Alert Diver June 2023

ALERTDIVER

THE MAKING OF AVATAR 2

THE WAY OF WATER

UNDERSTANDING OXYGEN TOXICITY

CONDITIONS? OUTCOMES?

WHICH IS MORE IMPORTANT FOR SAFETY?

UNDERWATER

FISH & FASHION

DIVING ETIQUETTE

THE MARINE ENVIRONMENT

FREEDIVING FRENCH POLYNESIA

THE SHALLOW-WATER WONDERS OF PARADISE

MASTERING PROPER TRIM

Editor DAN Southern Africa

Publisher DAN Southern Africa

Contributors

Nicolene Olckers, Dennis Guichard, Francois Burman, Kyle Kray, Helen Walne, Abbie Fish, Christine Tamburri, Audrey Cudel, Claudio Di Manao, Jessica B Adams, DAN Medical Team, Rhiannon Brenner, Gareth Lock, Dr Cleeve Robertson, Stephen Frink

Team

Morné Christou, Nicolene Olckers, Dr Frans Cronje

Cover photography

By John Vowles. It's a black pool, so I decided to go red for the lovely contrast Jade was happy with the idea She works with me when I need to test colours and lighting The lighting was above water to create this effect I diffuse the lighting so there will be no shadows around the subject I shot the image using my Canon 5D MK 4 camera, Canon lens 16/35 in my Nauticam housing My camera settings were F8 - ISO 100 - Speed 1/250 I also used my studio lights around the pool

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

@dan sa org

Alert Diver Philosophy

Theviewsexpressedbycontributorsarenotnecessarilythoseadvocatedbythe publisherorDANSouthernAfrica Whileeveryeffortismadetoensurethe accuracyofinformationandreports,thepublisherandDANSouthernAfricadonot acceptanyresponsibilitywhatsoeverforanyerrors,omissions,oranyeffects resultingtherefrom TothebestofthepublisherandDANSouthernAfrica’s knowledge,contributorshavenotindulgedinplagiarism Althoughtheutmostis donetoavoidsuchoccurrences,thepublisherandDANSouthernAfricawillnotbe heldresponsibleforthecontributors’orwriters’indulgenceinplagiarism Nopart ofthispublicationmaybeusedorreproducedinanyformwithoutthewritten permissionofDANSouthernAfrica E&OE

COVER THROUGH DAN

LIFESAVINGBENEFITS-24/7EMERGENCYHOTLINE-ACCESSTODIVE MEDICALEXPERTS-DIVINGRESOURCESTOKEEPYOUSAFE

Yourgatewaytodivesafetyservices&worldwidedive coverageatlowannualrates!

WWW.DANSA.ORG

Growing Safe Diving Communities

DIVE SLATE | PERSPECTIVES

TEXT BY MORNÉ CHRISTOU

For over two decades, DAN has been the go-to organisation for those in the diving industry looking for safety As a non-profit, our mission is to protect, give guidance and provide assistance to diving enthusiasts all around the world We are renowned for delivering emergency evacuation and medical aid when required; however, our primary goal is to prevent accidents from occurring in the first place

From the beginning, DAN has been committed to working hard to prioritise dive safety. Our programs are designed to prepare and safeguard divers, teach them how to recognise potential risks, increase their understanding of diving, and minimise any associated risks

The ultimate goal is to empower divers to be strong advocates for safety We motivate all members to remain committed to safe diving practices, oppose skill deterioration, and protest against taking shortcuts We recommend continuing education and advanced certifications to stay current with the latest industry standards In addition, first aid training should not be overlooked

YOUR HELP IS KEY

We acknowledge that the influence of peer pressure is a reality and should be utilised for positive outcomes As you strive to be safe, you can also serve as an example for others who want to do the same

Ensure all your dive buddies know that DAN is the go-to source for dive safety It has comprehensive resources, education, emergency assistance and other programs available to members Let them know they can enjoy protection throughout the year and have access to dive accident cover for a small annual fee - no less significant than their essential gear

Bringing new people to DAN not only adds members to the community but also creates a culture of dive safety Talk to anyone currently diving or interested in diving and explain how important it is to be part of the DAN family We all can make diving safer with the choices we make By working together, creating a safety culture can become standard for everyone So don't hesitate: to spread the word and encourage people you know to join DAN!

FORGING ALLIANCES

Our organisation is dedicated to aiding dive professionals, dive operators, and training agencies in dive safety To that end, the DAN

Safety Services team provides free consultations to ensure safe dive operations. We also strive to build and maintain alliances that encourage safety awareness through community outreach

STUDENT MEMBERSHIP

At DAN, we firmly believe that instructors play an essential role in teaching safe practices to new divers; this is why we have the Student Membership Program The program introduces divers to all the advantages of DAN membership, such as access to various resources and services

The Student Membership Program makes dive safety easily accessible with student dive accident benefits, providing up to R300,000 of dive accident coverage in the event of an accident during entry-level certification This is a crucial element in making sure entry-level divers are adequately protected

The Student Membership program provides instructors with a protective measure, allowing them to grant their students complimentary dive accident coverage Open to instructors from all training agencies All that is required is for the instructors to enrol as an annual DAN member to enrol their students through the online registration portal

Student membership is activated once registration is completed and a student member ID number is emailed to the instructor and the student Sign-up is straightforward, and student coverage takes effect right away Instructors should enrol their students before the start of their entry-level course so they are safeguarded by DAN from the moment they jump in the water We strongly recommend that instructors urge their students to join as annual DAN members after completing their course

DAN's safety and medical professionals are always on-call for students and instructors whether it be through our 24/7 Emergency Hotline for coordinating care in an accident or our Medical Information Line for

non-emergency medical questions such as fitnessto-dive considerations, the consequences of diving with a medical condition, or the impact of particular prescription medications. With no more reliable source on these issues than DAN, we are committed to assisting those who explore beneath the depths.

We are all part of the dive safety community, and we each need to do our part to ensure that accidents and injuries are minimised. As a member of DAN, you can set an example for other divers by following safe diving practices. Thank you for your commitment to this cause.

DIVE SLATE PROGRAM SPOTLIGHT

DAN works diligently to equip divers with the information they need to stay safe both in and out of the water Our Giant Stride publication provides newly certified divers or divers in training with a must-read introduction to key dive safety concepts and skills

An excellent companion piece to any entry-level course, this 52-page digital guide supplies relevant information about scuba gear, critical elements of dive planning, and dive etiquette After achieving certification, divers can continue to rely on the guide as an ongoing resource for dive physiology, health and fitness, and travelrelated information, both domestic and international

Help students and divers understand that knowledge of safe diving practices is as essential as their masks and fins to complete dives

successfully Dive professionals can incorporate Giant Stride in their training or share a copy with their students so they can take advantage of this free safety resource from DAN Doing so may instil in them the importance of continuing their dive education and demonstrate that learning never ends when it comes to the underwater world

Giant Stride is only one of many publications and resources that DAN has created for the benefit of all divers Access the guide by visiting dansa org/giant-stride and downloading the PDF

Guides such as Giant Stride provide a great reminder that all diving involves some risk and that DAN is one of the best, most reliable sources for expert risk mitigation

Divers learn in training to avoid diving when ill, but sometimes people become unwell or develop health problems during a dive Buddies who have not discussed how to communicate this may be unable to do so effectively underwater Instead, the affected diver may be reluctant but ultimately obliged to signal a basic request to end the dive, irrespective of how severe or trivial the health issue may be

Underwater signalling, by convention, requires that the buddy mirrors the signal and responds accordingly Without a prearranged communication plan, however, buddies who don’t know what is wrong may spend precious time trying to figure it out Even worse, they might respond inappropriately, such as letting the ill diver return to the surface unaccompanied

To help avoid such communication ambiguities while diving, PADI has developed a new standard hand signal for “I don’t feel well”

that the organization now teaches in its courses The signal is simple: With the fingers pointing toward themselves, the ill diver draws a large oval in front of their head and torso to indicate that they are physically unwell and need their buddy’s assistance This will usually result in the dive being ended Still, now – with a better understanding of the underlying reason – the buddy is more likely to be more willing to do so and more vigilant and supportive during the return to the surface

Having a specific signal for feeling unwell increases divers’ awareness of the importance of communicating clearly, which may also allow them to inform their buddies sooner and – in turn – encourage a quicker and more appropriate response

EXPLORE MORE

Watch a diver demonstrate the hand signal in this video - https://youtube/A2aKSfZxeSw

CONSIDER THE WEATHER

DIVE SLATE

TRAVEL SMARTER

With some forethought, gear, and preparation, you may still enjoy your dive despite inclement weather conditions The following considerations may be helpful as you plan your diving and create or review your emergency action plans (EAPs)

SUN

When diving in sunny conditions, bring a hat, a long-sleeved shirt or rash guard, and sunglasses to protect your skin and eyes Choose a sunscreen that’s less harmful to corals physical barriers such as zinc oxide and titanium dioxide are generally better than chemical barriers such as oxybenzone Ultraviolet (UV) rays penetrate clouds, so protect yourself from the sun even when the weather is overcast

When donning your wetsuit, remember that a dry diver in a black wetsuit can overheat quickly on a sunny day Hang your gear to dry in the shade rather than in direct sunlight to protect it

from UV rays Drink plenty of water and eat salty snacks if you’re hydrating aggressively

WIND AND RAIN

On windy days, be prepared for heavy seas Use a surface marker buoy to make yourself easier to spot in rain or surface chop If you are prone to seasickness, eat plain foods and use a seasickness medication you tolerate well

When diving from a boat, be sure to secure your gear and take extra care if the deck is wet and slippery Entries and exits can be more difficult in windy conditions, so time your exit correctly and be careful when grasping a moving ladder Listen carefully to the site briefing; the captain or crew may have specific instructions for boarding the boat in windy or choppy conditions Our bodies lose heat quickly when wet, especially in windy conditions, so consider bringing a rain jacket

LIGHTNING

In a thunderstorm, it is much safer to be indoors than anywhere outdoors Familiarize yourself with local weather patterns or listen to a forecast to avoid being caught in a storm In many areas, thunderstorms are more common in the afternoon, so plan excursions early in the day Even if a blue sky is overhead, lightning may still be a hazard if storm clouds are in the area

Avoid diving or being in the water during a storm It’s hard not to be the tallest object around if you’re on the water, and electric current can travel significant distances over the water’s surface Some might think staying underwater is a good idea because lightning does not tend to penetrate very deeply into the water column, but that is not practical in most situations Your gas supply, nodecompression limits, body temperature, and stamina are essential considerations

If you surface into a storm, staying at 6 to 9 metres might be reasonable, especially if you have surfaced far from the boat or shore and believe the storm will be short-lived or is quickly losing intensity However, you should consider this approach only if you can also follow all other safe diving guidelines A better option, usually, is to get out of the water quickly

Within the geographical confines of the Monterey Bay National Marine Sanctuary (MBNMS) is one of the world’s most ecologically diverse coastal marine environments The sanctuary boundary spans almost 6,000 square miles and contains more than 276 miles of California shoreline

A massive underwater canyon deeper than the Grand Canyon and comparable in size and length starts in the deep waters far beyond the sanctuary boundary and comes into the centre of Monterey Bay Every spring, the wind blowing along the California coast stimulates the cold water to upwell from the deepwater canyon, pulling up nutrient-rich water from the darkness, exposing it to the sunlight, and depositing it into the heart of the bay

This process fuels a sustenance explosion up the food chain, causing species to flock to the region in a yearly migration and churn the waves in group-feeding frenzies Writhing masses of sea lions, dolphins, and whales,

TEXT BY KYLE KRAY

https://www.montereybayaquarium.org/animals/livecams/monterey-bay-cam

https://elephantseal.org/live-view/

A SOUTHERN SEA OTTER HOLDS ITS MEAL - A DUNGENESS CRAB - WHILE

A SOUTHERN SEA OTTER HOLDS ITS MEAL - A DUNGENESS CRAB - WHILE SWIMMING THROUGH MOSS LANDING HARBOUR | SWIMMING THROUGH MOSS LANDING HARBOUR | ©DOUGLAS CROFT ©DOUGLAS CROFT

ANEMONES (URTICINA PISCIVORA) IN MONTEREY PISCIVORA) IN MONTEREY

BAY NATIONAL MARINE BAY NATIONAL MARINE SANCTUARY | SANCTUARY | ©ANDY ©ANDY SSALLMO ALLMO

The history of Monterey Bay and its adjacent coastlines is a history of human environmental exploitation The 1849 gold rush ushered in a mass migration of prospectors ready to tear apart the hillsides in search of the precious metal Many people who failed went into the existing fur trade, trapping sea otters for their pelts, while others chased elephant seals in the surf for their blubber Both species nearly became extinct in the process

A year after the gold rush began, the commercial whaling industry started in Monterey, with whaling stations dotting the coastline until 1921 Coastal residents would flock to the beaches to watch the whalers being towed back and forth across the bay by the harpooned deepwater creatures as they tried in vain to escape their pursuers Then some ventured out to deeper water to pursue whales, whose oil served as the energy source of the time

matched in fervour by birds diving in from above, create an awe-inspiring scene

Twenty-six species federally recognized as threatened or endangered reside in or migrate to the sanctuary, drawn from far away by more than just the spring upwelling In the summer, critically endangered leatherback sea turtles arrive after their nine-month, 7,000-mile journey from nesting beaches in Indonesia Each turtle in the sanctuary feasts on up to 50 jellyfish per day before completing their feeding cycle and initiating the nearly one-year migration from home to nest

Like the Serengeti National Park in northern Tanzania, which is well known as the site of the largest annual land animal migration in the world, it is no surprise that the Monterey Bay sanctuary is referred to in name as its aquatic counterpart due to the number and diversity of animals you can see in the bay on any given day.

Now a place where marine life and humans can coexist, MBNMS allows us to curb our natural instinct to dominate and consume the environment around us. But for this area of the U.S., that mindset was not always the case.

The coastal region’s seemingly limitless bounty proved otherwise when the otters, sea lions, and whales disappeared, and the bay became a watery desert Residents simply moved on to the next marine economy: harvesting giant California red abalone, the world’s largest abalone species A year before the last whaling station closed, nine different abalone

A DIVER HOVERS OVER A A DIVER HOVERS OVER A PAIR OF FISH-EATING PAIR OF FISH-EATING ANEMONES (URTICINA

HUMPBACK WHALES LUNGE-FEED ON HUMPBACK WHALES LUNGE-FEED ON ANCHOVIES IN MONTEREY BAY AS GULLS ANCHOVIES IN MONTEREY BAY AS GULLS SWOOP IN FROM ABOVE | ©DOUGLAS CROFT SWOOP IN FROM ABOVE | ©DOUGLAS CROFT

companies operated along the current sanctuary’s coastline, gathering abalone all day and shipping it worldwide.

When the abalone supply dwindled, the sardine industry exploded, leading to the region’s famed Cannery Row and Monterey becoming known as the sardine capital of the world But that title lasted for only a few years In the late 1940s, the local industry collapsed when the sardine bounty was exhausted This, in conjunction with the 1969 Santa Barbara oil spill that occurred approximately 250 miles down the coast, made many residents realize the impact of different industries on the local ecology

When politicians and oil industry executives set their sights on Monterey Bay for oil, gas, and mineral exploration and extraction, conservation efforts that had existed only at the grassroots level for decades began to grow exponentially Central California coastal communities rallied together and, with the leadership of local hero politicians, took the issue to Congress after years of legislative battling The combined efforts of everyone involved helped Monterey Bay achieve national marine sanctuary status in 1992, a designation it has held for 30 years

WHAT IS THE SANCTUARY AFTER THESE 30 YEARS?

It is a conservation success story Since the establishment of MBNMS, the ecosystem has recovered, and species populations have returned from their historically low levels and continue to thrive under strong protection efforts With the preservation of public access to beaches and coastal waters, Monterey Bay is a social catalyst where people gather together whether it’s beachgoers combing through rocky tide pools, surfers hitting the waves at the legendary Mavericks surf break, or scuba divers navigating through lush kelp forests, coral reefs, and canyon walls encrusted with colourful marine life

HUMPBACK WHALES LUNGE-FEED ON ANCHOVIES IN HUMPBACK WHALES LUNGE-FEED ON ANCHOVIES IN MONTEREY BAY AS GULLS SWOOP IN FROM ABOVE MONTEREY BAY AS GULLS SWOOP IN FROM ABOVE

It is a place of discoveries, such as the thousands of deepwater octopuses found laying their eggs three kilometres beneath the surface in the dark nooks and crannies of the Davidson Seamount area, which became part of the sanctuary in 2008 MBNMS has 463 reported shipwrecks within its waters such as the legendary USS Macon airship and its yellow- and blue-winged Sparrowhawk biplanes sitting 500 metres below the surface with more waiting to be discovered

It is a place of economy, where billions of dollars in revenue are generated yearly Once the whale-killing capital of California, Monterey Bay is now the whale-watching capital, generating more money than whale-hunting ever did Fisheries for abalone and sardines still exist, and the bay is the source of one of the world’s top markets for squid Enforced regulations ensure that overfishing of the bay’s resources won’t occur again

It is a place of science, acting as a living laboratory for research to enhance our understanding of the oceans and to help us make informed management decisions Eleven years after the 1987 outbreak of amnesic shellfish poisoning in humans in Canada, the

Monterey Marine Mammal Center discovered the domoic acid toxin in the sanctuary’s sea lions, which consume the same fish harvested by people in the bay They created a reporting chain for public health officials to help map toxin outbreaks and close harvesting locations When animals are identified with the toxin, fisheries in the affected areas can be regulated by ramping up testing followed by preventative measures

It is a place of growing concern The marine sanctuary encompasses no dry ground, with the shoreward boundary extending no further inland than the mean high-tide line The coastline of the sanctuary is vast, encompassing dense urban zones and four major shipping ports frequented by international vessels Approximately 8 million people live within 80 kilometres of the sanctuary shoreline, and thousands of square kilometres of coastal watersheds, adjacent to the sanctuary, drain waste disposal directly into the sanctuary’s wetlands and marine waters Plastic concentrations in the water exist at varying densities at all levels in the water column, from the surface down to 1,000 meters A 2022 Stanford University study suggests that blue and humpback whales in

the Monterey sanctuary may eat 10 million pieces of microplastics as much as 45 kilograms per day The data is so new that researchers are still uncertain of the future effects on whales and people Still, the ramifications of plastic in the ocean have historically been less than ideal for marine animals

MBNMS is more than just an environmental stronghold It stands as a model of sanctuary success for the US and inspires marine conservation efforts worldwide Thirty years as a national marine sanctuary is a victory Still, it is only the beginning when compared with nearly two centuries of negative human impact on the waters within its boundaries Some people believe the sanctuary is now in its most vulnerable state, not only from the studied effects of humanity on the environment but also from the false sense of protection in perpetuity without any need for further action: An enduring human effort is required to retain the true meaning of the word sanctuary Threats to the sanctuary are always on the horizon in the form of climate change, coastal development, pollution, and energy needs MBNMS requires continued funding and support so it can continue to preserve and protect the natural and cultural resources and qualities of the ocean and estuarine areas within its boundaries

CHASING THE SUN

LOCAL DIVING | TEXT BY HELEN WALNE

UnderwaterphotographerandwriterHelenWalnewasoncescaredof theoceanbutnowspendsallherfreetimeinCapeTown’skelpforests.

I used to despise the ocean – and for good reason. When I was six, a rogue wave at Durban’s Addington Beach knocked me off my feet and sucked me back and forth, grating my skin against the mussel-clad pier I cried when the nurse at the nearby hospital daubed mercurochrome all over my body

As a teenager, slightly drunk on Spiced Gold, I got felled by a breaker that relentlessly tumbled me, rubbed my face in the sand, and stole all my breath A man walking his ridgeback had to pluck me out

Then, two decades later, on a hot summer’s morning, my brother, Richard, swallowed a fistful of pills, waded out into Cape Town’s frigid Atlantic waters, and ended his life I couldn’t look at the ocean for two years I thought it had it in for me

Life is a strange, slippery thing After losing my other brother, Andrew, to muscular dystrophy seven years after Richard died, I began swimming First, it was in swimming pools: up and down; up and down – 65; 66; 67 It was meditative and soothing and loosened my tears After many months, I became fit and strong The cold had sparked me into being again I began to laugh at jokes

I was then ready to take my swimming further, and I approached an open-water group and asked a lot of questions: Would someone keep an eye on me? Were there waves? Would I get left behind? That first Sunday I joined the group, I was terrified and shy An icy shore break pummelled the shallows, and I clung to a large amiable man called Ali, who coached me through the waves and out into the silky blue It was the first time I had worn goggles in the sea And as I swam amid a windmill of arms and legs, I couldn’t believe what was below me: ribbons of golden kelp catching the light; flotillas of fish flitting among the reddest of algae; sun-rippled sand; sparks of silver I was entranced I needed to be here more!

After the next few months lagging the group as I ducked down with a terrible action camera, searching for light and kelp, I decided to swap swimming for snorkelling. That way, I could move at my own pace, taking in this crystalline world, learning about its creatures, and photographing little scenes of beauty I graduated to a better, compact camera; became obsessed with jellyfish; and eventually took a freediving course to help me delve deeper into this strange and inexplicable voyage How had I arrived here? Here, of all places? The very nub of all my fears and hurts! It is something I still can’t explain

Seven years later, here I am I freedive, suitless and sockless, every day Sometimes I even dive in the very place where Richard ended his life It is a beautiful spot, fringed by a towering kelp forest rooted in a bed of ruby seaweed Curious seals make silver spirals as they twirl and twist around you, while clumps of soft coral and jewel-like anemones stud the reefs and rocks

I now have a grown-up camera set-up I will be paying off for eternity And nothing brings me more joy than diving down into the kelp, wriggling into the undergrowth, and waiting for the light to be just right My knees, elbows and hands are constellations of urchin scars, and I wear them like aquatic tattoos

Much like the fynbos-clad mountains that rise from the city’s shores, Cape Town’s sea forests are home to a rich diversity of life Each dive is different: one day, you might be surprised by a short-tail stingray lifting off from the sandy seabed like an ancient pterodactyl; another day, you might be floating in a purple froth of jellies Curious common octopuses reach out their tentacles to “taste” your camera and arms while balls of silver sardines move like a single organism through the water Then there are the tiny creatures: nudibranchs as flamboyant as Rio Carnival dancers; teeny arthropods with googly eyes; specks of bryozoans meshed together in perfect fabric-like fractals

However, it is the interplay between kelp, sea and light that keeps me returning again and again I am addicted to how the sun shards through matted stands of bladder kelp and lands like a spotlight on anemones and sea fans I can’t get enough of the late-afternoon light that drenches the water, illuminating the sand and turning everything golden. Sometimes, I feel overwhelmed with grief when I dive – not for my brothers or for me, but for these pristine environments and the uncertain future they face

Surfacing these worlds via photography hopefully showcases the magic that exists – magic that requires us to become a better species.

I’m unsure what my life would have been like had I not experienced such profound loss I don’t think I would have found the kelp, the creatures, the light. And I wouldn’t have learnt that the ocean doesn’t have it in for me In fact, it has always been within me – I just needed to find my way back

Looking at many of the images made by professional photographer (and Nauticam Ambassador) John Vowles, it is hard to believe that they were all created in shallow water –often just below the surface John is known for his creativity and excellence in underwater fashion and beauty photography He is based in the picturesque town of Riebeeck Kasteel in the Western Cape, South Africa and is the Brand Ambassador for Nauticam and Dive Action in South Africa “I only use Nauticam equipment from Dive Action, as the parts are always available and the service is excellent”, says John

“I started scuba diving in 2010 and progressed to be a qualified AI PADI Instructor and have managed to stay current by assisting instructors and leading dives I very quickly tried my hand at underwater photography using a small compact and one strobe I was hooked”

UNDERWATER FISH & FASHION

LOCAL DIVING

TEXT BY ABBIE FISH

PHOTOS BY JOHN VOWLES

John Vowles is based in the picturesque town of Riebeeck Kasteel in the Western Cape, South Africa

2016 was a terrible summer for diving, and John realized that he needed to diversify and supplement his underwater photography and decided on model photography in a pool He discovered a whole new world of creativity, fashion and setting the stage for the models “My mentors around the world provided and supported me with the ‘tricks of the trade’, for which I am grateful”

John grew up in the Boland area of the Western Cape and has always enjoyed the summer days and nature In 2018 he bought a beach house in Pringle Bay and relished scuba diving and fishing He loves being close to the ocean Cape water is best for Macro Photography, and he focuses on this discipline For his macro images of all the small critters underwater, he uses a 60mm and 100mm macro lens Nauticam supplies all the necessary extensions and ports for these lenses

“I also have a Canon EOS 5DMK IV camera with a Canon 16-35mm wide-angle zoom lens for doing model photography For underwater wildlife and reefs scenes, I use a ‘fisheye’ lens”

Every underwater model shoot commences with a briefing about the shoot Ninety percent of John’s shoots are done in 15m water This makes it easier for the models to stand at any time They are never underwater for longer than 5 seconds at a time Another safety feature for the model is the scaffolding placed in the pool. This is there to hold on to just in case they need a breather.

“When I photograph models in the ocean, the shoot is mostly done in a rock pool as the water is generally calmer and warmer The model feels more comfortable. I like to maintain shallow dives when using fabrics, as ‘the clothing’ can become rather heavy. When doing a deeper model shoots, I always have a safety diver accompanying me with a hidden air source, said Vowles

John has dived in many locations, both abroad and locally. “But should I have to pick my favourite, it would be Sodwana Bay”

10 UNDERWATER PHOTOGRAPHY TIPS FOR BEGINNER DIVERS

GEAR|TEXTBYMARYKAPACE

Underwater photography presents an entirely new world of infinite photographic opportunities Even experienced photographers can find it challenging to start, as every aspect of the craft is more complex underwater. You might like to consider some of the top tips for getting a handle on the basics of this type of photography and avoiding those initial struggles

1. Being comfortable and safe underwater

If you are just starting to explore the ocean, whether, on scuba or freediving, you need to feel comfortable and safe doing so Diving safety begins with having proper working gear and a good dive buddy. It's vital that you remain aware of your surroundings underwater and not get too immersed in the photography, be safe! Have your dive buddy check on you, as you can easily forget where you are and how long you've been underwater while filming or photographing the mesmerising scenery and creatures underwater.

2. Plan the type of photography!

Your first question here is, do you want to take photographs, or do you want to film? This will determine if you add strobes or video lights to your camera system and therefore scale your camera system down and make it more simplified and less confusing/distracting when underwater Once you have decided that your next question is Macro or Wide-angle?

Choosing the lens, you will shoot with is better done the night before Ensuring your camera system and diving gear are ready gives you peace of mind and a relaxed feeling to enjoy your underwater adventure

3. Take that test shot!

A test shot can save you from reaching your depth, finding that perfect scene wanting to take the shot only to realise your lens cap is still on or your camera battery is flat. It allows you to check multiple things at once, (1) it checks that your lens cap is off, (2) that your SD card is in and working, (3) your strobes are firing, (4) the battery life of your camera, strobes and video lights are all good to go.

4. Practice makes perfect!

Get to know your camera and your camera housing! The more familiar you are with where all the buttons are on the housing, the easier and less frustrating it will be when at depth wanting to take that perfect shot If you have a

PHOTO OF PJ KOTZE TAKEN BY ROGER HORROCKS

PHOTO OF PJ KOTZE TAKEN BY ROGER HORROCKS

pool, jump in and test and play with the system If you don't have one, don't worry; your camera system also works topside The bottom line is that the more you have your camera system in your hands, the more you will learn where all your buttons are This will help you with muscle memory for when you're underwater and make it easier to concentrate on the beautiful scenery instead of which button to push

5 Setting up your camera system!

When setting up your camera system, remember to put your camera system together before you leave the house or if pushed for time in the car Avoid putting your system together on the beach or boat This can cause sand or water to go into your camera system, and if not cleaned properly, it can cause corrosion Setting up your camera system at home gives you plenty of time to ensure that there's nothing caught on the O-ring and to lubricate them before putting the camera system together You can then do your vacuum

check and have peace of mind that your camera system is adequately sealed Another thing to remember is to always work with the port side (the open side) of your dome port facing down to avoid anything falling into it and needing to clean the inside of the dome port With Nauticam they have a special multilayer broad-band anti-reflective coating inside, and therefore you will want to avoid rubbing on the inside to try and clean the dome as it might cause the coating to come off

6 Fogging!

Fogging inside the dome port, especially in summer, is a big issue Fogging occurs when the temperature on the inside of the camera system is much warmer than the temperature on the outside of the camera system There are a couple of ways of preventing/minimising it, (1) is to set up your camera system in a cool airconditioned room, be it inside your house or inside the car, (2) if spending the whole day on the boat or the beach doing multiple dives pack your camera system into a cooler box

PHOTO TAKEN BY ROGER HORROCKS PHOTO TAKEN BY ROGER HORROCKS

with ice packs that will cool down your system, (3) you can also use silica gel sachets on the inside of the housing however you would need to be careful as to where you place it so that it doesn’t interfere with any of the buttons, levers, gears or that it doesn’t fall around inside the dome port.

7. Be mindful!

Remember that it doesn't matter if you're doing underwater photography or diving; all the diving principles still apply to not touching the reefs and scaring your subjects. Respect nature! Buoyancy is essential! Ensure your buoyancy is correct before attempting to take your camera system underwater.

8. Gear maintenance!

Maintaining your gear in good condition is critical to the longevity of your camera system, let alone your diving gear. Many people don't spend time cleaning their gear correctly and only do a quick rinse and assume it is clean By only doing a quick rinse, you could be left with

a grain of sand or debris stuck between a button or lever, which can cause corrosion over time It is best to submerge it in a bucket of fresh water, and while it's in the water, press every button, lever or gear to ensure that there's no debris or that none of the buttons is stuck.

9. Shooting angle!

The angle at which you are shooting is very important. Shooting upwards or at the least level to your subject allows you to use natural light, especially if you don't have lights or strobes. The light will give more depth to your subject. It can also help frame your subject against the blue water and declutter the background. Remember to get up close, but at the same time, be respectful of the ocean habitat.

10. Enjoy!

Most importantly, your camera system should not stress you out Diving should be a fun and exciting experience!

PHOTO OF PJ KOTZE TAKEN BY ROGER HORROCKS

PHOTO OF PJ KOTZE TAKEN BY ROGER HORROCKS

Parting shot!

Hopefully, these tips make it easier for you to progress in your underwater photography. It can be challenging but incredibly rewarding if you master the basics. Please feel free to share any other tips with us at Dive Action and other underwater photographers.

Email: info@nauticam.co.za or info@diveaction.co.za

PHOTO BY HELEN WALNE PHOTO BY HELEN WALNE

This Fogging Mask Handy Tips GEAR

TEXT&PHOTOSBYNICOLENEOLCKERS

Havingaclearmaskwillmakeyoumorecomfortableevenunderlowvisibilitycondition

If there is one thing, any diver will tell you, they hate a flooded mask. This skill taught in the beginner phase of scuba diving has had many a diver reconsider becoming a diver. Some more experienced divers, however, will tell you that this is not the only irritation After a mask has flooded, there is the additional nuisance of having it continue to fog up because the unfogging liquid – usually saliva – has been rinsed off Now the diver needs to keep flooding the mask deliberately during the dive to rinse the fog off the visor, to remove the continuous fogging or endure a disappointing hazy dive And that's when being a master at the mask-flood-and-clear skill will serve you well You might not enjoy the dive as much, but you will at least be able to see the whale shark you have wanted to see since learning to dive

WHY IT HAPPENS

During manufacturing and assembly, the producers of your valuable window to the underwater world use a silicon spray to protect the glass and flexible silicon rubber components Due to this 'greasy' protection,

your mask will need proper cleaning and preparation before taking it on a dive.

PRE DIVE CARE

Every diver will have their bit of advice Your main goal is to remove the grease from the glass Not doing this will cause the mask to fog up New or beginner divers might find this stressful as they are unable to see the environment clearly and/or dread performing the mask flood-and-clear skill they were taught during the open water course

If you bought a new mask, you could try one of the following methods to degrease the inside of the lens

(1) THE MINTY

Unpack your mask, ie, take it out of the packaging DO NOT DUNK IT IN WATER AT THIS STAGE! Use plain white, whitening (which has polishing granules) toothpaste and add two small buds to each lens on the inside If you have a single lens mask, just add two dots

one left and one on the right-hand side

THE MINTY – ADD A SMALL DOLLOP OF PLAIN TOOTHPASTE TO THE INSIDE OF EACH LENS

THE MINTY – ADD A SMALL DOLLOP OF PLAIN TOOTHPASTE TO THE INSIDE OF EACH LENS

THE MINTY – SPREAD THE PASTE OVER THE LENSES INSIDE SURFACE AND LEAVE TO GO TACKY THE MINTY – SPREAD THE PASTE OVER THE LENSES INSIDE SURFACE AND LEAVE TO GO

Without adding water rub the toothpaste to cover the lens with your finger. Make small circular movements and use a little force. Continue rubbing until the paste becomes sticky or dry Let the paste dry out overnight or – if you are a bit rushed – at least for a few hours Once it has dried, dip your finger in water and polish the paste until it is crumbled

If you find the corners filled with toothpaste, you can use a toothbrush to remove the remaining paste Then let the mask dry completely

ONCE YOU USE THE MASK

Collect some saliva in your mouth and spit onto the dry mask Spread it over the inside of the lens Leave as is and rinse briefly right before donning it on your face

NOTE

The spitting trick doesn't work if you dunk the mask before applying the saliva

You might have to repeat the toothpaste procedure once or twice to degrease the glass It may seem a little gross, but it works!

THE BABY

You can use baby shampoo to prepare the mask similarly. Two small dabs of soap are used to cover the dry mask lens. From there, you would rinse it lightly before donning it This does not always keep the fogging at bay, but perhaps I am just doing it wrong!

NOTE

If you rinse it too well, the mask will fog up, and you must resort to the flooding manoeuvre during the dive

You might also find that although the shampoo manufacturer states that it will not burn your eyes if you accidentally get this into your oglers It isn't enjoyable

Getting a soapy taste in your mouth that stays for the duration of the dive is also not very pleasant

You will always need to pack the container when diving to protect your mask

THE BUSH WASH

This one is very effective if done correctly and when you are in isolated places or have not done any preparation between purchasing and

THE BURN – PROCEED WITH CAUTION WHEN DOING THIS THE BURN – PROCEED WITH CAUTION WHEN DOING THIS

THE BURN – PROCEED WITH CAUTION WHEN DOING THIS

THE BURN – PROCEED WITH CAUTION WHEN DOING THIS

using your new mask. You would use approximately a quarter teaspoon of liquid dishwashing soap mixed with the finest beach sand or earthy soil to perform "the Minty". The degreasing liquid soap and sand will need to be adequately rinsed from your new mask as it can be irritating should it get in your eyes

From here, you will do the spit routine again or use the baby shampoo

NOTE

This one worked very well for me while I worked in Mozambique

BURN

IT, BABY

WARNING! This technique can damage your mask's silicone rubber skirt /seal if done incorrectly.

You need a cigarette lighter, but not one with a blowtorch-like flame Be sure to guide the flame touching the inside of the lens carefully The flame should leave a black residue due to the burnt protective oil/grease layer Take care not to burn the rubber skirt of your mask! Once you have completed the burn, leave the mask to cool down Wipe away the black, sooty

matter with tissue paper or wash it with soap. From here, you can use the baby shampoo or the spitting technique to keep the fog at bay.

NOTE

Do not dunk the mask in cold water immediately after heating the lens with the flame It might shatter the glass Be careful not to burn/scorch the rubber skirt, the manufacturer made it perfectly flexible, and in some masks, these are very thin

THE MASK

Purchasing a mask is a personal preference

The mask should fit you It might look like they are one-size-fits-all, but they are all different You will need to be comfortable with it Some masks will need a few breaths to clear while others would require half a breath – low volume or -profile masks They come in fashionable colours or with transparent rubber skirts, allowing more light around your view Some divers, specifically photographers, prefer blacked skirted masks as this will enable them to see the image on the camera better For some divers, the black skirted mask might feel like they have tunnel vision

AFTER THE DIVE

Wash your mask in clean water and leave it out to dry before storing it in a protective container If you lost the container or never had one, the most straightforward alternative is to tuck the mask in the foot pocket of one of your fins

CONCLUSION

Because your mask is your window to view the underwater world, having a good, comfortable, fogfree visor is non-negotiable You will want clear glass through which to see all those magical creatures It is the key to having great underwater memories After all, seeing is believing

THE DIVE LIGHT | A TOOL FOR ALL DIVERS

GEAR

TEXT BY CHRISTINE TAMBURRI

The dive light is essential equipment that can benefit all divers on most dives There are several types of lights with various uses and a few key considerations you should make before purchasing There is no one-size-fits-all approach to dive lights, so each diver must carefully consider their own goals and needs before deciding which model is most helpful

DIVE LIGHT USES

Divers often believe that lights are solely for illuminating what lies below the surface on night dives, but that is only one of several applications On dives where no ambient light exists (such as night or cave diving), dive lights will illuminate your surroundings, but you can also use them to communicate with other divers

With ambient light, dive lights can restore colours lost with depth, help with high-quality photos of underwater life, and illuminate small creatures under ledges or in crevices You can use dive lights to communicate in these conditions, although your signals likely will be more challenging to see

A dive light can also help signal an emergency above or below the water A rapid back-andforth motion underwater indicates a diver in distress On the surface, a dive light can get the attention of the dive boat or a rescue helicopter, assuming conditions will allow it to be visible from afar

Nontraditional uses of dive lights include illuminating a dive flag that a diver is towing at night or lighting a pavilion for setting up gear after the sun sets One manufacturer even encourages customers to use their lights around an outdoor grill for evening postdive snacks However, not all dive lights can function safely while out of the water for long periods, so divers must research before using them nontraditionally

TYPES OF DIVE LIGHTS

Each type of dive light has unique applications Recreational divers usually use cordless, handheld lights that are easy to transport, simple to use, and typically reasonably priced Technical divers often prefer canister lights for their longer burn times and the ability to drop

them without losing the light head Several manufacturers have developed cordless lights with specifications similar to canister lights, so many technical divers are making the switch

LED (light-emitting diode) lights are becoming more popular due to their powerful beams, but some divers prefer HID (high-intensity discharge) lights with beams that work well in murky water

Divers must also consider mounting options

Some people use a hard or soft Goodman handle, while others use a hand strap You can also mount dive lights on a mask strap or helmet

CONSIDERATIONS BEFORE BUYING

High-quality dive lights are expensive, and divers should educate themselves before purchasing one. The intended application governs the burn time you’ll need. A cave diver, for example, needs longer burn times than an open-water diver doing daytime reef dives.

Your needs and uses will help determine what

intensity (measured in lumens) and coverage (measured in lux, or lumens per square meter) you’ll want in the dive light’s beam The beam angle is also crucial for using light to communicate The tighter the beam, the easier it is to discern signals The beam’s visibility is especially critical in conditions without ambient light or on technical dives that require precise and concise team communication

It is essential to buy a dive light from a reputable manufacturer Their products have proven quality and reliability, and getting trustworthy repairs and assistance through customer support is more accessible

TIPS AND TRICKS

Regardless of which dive light you choose, some tips can help make diving safer and more enjoyable

Burn tests help divers identify when it is time to replace batteries to optimize the lights’ performance You should perform a burn test on all dive lights every six to 12 months: Turn on your fully charged lights and put them in a bucket of water Record the time it takes for the battery to die, and track any changes from previous tests

Divers should use proper light etiquette while in the water Keep the beam forward and stable as much as possible Move the beam slowly, and avoid jerky movements that others may mistake as emergency signals Always pay attention to where you point it so that you don’t shine it directly into other divers’ eyes

The lead diver in a group should consider dimming their light This practice allows the light of anyone following to be more visible, which enhances team communication and allows for safer diving

Pros Choose DAN

TrustedWhenItMattersMost

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

THE SEA FROG SWIMS AGAIN GEAR

TEXT&PHOTOSBYNICOLENEOLCKERS

Photography underwater only came to my interest once I was working as a scuba instructor at a busy resort not far from the then-notorious Manta Reef Underwater photographers came from all over the world to dive with and photograph the iconic Manta Rays and Whale sharks in the Mozambican Indian Ocean

Last year, I had the privilege to use the ‘Rolls Royce’ of housings, the Nauticam, with an 8inch wide-angle dome port for a short while To say I felt spoilt rotten is a gross understatement I own a Sea Frogs housing 9 (also called the Meikon housing) Both housings fit the Canon EOS 5D MK IV with a 1635mm f28 MK II lens

On a recent trip around the country’s coast, visiting dive centres for marketing purposes, I had the privilege to dive with shark legend Walter Bernardis He took me to see the Bull Sharks around the Aliwal shoal reef This female, known as ‘Smiley’, suffered a broken jaw after being caught on a heavy hook Equipment: Canon EOS5D MK IV, 16-35mm Mk II lens set at 20mm, 1/160 sec, f/71, iso 640, Manual spot metering in the Sea Frogs housing)

I will not compare these housings and will let you know my thoughts and experiences of owning the composite Sea Frogs housing instead Yes, the logo is still on the housing The housing was originally purchased online The package deal included a flat or so-called “standard” port and the small 6-inch dome port It was given a name after all – the “Vlei Parra” The translation to English is the Wetland Frog because it wants to float to the surface

SEEING IS BELIEVING

Most serious photographers would, by now, just shake their heads Buying a plastic housing, online, to take an expensive camera underwater is not for the fainthearted, and most would tell you that you are taking a considerable risk. Taking any digital camera, in any underwater case, is risky business. You need to know how to look after the housing. How to set it up and what precautions to take once you have loaded the camera and connected the lighting systems.

This setup procedure must be done preferably the night before diving. It will allow you to test that every switch, dial, and strobe is working or doing what it is supposed to do before you go underwater. But you all know that by now.

BULL SHART ON ALIWAL SHOAL REEF BULL SHART ON ALIWAL SHOAL REEF

HOUSING WITH STROBES FITTED HOUSING WITH STROBES FITTED

My initial impression of the Frog was that it was bulky but lightweight The box showed that it would be able to either house the Canon EOS 5D MkIV Or the MkIII camera with minor changes The first issue was to find out what lens would fit in the flat port that arrived fitted to the housing Nowhere in the paperwork, on the port or the web, does anyone advise you on which lens to use with this port It also has no markings to indicate this I only use the flat port when I feel like trying some macro images with a Canon 50mm compact macro lens

The dome port - WA 0005 -comfortably fitted the 16-35mm Mk II wide-angle and the 2470mm Mk II lenses These are the ones I use primarily for underwater photography I find it relatively easy to do wide-angle underwater images, although I prefer an 8-inch dome And don’t forget the Tokina 11-17mm fisheye lens for those perfect superwide close-ups (the latter is on my wishlist)

THE VACUUM

Generally, the housing does what it was designed for – to keep the imaging equipment inside safe, dry and operable

Fellow diver and renowned macro photographer, Carel van der Colff, advised me to invest in the vacuum system as the housing design includes a vacuum port The sensor and pump can be purchased separately Once again, it is a simple design that takes getting used to With the miniature pump, to evacuate the air from the housing, you feel like pumping or vacuuming for a long while before the red indicator light change to green The green light confirms the housing is sealed The vacuum unit manual states that one should remove the unit after testing the seal I leave it in place and have dived with it to 37 m without issues All controls or buttons are operational outside, and the green light blinks cheerfully

ZOOMING

With both lenses having zoom capabilities, it is possible to fit them with a zoom accessory. I received one that fits the 24-70mm lens circumference. The basic design is crude, and I find the zoom to be uneven and scratchy. The gear ring also tends to move out of alignment when fitting the camera into the housing and port. So, I don't usually use this.

STILLS OR VIDEO

The next issue was experienced while diving on the wrecks at Smitswinkel Bay, Western Cape.

THE FITTED VACUUM UNIT THE FITTED VACUUM UNIT

THE PUMP BEING USED TO VACUUM SEAL THE HOUSING

THE PUMP BEING USED TO VACUUM SEAL THE HOUSING

THE STILL-VIDEO CONNECTOR - OUTSIDE OF HOUSING THE STILL-VIDEO CONNECTOR - OUTSIDE OF HOUSING

As usual, I fell off the boat, holding the camera close to my chest Doing so protects it from the water impact Once underwater, I discovered that I had accidentally switched from camera to video mode and could not return the switch to camera mode Even if you get it set up correctly on the surface, once underwater and the control makes it impossible to revert back The arm/switch connector design is really silly Once you use it, you cannot switch it back without opening the housing This happened to me on several occasions, so since then, I have realised that I have to decide in advance whether I will be shooting still images or doing video clips before setting the vacuum and going underwater

LIGHTING

The housing is fitted with a standard Nikonos bulkhead for strobe connection Although Ikelite state on their website that their cable does not fit this housing, I have tried it and found it fits and functions with two DS 160 Strobes Fortunately, I was given an Ikelite to Ikelite dual sync chord and found that the standard Ikelite bulkhead fits the opening where the Nikonos bulkhead connector was The non-TTL and hot-shoe connector works

and fits perfectly

CONCLUSION

Many underwater photographers in South Africa are fortunate to have the means to purchase durable equipment at least once in their lifetime Looking at the cost of wellknown housings, this is a bargain There are some niggles and simple design issues, but – in the final analysis – it works With the rate at which technology in photography is developing, one will need to upgrade constantly to have the best at your fingertips and hope that you can justify spending a small fortune on the equipment most would use 2 to 5 times a year This housing does what it was made for and keeps your gear safe, just like the more expensive ones do Yes, it does not look like much, but treated correctly, it will work fine – both under and on top of the water.

This Frog loves diving, and having proof of what I witnessed underwater, put a warm hand on my heart many times. And I certainly have a few new cool images in my archives, thanks to that.

INSIDE THE HOUSING, THE IKELITE NON-TTL INSIDE THE HOUSING, THE IKELITE NON-TTL HOT-SHOE AND BULKHEAD CONNECTORS ARE VISIBLE HOT-SHOE AND BULKHEAD CONNECTORS ARE VISIBLE

INSIDE THE HOUSING, THE IKELITE NON-TTL INSIDE THE HOUSING, THE IKELITE NON-TTL HOT-SHOE AND BULKHEAD CONNECTORS ARE VISIBLE HOT-SHOE AND BULKHEAD CONNECTORS ARE VISIBLE

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Life itself is a heck of a ride, isn’t it? The endless rollercoaster of highs and lows The ecstasy of life's wins when we get a dose of the good And the withdrawals and depressions of the lows when we get dealt a dose of the bad Life itself is a drug

I take cannabis daily I grind the seeds, along with pumpkin, sunflower, and flax seeds, into a fine powder which I shovel onto my porridge oats every morning for breakfast The fibre is pure magic for my colon microbiome, and the hemp seeds are packed full of nutritious plant protein, essential fatty acids, vitamins, and minerals Cannabis is pure gold, but the form I use it for is safe to do so in combination with my scuba diving and hyperbaric activities

Cannabis has been around for aeons It seems to have originated in central Asia some 12,000 years ago There are also records of it being farmed by the Chinese over 6000-years ago It was treasured for its protein-rich content, oils, and essential fibres for human health

TO SPLIFF OR NOT TO SPLIFF

WHAT A GREAT QUESTION EDUCATION

TEXT BY DENNIS GUICHARD

A review of how smoking marijuana impacts risk in scuba diving

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

Hashish, a resin obtained from the flowering buds of the plant, has even been found in Egyptian mummies.

The word ‘dagga’, as we know it in South Africa, is a Khoi-derived word meaning ‘intoxication’, which suggests that the locals of that time had also already identified that it had an attractive psychedelic side besides its nutritional content value

The cannabis plant contains some 450 chemical compounds, of which some 60 are classed as cannabinoids These bind to receptors on the surface of cells in different parts of our central nervous system to exert their effect

There are various classes of cannabinoids, with the two of most interest being the psychoactive delta-9-TetraHydroCannabinol (THC) and the medicinal-rich Cannabidiol (CBD) THC is the compound that gets you as stoned as a pebble beach, whereas CBD is the compound reported to have medicinal value for relieving pain and anxiety

Once consumed, THC is rapidly broken down within our bodies into molecules known as metabolites As many as 80 different metabolites are formed from THC Each of these has differing effects on our bodies depending on which receptors they bind to The metabolism of cannabis, and the production of these metabolites, are also determined by the method of consumption

Inhaled THC enters the bloodstream quickly and can reach peak levels within 6-10 minutes

Inhaled THC hits hard and fast but also recovers relatively quickly ‘Normal’ functioning can return within perhaps 2-4 hours The bioavailability of inhaled THC is only about 1035%

Oral consumption of THC produces a lower psychoactive effect than ingestion, with a

lower peak concentration. Once consumed, it travels to the liver, where most of it is either eliminated directly or metabolised into different forms. The bioavailability of ingested THC is only between 4-12% THC is highly soluble in our fatty tissue and is slowly released back into the bloodstream from these fat stores It thus has a longer half-life estimated at between 4-6 hours

The bioavailability of CBD is relatively low at only about 6% in humans when consumed orally but higher at about 31% when inhaled The brain, fatty tissue, and organs rapidly absorb CBD The half-life of CBD is estimated at between 18-32-hours

Women tend to absorb cannabis metabolites slower than men but also take longer to eliminate them THC can be detected in the blood for up to about 12 hours, in our saliva for approximately 24 hours, and in our urine for about 30 days THC residue can be detected in hair for up to 3 months in chronic users

Smoke from cannabis contains many of the same toxins, irritants, and carcinogens as tobacco smoke does Smoke inhalation can cause increased coughing and sputum production due to epithelial cell injury along the respiratory airways This damage then triggers goblet cell production, leading to increased mucus production in the lungs, increasing the risk of mucus plugs, air trapping, and gas embolism Smoking can also cause the lungs to become hyperinflated and develop patches of inflammation

Like tobacco smoke, a spliff also produces carbon monoxide, which binds chemically to the haemoglobin in our red blood cells and reduces the oxygen-carrying capacity of our blood, which we instead need when diving to provide our muscles and organs with energy so that they can function properly The carbon monoxide can also cause an increase in brain blood flow which might elevate the risk of

cerebral decompression sickness after diving. Smoking after a dive also interferes with bubble mechanics hindering the effective elimination of inert gas.

Cannabis THC consumption negatively impacts our concentration span, reaction time, shortterm memory, hand-eye coordination, time perception, and decision-making, making us stupidly invincible THC also causes an increase in heart rate and blood pressure all a recipe for disaster when combined with scuba diving

DAN’s guidance on consumption of cannabis is to avoid diving for at least 6-8 hours following ingestion of any ‘cookies’ Impairment from smoking a spliff is likely to be shorter Impairment is commonly both dosedependent and bio-individual, but blood THC levels seem to drop back to a ‘normal functioning’ level after perhaps 4-hours

I might be one of the dullest people on earth, but ‘spliffing’ is certainly not for me It is my ethos that we have no real purpose here on earth, in the relatively short time across the

aeons that we enjoy being here, other than to engage with the experience of being as fully as possible.

Life’s an endless rollercoaster that we need our wits for, and scuba diving is always mindblowing on its own When I get away on weekends to blow some bubbles off our coastline, I don’t even consume alcohol When I scuba dive, I always want to be as alert and well-rested as possible to engage in the magic of diving fully There is so much to see and absorb in life as much as in scuba diving, that I just don’t know why anyone would want to numb the experience of being from the full potential it offers But everyone fairly to their own

My ‘hemp seed mix’, which I shovel onto my breakfast porridge oats daily, is nutritious It is a healthy way to start every day and to ensure I can optimise my love of scuba diving and the experience of being

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MASTERING PROPER TRIM

EDUCATION

TEXTBYAUDREYCUDEL

"There is a basic rule I always teach my students: Where the head is pointing, the backside will follow. It usually triggers a series of chuckles and smirks, but the truth is that if we are not trim in the water column, we will struggle during the entire dive Trim is the diver's angle through the water in terms of alignment with the direction of motion For most of our dives, we want to be in neutral trim, a horizontal position parallel to the direction of travel When we control our trim, we reduce our swimming effort by reducing the surface area the diver presents to the water Consequently, we consume less gas, efficiently use our energy throughout the dive, and become less tired Being able to keep trim on the dive will significantly benefit our buoyancy control and our breathing patterns

To achieve trim, we need to balance the gear we are wearing, considering our exposure suit, the position of our cylinder or cylinders, and the distribution of weights These items adequately adapted to our body should facilitate our dive, not create additional effort and struggle

Working on the trim is a big part of becoming a good and comfortable scuba diver"

While mastery of breathing and buoyancy control is the ability of a diver to achieve and hold a specific position in the water column, trim defines the angle of the body in the water, in either static or propulsion mode Have you ever spotted a Seahorse? Its vertical trim in the water is typically the opposite of what a diver's trim should be Theoretically, a diver's trim could be identified as neutral, positive (slanting upward), or negative (slanting downward) However, in practice, and apart from constraints imposed by overhead environments, keeping the trim as neutral as possible throughout the dive and avoiding slanting upward or downward is the true skill to master

If you think of a diver as a helicopter taking off,

flying at various altitudes before landing, a diver's body line should remain horizontal at all times, knees and ankles bent ninety degrees to keep the fins above the body level and parallel to the bottom, just like a helicopter's blades rotating parallel to the ground Laying face down as if on a virtual platform, the diver's hands, arms, chest, hips and upper legs are all at the same level, and no part of their equipment should dangle below the body line Beyond being environmentally friendly, the less resistance a diver creates passing through the water and staying aligned with the direction of motion, the better the hydrodynamics, the less the swimming effort and subsequent gas usage, and the safer the dive

Many factors can offset a diver's horizontal axis However, apart from the body tension required in the shoulders, core and gluteal muscles, holding a horizontal posture should not be too much of an effort, provided all weight components and gas distribution don't alter the diver's centre of gravity

Achieving proper trim is largely a matter of weight positioning As Greek mathematician and physicist Archimedes once observed, "Equal weights at equal distances are in equilibrium, and equal weights at unequal distances are not in equilibrium but incline towards the weight which is at the greater distance" In the case of a diver, the weight components are cylinders (and all related equipment: valves, regulators, backplates), ballast weights and fins Whether you're diving a single or doubles, there is a limit to the adjustments that can be made to the cylinders' position relative to the body, be they back or side mounted, independent of the type of cylinder Also, for safety reasons, divers need to be able to reach their valves in case a valve shutdown is required

Many divers with poor skills experience before surfacing, usually with back pain However, the distribution of a diver's ballast weights is a

CRISTINA ZENATO, CAVE EXPLORER, ADVANCED CAVE DIVING INSTRUCTOR, SIDEWINDER

CRISTINA ZENATO, CAVE EXPLORER, ADVANCED CAVE DIVING INSTRUCTOR, SIDEWINDER

REBREATHER INSTRUCTOR, MEMBER OF THE WOMEN DIVERS HALL OF FAME, EXPLORERS CLUB FELLOW

REBREATHER INSTRUCTOR, MEMBER OF THE WOMEN DIVERS HALL OF FAME, EXPLORERS CLUB FELLOW

major contributing factor to their trim, and they can act on it. Once a diver has determined the amount of ballast weights required, wrapping a metaphorical anvil around the waist on a heavy, ill-fitting weight belt is arguably not the smartest nor the safest strategy The effect is the one of an unbalanced seesaw that can force a diver into a vertical position Instead, they need the right amount of weight, positioned and secured in the right place Securing one's ballast weights in the proper location not only guarantees that none of the weights will be dropped accidentally, but it avoids having them shift in a dissymmetric way that would make the diver roll sideways

Fins can also significantly impact a diver's trim; travelling considerations should not be the primary concern when choosing their dry weight Beyond obvious requirements such as an appropriate foot pocket size and a blade surface matching the diver's leg power, the dry weight and saltwater buoyancy weight can vary tremendously from one model to another and from one size to another Selecting the appropriate size and weight of fins makes ankle weights unnecessary It prevents the knees from dropping under the horizontal axis

Provided the weight is distributed correctly, enabling the diver to position themselves face down, gas distribution is the second major factor to consider when tuning a diver's trim The action of inflating or deflating a wing (or buoyancy compensator device), a drysuit, or ensuring the right amount of gas flows through a rebreather's diver's counter lungs during the dive are done to maintain buoyancy and comfort However, where the gas flows, the diver goes

Provided the design and sizing of such equipment are appropriate, finding the balance between the centre of gravity and the centre of buoyancy is a skill to master

Wings and buoyancy compensator devices

come in different designs with different gas distribution characteristics. For example, gas spreads more quickly in a doughnut-shaped wing bladder compared to a horseshoe design. To be in equilibrium underwater, the centre of buoyancy must be directly above the centre of gravity Any variation requires exertion on the part of the diver to maintain a hydrodynamic position This can increase gas consumption when static in the water compared to the propulsion phase, where the speed makes up for a positive or negative trim

Drysuits tend to be disregarded by many divers who find them hard to manage and only see them as providing thermal comfort However, the amount of gas required to provide thermal protection while avoiding squeezes or vasoconstriction plays an active role in a diver's trim and should allow for slight trim adjustments This is accomplished through the efficient gas distribution within the suit, which can only be achieved in horizontal or neutral trim

Once a diver has performed a buoyancy check, a trim check will enhance their underwater experience This check is not about a diver's ability to perform but about verification of proper weight distribution together with the alignment of centres of buoyancy and gravityIt only takes a few minutes for one to maintain proper body tension, remain still in shallow waters, deflate his drysuit, look forward, find neutral buoyancy by inflating the wing and adopt a normal breathing pattern to find out whether they shift forward, backwards or sideways

Trim mastery and breathing and buoyancy control represent two of the fundamentals of safe and advanced diving Any deviation can create numerous hazards and jeopardizes the diver The team's safety and the environment loss of buoyancy and breathing control, along with the seesaw depth profile created by being out of trim can negatively impact team

awareness and ability to communicate effectively, impact the environment, create depth and gas management issues, and even result in less than optimal decompression Once entropy has turned into equilibrium, the resulting balance and order enable the diver to focus on their surroundings and the team rather than themselves, perform tasks, and move on to the next level of their 'House of Cards'

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

It’s an amazing gift to be alive isn’t it The relative blink of a moment across the eons of time that we get to be here at all And on top of that that we get gifted the opportunity to scuba dive Surely nothing could be better

Our being here at all however is a very fortunate quirk of physics and physiology Our life systems are immensely fragile and can only survive in a very narrow range of oxygen tolerance pressures And our atmosphere currently happens to give us exactly what it is that our cells need to survive Any less oxygen, or too much more, and our atmosphere would kill us

Oxygen is a critical component in the metabolic processes that give us life Nearly every cell of our body houses thousands of tiny power structures called mitochondria The function of which are to convert the nutrients we eat into an energy source called ATP that our cells can further use for energy for all the bodily functions we require And oxygen is a

UNDERSTANDING OXYGEN TOXICITY

HOW DOES IT IMPACT OUR BODIES EDUCATION

TEXT BY DENNIS GUICHARD

A breath of fresh air understanding how high partial pressures of oxygen impact our body

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

critical component of that process. But the generation of ATP is a messy process and our cells also generate various forms of reactive oxygen species (ROS) when some oxygen molecules react badly with electrons and spill out from the mitochondria

But the body is clever because it has some inbuilt protective defence systems, called antioxidants, who’s function it is to hunt down and clean up these destructive ROS The most powerful antioxidant called glutathione, one of many in our body, is produced in our liver as long as we provide the essential nutrients to generate it The problem however occurs when our antioxidant systems are either insufficient, perhaps through poor diet and/or from a poor lifestyle, or when our antioxidant systems are overwhelmed with too much ROS

A misnomer that we’ve all been lead to believe, or that we’ve all admittedly been teaching as dive instructors for literally decades, is that oxygen toxicity in diving only occurs at certain limits And this is not strictly true

A certain amount of ROS are valuable in our

bodies because they function as signalling molecules that control many physiological processes. Amongst many benefits of course in hyperbaric medicine, we also specifically administer high partial pressures of oxygen in the chamber to purposefully generate excess ROS These trigger stem cell release critical for wound healing So ROS can be a good thing as long as we keep a delicate balance in check

The extent of oxygen toxicity (excess ROS) is influenced by intensity of exposure (partial pressure of oxygen), the duration of exposure (time), exercise (metabolic rate), immersion (wet vs dry), and also individual susceptibility Overwhelm our antioxidant defence systems and that good can very quickly become bad

ROS are generated in our tissue cells endlessly even at the atmospheric pressure at which we’re fortunate enough as a species to survive The ROS/antioxidant toxicity battle between vital cell signalling and destructive cell damage balance is a delicate and endless process

Up to about 050 bar ppO2 and for relatively short periods of time, our bodies cope well in

cleaning out the rampant ROS. At levels of up to about 1.20 bar ppO2 our lungs seem to be one of the primary organs of decay. Beyond a level of about 1.60 ppO2 central nervous system (CNS) decay starts to dominate as the exposure-limiting process

At low levels of hyperoxia the ROS predominantly damages the alveolar-capillary barrier in our lungs over time Plasma leaks into our alveoli and our critical gas exchange interface is hindered until we literally drown in our own plasma Given enough time, even breathing 100% oxygen at surface pressures (100 ppO2) would kill us Reason enough why air breaks are always included in oxygen breathing administration This process starts as

soon as we breathe elevated ppO2 above atmospheric pressure (0.21 ppO2). That alveolar cellular damage also leads to secondary acute inflammation further compounding the injury.

The production of excess ROS ceases as soon as we stop breathing the elevated ppO2 mixture The cellular alveoli damage will immediately start to recover, although the inflammation process can still continue for many hours

Various mathematical models have been proposed over the decades to try and help predict the detrimental effects of both pulmonary and CNS oxygen toxicity, all of which have their benefits and shortfalls

"Watch this space for forthcoming editions where we will look at oxygen toxicity more closely..."

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

DIVING ETIQUETTE

THE MARINE ENVIRONMENT

EDUCATION|TEXTBYCLAUDIODIMANAO

Imagine you are having a party at home, a wonderful house fitted with paintings, carpets, fine porcelain, and antique furniture Now, imagine some of your guests, in the middle of the party, starting to display really odd behaviour: one is feeding chocolate to your cat; another is playing Tarzan on your curtains; and yet another stumbles into your precious vases, smashing them to pieces It is unlikely that you will be amused, yet this is often how we treat the underwater environment that is meant to be shared with others who will follow us

We can harm marine environments in hundreds of ways, but marine life sometimes strikes back! Marine creatures aren’t always graceful and passive Several of them come equipped with barbs, stinging cells and teeth You really don’t want to upset them

LIKE A BULL IN A CHINA SHOP

Corals are not the same: some fragile and carelessly dangling submersible pressure gauge may literally break pieces off it Other corals are hardier, and divers are less likely to cause permanent damage And then, of course, there are the corals that get back at you -- fire coral being one of the best examples

As a rule of thumb, try to stay at least a metre away from any coral structure Most corals are sensitive to the chemicals contained in typical suntan lotions If possible, try to make the extra effort and acquire suntan lotion that is produced to be specifically coral friendly Remember that corals aren’t merely animals in isolation They provide a protective habitat for myriads of other ocean speciesThe destruction of corals may render a former underwater oasis into a desert wasteland

SEAGRASS AND SANDY BOTTOMS

In former years, using scooters and dragging anchors was considered normative, and the impact on the environment was disregarded or at least poorly understood We don’t do it anymore. Nowadays, dive boats try to use fixed buoys rather than weighing their anchors. Sandy bottoms are also chosen deliberately if anchors need to be used. Don’t forget that ocean flora produces the greatest quantity of oxygen in our atmosphere. By killing ocean life, we take our own breath away -- quite literally.

COLLECTING SHELLS

Collecting shells is sea burglary to put it bluntly! It is frowned upon for a variety of

reasons The first and foremost reason for not collecting shells underwater is that this deprives other divers of the pleasure of seeing the creatures in their natural habitat

Sometimes shells may appear lifeless, but if left alone for a couple of minutes, their shy owner may decide to make an exhilarating appearance Some shells, and cone shells, in particular, can envenomate a diver through a pocket or bag There have been several deaths attributed to this Again, adhere to the mantra “Take only pictures, and leave only bubbles”

RIDING FISHES, REPTILES, AND MAMMALS

When recreational diving was still in its infancy, divers would often attempt to ride, or allow themselves to be dragged by sea creatures, including turtles, rays, and sharks, such as basking- or whale sharks We now know that this behaviour can be devastating and sometimes even fatal to these creatures We actively discourage divers from doing this

OLD BRASSES FASCINATION

Pillaging brass objects such as ships bells and

portholes were very common in the early days of diving While it is true that many of these structures will eventually either be corroded or encrusted with marine life, it is considered something between theft and selfishness to remove objects from wrecks Don’t be selfish Consider the enjoyment the next group of divers will have in finding them

FEEDING

Feeding fish varies from specific attractions, to an informal and very hazardous individual activity Just like domestic pets, sea creatures soon come to expect to be fed if this happens with any regularity If you find yourself without anything to offer, they may choose a body part as a snack Because of this, feeding fish and other marine life is discouraged unless it is undertaken in a deliberate and disciplined way.

POLYMERS ARE FOREVER

Plastic containers and many other synthetic products last almost indefinitely. Not only are they unsightly, but they can cause the death of several sea creatures. Take every possible precaution not to contaminate the oceans with polymer or plastic containers or other synthetic objects.

THE ORIGIN OF BON-TON IS AN EVERLASTING INSIGHT

The sea is full of mythological vignettes Some Greek myths attribute the actions of scorpions and snakes to angered immortals Be that as it may, there are certainly many sea creatures that are capable of inflicting severe if not fatal wounds on humans Fortunately, only 2% of injuries attributed to diving eyes are the result of hazardous marine life Of these, the scorpion-, lion-, and stonefish (all of which belong to the Scorpaenidae Family) can inflict significant injuries The appropriate response is respect, slow movement, not touching marine life, and avoiding inadvertent crash landing on dive sites Most marine life is shy and, if given a chance, will retreat If they are cornered, however, they will defend themselves sometimes with fatal consequences So be gentle and kind

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When planning an effective fitness program, it is important to separate fact from fiction

Fitness folklore spreads quickly because many people are drawn to promises of magical quick fixes The reality is that fitness is a way of life A surefire path to success includes proper nutrition, hydration, sleep and exercise, all incorporated into your daily life You should make time for these things each day just as you manage to find time to shower, brush your teeth and eat

DRINKING COLD WATER DURING OR AFTER EXERCISE IS BAD FOR YOU. MYTH

Cold water has actually been shown to be absorbed more quickly, so it can effectively rehydrate the body during or after exercise An additional benefit of cold water is bodytemperature regulation, which is particularly important on hot days Hydration is the priority and the water temperature is secondary If you are freezing following a dive, drink warmer water If you are sweating topside, drink cooler water Pay attention to how you feel and ingest fluids according to your thirst

FITNESS MYTH OR FACT?

DIVE FITNESS

TEXT BY JESSICA B. ADAMS, PH.D

DAN recommends that divers avoid strenuous exercise for 24 hours after diving This avoids increasing the chances of decompression sickness. During your annual physical exam or following any changes in your health status, consult your physician to ensure you have medical clearance to dive

DRINKING COLD WATER DURING OR AFTER EXERCISE IS BAD FOR YOU - MYTH

DRINKING COLD WATER DURING OR AFTER EXERCISE IS BAD FOR YOU - MYTH

IF YOU ARE WORKING OUT, YOU NEED A SPORTS DRINK - MYTH IF YOU ARE WORKING OUT, YOU NEED A SPORTS DRINK - MYTH

THERE IS NO BENEFIT TO A SHORT WORKOUT. — MYTH

One of the largest barriers to exercise is time. Therefore, any amount of time that you can use to squeeze in some physical activity is beneficial The greatest health benefits of exercise are shown between inactivity and some activity In other words, every step counts Three 10-minute workout sessions are just as beneficial (if not more so) than a single 30-minute session

IF YOU ARE WORKING OUT, YOU NEED A SPORTS DRINK. MYTH

A tendency to drink sweet beverages when exercising places many exercisers (especially new exercisers) in a positive caloric balance, which leads to weight gain (fat not muscle) A typical 500 ml Powerade contains approximately 155 calories and 30 g of sugar If you consumed the whole bottle you would need to run over 1 km to break even A good rule of thumb is that if an exercise session does not exceed 90 minutes in duration, water should be your drink of choice

SIT-UPS AND CRUNCHES ELIMINATE BELLY FAT. MYTH

There is no factual basis for spot reduction of body fat Sit ups and crunches will firm up muscles that lie under the fat, but there is no connection between this muscle development and local fat cells The only way to reduce body fat is to burn more energy than you store Unfortunately, where you lose and gain weight first is genetically determined Feel free to blame your parents Sit ups and crunches target very specific muscles and are not high energy expenders So I am sorry to say that these exercises will not do much to improve your overall body composition or eliminate that extra weight around your middle

WEIGHT GAIN CAN BE CAUSED BY LACK OF SLEEP FACT

Have you ever found yourself eating more when you are tired? This behaviour is not because of a personal lack of control but rather there is a physiological basis for it Lack of sleep creates a hormone imbalance:

The levels of the hormone leptin (which tells your body to stop eating) fall, while levels of ghrelin (which makes you think you are hungry) rise. Have you noticed that you choose high-carb, high-sugar foods when you are tired? This is because the brain runs on glucose, the simplest form of sugar When the brain is tired, it wants sugar This combination of increased caloric intake in the form of highsugar foods leads to weight gain Proper sleep is vital to maintaining caloric balance and having energy for exercise

YOU HAVE TO STAY IN THE “FAT-BURNING ZONE” TO BURN FAT. MYTH

Many exercise machines indicate that low levels of exertion are considered the “fatburning zone” It is true that as much as 90% of your energy at this low level is fuelled by fat But keep in mind that the rate at which calories are burned will be low: 90% of a little is still a little By extension, would you rather have someone give you 90% of R1 or 25% of R100? When exercising at higher intensities, a smaller percentage of your activity is fuelled by fat, but the total calories burned at that higher intensity will be much greater than during a low-intensity workout of the same duration

EXERCISE IMPROVES BRAIN FUNCTION. FACT

Pay attention to your productivity I have found solutions to many work and personal challenges following an exercise session Brain scans have shown that exercise boosts blood flow to the brain and increases brain activity

An additional benefit of exercise is neurogenesis, the building of new brain cells and new connections between brain cells Yes, exercise can make you smarter

It does not matter how you fared in this test of fitness folklore By simply reading this article you are now better informed about some common misconceptions of exercise Keep in mind that everything you hear at the gym is not necessarily true Consider the science behind the statements, and remember that much advice is well intentioned and framed in partial truths There is no magic bullet for wellness

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DIVING FIT IN 7-DAYS OR YOUR MONEY BACK

DIVE FITNESS

TEXT BY DENNIS GUICHARD

Watching a YouTube documentary the other night on how in March 2022, the South African freediver Amber Filary set a new 90m Guinness World Record for the longest underwater ice swim on one breath, with no fins, weights, or even a wetsuit, I thought to myself sitting on my couch: 'That can't be hard' !?

On a recent dive trip to Sodwana, I paid a small ransom after remortgaging my car to afford to dive with Nitrox I intended to keep my nitrogen load to a minimum to avoid the otherwise inevitable afternoon nap But the benefit of Nitrox is that it's also supposed to let you safely dive for longer

To my dismay, not having dived in over a year and a half, I found I was often the first one back on the boat with an appalling air consumption rate That, and the discovery that you don't get lollies after the dive anymore, which were more often than not part of the highlightThe defence was that people too commonly discarded their wrappers and sticks into the sea, and which was an environmental move, but it still somehow

saddened me, which has absolutely nothing to do with my point

I attributed my appalling breathing rate to the sheer excitement I felt just being back in the water My 'engine' uses a lot of energy What I lack in speed, I make up for with optimism Well, that and the grandiose effort of energy it now takes to squeeze into a wetsuit seemingly once fit for a dwarf

Follow that with the trek across the soft beach sand to the dive boat, helping scrum the vessel into the surf, struggling yourself up over the pontoon after numerous failed attempts only to collapse on the deck floor like an up-ended turtle, holding on for dear life through the launch and boat trip, and then trying to reach your feet to get your fins on; it's no wonder any of us (speaking for myself) have much energy left to actually dive

Inspired by the YouTube clip and suddenly overflowing with optimism about what might be possible, I set my mind to getting myself back to

MY STRATEGY FOR IMPROVING MY AIR CONSUMPTION AND LOOKING LESS LIKE A POTATO ON THE DIVE BOAT

the full level of diving fitness I'd lost somewhere back in my youth. Ageing and being an introverted desk-bound recluse, drafting articles for the DAN magazine isn't for the meek This is a chance for a new me well, a new 'us' if you follow the plan too

DAY 1

Move all those empty shoe boxes you've been saving in the garage for another day to find your dive box buried under dust in a corner Have a can of Doom and one of your kids' flipflops handy for the roaches that have long since made your dive box their home Chances are they will all starburst outwards in an equal level of squealing shock that your dive gear is seeing the light of day Standing on a cooler box before you open the dive box will prove to be a smart move you'll thank me for later

Retrieve your wetsuit, giving it a good shake to ensure no more bugs are harbouring inside It'll probably smell worse than the current Durban beachfront, so you'll probably want to give it a cold soapy wash

They say that the first key to success is just getting started A marathon starts with the first step Ambition is half the challenge You've done well for Day 1; let's pace ourselves Hang the wetsuit to dry, and put the kettle on for afternoon tea and another biscuit Tomorrow's another day

DAY 2

Put the wetsuit on As it's now at least two sizes smaller than it needs to be, you'll best start this task sitting down You'll exercise all the main muscles in your arms and shoulders and need to breathe in deep, exercising your diaphragm muscles if you stand any chance of pulling it up over your abdomen

It's rumoured that things get easier once you've breached the wetsuit over your waist, but with your fingernails missing, you might need to do the rest using your teeth

Draw the wetsuit over your shoulders, dislodging your scapula whilst trying to get your arms down the sleeves. Ask Siri to phone for a chiropractor, which you'll need for your cramping back

At this point, you'll realise the zip is oxidised solid and doesn't move A squirt of Q20 might help, as will laying on the floor in a puddle of sweat until the crusty seizure dissolves away

DAY 3

Having slept overnight on the kitchen floor in the wetsuit, enjoy a gentle jog around the suburbs of only 3-5km Slow down at the first signs of hamstring cramping Some lightheadedness and gasping can be expected The onset of projectile vomiting (reminding you of those tequila nights as a teenager) should be a good benchmark for when you've peaked Try not to howl like a hyena, as this may excite the neighbourhood dogs when you might not yet be ready for a sprint finish

After a couple of weeks, you might want to wear your weight belt or carry a dive cylinder on each shoulder Two cylinders are better than one for balance and protecting your back, especially if you're attracted to trying out this sidemount diving larky

If your fingernails have started growing back, remove your wetsuit each evening Lathering yourself in gate grease might assist in getting it back on in the morning Drink lots of water You're doing well

DAY 4

Sleep DAY 5

Pushing an inflatable dive boat up the beach sounds harder than it really isIt's easier if you get a few dive mates involved with your fitness program and keep the boat balanced on its keel as you go The pontoons are full of air if

you think about it By now, your fitness should be improving, so this task should be a breeze

If you find it's too easy, you can always invite a bunch of kids to sit on the boat as you do circuits along the sand dunes

End the session by deflating the boat pontoons and orally reinflating them It's not unlike blowing up an inflatable mattress when you go camping, so you will quickly get the hang of it

DAY 6

Remove the twin 90hp Evinrude engines from

the back of the dive boat Tuck one under each arm for balance and repeat the neighbourhood run, extending your distance to a comfortable 10-12km

You'll be surprised at how your fitness should improve and how well you adapt to the challenge Add extra weights to your belt if you want to push yourself

DAY 7

Sell all your diving gear on Facebook Marketplace and take up darts

JOINT PAIN AND DIVING

FROM THE MEDICAL LINE DAN MEDICS & RESEARCHERS ANSWER YOUR DIVE MEDICINE QUESTIONS

Q | I have non-radiographic axial spondyloarthritis and hope being underwater will help relieve my joint pain. I take Celebrex as needed, and my recent stress and lung function tests were normal. Is it safe to dive with my condition?

Nonradiographic axial spondyloarthritis (nraxSpA) is not well understood in rheumatology The symptoms vary in each person, so doctors must evaluate everyone individually Back pain is often the first sign of the disease and may be problematic for diving Divers carry between 40 and 50 pounds of weight, including gear and cylinders

Divers should be able to don and doff their gear unassisted, move around on rocking boats, perform shore entry and egress (often under challenging conditions), and climb dive ladders with gear on Any of those scenarios could potentially exacerbate your symptoms Although the shoulders bear much of the gear weight, it can also transfer to your back and hips You should also consider if the condition is affecting your other joints, which often occurs with nraxSpA

Your effort to relieve joint pain involves achieving neutral buoyancy, which requires some physical exertion Additionally, nr-axSpa often progresses into ankylosing spondylitis with inflammation where tendons, ligaments, or joint capsules enter the bone, leading to spinal fusion and reduced mobility It can take years for the disease to progress that far, or it may never progress, but it is still a consideration

Your physician should also consider other symptoms, such as psoriasis plaque, gastrointestinal upset, and eye inflammation often associated with spondyloarthritis, when determining your medical fitness for diving

Guidelines for diving may exceed the exertion required for land-based sports DAN can provide those guidelines to help you and your physician make an informed decision about your fitness to dive

The most crucial factor is your ability to handle diving’s physical demands If the medication manages the disease and your physician

considers the condition well-controlled, diving may not be an issue. Experiencing side effects such as dizziness, nausea, vomiting, or abdominal pain is reason enough not to dive Pain should be controlled so it won’t confuse the presence of pain-only decompression sickness (DCS), shoul It occur

Anything that compromises your safety is an absolute contraindication for diving Since this condition involves inflammation, it is important to understand that dive medicine experts believe inflammation plays a significant role in the pathophysiology of decompression illness We don’t know if someone with an underlying inflammatory condition has a significantly higher risk of DCS If you decide to dive, it would be prudent to be conservative

Lana P Sorrell, MBA, EMT, DMT

Q | I have Holmes-Adie syndrome and have had a CT scan, an MRI, and visits to an optometrist and ophthalmologist. My pupils are different sizes, and the tendons behind them don’t respond, so they do not contract as they should in sunlight. Can I dive, or will diving make it worse?

The primary manifestation of the neurological disorder Holmes-Adie syndrome is unequal pupil size resulting from the eyes’ slow reaction to direct light. Potential causes vary, but many cases result from inflammation or damage to the nerves that carry the signals that help control the body’s involuntary functions, such as the pupil’s response to stimuli

Common symptoms include blurry vision, unequal pupils, photophobia (sensitivity to bright light), headaches, facial pain, and sluggish tendon reflexes Some of these symptoms can mimic those of DCS and may make it difficult for a physician to assess an issue you have while diving Consider obtaining a note, image, or description from your physician that documents your current medical status and baseline symptom presentation Keep the letter with you to present to medical personnel if suspected DCS occurs

The fluid-filled eyeball attains ambient pressure with no volume change, so the pressure increases at depth aren’t a concern, but seeing clearly before, during, and after diving is

essential If your syndrome affects your vision, you may be unable to read gauges or adequately respond to a situation requiring urgent attention Divers should be able to read a compass and pressure, depth, dive time, and decompression gauges and instruments Your vision needs to be clear to locate and navigate entry and exit points and see and recognize your buddy

Before diving, seek a fitness-to-dive evaluation from your treating medical physician Your physician team must evaluate if your condition is benign and, if necessary, rule out a range of serious conditions that could be its cause DAN can consult with your physicians and help them better understand your needs as they pertain to diving

Anne Strysniewicz, AEMT, DMT

I recently returned from a liveaboard trip to Turks and Caicos, where I did three dives every day for one week. My mouth began to hurt during the final two days. I assumed it was related to holding the regulator for so many hours underwater. Since I returned home, however, I’ve developed a case of oral thrush. I saw my primary care physician and am now using antifungal

medication. Can oral thrush be associated with diving?

These infections can affect anyone, and the causative organism (a yeast called Candida albicans) is ubiquitous Under normal circumstances, our immune system and our normal flora keep it at bay by working to repel harmful invading organisms If our immune systems weaken due to ageing, an underlying medical cause, or when we destroy our normal flora with antibiotics or antiseptics, an opportunistic infection may develop

Poorly fitting dentures or other dental prosthetics have also been associated with this condition Even prolonged use of a poorly fitting mouthpiece may have precipitated the infection

The yeast is ubiquitous: it can be found everywhere including in our skin, mouth, and digestive tract so it may be challenging to establish a direct cause-and-effect relationship between your recent dive history and the oral thrush A medical doctor should be able to assist you and rule out a weakened immune system as the underlying cause Once the condition clears and you are no longer taking medication to treat it, and any underlying causes have been ruled out (or treated effectively), you should be able to return to diving once cleared by your doctor –preferably one acquainted with diving

Shannon Sunset, NCPT, NREMT

Pros Choose DAN

TrustedWhenItMattersMost

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

THIS EQUIPMENT MEASURES BRAIN CELL ELECTRICAL SIGNALS, CALLED ACTION

THIS EQUIPMENT MEASURES BRAIN CELL ELECTRICAL SIGNALS, CALLED ACTION POTENTIALS, DURING EXPOSURE TO HYPERBARIC OXYGEN. AT THE LOWER RIGHT OF POTENTIALS, DURING EXPOSURE TO HYPERBARIC OXYGEN. AT THE LOWER RIGHT OF THE PHOTO ARE REPRESENTATIVE ELECTRICAL ACTION POTENTIALS MEASURED IN A

THE PHOTO ARE REPRESENTATIVE ELECTRICAL ACTION POTENTIALS MEASURED IN A SINGLE BRAIN CELL IN A BRAIN SLICE (* ON THE MONITOR AT THE TOP RIGHT). SINGLE BRAIN CELL IN A BRAIN SLICE (* ON THE MONITOR AT THE TOP RIGHT).

Jay Dean, PhD, is a molecular pharmacology and physiology professor at the University of South Florida (USF) He studies the effects of oxygen, carbon dioxide, and barometric pressure on the mammalian central nervous system His research has increased our understanding of oxygen toxicity seizures and the warning signs and symptoms before a seizure Dean and his colleagues have continued to work toward preventing oxygen toxicity via ketosis and administering supplements

WHAT IS YOUR ACADEMIC BACKGROUND?

I did my undergraduate work in biology at Central Michigan University and received my master’s degree in biological sciences at Michigan Technological University During my master’s program, I worked on comparative respiratory control with northern water snakes, which are pugnacious 3-foot-long snakes that like to bite you I studied the effects of temperature and carbon dioxide rebreathing on their ventilation and blood pH regulation

OXYGEN TOXICITY RESEARCH

RESEARCHER PROFILE

TEXT BY RHIANNON BRENNER

PHOTOS COURTESY OF JAY DEAN

After that, I went to Ohio State University for my doctorate to continue working in comparative respiratory control but instead ended up at a lab where I did neural control of body temperature That’s where I learned about the central nervous system and electrophysiology to study brain cell signalling

As a postdoc, I got back into respiration, which has always been an interest of mine At the University of North Carolina at Chapel Hill, I worked on the central carbon-dioxide chemoreceptors, which tell you when you have too much carbon dioxide in your system That accumulation is your primary stimulus for breathing I studied carbon-dioxide-sensitive neurons and their location in the mammalian brain stem

While doing that work, I began to think about other gases and how they affect the brain I read about how some gases, such as nitrogen, don’t really affect us at sea level, but putting it in a scuba tank and diving deep enough while breathing it raises concerns about nitrogen narcosis We also usually do fine with oxygen, but if it gets to be a high enough partial pressure, if you increase the fractional concentration (such as in nitrox), or if you go for pure oxygen, you have to worry about central nervous system oxygen toxicity

After finishing my doctoral and postdoc work, I got my first faculty position at Wright State I was awarded an in-house seed grant that funded the development of my first hyperbaric chamber I adapted the tools I was using to study the effects of carbon dioxide on brain cells for use under high pressure for oxygen toxicity That was how I got my foot in the door in undersea medicine In 2000 I received financial support from the Office of Naval Research Undersea Medicine Program I came to USF in 2006 and continue to work for ONR Undersea Medicine

WHAT ARE YOU CURRENTLY WORKING ON?

I’m working on the mechanisms and mitigation of central nervous system oxygen toxicity and trying to answer the following

questions: Why does the brain suddenly develop seizures when exposed to too much oxygen under pressure? Are there ways to delay it? Are there ways to predict that your level of oxygen exposure is taking you to the point where you’re going to have a seizure? Can we identify physiological markers that will warn us before a seizure begins?

The problem is the tremendous variability in sensitivity to hyperbaric oxygen in terms of when seizures occur between individuals and within the same individual from day to day We don’t quite know why that is

We asked if a rodent’s breathing would pick up before it had a seizure Was that possibly an early-warning physiological marker? So we did the experiments and observed that their breathing picked up anywhere from 8 to 15 minutes before a seizure (Note: The USF Institutional Animal Care and Use Committee (accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International) and the US Department of Defense Bureau of Medicine approves all animal use)

Since then, we’ve looked at other things We found that there’s an increase in electrodermal resistance, or skin resistance, that precedes the seizure by several minutes The heart rate tends to slow initially during the dive, which precedes a seizure by several minutes in an unanesthetized animal Another marker seems to be a drop in body temperature, although the jury is still out on that What is clear is that several of these physiologic changes precede and forewarn impending seizures

We’ve also successfully delayed seizures in rats by using an exogenous ketone ester developed by my colleague Dominic D’Agostino, PhD Within 30 minutes, their blood profile looked like they had been on the ketogenic diet for a week Replacing your body’s usual primary energy source (glucose) with ketone bodies seems to have several neuroprotective effects For example, it decreases free radical production during exposure to hyperbaric

oxygen. This process delayed the seizures from 300 percent to 600 percent, creating a longer, safer dive for the rodent. The ketogenic diet will affect the brain’s oxygen consumption and utilization and do several other things that delay the onset of seizures

WHERE DID YOUR RESEARCH LEAD YOU?

An unanswered, fundamental question that has kept us from targeting the cells critical for seizure genesis is knowing where oxygen toxicity seizures originate What parts of the brain are involved? Research indicates seizures seem to originate at multiple subcortical sites in the brain

In 2019 we hypothesized that the early, abnormal cardiorespiratory changes that precede seizures suggest that so-called “ox-tox trigger zones” exist in cardiorespiratory control centres of the brainstem These ox-tox trigger zones get stimulated by a big hit of hyperbaric oxygen and begin generating their depolarizing signals Other ox-tox trigger nuclei start to activate and then amplify and relay the signals The activation level determines the size and complexity of the seizure Animal models for oxygen toxicity show that the seizures are quite complex They can range from subtle to dramatic, depending on how much the brain gets activated

We’re currently using radio-telemetry to determine parts of the brain that are activated during seizure genesis that is, implanting a transmitter with embedded wires to measure brain activity in various regions and respiratory muscle activity We’ve adapted the process so we can embed electrodes deep in the brain, where we think the ox-tox trigger nuclei are, as well as over the motor cortex, which turns on when the seizure manifests

Our initial studies show that these brainstem ox-tox trigger zones appear to turn on minutes to tens of minutes before we see seizure activity in the motor cortex or physical convulsions We can study animals unrestrained, behaving freely, and unanesthetized with these implanted

radio-telemetry modules. It’s a powerful technique.

Delaying seizures is another current focus. We are using compounds to inhibit nitric oxide synthase, which has been beneficial in delaying seizures The question is whether that can translate into something the US Food and Drug Administration can approve for use The holy grail is finding a substance that works in animals and can be approved for human use

WHY CONDUCT PHYSIOLOGICAL RESEARCH ON RATS RATHER THAN HUMANS?

Animal research is critical Everything we know in medicine including undersea medicine starts with animal research, particularly with mammals I’ve always been interested in fundamental questions, plenty of which we could initially answer in animals but not humans There’s not a lot of basic research in the undersea medical community, and our goal is to have our work translated into larger animals and human divers Animal research is essential in that chain of events, and I’ve been contented to do that for my career

WHAT DO YOU LIKE TO DO WHEN YOU’RE NOT IN THE LAB?

My main hobby is studying the history of aviation medicine during World War II I tell people that I work at depth under hyperbaric pressure and high oxygen during the day Then I ascend to altitude at night and study hypoxia, decompression, and high altitude

Fred Hitchcock was a big-time physiologist who ran the aviation medicine lab at Ohio State University during World War II and studied explosive decompression at high altitudes He had just died when I began graduate school at Ohio State After I passed my comprehensive qualifying exams, I moved into what turned out to be Fred Hitchcock’s office as an emeritus professor He had no family, so all his stuff was still there One day I opened a closet to find a huge box filled with films, slides, negatives, and other documents Later, my first faculty position was at Wright State, next door to WPAFB, and I started

spending Fridays in the archives going through declassified USAAF Aero Medical Lab reports

An interesting dive-related story from World War II that I uncovered is the development of using aviation oxygen equipment for scuba in a water-ditching emergency. American aviators were drowning before they could safely escape from aeroplanes ditched at sea during the war The US Army Air Forces Aero Medical Laboratory at Wright Field tested to see if pilots could use their aviation oxygen masks and walkaround oxygen bottles as scuba equipment to allow for a safe evacuation from their submerged aircraft, and it worked!

I eventually began touring the country to speak about aviation medicine The aerospace, medical community has been excited about the historical perspective. I just gave a talk in Reno, Nevada, at the joint meeting of the Aerospace Medical Association and the Undersea and Hyperbaric Medical Society I was part of a panel discussion on conquering pressure barrier environments, and I spoke on the research done during World War II.

There’s a lot of overlap between the people who worked in undersea medicine and who continue to work in high-altitude research and vice-versa

Pros Choose DAN TrustedWhenItMattersMost

Michael Clarke, Group Director, Watersport & Marine Division, Sandals and Beaches Resorts, PADI® Course Director, explains why he chooses DAN

THE DAN WORLD-WIDE RCN

RISK MITIGATION

TEXT BY FRANCOIS BURMAN, PR. ENG., MSC

DAN collates information on all hyperbaric chambers capable of and willing to treat injured scuba divers

Ideally, chambers are located in close proximity to a medical facility, to facilitate comprehensive evaluation and diagnosis, and support where additional medical treatments may be required However, especially in many remote areas, chambers may be located in local clinics or even as stand-alone facilities

With accurate information and direct contact, our team of diving medical doctors and hotline specialists can triage with almost any facility as long as we have some basic information

The most important details that we endeavour to collect include:

Location and whether hospital based or not

Emergency contact names and details

Availability: 24/7, office hours or on-call only

Level of on-site medical supervision

Diving injury treatment protocols offered

Essential facility equipment, such as redundant air and oxygen supplies

Essential safety equipment such as fire extinguishing systems, alarms, and gas analyzers

Maintenance program

Appropriate staff training and certifications, and

A willingness to work with the DAN diving medicine team

Facilities, personnel, contact details and availability are all likely to change with time, and our chamber network team regularly updates this information through direct and regular contact

The information we gather is captured in a realtime, on-line database to enable rapid identification of an appropriate facility, and to be able to establish immediate communication with them in the event of an emergency

It is important to note that this information is not made public as the status of chambers

THE DAN RECOMPRESSION CHAMBER NETWORK

changes frequently. However, we do provide specific information to organizations such as hospital ER’s, the armed forces, and dive operators and professionals preparing their emergency action plan

There are two programs associated with the RCN that are intended to ensure availability and rapid response

(1) The DAN Recompression Chamber Assistance Program, or RCAP, intended for chambers in locations essential to us that require our help to ensure their availability and capabilities We provide technical and operational advice and offer on-site safety assessments and training These chambers are usually located in more remote areas and often have a greater reliance on diving patients for their income and sustainability

(2) The DAN Preferred Provider Network, or PPN, established with key recompression chamber facilities in important diving areas, that are sufficiently equipped to provide treatments to all divers Critical care capability is not required We maintain regular communication, which allows immediate access to treatment in emergencies, without the need for payment guarantees

In many areas, recompression chamber facilities can really only deal with stable and generally ambulatory patients. This requires us to locate facilities capable of a higher level of care where critically ill divers can be evacuated to This is a challenge in many of the remote areas

Where we identify regions where details on any chambers is limited, we conduct first-hand, field assessments to allow us to capture the essential information We have just completed a trip to the most popular dive regions within Indonesia, where we conducted safety assessments and training, and added some suitable facilities to the network

These are generally hands-on and intensive programs, and managed jointly by our medical and safety services departments

Finally, this collaborative initiative involves all the DAN organisations including America, Europe, Southern Africa, Japan, and World, to ensure that the RCN database extends to as much of the diving world as possible Divers can rest assured that in the event of a diving emergency, where recompression therapy is the required treatment, DAN has the ability to ensure the rapid and effective referral to the closest suitable chamber

COVER THROUGH DAN

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CONDITIONS? OUTCOMES? WHICH IS MORE IMPORTANT FOR SAFETY? RISK MITIGATION

BYGARETHLOCK

In May 2019, a student on a rebreather training class died when he made some errors in preparing his equipment prior to entering the water Unfortunately, the mistakes that he made are the sorts of errors that many divers make all the time, but in this case, the errors that were made also aligned with conditions which meant that when he jumped in, his rebreather didn't support life, he went unconscious, sank, and drowned

While executing a pre-dive checklist would have likely prevented THAT particular situation, there were multiple other factors that, if not corrected, could have led to a similar event in the future – almost the same event occurred two weeks prior Still, those factors weren't picked up in a post-dive debrief But how did it make sense for the diver not to use the checklist to trap the incorrect configuration effectively? What were the social, environmental, psychological, physiological, and cultural factors which made it easier not to use one?

CONDITIONS NOT OUTCOMES

We know what the causes of diving fatalities are - drowning, hypoxia, hyperoxia, hypercapnia, insufficient breathing gas,

pulmonary barotrauma, AGE, blunt trauma, massive blood loss, hypothermia/hyperthermia – but we have less knowledge about the conditions that lead to errors that lead to these outcomes Note error is not a cause of an accident, it is a precursor to an accident occurring, and if a report says the reason was 'human error', then the investigation stopped too early, and you need to start digging some more

As with many aspects of bringing Human Factors into diving, the good thing is that researchers and practitioners from established high-risk environments have already done the hard work! In this case, the Institute of Nuclear Power Operations (INPO) analysed thousands of adverse events to determine the conditions surrounding error-like situations and their associated error precursors and produced a reference guide

THE WITH MODEL

The article will briefly look at the different elements in the WITH model, how they can apply to diving and how we take them into account while managing risk and uncertainty in our diving and diving instruction The WITH model is broken down into four areas Work

Environment, Individual Capability, Task Demands and Human Nature, which are explained below

Work Environment

The general influences of the workplace, organisational, and cultural conditions that affect individual behaviour, e.g., distractions, awkward equipment layout, complex procedures, atrisk norms and values, and a risk-seeking or causal attitude toward various hazards.

Task Demands. The specific mental, physical, and team requirements to perform an activity that may either exceed the capabilities or challenge the limitations of human nature of the individual assigned to the task, e.g., excessive workload, reduced time constraints, concurrent actions, unclear roles and responsibilities, and vague standards.

Individual Capabilities. The unique mental, physical, and emotional characteristics of a particular person that fail to match the demands of the specific task, e.g., unfamiliarity with the task, unsafe attitudes, lack of education, lack of knowledge, unpractised skills, inexperience, health and fitness problems, poor communication practices, and low self-esteem

Human Nature

The generic traits, dispositions, and limitations common to all humans may incline them to err under unfavourable conditions, eg, habits, shortterm memory, fatigue, stress, complacency/efficiency, and mental shortcuts or heuristics

Error-precursors exist before the dive starts –they are latent conditions which 'come to life' when inevitable active failures like slips, lapses and mistakes happen. As these conditions are already present before the dive, we can be proactive, looking to reduce or eliminate the precursors and increase the chance of a successful outcome on a dive. This addresses Professor James Reason's point, "We can't change the human condition, but we can change the condition in which humans work".

Unfortunately, the quality of incident data in diving incidents is poor, with limited consideration given to the context surrounding the activity and the error-producing conditions that would have been present. As such, there isn't an opportunity to create a data-driven version of this table based on INPO data Despite this data coming from the nuclear sector, the following explanations and

examples should give you an idea of what to look for in your own diving operations to improve performance

Given the limited space in this article, I can't go into detail about what each of these means, but you can download an extract from the INPO reference guide from above

HOW TO USE THESE 'CONDITIONS' TO IMPROVE PERFORMANCE AND SAFETY IN DIVING

There are a couple of ways to use the table above and in the linked document

Firstly, you can use it as part of your own risk assessment and pre-dive preparation Consider whether you've got a number of these precursors present If so, think about what you will do to control the likelihood that a slip, lapse or mistake will happen given the different letters in the WITH model

Secondly, given the insufficient data regarding incidents and accidents in diving, think about whether these error-producing conditions were present at the time of the dive Whatever that person did, it must have made sense for them to do what they did, and these precursors make up part of that story

Remember, you need an error-likely situation (an action, a hazard, and conditions) for an adverse event to occur

If you are part of an organisation that looks at quality and incidents/nearmisses, seriously consider looking at the conditions which appear in these incident/quality reports In industries with a relatively high level of safety maturity, investigations look at the extent of causes surrounding an event and whether they are present elsewhere in the business unit or company if spread geographically to stop them from happening elsewhere A more modern view is to look at the error-producing conditions surrounding an event and whether they can be changed too

how it made sense for them to do what they did and see if those conditions can be changed, or at least highlighted before the event so divers and instructors are aware that they are more likely to make an error

If you want to learn more about this specific event, visit wwwthehumandivercom/ifonly, where you can watch a documentary of the event told through the lens of human factors and also download a free guide which will allow you to run a workshop using the video as the basis for discussion

LOST DIVERS | MISSED OPPORTUNITY

INCIDENT INSIGHT

BY DR CLEEVE ROBERTSON (MBCHB FEMSSA)

Some time ago, I gave a talk at a DAN Workshop at False Bay Underwater Club on lost divers, perhaps naively thinking that these occurrences are rare Still, in the recent past, the last few weeks, there have been several lost diver incidents, mainly along the East Coast

We spend hours looking for lost divers, meaning that if you get lost, you will be in the water for a long time

I will never forget the story of my mate who, during an ascent on Deco, had to release a jammed buoy line, and by the time they surfaced, the boat was nowhere to be seen, and they drifted through the night somewhere off Zanzibar until they were found the next day Or my trip to Bassas da India, almost thirty years ago, when the boat guy, not a diver and with no diving experience, overshot the dive group and ended up two kilometres down the reef Fortunately, we could swim to the submerged reef and walk backwards until we could swim to our yacht Then on my last trip to Zanzibar, I surfaced with the DM in quite a hostile choppy

sea, off Mnemba Island, only to find the boat was attending to the snorkelers closer in, about a kilometre away We waited over thirty minutes before waving down another boat and getting a lift back to the ‘mother ship’!

On the positive side, in 2019, I took an adventure diving trip off Agulhas and was dropped into 30m of water 12 nautical miles from the Southern Tip of Africa When we surfaced in 23m swells, choppy sea and a strong Westerly, the skipper was right on top of us

It goes without saying that prevention is better than a kick in the pants, and there’s a definite psychology involved in making sure that divers never get lost I’ve learned in Emergency Services that systems involve team dynamics and that a team’s collective, coordinated action ensures safety Everyone knows about the Swiss Cheese Model and the Domino Theory of Accident evolution, and the challenge is to close those holes and keep the dominoes upright by ensuring that each team member does their job

Although Maritime Law places the responsibility for safety on the boat skipper, we’ve learned, from recent litigation, that responsibility and accountability accrues to everyone in the dive group from the dive business, operator, instructor, divemaster, skipper and even the dive buddy Each one has a unique role in a sequence towards safety

Safety is a culture, and although checklists, operating procedures and tick boxes may be useful, people's ownership and commitment to safety make the most significant difference Reputations make an industry, and financial sustainability individually and collectively depends on a reputation for safety

So lost divers start with the leadership in the business, the quality of training, the experience of operators, the responsibility demonstrated, and the diligence to elements that guarantee safety

I once had an attorney greet me after a talk I had given at the Royal Cape Yacht Club He had been one of my dive trainees thirty years before, and he remembers that one of the most important lessons I had taught him was that sometimes the conditions were not safe to dive He recalled that one lesson, not safe! (he was referring to a howling offshore South Easterly wind on a shore dive)

The obvious immediate preventative actions related to each dive concerning lost divers include weather assessments, dive briefings, communication between skipper and divemaster, group sizing and the use of location aids

Each operator should have limits, wind, swell, visibility, and current, in terms of which a dive can be safely conducted One can use a simple hazard identification and risk assessment tool to compute the combined risk, which assists decision-making Swell and sea conditions are significant components of being able to locate divers on the surface Searchers use terms like

Probability of Area (POA) which relates mainly to current, and Probability of Detection (POD) which relates to the environmental and sea conditions. If you don’t know, don’t go!

Dive briefing must include information that facilitates the group's understanding of the dive and all the safety aspects that prevent diver separation and loss Maintaining the relatively appropriate diver proximity for visibility is very important, and divers should easily be able to identify the divemaster/lead in their group Night dives present unique challenges, but a flashing underwater strobe, for example, can differentiate the leader from the rest with cyalume sticks Brief for belief!

The divemaster, as is standard practice, should drag a buoy that is visible to the skipper on the boat at all times This may be difficult on deep dives with a strong current I always insist that every diver has a reel and buoy because any one of the group can become separated Recent incidents have indicated that the wind often knocks over the tube buoy that divers deploy, so it’s essential to keep it under tension and vertical in the water if you are separated from the boat These physical detection aids and practices are probably the most effective actions to ensure detection Be for Buoys!

Sound devices attached to the BC power feed may be helpful but are unlikely to be universal

I’m often asked about VHF radios, AIS Beacons, Personal Locator Beacons (PLBs) and cellphones as ways of sending a location from a lost diver The answer is that the communication loop needs to be closed, which means the device has to be part of a system that someone will respond to It’s useless activating a device if nobody detects or receives the message and activates a response AIS beacons set off an alarm on the boat they are closest to, but the skipper must recognise the alarm Most skippers have never heard one go off! Once recognised, finding the person is easy because the missing person is GIS located

on the vessel plotter. These AIS PLBs would need to be waterproofed for pressure to be used by divers.

Short Range VHF radios designed for diving use are also on the market, but again if nobody is listening or monitoring, the message or distress goes nowhere We haven’t created a national network and structure to detect and respond to these devices

The NSRI manages a very successful cellphone App called SafeTRX, which requires that the cellphone be dived in a waterproof pouch It also needs the cellphone to be within network range Our experience with the Surfski community has demonstrated that it works well even far out to sea, but there’s no guarantee

Smoke flares are another possibility, but they are expensive, not universal and difficult to waterproof

SO, IN SUMMARY.

Owning responsibility and accountability for safety is non-negotiable

A safety culture is a must Planning and preparation to prevent lost divers are essential Team dynamics and cohesion are key Create HIRAs to inform safe diving conditions

Ensure dive group proximity and contact Use practical detection aids, and buoys, collectively, and individually Don’t depend on electronic communication devices unless you’ve tested the system

EXAMPLE DIVEMASTER BRIEFING ON LOST DIVER PROCEDURE

Lost diver briefing:

(1) Must be clearly and powerfully delivered –it's essential!

(2) Make sure your divers hear it, and understand it, i.e. make eye contact with them as you are delivering it to ensure comprehension.

THE BRIEF

Avoiding getting lost in the first place:

(1) Stay within sight of the buoy line & person holding the buoy line always (Descent, during the dive, on ascent)

(2) Don’t descend if you cannot see the line/person holding the line – you won’t find them underwater!

How to know if you are lost:

(3) If during the dive, you find yourself away from the buoy line/holder, ascend a metre or two, rotate and search for bubbles/bright colours to locate the buoy line/holder But

take no more than five breaths doing this If, after five breaths, you can’t see the buoy line/holder (irrespective of whether you are on your own or as part of a group), you are lost!

What to do if you are lost:

(4) Surface as quickly as is safe Deploy your SMB and keep the line under tension to ensure maximum buoy height Avoid your safety stop if safe to do so Remember that during strong current drift dives and in rough conditions

the surface 5m of water moves much faster than the group at the bottom, and thus further away from the boat watching the buoy line If you surface more than 50m from the buoy line, there is a good chance the boat won’t see you –so get to the surface quickly to reduce the chances of not being seen by the skipper

(5) On surfacing – at about 5m depth – “purge” your regulator to make a plume of bubbles that is visible on the surface This “warns” vessels that a diver is below and surfacing – to reduce the possibility of being run over, and

alerts good skippers that divers are away from the group.

(6) On the surface, unless you see that the boat is aware of you, inflate your SMB as soon as possible, and hold it taut so it is vertical in the air (all divers should have one) If you don’t have one – use a fin to wave in the air – to increase your height of visibility by a vessel

(7) Use your whistle (sometimes on snorkel, sometimes on BCD, etc) to attract attention

(8) If you are not picked up by a vessel in 10 min – consider self-rescue to the shore Always stay together with your buddy/group – never separate! Together you add more visibility than a single person Self-rescue (no matter how far offshore) is a mind game, so stay calm, keep focused, and maintain an economical pace that you can maintain for a few hours – slow but steady Don’t tire yourself; the current will help

(9) Use any signalling/tracking device you may have but know how it works before you need to use it!

What to do if you are the DM and notice a lost diver/group of divers?:

(10) A good DM constantly counts their divers to know that all are accounted for

(11) If you notice that one or more divers are missing, then essentially, it is the same procedure:

(12) Surface a few metres to search for bubbles/bright colours, etc Take no more than five breaths doing so

(13) After five breaths, and no one is found, terminate the dive and get everybody to the surface as quickly and safely as possible

Annoyed-off customers are better than lost divers never found; it’s not an option By explaining this consequence in the briefing – divers are more likely to ensure that they stay with the group

(14) Alert the skipper as soon as you break the surface – to check if the “lost divers” are on board. If not – the skipper can take a minute (no more) to do a quick circle around the group (before loading the divers but keeping the divers visible) to see if they can spot the lost divers If none are found after 1 minute, then return to the group, and alert shore/base/other operators/other vessels/NSRI to begin a search/process

(15) The sooner the search begins – the smaller the search area After an hour – the search area grows exponentially – especially in strong currents Rather call out the NSRI and stand them down after 5 or 10 minutes than wait a few hours when search success becomes more difficult

(16) Once the not-lost divers are loaded, the vessel should stay on-site and search for as long as fuel allows Relaying the following information as soon as possible is critical:

The exact time and location the lost divers were last seen Dive conditions – current strength (bottom/top) and direction The more precise, the better (ie bearing of 190 degrees vs Southerly current) Details of the persons being searched for (gender/name/age/colour wetsuit, etc)

(17) The NSRI has sophisticated search tools, programmes & techniques, which depend on the data accuracy given The earlier and more accurate – the better chances of a good outcome for the lost diver

Tips for good skippers/vessel operators:

(18) Maintain visibility of the buoy line at all times

(19) Good skippers also maintain visibility of bubbles (when not too deep/too rough) and “groups” of bubbles moving away from the buoy line so that despite divers' best effortsthe skipper doesn’t lose them

(20) The ability to take landmarks (when visual) gives skippers a great spatial awareness of the reef and current strength and conditions This skill has tended to be lost in the age of GPS but is valuable in knowing where divers are and are going

(21) Be careful of relying on your senses when further offshore and out of sight of land – rather trust a compass / GPS for directions than your “feeling”

(22) Vessels must have communication -whether cell phone or VHF radio Communicating positions and the fact that an emergency has happened is very important Operators that don’t have or do this endanger lives, the business and the industry

(23) Skippers should “mentally practise” the various emergency procedures so that if and when they do happen, they are executed as effectively as possible Rescue diver courses are also great practice for skippers – instructors should include them when possible

FREEDIVING FRENCH

The chronology of my last sojourn to French Polynesia was much longer than the travel time from Seattle, Washington, to the capital Papeʻete on the island of Tahiti I started contemplating an article about the South Pacific country’s shallow waters during a 2003 charter to the Tuamotu Archipelago, where I shot some over-under images with coral reef foregrounds and palm trees in the background. Since then I’ve often thought about the clear visibility and abundant reef and marine life in the first 20 feet of water there

I had intended to make a serious effort for that kind of shoot, which would involve freediving, but scuba destinations kept filling my schedule Walls of sharks in Fakarava, dolphins in Rangiroa, and schools of colourful

tropical fish almost everywhere are potent distractions, and the shallows remained a secondary consideration

The 2003 trip was so good that I returned a year later to Bora Bora and Tahiti Having heard about humpback whale sightings around Rurutu in the Austral Islands, we made a brief expedition further south during this visit I was wearing so much neoprene for the cool water that I couldn’t get much deeper than 20 feet I could see a whale resting on the lagoon floor below I just needed to wait for her to come up for a breath, which she did more than 300 feet away.

The one morning I had dedicated to whale sightings was far too brief because I didn’t yet realize the patience and time investment necessary for humpback encounters While I

Abird’s-eyeviewfromMooreareveals theverdanthillsidesoftheislandandthe multiplehuesofblueandgreenoffshore

POLYNESIA

RachelMoorefreedivesintoa congregationofgrayreefsharksoff FakaravaintheTuamotusArchipelago.

didn’t get the shot, the memory of my clear, blue surroundings inspired more dreams of their potential

An interlude during a 2005 dive trip took me to Moorea’s shallow reef A secluded sandbar cresting only 4 feet below the surface had stingrays and blacktip reef sharks everywhere, and the island’s verdant hillsides provided a gorgeous backdrop for the above portion of my split shots

In 2008 I was on a magazine assignment aboard a cruise The ship was akin to a modern clipper with swimming pools, gourmet food, and a dedicated dive service, but nobody would mistake it for a liveaboard Most of the guests were not committed to scuba diving, so the sites we visited were relatively benign and predictable The week’s most memorable inwater experience was snorkeling in the crystal waters, viewing the exquisite coral and abundant, approachable reef fish at Tahaʻa.

Diving Rangiroa and Fakarava was the primary motivation for my 2017 and 2019 trips to the Tuamotus, but the shallow water beckoned during some photo-friendly surface intervals The blacktip reef sharks and sicklefin lemon sharks at Blue Lagoon, about an hourlong boat ride from Rangiroa’s main villages, are worth booking a dedicated excursion. Wading right in front of your guesthouse in Fakarava will reveal pristine hard corals, tropical fish, blacktips, and even gray reef sharks A skilled freediver can find large congregations of reef sharks just a little farther offshore, close to Tumakohua Pass

These chance encounters during breaks from scuba diving finally reached a critical mass This collection of accidental-tourist events made me want to build a freedive-only trip during humpback whale season, from August through the end of October, so I worked out the details with Noel Morrison of Tahiti Tourisme during the Scuba Show in Long

Beach, California While I would have loved to revisit Tahaʻa, Rangiroa, and Fakarava, time would not permit all the inter-island domestic flights to make such an itinerary possible during one trip Instead, we concentrated on two of the most iconic shallow-water marine life encounters: the humpback whales of Moorea and the manta rays of Tikehau.

MOOREA

The whale swims in Moorea are becoming increasingly popular because of their proximity to the island and the consistent quality of the encounters Flights to Papeʻete are about nine hours from Los Angeles or Seattle, making Moorea more accessible than other humpback destinations such as Tonga and Silver Bank in the Dominican Republic The trip from Tahiti to Moorea is a short ferry ride offered many times daily

On our first day of scheduled whale watching, we departed Tahiti on the ferry at 8 a.m., landed in Moorea about two hours later, and took a taxi to the dock to rendezvous with our whale boat After a thorough briefing on humpback protocols, we shoved off At 11:30 a m I was having the best encounter I’ve ever had with a baby humpback and vigilant mom We were in the water for a world-class whale interaction just three and a half hours after we left Tahiti!

My previous encounters with humpbacks had been fleeting and distant, so I wasn’t prepared for the calf making a beeline for me. Our inwater guide didn’t know how I would react around this baby a 20-foot-long, 2-ton baby barreling toward me, so she was a little alarmed while I was ecstatic I learned to get out of the way of a whale that was getting too close, a skill that I’d never had the occasion to learn before this trip

We had multiple encounters I couldn’t imagine that any number would be enough,

but I was still amazed The best one was with a mom and calf on the last day The sun was shining, and the water was crystalline The mom seemed mellow about her calf being close to us, so it was really good and getting better by the moment. I saw it all unfolding in my imagination as they edged closer This was going to be the whale shot of my career until one diver with the skill and breath control to submerge to about 20 feet gently touched the mother whale on her pectoral fin, and that was all it took The whales immediately swam away, and we never saw them again that day

The rules are in place for the whales’ benefit and to ensure optimal respect so whales and freedivers alike can have successful encounters. Touching a whale is definitely not acceptable behaviour

Whale encounters aren’t by accident. The whale boat crews are a close-knit community, and they let each other know where whales are on any given day We were lucky they were near us for that first encounter, which wasn’t necessarily the case on the other days We spent a fair bit of time searching the horizon for whales, but we always found them I booked two and a half days for the whales this time, having learned my lesson in Rurutu, and the excursion was productive every day The clear water and abundance of friendly, approachable whales make Moorea an extraordinary opportunity.

The other marquee shallow-water encounter on Moorea is the shallow sandbar we came across in 2005 We were the only boat there that day in 2005, but it was a different story at noon on a beautiful day in 2022 Peering into the water revealed plenty of stingrays and blacktip reef sharks, but there were also four tour boats, 14 personal watercraft, and two stand-up paddleboards I learned a lesson from my travel companions, Kelsey Williamson and Andrea Ference, about avoiding the crowd

They got up at first light to kayak to the sandbar and had it all to themselves in calm conditions and magical morning light Kelsey came home with wonderful images from that morning, and I’ll know to do the same thing next time.

TIKEHAU

Tikehau was totally new to me; truthfully, I didn’t know where it was There are so many islands that it’s difficult to remember the long list of names, but I trusted that the pilot for the short flight knew where we were going It turned out to be in my favourite island group on the planet: the Tuamotus

Seeing it on the map, I understood why I’d never been there. I’d only visited the Tuamotus by boat, and there is plenty of diving to satisfy a 10-day trip between Rangiroa and Fakarava. We’d usually fly into Rangiroa, cruise from west to east, and fly home from Fakarava. Tikehau, being northwest of Rangiroa, was out of the way on that itinerary. It turned out that being out of the way is what Tikehau does best

Tikehau is a small, circular atoll only 16 miles across, and the best diving is along the western shore near the Tuheiava Pass The area is well-known for tiger sharks Shark fishing and trading have been banned since 2012, so the populations are healthy. French Polynesia law currently prohibits feeding sharks in lagoons and passes and within a 0.6mile (1-kilometre) radius of a pass The sharks are there, but protecting them also means we aren’t guaranteed a close encounter

Visitors to Motu Mauu on Tikehau can have a world-class manta ray encounter Eight to 10 large mantas consistently come to the cleaning stations amid the shallow coral heads each morning The seafloor is only 28 feet there, but the isolated coral heads rise 12 to 15 feet from the bottom, and a bank of hard coral is in less than 10 feet of water While some of

us chose to scuba dive there, the site is qui good for freediving as well

I rented scuba gear for the first day and h a good shoot by stationing myself near the coral heads and photographing the mantas when they came near. I discovered it wasn’ like the Maldives, where one coral head hos the fish that perform the piscine hygiene o the mantas Many coral heads had populati of cleaners, and the rays were very active, flitting from one to another

We returned to Motu Mauu the next morning I didn’t want to breathe compress air because we were flying out that afterno so I tried freediving It was far more produc than my dive on scuba I wasn’t nearly as go at breath-holding as our guide, Denis Grosmaire, who is training to make a 100meter (330-foot) freedive. The coral heads w shallow enough, however, that the enhance mobility without a tank or BCD provided far better encounters

My time in Tikehau and Moorea ended all too soon, and we made our way back to Tahiti for the flight home Most flights to the U S depart late in the evening, so the morning is free for sightseeing You might be surprised by the affordability of French Polynesia As of this writing, the U S dollar is strong against many currencies used in the country The perception is that Tahiti is expensive, and yes, it is difficult and costly to bring food and other supplies to remote areas of the Tuamotus. But I found goods and services to be a relative bargain on this trip compared with some of my previous travels

On this trip and the previous one, I took a taxi to Teahupoʻo along the southeastern coast and then booked a water taxi to the surf break at this world-famous surfing spot The water taxi drivers are likely surfers themselves, and they’ll know where to position the boat relative to the break close enough for the perfect shot but far enough not to get swamped

ANDREA FERENCE SITS ON A SHALLOW SANDBAR OFF ANDREA FERENCE SITS ON A SHALLOW SANDBAR OFF MOOREA, SURROUNDED BY HIMANTURA STINGRAYS MOOREA, SURROUNDED BY HIMANTURA STINGRAYS

Alert Diver is a dive lifestyle magazine, not a surfing magazine, but I figure we wouldn’t be divers if we didn’t love all aspects of the ocean. Seeing the power of the waves at Teahupoʻo and the sheer talent and athleticism of the surfers it attracts is quite inspiring. The water is a mesmerizing shade of blue here, and the photo opportunities for anyone with the foresight to bring a long lens are amazing. If the conditions are right, it is among the best places on the planet for surf photography.

French Polynesia is full of potential for divers and photographers alike, from the surface to the shallows to the depths.

REGULATIONS FOR HUMPBACK WHALE INTERACTIONS

Regulations are subject to change from season to season, but the following are the whale interaction rules from my trip in 2022.

There is no limit to the number of boats allowed per whale, but tourism is growing on Moorea, and three boats at once is usually considered the upper limit of respectful pressure on a whale from people You can’t approach whales inside the lagoon, so it is always an open-ocean experience Humpback whales are there to mate and calf, and they need their reserves for the long trip back to Antarctica. They don’t feed during their time in Moorea, so anything tourists do to cause the whales to expend undue energy can jeopardize their well-being and even their lives.

Boats can’t approach closer than 330 feet (100 meters) for adult whales or 500 feet (150 meters) for a mother and calf This activity’s long swim may include surface chop or current and may be very challenging if you lack good water skills

There is no freediving with the whales Assuming you are weighted properly, you can expel breath and sink, but duck diving is not allowed The whales hold their breath for five to 30 minutes, so patience is paramount. They are mammals and will eventually surface to breathe

Chasing whales is forbidden, and you must stay with your group and guide If a whale swims directly toward you, you should move out of the way

Regulations may be revised for the 2023 season, so confirm the latest rules with your whale tour outfitter in advance

BLACKTIP REEF SHARKS ABOUND AT THE BLUE LAGOON ON RANGIROA BLACKTIP REEF SHARKS ABOUND AT THE BLUE LAGOON ON RANGIROA

DOUBLE-SADDLE BUTTERFLYFISH SWARM AN UNDERWATER DOUBLE-SADDLE BUTTERFLYFISH SWARM AN UNDERWATER PHOTOGRAPHER SNORKELLING TAHAʻA PHOTOGRAPHER SNORKELLING TAHAʻA

MANTA RAYS (MANTA ALFREDI) SWIM AT TIKEHAU MANTA RAYS (MANTA ALFREDI) SWIM AT TIKEHAU

Underwater photographer Stephen Frink prepares to photograph a humpback whale calf off Moorea

Underwater photographer Stephen Frink prepares to photograph a humpback whale calf off Moorea

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Upon its release in December 2022, Avatar: The Way of Water drew massive attention from the dive community for its remarkable underwater scenes Curious to delve into the behind-the-scenes story of what it took to achieve the technical mastery those scenes displayed, I chatted with producer Jon Landau, freedive instructor Kirk Krack, director of underwater photography Pete Zuccarini, and supervising master diver and safety officer John Garvin

The sequel to 2009’s Avatar introduces the Metkayina, Na’vi, who are born in the ocean and have adaptations such as tails shaped to help enhance in-water propulsion and eyes that provide better underwater vision. The in-water skills the Metkayina characters demonstrate are rooted in hydrodynamics. They move through the water much like freedivers without fins Landau explained his quest for authenticity in greater detail

MAKING AVATAR

THE WAY OF WATER

TEXT BY STEPHEN FRINK

PHOTOS COURTESY OF 20TH CENTURY STUDIOS

JAKE SULLY (SAM WORTHINGTON) PILOTS THE SKIMWING, THE WARRIOR’S MOUNT OF THE METKAYINA

JAKE SULLY (SAM WORTHINGTON) PILOTS THE SKIMWING, THE WARRIOR’S MOUNT OF THE METKAYINA

What was the thought process that went into making an extensively underwater film?

Jon Landau: The first thought was the story Going into the sequel, we saw the ocean as a transportive journey for our audience to go to the incredible places you’ve been to or that I’ve been lucky enough to dive into, and for sure, those Jim Cameron has explored. Pandora is a world with water, like Earth. Not all of this film is underwater, of course, but as we saw from the first movie’s fantastical forest and floating islands, there is also a great deal of joy and wonder in the oceans of Pandora.

Think about when you swim around a reef structure and suddenly see a manta ray or a whale shark. You’re amazed! We wanted to take what ocean life has shown us and stand it on its tail. We know from experience what a sperm whale looks like underwater, and we wanted our whale variants, the tulkun, to grow to 300 feet long and have amazing new functionalities and a spiritual relationship with the Metkayina That was the kind of ocean environment we envisioned

I saw that in your coral reef. The fish were generally similar to fish we see on Earth as if they had some distant relation to jacks, butterflyfish, and jellyfish. We saw the basic forms of sharks, whales, eels, and even a flying fish, but clearly different. This isn’t your first splash into underwater films. Jim made The Abyss in 1989, and you and he collaborated on Titanic in 1997. There was a lot of waterwork in that one.

Yes, but this one has something Titanic did not: breath-hold diving! When Jim approached Sigourney Weaver to do this movie, he told her she needed to be able to hold her breath for three minutes to do a scene. She said, “Jim, I can’t hold my breath for 30 seconds.” Yet eventually, she could do much more than that, working her way up to five minutes of static apnea.

You’ve seen movies that are dry-for-wet; Aquaman is an example. The underwater scenes are typically simulations in front of a green screen, and performers levitate on cables to approximate what they might look like moving within an environment more than

800 times denser than air Wind machines blow their hair, and computer-generated imagery techniques are added during postproduction That was not good enough for Jim He wanted the authenticity of wet-for-wet, which meant that everyone actors and camera crew had to be skilled freedivers

The technology has been around long enough that your readers probably know something about performance capture You would probably recognize the round beads sewn on suits in behind-the-scenes shots from Avatar or other movies But now the reflective marker dots would have to be on wetsuits, and the underwater cameras can’t really differentiate between a marker on an actor’s suit or an exhaust bubble from a scuba regulator

As Jim explained it, “Everybody who was working in the tank was holding their breath If there was someone down there holding a light, they were holding their breath If they were operating a camera, they were holding their breath The actors, of course, also had to

hold their breath” That bit of physics the inability to differentiate between a performance-capture suit marker and an exhaust bubble is why Avatar: The Way of Water had to be a freediving film

TRAINING ACTORS AND CREW

To better understand the freedive aspect of the film, I interviewed Kirk Krack, founder of Performance Freediving International For the past five years, he has been intimately involved in establishing protocols and instructing cast and crew to operate at the high levels of breath-hold efficiency required for this film

I learned about the huge tanks you were using for filming. The tank at production company Lightstorm Entertainment’s Manhattan Beach, California, studio was 120 feet long, 60 feet wide, and 30 feet deep. It held more than 250,000 gallons of water and could simulate waves breaking on the shore. That was just one of the six tanks, so this film had significant in-water infrastructure. I understand why bubbles were an

RONAL (KATE WINSLET) JOINS TONOWARI (CLIFF CURTIS) AND THE METKAYINA CLAN RONAL (KATE WINSLET) JOINS TONOWARI (CLIFF CURTIS) AND THE METKAYINA CLAN AS THEY DELIBERATE ACTIONS TO COUNTER THE ASSAULT OF THE SKY PEOPLE AS THEY DELIBERATE ACTIONS TO COUNTER THE ASSAULT OF THE SKY PEOPLE

issue for the wet-to-wet film technique, but couldn’t rebreathers have worked as well?

Kirk Krack: In shallow water, rebreathers aren’t necessarily totally bubble-free Even more important, the Metkayina have evolved for life in the sea, so they needed to move like freedivers. The underwater “volume” (the name for performance-capture stages) was a huge tank with 200 cameras mounted at three levels, plus the cameras that Pete Zuccarini and the assistant camera operators were shooting. We couldn’t have some people on scuba, some on rebreathers, and some freediving. With that as the prerequisite, we had to consider what it would take to make everyone in the tank into freedivers.

I saw it as a two-pronged approach. We’d have to start with a training regimen to make the cast, crew, and camera operators into freedivers if they weren’t already, and if they were, make sure they would follow the same protocols as our new freedivers Once we were filming, we utilized technical freediving to

enhance performance capabilities At times, people in the tank might be prebreathing 50 or 80 percent nitrox before their freedive performances Being on the set made everyone appreciate the cutting-edge technology necessary to bring the ideas to fruition

I read about the technology in the production notes. Cameron said his virtual camera integrated the two performance-capture volumes (air and underwater) in real-time.

The virtual camera was especially mindboggling. You had all these cameras filming people with marker dots moving in a tank, yet on the topside monitor, we saw them swimming in the surreal Pandoran sea in realtime. It was a unique form of moviemaking. I predict the upcoming film awards season will fully recognize this film’s degree of technical achievement.

There was something special about this project Cameron’s demands for perfection meant we had time and motivation to

JAMES CAMERON CHATS WITH ACTOR JACK CHAMPION (SPIDER), AS

JAMES CAMERON CHATS WITH ACTOR JACK CHAMPION (SPIDER), AS JOHN GARVIN(LEFT) AND KIRK KRACK (RIGHT) PREPARE FOR AN UNDERWATER SCENE JOHN GARVIN(LEFT) AND KIRK KRACK (RIGHT) PREPARE FOR AN UNDERWATER SCENE

thoroughly train the people involved Some of the cast and crew were water savvy, but some were almost afraid of the water We had the luxury of concentrating on freediving theory, water safety, and technique We had to make them such good freedivers they could go beyond merely holding their breath. They couldn’t look like they were trying to survive; they had to be able to act.

It was quite challenging for me and the stunt performers. I often did more than three hours of breath-hold diving in a 12-hour workday: At 6 a.m. I might be up vacuuming the tank, and at the end of the day, we’d blend the nitrox for the next shoot day. We had up to 30 people in the water at once and logged more than 250,000 free dives in this movie. All the actors could do more than four minutes in static apnea, and Kate Winslet could do more than seven minutes!

How did that work practically? Was everyone on the surface waiting for Jim to call “action,” and then you all dived to shoot?

No, it was exactly the opposite All two-hundred people working on the scene would be waiting on us Our freedive performance was the linchpin We’d count down to our signal to dive after we’d prebreathed and established comfort level for performing We used technical freediving with nitrox to reduce hypoxia risk, recover more rapidly, and become comfortable enough with the in-water experience to act

FILMING FREEDIVERS

When a big-budget Hollywood film needs an underwater camera person, Pete Zuccarini is likely to be called into action Unsurprisingly, Zuccarini was involved when Cameron was recruiting the top talent for this project It no doubt helped that he is a talented freediver Even though the performance capture for Avatar: The Way of Water commenced in September 2017 and ran for roughly 18 months, Zuccarini already joined the project in April 2017

Typical of the preparation that goes into a James Cameron production, Zuccarini was called to shoot tests in different environments, including San Pedro Harbor, Catalina Island, and the Bahamas In the Bahamas, they filmed

record-setting freediver William Trubridge freediving without fins so they could study and consider his technique

It seems like there are scenes in the movie that someone who isn’t a diver and hadn’t seen such an interplay of light somewhere beneath the sea couldn’t have scripted. James Cameron, in particular, has apparently been diving with a different objective over the years, for I see decades of studying light underwater in every frame.

Pete Zuccarini: The interplay of light at different depths and sea states was actually scripted. During our open-ocean tests in the Bahamas, Jim asked me to shoot very specific elements in 8K at high frame rates. We studied how the light filtered down through the water column under large ocean swells, windy, choppy surfaces, and glassy smooth surfaces. We captured the qualities of light dispersing through particles and how the refractive patterns play on the benthic substrate at different depths

The visual effects team pretty well understood the filtering of colour wavelengths at different depths, so we were going after more subtle physics details, such as the way the sand was twirling off the tops of the ripples in the sand under the waves We looked at how swell and turbulence move things such as hair, clothing, skin, and seagrasses These high-resolution real ocean images provided reference data to better inform and communicate with the visual effects team responsible for creating Pandora’s ocean

To experience the feeling of riding a large, powerful aquatic animal in the open ocean, the stunt team created mechanical proxies of the tulkun, ilu, and skimwing These mechanical creatures were towed by boats or powered by a proprietary jet-propelled apparatus to simulate the movement and manoeuvrability of the creatures you see in the movie

An underwater stunt “driver” and another stunt performer would hang on rodeo-style at incredibly high speeds The velocity of the rapid ascents and descents required the stunt team to accomplish unprecedented feats of breathholds, equalization, and strength Imagine riding a creature with enough inertia

DIRECTOR JAMES CAMERON ENJOYS A LIGHTHEARTED MOMENT WITH ACTOR SAM

DIRECTOR JAMES CAMERON ENJOYS A LIGHTHEARTED MOMENT WITH ACTOR SAM WORTHINGTON JUST PRIOR TO SHOOTING A PERFORMANCE-CAPTURE SEQUENCE WORTHINGTON JUST PRIOR TO SHOOTING A PERFORMANCE-CAPTURE SEQUENCE

to go from underwater, jump 12 feet out of the water, and then descend in seconds to a depth of 40 feet All the while, the stunt performers were doing hand signals and facial expressions to remain in character while travelling 5 knots underwater

Jim wanted reference cameras to record every moment of these runs from multiple angles. In addition to attaching action cameras to the creatures and stunt people, we set up two extremely fast diver propulsion vehicles (DPVs) to track along with the action. I operated in tandem with Charlie Arneson to stay with the action underwater. These camera sledges were fast enough to require a cowling to keep our dive masks from being ripped off of our faces.

I used a special nose clip that allowed me to equalize my ears and mask hands-free. The need to follow the subject through the rapid ascents and to remain streamlined and agile dictated that we operate as freedivers. From these tests, Jim fine-tuned what he wanted to see in the design and utilization of the performance-capture tank Lightstorm built at Manhattan Beach Studios

SUPERVISING SAFETY

One of the most important people in this film was John Garvin, who oversaw the tens of thousands of scuba dives and hundreds of thousands of free dives over the four years of shooting Up to 30 divers stunt performers, grips, lighting technicians, camera operators, safety divers, and actors could be working in the tank at any given time The work was often spread among a dozen different dive teams in a rapidly changing environment No one got hurt during the production, which says much about Garvin’s professionalism and commitment

What you had to do sounds like a daunting challenge. How did you go about it?

John Garvin: My first task was to write our dive safety operations manual We had to define the hazards and mitigate them The lighting department had to move up and down through the water column, so we adapted the Tasmanian Bounce Diving Tables for our nitrox mixes We had dive computers on every wrist, and while decompression sickness was not

our first concern, it could happen with spending up to 12 hours a day in the water Each production tank had specific emergency drills based on its characteristics

We also consulted with the top experts in their speciality fields, such as Neal Pollock, PhD, and Simon Mitchell, MB ChB, PhD. Another tenet of our approach was learning from our mistakes along the way. We never had any shallowwater blackouts, but we had a loss of motor control event at the surface early in the process. That incident told us that prebreathing nitrox was necessary. Our baseline goal was a two-minute working breath-hold for each actor, which we surpassed. The Metkayina are born in the water, so the other critical goal was for all the actors to look comfortable underwater as if they were water-born as well.

Was there any specific tank hazard that kept you up at night, wondering how to mitigate it? The diffusion balls that floated on the surface caused me a lot of anxiety While they were the perfect size for light transmission and allowing the diver to punch through to the air, they were also perfectly trachea sized Not only did divers have to get to the surface, but they also had to raise their heads through the 3-inch blanket of these balls to get a breath We prepared safety protocols in case of ingestion For all the hightech innovations on this film, a $2 pool noodle for the actors to rest on at the surface was what we all depended upon

How did you communicate underwater? I can’t imagine hand signals were enough for a project this complex.

I give a huge shoutout to Ocean Technology Systems The set was quite noisy underwater, yet everyone had to follow their team’s directions That meant operating on different channels with multiple hydrophones and noise gates The grips had to constantly talk to each other to do their job, for example, but the actors needed to hear Jim

His communication with the actors was invaluable because Jim is a tremendously experienced diver He knows that water dictates movement You can’t fake that Even non-divers in the audience will intuitively pick up on underwater physicality that isn’t right

PAYAKAN, AN ADOLESCENT TULKUN SHUNNED BY HIS KIND, IS BEFRIENDED BY NA’VI TEEN LO’AK (BRITAIN DALTON)

PAYAKAN, AN ADOLESCENT TULKUN SHUNNED BY HIS KIND, IS BEFRIENDED BY NA’VI TEEN LO’AK (BRITAIN DALTON)

THE VILLAIN QUARITCH (STEPHEN LANG) IS AN AUTONOMOUS AVATAR EMBEDDED

THE VILLAIN QUARITCH (STEPHEN LANG) IS AN AUTONOMOUS AVATAR EMBEDDED WITH THE MEMORY OF THE HUMAN WHOSE DNA WAS USED TO CREATE HIM WITH THE MEMORY OF THE HUMAN WHOSE DNA WAS USED TO CREATE HIM

The Making of Avatar TheWayofWater|SportScience

The making of the new film Avatar: The Way of Water involved the sport of freediving, and the cast of the movie, Kate Winslet, Zoe Saldaña, and Sigourney Weaver had to train to hold their breath underwater for minutes at a time. In this ESPN Sport Science, Kirk Krack, the film’s performance free diver instructor, explains how the cast and crew learned to safely free dive. Avatar: The Way of Water is now playing only in theaters.

for some reason, which then severs the emotional attachment. That’s why this film is wet-for-wet. We hope it will resonate with anyone who deeply loves the ocean, but it will be particularly relatable to divers.

We did everything underwater that you see underwater in this film. The team came to understand the technical challenges of bringing James Cameron’s vision of underwater Pandora to life. Yet, as Landau pointed out, while the ocean provided the backdrop to tell the story, the story was still paramount. Our job was to collaborate with Jim, the entire crew, and the actors to bring the underwater visuals of that story to life.

BEHIND-THE-SCENES VIEW SHOWS JAMES CAMERON TALKING WITH SCIENTIST NORM SPELLMAN (JOEL DAVID MOORE)

BEHIND-THE-SCENES VIEW SHOWS JAMES CAMERON TALKING WITH SCIENTIST NORM SPELLMAN (JOEL DAVID MOORE)

Avatar: The Way of Water ActingInTheVolume|Featurette

Set more than a decade after the events of the first film, “Avatar: The Way of Water” begins to tell the story of the Sully family (Jake, Neytiri, and their kids), the trouble that follows them, the lengths they go to keep each other safe, the battles they fight to stay alive, and the tragedies they endure. Directed by James Cameron and produced by Cameron and Jon Landau, the film stars Zoe Saldana, Sam Worthington, Sigourney Weaver, Stephen Lang, Cliff Curtis, Joel David Moore, CCH Pounder, Edie Falco, Jemaine Clement and Kate Winslet.

REVIEW FROM A DAN MEMBER

JACKY DU PLESSIS

Our family has benefited from being a member of the DAN Southern Africa family (and I do not use that word lightly) on more than one occasion, the most notable being the medical advice we received over the phone when arriving in Sri Lanka. During the flight from the Maldives, where we had been on a scuba diving liveaboard holiday, to Sri Lanka, my son developed strange symptoms - tunnel vision, cold, clammy sweat and an extremely fast and erratic heartbeat - and was put on oxygen by the aircrew who also found a doctor on the flight to monitor him. We obeyed all the diving rules, so we were alarmed and confused about what these symptoms meant. As soon as we landed, we contacted the DAN Hotline and spoke to a dive doctor on the other side of the world in South Africa, who, having talked through his symptoms with us and consulted other diving doctors, reassured us that this was unlikely to be related to diving Upon returning to South Africa, we eventually discovered the possible causes and further tests. But the compassionate and efficient attention to our concerns saved our holiday and allowed us to continue diving in Sri Lanka

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

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

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

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?

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PARTING SHOT

RAE DU PLESSIS

ALPHA FEMALE SHARK

I took this picture on March 4, 2023, on a baited shark dive on Aliwal Shoal This female Blacktip Shark (Carcharhinus Limbatus) is the most active feeder; hence the number of remoras accompanying her She almost looks like a small aircraft carrier We call her the alpha female, and the other sharks know she is in charge. I love all animals, but sharks have been my passion ever since I started diving. The way they move in the water has always fascinated me I never get bored of them, and even though I have been diving with sharks for 14 years, each time I have a memorable encounter, it’s like the first time I particularly love shooting with my setup on baited shark dives It’s the sheer amount of sharks, and because I use ambient light (no strobes), I’m at the mercy of the right amount of light to help me illuminate my images. I use a Lumix GH4 with an Olympus Pro 7 - 14 mm f28 lens, an Ikelite housing, and an 8-inch dome I shot this in a complete manual F45 SS 1/500 ISO split shot