surfacing, 97% within 2-hours, and very rarely any much longer than that

There seems to be a greater incidence however of the vestibular-type injury (ie, vertigo and nausea) in IEDCS than the cochlear, although a combination is not uncommon And hence why diagnosis can become difficult Whereas IEBt is almost always predominantly cochlear in nature

(ie, hearing loss and tinnitus) But the presentation of one does not rule out the possibility of the other DCS is a fascinating often multi-organ challenge that can present in any combination of symptoms and injury

As long as IEDCS is recognised early its treatment and resolution can be very successful But it is one where a longer delay also gives diminishing returns of success It is thus critical that IEDCS is recognised early, that the DAN hotline is called, that the nearest chamber facility is activated, and you can get yourself or your patient due care as urgently as possible Every minute counts

As the nature of our diving has changed over time so has the nature of DCS that has been seen worldwide In the earlier days of tablebased diving we were doing shorter dives but faster ascents and often without safety stops. Skin and joint bends were resultantly most prevalent. As diving practices have changed and dive computer use has become more mai ’ for longer. Neurol DCS seems to have

We don’t need to long to get I supersaturation o occur due any of factors The presen associated in so although it can st one Some publish IEDCS is most com ear, although clin can present equall

Vestibulocochlear/ with pushing our between 20-40m multi-day diving th deep tissues In on

DCS treatments over a 13-year period, IEDCS presented in 24% of all DCS cases It is seemingly fast becoming one of the most prevalent presentations of DCS worldwide More common even than neurological DCS

IEDCS is a common presentation of DCS which can follow an otherwise unprovocative seeming recreational scuba dive, but the therapeutic response (worldwide) seems to remain poor Because injury to the inner ears can often not heal fully it’s imperative that you do not hesitate to call DAN and get to a chamber as soon as you suspect ANY form of DCS

We’re grateful for the experienced divededicated physicians, with extensive experience in diving related maladies, who make correct diagnosis and prescribe adequate treatment under often difficult circumstances.

When in doubt always call DAN.

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Fishing and being on the water with family while growing up influenced Michael Lombardi to study marine biology He and a friend got certified to dive during his junior year of high school, thinking it would be a useful tool for his desired field Lombardi had no idea what professional diving meant or where it would take him

After obtaining his certification, Lombardi flipped through the phone book and called multiple dive companies looking for work opportunities. One asked if he was interested in cleaning boats, and he accepted, which led to him spending his summers doing hundreds of task-loaded dives.

With so much time spent underwater, this work set him well ahead of his peers. By the end of college, he had become a dive instructor, performed commercial dive work, and helped teach scientific diving

LOMBARDI PREPARES FOR A TRAINING DIVE IN NUYTCO’S EXOSUIT ADS

LOMBARDI PREPARES FOR A TRAINING DIVE IN NUYTCO’S EXOSUIT ADS

MICHAEL LOMBARDI

IMMERSED IN SCIENCE RESEARCH PROFILE

TEXT

BY MADELINE COOMBS AND FRAUKE TILLMANS, PHD

He decided to become a working diver, leading to more than 25 years in commercial diving, harbour service, construction and engineering work, and more His interest in ocean exploration has created numerous opportunities to benefit from this working experience

WHAT DO YOU LOVE ABOUT DIVING?

Technical, operational, environmental, or physiological challenges always led me to build and create different tools Portable underwater habitats have been an important part of that

HOW WOULD YOU DEFINE AN UNDERWATER HABITAT?

A habitat is a structure that creates a dry or semi-dry space for humans to enter and complete tasks underwater, whether sitting and decompressing, carrying out tests or science experiments, or eating and sleeping. It is a dry space created within the underwater environment.

HOW DID YOUR INVOLVEMENT IN UNDERWATER HABITATS START?

In the early 2000s, Win Burleson, a student at the Massachusetts Institute of Technology (MIT), was involved with space simulation and wrote an article in the MIT student newspaper about the concept of underwater camping, comparing it to what was already being used in space It made me ask further why underwater habitats weren’t more attainable, so I reached out to him

After a decade of various involvement with technical diving for science projects, I received funding from the National Geographic Society (NGS) in 2010 to test techniques for deep-diving work to more than 400 feet I learned that the pressure and stress of doing these very long decompression times of up to five hours is extremely taxing That time could be more pleasant in an underwater habitat

In 2012, we received a second round of funding to prototype a portable inflatable underwater habitat to address this time inefficiency Later that year, we completed designing and building our first-generation Ocean Space Habitat and securely anchored it in the Bahamas

We did an exercise where we went on a sub400-foot dive and spent our decompression time in the habitat rather than hang on a line for hours We could look at the biological samples we had just collected, stay warm, and talk to each other rather than use hand signals We made productive use of unproductive time.

That mission led to more deployments, with developmental progress and procedure refinement accompanying each one. In Rhode Island in 2018, we successfully deployed and anchored a habitat out of a pickup truck. Now two people can conveniently deploy the portable underwater habitat with all of its life support, supporting missions for up to several days without any significant infrastructure support, which is a stark contrast to the old habitat paradigm from half a century ago I’ve shipped systems as far as Hong Kong for remote use

HOW MUCH TIME CAN A HUMAN SPEND IN A PORTABLE HABITAT?

This was our challenge when we partnered with researchers from a Discovery Channel Shark Week program, The Great Hammerhead Stakeout The researchers wanted a means to spend enough time in a habitat to observe environmental changes in a specific area through a full tidal cycle

We established a dive protocol that allowed the team to spend 11-12 hours inside the habitat At the same time, they made five excursions out of the habitat up to 110 feet without incurring any required

AN ADVANCED OCEAN SPACE HABITAT VARIANT DEPLOYED FOR THE DISCOVERY+

AN ADVANCED OCEAN SPACE HABITAT VARIANT DEPLOYED FOR THE DISCOVERY+

FEATURE, THE GREAT HAMMERHEAD STAKEOUT, ALLOWED TWO RESEARCHERS TO REMAIN

FEATURE, THE GREAT HAMMERHEAD STAKEOUT, ALLOWED TWO RESEARCHERS TO REMAIN

ON LOCATION THROUGH A COMPLETE TIDAL CYCLE TO OBSERVE CONDITIONS AFFECTING

ON LOCATION THROUGH A COMPLETE TIDAL CYCLE TO OBSERVE CONDITIONS AFFECTING

SHARK MOVEMENTS THROUGH VARIOUS ENVIRONMENTS. SHARK

THROUGH VARIOUS ENVIRONMENTS.

decompression This achievement proved to me that this technology has a future that offers the gift of time

By optimising the coupling of rebreathers and habitats, divers can potentially spend multiple days underwater as an extension of today’s technical diving regimen and at a fraction of the cost of saturation diving Our 11- to 12-hour effort was a good start, but I wanted to make it possible to stay overnight in the habitat

To do so, Burleson and I had to become comfortable with the system and enable it to carry enough life-support consumables, sustenance such as food and water, waste management items, and sources of warmth for a comfortable overnight stay. We conducted this experiment at the University of Arizona’s Biosphere 2 Ocean facility.

The next benchmark planned is a multiday event at a location yet to be determined. The concept of having multiple days available represents a paradigm shift where people can become part of the ocean ecosystem We’re working with scientists who are just starting to consider the possibilities with that type of time routinely available to them

WHAT DOES HABITAT DEPLOYMENT LOOK LIKE?

We have built five systems, with each new one improving on the last The exterior is comparable to a lift bag The interior generally has seats, life-support hardware, structural framing, a workbench, and food and water supplies It all collapses on itself when packing up, and two people can manage the whole package plus rigging

A habitat that comfortably holds two people sitting at rest is 3,500 pounds buoyant, so to safely anchor it you need at least 3,500 pounds plus safety Anchoring can take a couple of hours to a couple of days, and

there are many ways to achieve it, all similar to techniques we use in commercial diving The method depends on the environment, available resources, and infrastructure access

We deploy the anchor first, and then two people can easily toss the habitat overboard We designed and engineered the rigging to be straightforward, using hooks with shackles

TELL US ABOUT SOME OF YOUR OTHER PROJECTS.

I really enjoy deep reef diving for science and that feeling of conquering the abyss. Closer to home, I’m underwater almost every day and have done things from as mundane as scraping barnacles to as elaborate as diving in compost digestion tanks.

That thrill of discovery is what makes it all worthwhile. It’s not an experience you can buy it happens only with time in the water On one deep dive, I was collecting cryptic fish for an ichthyologist, and one specimen turned out to be a new species

With new discoveries, you typically get to choose between copublishing or naming the species I had published many papers, so I chose Derilissus lombardii In another more recent instance, I stumbled upon what may be a very old submerged indigenous settlement here in Rhode Island These accidental discoveries help move aquatic life forward

And then there are the technology projects I design and build all of my own rebreather systems and, together with partners, have brought a unit to market In 2013 I was invited to be one of the first trainees in the Nuytco Research Exosuit ADS It’s a remarkable tool: an atmospheric suit with no water pressure on the operator, so a person could spend all day in it without having to decompress I also wrote a training program

that Technical Diving International accepted and trained a group of researchers who took the system to the legendary Antikythera wreck site in Greece Atmospheric diving suit technology is still in its infancy and needs some improvements, but working in this field is very exciting

WHAT WOULD YOU LIKE TO SEE IN THE FUTURE OF DIVE SCIENCE?

I would like to see rebreather training earlier in the average diver’s career not technical rebreathers necessarily, but the basic science behind atmospheric management If we introduce a good baseline of knowledge earlier, we could do much more with people beneath the sea Broadly embracing that gift of time cannot be achieved without this improved understanding of atmospheric management it applies to everything, from rebreathers to habitats, atmospheric diving, and submersibles

I also think there is an opportunity to treat diving itself as a science. I think diving is

often overlooked and used as a tool to complete a task

We often ignore the science of advancements in diving, which is not just the physics and physiology behind them but also the technology and engineering and their applications Suppose we create a focal point on diving In that case, it will improve all aspects of underwater activities, science, and conservation measures and better appreciate how we humans can interact with the underwater world

DO YOU HAVE ANY ADVICE FOR THE NEXT GENERATION OF DIVERS? WHERE DO YOU SEE YOURSELF IN THE NEAR OR MORE DISTANT FUTURE?

My best advice is to put in the time doing what you love to do Don’t be afraid to volunteer, ask questions, and look for answers That is what science is all about I’m still doing that and hope to be doing that for several more decades. I wouldn’t pass up this aquatic life for anything.

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CLONINGTHEHUMANDIVER RISK MITIGATION

HARNESSING INNOVATIVE TECHNOLOGY FOR DIVING SAFETY AND ENJOYMENT

TEXTBYGARETHLOCK

In November 2023, a professional connection of mine showed me a Chat GPT-based large language model that allowed the ideas and knowledge of an ex-Royal Marine and author to be discovered by anyone – this knowledge wasn’t general knowledge, but specifically applied to leadership and teamwork, something the Royal Marines are pretty good at. This demonstration showed how targeted research and education can provide specific answers to questions that a general language model, like ChatGPT 35 or 4, can’t achieve You only have to see some of the answers that come back to recognise the flaws in the wider GPT models

So, what does this have to do with cloning the Human Diver?

My challenge within the Human Diver has always been how to scale the knowledge and practices that I have learned and developed over decades into something that can be used by the diving and non-

diving communities alike. I started The Human Diver in 2016 and delivered a couple of pilot classes to a total of 12 people. The feedback was really positive, but always ended with ‘I have no idea how you are going to market this’ because it doesn’t fit in with any of the existing business models for diving. The agencies don’t appear to be interested because they can’t work out how to make money from a discretionary activity (learning) and they don’t want to mandate something that introduces barriers to course sign-ups (instructor and students) because they are worried about losing market share Unfortunately, the most common model for determining value in the sports diving is low price rather than added value and content

The feedback from the overwhelming majority of Human Diver course graduates is that human factors and non-technical skills should be explicitly taught in diver training and instructor development programmes This includes feedback from Instructor Trainers and Course Directors

Several dive shops have now put their complete teams through Essentials and face-to-face programmes to raise their competence to reduce the likelihood of errors occuring and give their clients a better, safer experience I can’t be everywhere, so, since 2020, I have been running instructor development programmes and there are now 14 instructors across the globe trained to deliver one- and two-day Human Factors in Diving courses However, some of those instructors have subsequently stopped teaching for personal reasons or because the markets in their locale do not support a ‘quality’ market rather one that is based on scale and low-cost. Last year I personally taught 18 classes across the globe, and have trained more than 500 people face-to-face since January 2016.

Notwithstanding this number of instructors, the number is still a drop in the ocean when it comes to creating positive change across the global diving community Instructors certify tens of thousands of divers each year,

but none of them have formal or structured training materials from their agencies that help develop their own or their students’ knowledge about human factors, nontechnical skills, psychological safety, and a culture of justness, and how to apply it

That is where Chat-THD comes in

Chat-THD has been trained on more than 400 000 words covering the book Under Pressure, more than 250 blogs from The Human Diver, the transcripts from 30+ presentations and 30+ podcasts and interviews, along with research papers and personal MSc submissions. (New content is being added as it is being produced, ensuring the model remains current and relevant).

This means that Chat-THD is well educated when it comes to answering questions about Human Factors in Diving and, as one AI specialist noted, is 'on brand' when it comes to creating a curious, learningfocused, non-judgemental approach

because of the answers provided The ChatTHD model allows conversational and branching questions, just like chatting with a Human Diver instructor One of the things that is critical to developing learning is being specific with a question, and the Chat-THD model allows you to ask a specific question, and then dig into the subsequent answers with more questions

For example, a multiple page conversation developed through the following questions:

What question do you think would be the most useful for me today?

"What key principles should I follow to manage risks effectively in my diving practices?"

"What key principles should I follow to manage risks effectively in my diving practices?"

Answer

How do my own safety practices fit into the wider scheme of safety in diving?

Answer

Why is context important?

Answer

What can I do to learn from an experience rather than just look at the outcome?

Answer

The answers haven’t been provided because of the limitations of word count of this article, but each of the subsequent questions was based on something that Chat-THD had replied with To ensure that the model was useful to the diving community, it was trialled with 20+ testers covering recreational and technical divers, as well as diving instructors before Christmas One question provided by a test was this, a fairly common issue

“How would you respond to someone who calls you an idiot when you confess to making a mistake?”

In the face of such a situation, it's important to uphold the principles of psychological safety and a Just Culture (response from Chat-THD):

Stay composed: Maintain your composure and respond with civility Reacting emotionally can escalate the situation

Affirm boundaries: Let the individual know that while you're open to constructive criticism, personal attacks are not acceptable or productive –

Seek understanding: Sometimes, negative responses come from a place of pressure or stress Ask them to discuss their concerns without resorting to personal insults.

Emphasise learning: Remind them that acknowledging mistakes is a cornerstone of progress and safety in diving. Explain that this approach contributes to a culture where everyone can learn and improve.

Report if necessary: If such behaviour is part of a pattern, it may need to be reported to higher management or a relevant authority to address the toxic behaviour and protect the team's psychological safety

Remember, everyone has lapses in behaviour, but consistently hurtful responses require attention and resolution within a team or organisation

There were only a few questions that couldn’t be answered because they went beyond the training that Chat-THD had been provided, eg, what happened to Shek Exley on his final dive Overall, the answers that were given during the testing aligned with the ideas and concepts of the Human

Diver programmes (hardly surprising given that is what it had been trained on!)

This Chat-THD model is not here to teach divers how to dive, but rather to understand, through a curious questioning approach, about how to apply human factors, nontechnical skills, psychological safety, and a culture of justness to their diving Thereby making it easier to do the right thing, and harder to do the wrong thing That ‘thing’ might be communication, decision-making, leadership, teamwork, being a good follower/team member, or how to create a psychologically safe environment in your team or dive centre

The goal is also to provide a live reference tool such that every graduate from a Human Diver class, be that Essentials, live-webinar training, or face-to-face simulator training, has a resource they can go back to and refresh their knowledge and ideas. This spaced learning allows the knowledge to be more 'sticky' and easier to recall when the time is needed.

Human factors is general in nature and specific in application Furthermore, learning should be focused on the needs to be student Chat-THD allows both of these needs to be met because the student, be that a diver or a diving instructor, is asking the questions that they need an answer to This capability allows instructors to build specific ideas and concepts into their training programmes and provide better answers to questions that students might ask during class It also gives those involved in incident investigations questions to consider regarding local rationality and how it made sense

Access to the Chat-THD is $5/month for those who are not graduates of a Human Diver training programme You can cancel at any time You can get access by visiting this link www.thehumandiver.com/chat-thd. If you’d like to know more about the Human Diver, get in touch with the Founder, Gareth Lock, at www.thehumandiver.com/contact.

CYLINDER VALVES

AND ACCIDENTS IN SCUBA DIVING

RISKMITIGATION|TEXTBYGUYTHOMAS

One would expect diving cylinder valve connections to be the same worldwide. However, this is not the case; some fundamental differences have led to confusion, dangerous situations, and even fatal accidents.

PHOTO BY: DAN EUROPE STAFF

PHOTO BY: DAN EUROPE STAFF

VALVE OUTLET CONNECTIONS

Most divers know that cylinder valves have an INT (aka Yoke or A-Clamp) or a DIN outlet connection to their first stage Unfortunately, there are different DIN outlet connections depending on the cylinder pressure and gas used, and this needs some explanation

We commonly refer to DIN Air when discussing the DIN valves on an air cylinder However, there are two configurations: the 232-bar connection (generally called a 200-bar connection) and a 300-bar connection DIN is an old term referred to as DIN 477 #13 for up to 300 bar, and then #56 for 300 bar and above Today, the correct specification is ISO 12209, but we still call these DIN connections Both of these DIN fittings have a G5/8-inch internal thread However, the 200-bar version has a thread with five turns, while the 300-bar version uses a thread with seven turns and is thus slightly longer A 300-bar first stage will fit on 200- and 300-bar valves, but a 200-bar first stage will not seal in a 300-bar cylinder valve This is for safety, to prevent inadvertently overpressurising a 200-bar first-stage regulator

In Europe, you also have the larger diameter M26 valve for cylinders containing a breathable nitrox gas with an oxygen content greater than 22 % This valve, introduced in European standard EN 144-3, is intended to prevent the filling of cylinders with the wrong gas and use air-only regulators with a cylinder containing a higher concentration oxygen mix, as in both cases, this could lead to a fire hazard. If you dive with nitrox, your cylinder valve and first-

stage regulator should have the M26 connection The problem, however, is that the M26 valves are rare outside the European Union In most other countries, normal DIN (or INT) valves are used, meaning you would need an adapter to have your M26 regulator inlet fit onto a standard DIN cylinder valve This, of course, is exactly what one wanted to avoid with the EU directive The M26 valve is also available in 200 and 300-bar configurations

The INT (Yoke or A-clamp) valve is only used on 200/232 bar cylinders Most 200 bar DIN valves can be converted into an INT valve using a DIN to Yoke insert

VALVE INLET THREADS

The cylinder-to-valve connection refers to the cylinder neck thread This is where we have the biggest safety concern

The British Imperial BSP (British Standard Pipe) G3/4-14 and the metric M25x2 thread are the most commonly used threads These threads are very similar, which, unfortunately, makes inserting the M25x2 valve into a G3/4 cylinder neck possible When this happens, the first turns will feel loose, and one will experience some resistance about halfway in With a bit of extra force, the valve can however be screwed further down into the cylinder neck This will damage the thread, and the connection becomes unstable While filling the cylinder, the force exerted at the connection will become so high that the valve will be blown off the cylinder. When this happens, the sudden pressure release will create an enormous shock wave and can do extensive damage.

PHOTO BY: DAN EUROPE STAFF PHOTO BY: DAN EUROPE STAFF

Additionally, the valve will become like a projectile, and the cylinder will fly around, possibly damaging the area and persons in the vicinity If the valve is not blown off during filling, it will just be a matter of time before it will happen: in the car, at home, in the pool, at the dive site This has led more than once to fatalities and serious, permanent injuries

You can also find other threads, such as M18x15, used on cylinders where the neck is not large enough to fit, for example, an M25x2 thread The thread is so different here that you will immediately notice the fitting is incorrect

As a general safety tip, only certified and competent persons should fit valves to cylinders and only after checking the threads, making sure they match The valve and the cylinder should also have the type of thread stamped on the valve/cylinder, but this is not always the case or might no longer be visible

In the US, the 3/4” National Pipe Straight Mechanical (NPSM) connection is used Similar but not equivalent to the BSP 3/4” valve, this valve poses the same safety concern described in this article

To add to the confusion, many people think M25 and M26 both refer to the valve outlet connection and do not realise that there are different inlet connections on the market As written above, making this mistake can lead to severe consequences However, they can easily be avoided with proper caution.

The following are some of the incidents on the subject reported in the media:

Diver injury during air cylinder recharging – IMCA (imca-intcom)

HSE – Mismatching valve threads

Dive instructor dies after tank explosion (divernetcom)

Zwaargewonde door ontploffing van duikfles in Brugge – DuikeninBeeld

Zij kan het nog navertellen – DuikeninBeeld

Duikinstructeur komt om in zwembad – DuikeninBeeld

Kraan schiet van fles – Arbeidsinspectie waarschuwt – DuikeninBeeld

Het gebeurt nog steeds – gevaarlijke combi van fles en kraan –

DuikeninBeeld

Esplode bombola da sub: morto un cinquantaquattrenne | Sicilia Oggi Notizie

Dive Instructor Killed In Diving Cylinder Explosion – DIVERS24COM

Croatie: une Polonaise se tue en plongée (lefigarofr)

Tauchlehrer nach Explosion im Schwimmbad von Amstelveen gestorben, 1610 – Forenbeitrag auf TaucherNet

ABOUT THE AUTHOR

Guy Thomas is an expert Diving and First Aid Instructor Trainer and works fulltime as Director of Safety Programs at DAN Europe, where he is responsible for developing and implementing the DAN Europe Safety Initiatives He is also a member of the Special Rescue Team of the Italian Red Cross. He operates as a Helicopter Rescue Swimmer/Diver Medic onboard a SAR helicopter of the Italian State Police.

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Yourgatewaytodivesafetyservices&worldwidedive coverageatlowannualrates!

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DISINFECTINGDIVEEQUIPMENT RISK MITIGATION

BEST PRACTICES FOR DISINFECTING DIVE EQUIPMENT

TEXTBYFRANCOISBURMAN,PR.ENG,MSC

After the initial scare and lockdowns from COVID-19, divers soon started to explore ways to get back into the water safely Disinfection has always been a consideration in diving, but we needed new standards to allay fears of uncontrolled transmission of infectious diseases

Fortunately, the industry responded rapidly to provide sufficient confidence to resume dive operations We don’t have significant evidence of mass infections on dive boats, around dive sites, or in classrooms or retail shops, so it’s likely that the processes we followed played a major role in ensuring that diving was not a significant COVID-19 infection risk.

Even if we don’t face a similar pandemic again, microbes are still out there waiting to make our lives miserable and keep us out of the water. The lessons we learned during the pandemic provided some best practices in infection control that are also sensitive to our environment

There are three approaches to dealing with infections: cleaning, sanitising, and disinfecting Cleaning removes most surface contaminants, sanitising neutralises 95 percent of pathogens lurking on surfaces, and disinfecting removes 99 percent or more of the organisms we are concerned about Cleaning is perhaps the most important of the three

If you suspect an infectious germ, disinfection is the correct response Do what is practical and achievable; you do not need to disinfect everything in sight

When using and not sharing your gear, good hygiene is sufficient Wash your equipment at the end of the day, use regular soap or shampoo on your wetsuit and other porous equipment, rinse thoroughly, and dry it completely where there is sufficient fresh air or ventilation

Disinfection should be standard practice for common areas Surface cleaning helps avoid fungus, mould, and bacteria

Carefully consider whether to use communal rinse buckets, with or without sanitising solutions If you do elect to use them, ensure they are refreshed frequently

Rental gear requires thorough cleaning and sanitising or disinfecting Be sure to check with the dive operator about their rental gear cleaning practices

Many products are effective, but some are not environmentally friendly and require careful disposal, so consider all aspects before selecting one.

Immersing or wetting your gear for at least a minute in a 2 percent solution of household bleach in clean water and then thoroughly rinsing it and letting it dry naturally will deal with most microbes. More bleach is not more effective and can damage some equipment, leave a bad smell, and make effective rinsing more difficult No odour or taste should remain after taking these actions

After learning a lot in the past few years, we should be able to achieve suitable infection control without significant expense, expertise, or concern about missing something, but we should not become complacent Use common sense when disinfecting your dive gear, and observe how dive operators manage their cleaning processes

With proper precautions, diving does not have a higher infection risk than other sports in which people are in close proximity

Best Practices for Disinfecting Dive Equipment

Award-winning documentary Cinematographer and shark specialist Barry Skinstad tells us how he became fascinated by these majestic animals

Growing up in Eshowe, Kwazulu-Natal, not far from the coast, I started diving when I was 13 or 14 and only scuba-dived much later in life The family dentist in Eshowe, Dr Andrews, was a keen spear fisherman We would travel either to Sodwana Bay or Cape Vidal to go spearfishing. Having done my military service in the Navy and practised my spearfishing skills while working in Mozambique and Sodwana, I gained more underwater experience.

“My wife, Noleen and I moved to Plettenberg Bay in 2014, said Barry. He was still doing quite a lot of work on the Survivor Series in Fiji. “We run a small farm, and my wife has a livery with a couple of horses I do as much work in the

BARRY SKINSTAD

SPECIAL INTEREST

INTERVIEWED BY NICOLENE OLCKERS

ocean as I can I noticed there are many sharks – Great white sharks - that congregate here” They arrive in the bay during early winter and spend from April until October or November along the Robberg Peninsula Over the last six years, I tried to do some work with them, diving and filming the sharks that visit the peninsula

“I also work with the acoustic listening stations around here; several of the tagged Marine animals swim past these listening stations, and these underwater listening stations record them passing by or through the area I enjoy the whole science side of this and anything to do with Marine sciences

“The first shark I ever saw on one of those first spearfishing trips with Dr Andrews was a tiger shark. I didn't even know what it was. I told him that I had just seen a shark with stripes. They are distinctive.

My genuine interest in sharks started in Mozambique at the end of 1993 or early 1994.We discovered a dive site called the Pinnacle. In the summer, it is heavy with sharks. We took photographs there at the time, and there were probably 10-14 Zambezi or Bull Sharks in one frame It was impressive and something special to see We spent so much time free diving on the Pinnacle and later scuba diving there We learned a lot about the shark’s behaviour

I started filming when the Annual Sardine Run was first promoted as a commercial venture I was with quite a few guys that used to come to Mozambique They wanted to film sharks and other big marine species Seeing them diving and thinking: Jeepers!! They can hold the camera and are pretty good photographers, but they have no clue about the marine environment and how to get close to the animals

Operating the camera and working with the animals was much easier because I understood the sharks’ behaviours well Learning camera skills was easier for me than for somebody to learn animal behaviour in the ocean That was my advantage

I landed a job with Earth Touch in 2007 or 2008 and led one of the marine teams for about 7 or 8 years I travelled up and down the (South) African coast and worldwide diving and filming natural events, which was great We filmed most of the annual Sardine Runs, travelled worldwide to Palau, did a lot of work in Mozambique and filmed the Great White Sharks in the Cape I also filmed Bull sharks (Zambezi’s) and Tiger sharks up in Mozambique, and whale sharks and Manta rays at Mafia Island Working with a company such as Earth Touch was a considerable advantage (privilege), and moving around the world and witnessing all these fantastic events was a huge advantage (privilege). I have done quite a few films since, with the BBC, NatGeo (National Geographic) and another with Netflix that is about to come out.

The logistics involved are the biggest challenge of working with international film companies

Everything must be entirely above board Everybody's on the same boat as to what is needed and how we can achieve what we want with the filming Especially with the white sharks, everybody knows that diving in the Cape is impossible to get in the water every day

Unlike Mozambique, where the water is clean, you can have good daily visibility The conditions in the Cape dictate if we will have a three- or four-week window We will probably be in the water for three to five days in that time frame

It is a barrier, making it more difficult for people to come along and do the same work. Another hurdle is the permits that are needed. These must be in place before filming can commence. The great white sharks are a protected species; you must obtain permits from the necessary authorities, such as the Department of Environmental Affairs, SANParks, or whoever manages the area that you're working in Obtaining a permit can be problematic, and they do not often issue permits to operate outside a cage Working with reputable agents to get them takes time and effort and is very expensive

As a cinematographer, you must have a decent reputation for working with sharks and have produced decent work You cannot be gung-ho about it, like diving in the water with sharks in harmful conditions You must know when it is safe to get in the water with them and, at most, be able to sense the shark’s behaviour

We are fortunate to be in the position to do this work and have established a good reputation. We have not had any incidents, and the crews working with us have strict procedures. Decisions are based on observing the animal, when you can see it clearly, and watching its behaviour. Once we determine that the animal/s is relaxed, we only call to get in the water. It's pointless to dive with the animals in dirty conditions It puts all those involved at risk and is not the wisest thing to do

I think any exposure to any wild animal is good, especially for the White sharks They have been under the microscope These sharks have possibly been responsible for most shocking or fatal shark attacks around the world To portray them in the right light is very important I hate it when people emphasise their teeth and the jaws sort of scenario Unfortunately, that's how these sharks are; they swim around with their teeth exposed and out, unlike other sharks, such as the

TIGER SHARK INCOMING TIGER SHARK INCOMING

Zambezi and tiger sharks, in which you'll see their teeth but not as pronounced. I do not try to portray them in a bad light. I am more for describing their beauty and grace in their natural underwater realm. I do not appreciate a gung-ho attitude. When people start riding dorsal fins, pulling the tails or anything like that, it puts the animal and the people at risk.

People are always fascinated by giant animals, whether it's a lion or a big shark “That is pretty much a general rule throughout the world Big sharks, big tiger sharks, big great white sharks are very impressive to see underwater, says Barry “You don't often see those big animals anymore”

I think I've seen one white shark over 5 meters, and I wasn't in the water, but I've seen a couple of sharks between four and 4 1/2 meters, and even those are impressive Once you get close to them, you realise their size and the girth of these animals In their environment, they are in their element

I've managed to get some of the best shots of white sharks. At first, you are somewhat apprehensive and watch them. Once you have been in the water with them and watched them for a while, you always try to get a better shot. One of the shots I got was of these big white sharks of about four, maybe 4.2 meters, swimming right over our heads. Being underwater and holding your breath while it comes overhead was mindboggling I got the images to show Not in stills but as footage “It's imposing to see”

Sharks, as with most underwater animals, can surprise you very quickly They can switch their behaviours very fast They become a bit bolder in different conditions

The white sharks in cooler water seem a little more aggressive, as with Ragged Tooth sharks, and it plays a role in their behaviour

With most sharks, you can see the change in how they move Observing their erratic movements, where and how they hold their pectoral fins, enables you to see if they're a bit more turned on or aggressive than at other times Temperatures and conditions

FREEDIVER APPROACHING A TIGER SHARK FREEDIVER APPROACHING A TIGER SHARK

play a role when working or filming these animals. What always fascinated or interested me more is how quickly they can appear and disappear in the ocean. You can look in an area and look away for half a second, and when you look back, there will be a shark right there. In the water, you must be vigilant and constantly look around you.

I have been involved with two or three of the NatGeo shoots here in Plettenberg Bay and the latest one for BBC Planet Earth III It was released recently, and we managed to get the opening sequence It was exciting to see how the seals turned against the sharks The sharks will only move into the areas where the seals are when they are on the hunt or trying to prey on the seals More often than not, they will hang around towards the beach, where they seem to be in a kind of limp mode, just moving in and around a space of about 300 or 400 meters Not go anywhere near the seal colony But when they do go to the colony, as soon as the seals notice them, you see packs of between 20

and 30 seals mobbing the sharks and chasing them out of the area.

It will be nice to think that people's perceptions and awareness of sharks are becoming more in tune with how they are. Rather than seeing them in the JAWS!! Perception. There's been so much exposure, and so many forms made that one would think people would tire of it, but apparently, people love sharks across the board We have done a couple of Shark Week films as well, and I reckon that Shark Week is probably one of the best TV shows that shows you the fascination for sharks worldwide

We've done a lot of work with Crocodiles in the Okavango delta; honestly, it's not a fun experience It is impressive, though “I would prefer to dive with a shark rather than a crocodile, " jokes Skinstad Crocodiles are more unpredictable, and the conditions are much more challenging It's dangerous, and it certainly is much nicer to dive with the sharks

WHITE TIPPED SHARK WHITE TIPPED SHARK

Producing significant documentaries takes a long time Not only because of underwater sequences but also because they use sequences from worldwide, stringing them together I worked on the BBC Planet Earth I for three years, and we would have about four weeks every year to shoot Ultimately, it is scrunched down to about 8 minutes of footage in the show That gives you an idea of how much footage you would need to produce a section or a segment Regarding the Shark Week shows, you will probably spend a week and a half of actual filming If you get good conditions, both topside and underwater footage, it will be quickly cut into a 52-minute documentary It depends on the production

This year thus far has been quiet It usually only starts picking up around the end of January or February, and I'm sure one or two Shark Week shows will come up

On my diving Wishlist, I'd like to go and dive with the Humpback Whales in a place like Tonga I haven't done that in clean water, though I have done a lot of work with humpback whales, but not in crystal-clean water They usually move pretty quickly Any significant events are always a great attraction to see and document It is nice to document some of these events and share them with millions worldwide

ProsChooseDAN

TrustedWhenItMattersMost

Richie Kohler, Professional diver, shipwreck researcher, and film-maker, explains why he chooses DAN.

CRAFTING UNDERWATER PERFECTION

SPECIAL INTEREST

TEXT & PHOTOS BY KEN

FINDLAY

Ken Findlay is a marine biologist passionate about ocean and wilderness photography. With over thirty years of experience in marine mammal sciences in southern Africa, the Southern Ocean and elsewhere, Ken’s more recent work centres on ocean governance and the management of ocean economies and their associated conflicts. His career has allowed him to travel extensively, including to many of the world’s wild spaces (often with a camera) His passion for wildlife, wilderness and ocean photography merged with his diving and freediving interests early in his career Starting with a Nikonos IV in the early 1980s, Ken’s happy space is in the shallow kelp forests of False Bay, where he is continually amazed by the ocean and reef colours, patterns and diversity

“I like clearly understanding the images I want before a dive or a trip How much of that I can achieve depends on the opportunities Merging my imagination with my experience to develop images and allow others to see ocean and wilderness as I see

them is what grabs me about the mindfulness of photography.”

“I often try to position underwater subjects within their environment in what I would call close-wide imagery. I seldom use the camera viewfinder, preferring to compose images over the top of the camera and allowing closer and tighter framing of images while at the same time keeping me well off the reef substrate Most of my kelp forest photography is carried out while freediving, allowing greater flexibility and access than I would have on scuba Images are often crafted over multiple surfacings, in a process that includes looking for subjects, assessing the ambient light, backgrounds and best angles, looking for the best access to the subject and only then starting to craft rather than “take” the photos I might spend most of a free-dive session on one subject, experimenting with different lighting angles and camera and strobe settings to reduce the backscatter so prevalent in Cape kelp beds”

The portfolio showcased here is a small selection of Ken’s imagery that can be viewed at www.kenfinphoto.com. Please get in touch with him via his site if you have questions about images or how they were crafted.

“Kelp forests are, to me, the most awesome underwater environment to photograph I love the combination of the freediving exercise and the creativity of photography I largely shoot upwards towards the surface against the ambient light (please, please never try to shoot downwards from the surface unless the subject warrants it – results are often so disappointing) Get low, get close (and then closer), and look upwards while at the same time being aware of where you are about fragile reef fauna There are some days that I see great subjects or potential images but know that surge will not allow access, that light or tidal depth might be better at a different time of day, and often, I will come back when I feel conditions on that subject will be a little better”

He currently shoots the underwater world using a Canon 5Dmkiii or 7Dmkii camera bodies in Nauticam housings Lighting is supplied by one or two Inon Z330 strobes (usually at very different settings and positioned differently for each subject) All images are shot manually at a set shutter between 1/90th and 1/160th of a second with aperture settings based on ambient conditions

Most images are shot using a Tokina 10-16 fisheye lens that allows extreme close-focus photography through a minidome port However, he also uses a Canon 16-35 f28 in a giant dome port to shoot more comprehensive scenic images It has taken him some time to learn the optimal settings for different depths, visibility and aspects within kelp forests as opposed to open water or other reef systems where similar settings produce very different results Critical here is the understanding that the camera settings capture the wide. In contrast, the strobe settings charge the close, with varying distances of the strobe having a significant bearing on close exposure.

ProsChooseDAN TrustedWhenItMattersMost

Captain Breezy Grenier, Owner, Breezy SEAS, explains why she chooses DAN.

REVIEW

FROM A DAN MEMBER

DIANE MAY

A recent episode of decompression sickness in Madagascar made me aware (again) of the importance of being a DAN member All throughout my treatment DAN was available for advice It was very fortunate to have a hyperbaric chamber on Nosy Bé with trained, dedicated staff Please do not dive without the protection of a DAN membership. We all think it will not happen to us!

CALLING THE DAN HOTLINE

WHEN SHOULD I PHONE THE DAN HOTLINE?

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

WHAT DO I NEED TO HAVE READY?

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

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

WHAT HAPPENS AFTER I HAVE LOGGED THE EMERGENCY?

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

WILL I GET EVACUATION BY AIR?

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

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.

DIVE ESSENTIALS

IMPORTANT FACTORS TRANSPORT

THE AVAILABILITY OF TRANSPORT

Is an air ambulance or a helicopter available?

THE INJURY

THE NATURE OF THE INJURY

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

THE LOCATION

THE LOCATION OF THE PATIENT

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?

VARIOUS ASPECTS REGARDING THE LANDING ZONE OR AIRPORT

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?

PARTING SHOT

NICOLENE OLCKERS

CAPE FUR SEAL

I find it quite difficult to photograph Cape Fur Seals underwater Most of the time, they move very fast, bark, and flash their teeth in an intimidating manner. This seal was very interested in the flashing lights and would swim down to 28m to get our attention. The image was made with a Canon EOS 5D MKIV fitted with a Canon 16-35mm lens set at 16mm The camera was housed in an Ikelite 200DL housing with an 8-inch dome port and two DS 160 strobes Settings: ISO 200, 16-35mm@16mm, F71, 1/160sec Manual mode, no TTL