Alert Diver Magazine Q2, 2016

The Magazine of Divers Alert Network Asia-Pacific SUNSCREEN ISN’T GREEN GOING WITH THE FLOW EVACUATED FROM FIJI ESSENTIAL OXYGEN KIT

Quarter 2, 2016 danap.org

Contents

Perspectives

Stephen Frink

ON THE COVER A clownfish with host anemone makes up part of the Maldives’ vibrant seascape Image © Stephen Frink Settings: f/16, 1/60s, ISO 320

55 Perspectives

66

SHOULD I BE DIVNG? Text by Scott Jamieson

58 DAN Was There For Me FACING THE FEAR IN FIJI

Text by DAN AP Member Nigel Smith

64 Incident Insight QUIET RUPTURE

Text by DAN AP’s John Lippmann and Scott Jamieson

66 Advanced Diving DIVING IN CURRENTS Text by Mike Ange

70 Skills In Action REMOTE BUT READY Text by Danielle Claar

Stephen Frink

72 Gear

EMERGENCY OXYGEN UNITS Text by Robert N. Rossier

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74 Water Planet

SUNSCREEN POLLUTION Text by Craig Downs, Ph.D.

ALERT DIVER’S PHILOSOPHY

Alert Diver is a forum for ideas and information relative to diving safety, education and practice.

Any material relating to dive safety or dive medicine or accident management is considered for publication. Ideas, comments and support are encouraged and appreciated. The views expressed by contributors are not necessarily those advocated by DAN Asia-Pacific. DAN is a neutral public service organisation which attempts to interact with all diving-related organisations or persons with equal deference. Alert Diver is published for the use of the diving public and it is not a medical journal. The use and dosage of any medication by a diver should be under the supervision of his or her physician.

Alert Diver is published as a separate, independent magazine within Scuba Diver AUSTRALASIA (SDAA) magazine. DAN AsiaPacific is not responsible for the content provided elsewhere within SDAA, and therefore this content should not be assumed to represent the views, policies or practices of DAN Asia-Pacific or Alert Diver magazine. ©Alert Diver text, illustration or photographs may not be reproduced or reprinted without the expressed consent of Divers Alert Network and its authors, artists and photographers. Many articles are reprinted with the kind permission of DAN America.

Email: info@danap.org For more information on membership, insurances and training programmes, visit our website: www.danap.org

Content Coordinator Stephen Frink Editors Brian Harper and Diana Palmer Founder, Director of Research & Chairman of the Board John Lippmann General Manager Scott Jamieson Administration Manager Sim Huber Marketing & Communications Manager Melissa Cefai DAN AP Board of Directors John Lippmann, David Natoli, Malcolm Hill, Dr David Wilkinson, Mick Jackson, Stan Bugg, Tom Wodak, Nicholas Cheong & Dr Andrew Ng Memberships & Certifications Heidi Powell, Julie Parsonson, Cynthia Van Zyl, Mina Chivotti, Adam Lippmann, Sophie Kayne, and Diane Boyle Training John Lippmann, David Natoli and Tim Vernon-Smith Marketing Assistants Haili Mu & Adam Lippmann Accounts Anny Limbek DAN AP does not necessarily endorse the products or services of any organization or company whose advisements appear in Alert Diver

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Perspectives

From DAN Asia-Pacific

SHOULD I BE DIVING?

Part of the DAN Asia Pacific team.

From left, Mel, Cynthia, Julie, John, Heidi, Scott, Haili, Anny, Adam, Sim

ALL THE DIVES that we undertake carry a degree of risk that needs to be assessed and managed. In order to increase the likelihood of a problem-free dive, it is the responsibility of all divers to honestly ask themselves, “Should I be doing this dive?”

In determining whether the answer is “Yes” or “No” you need to consider numerous factors: the dive plan, the conditions, your level of training and experience; as well as your health and fitness.

No diver should undertake a dive they are not 100 percent prepared for. Even the most simple of dives carries risk, which increases if the diver is not properly equipped, physically and mentally, to deal with issues that may arise whilst underwater or on the surface.

Conditions are usually easy to assess: Is it too rough? Is there too much current? It is the diver’s ability to cope with the dive that is harder to quantify. Your training level provides only a very rough indication of ability, yet it is often used by operators to assess if a diver can undertake a certain dive. While this is common, it doesn’t give an ideal assessment of a diver’s experience in certain conditions. Only the diver can provide this information, and to ensure a safe and enjoyable dive, they should be honest in their self-assessment.

Additionally, the diver is often the only person who knows if they should cancel a dive for health reasons. Diving places stresses on the body that we do not experience normally. And these stresses can trigger medical events that may not have occurred on land.

Over recent years, medical conditions, primarily cardiac, have started to feature prominently in fatality reports. Divers need to be aware of how certain illnesses or injuries they have may be exacerbated by diving. Discussing your medical conditions with a diving doctor is the first step, but monitoring and maintaining your own health and fitness is also invaluable.

The DAN AP website (check out the “Diving Safety” section at www.danap.org) contains information about diving with a number of different medical conditions.

Being able to evaluate if the dive you are about to undertake is within your diving ability and whether your health and fitness level is sufficient for that dive, will go a long way to reducing some of the risk factors involved.

Bottom line: If you don’t feel comfortable, don’t dive.

Dive safely, Scott Jamieson, DAN AP General Manager

Dive Tip Engage with DAN on Facebook for insights into various dive safety and medical issues.

Scan here or search DAN Asia Pacific.

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Research, Education & Medicine

DAN Was There For Me

FACING THE FEAR IN FIJI Dealing with severe DCS in Fiji would have been far worse without the support of DAN Asia-Pacific Text by DAN AP Member Nigel Smith Images by Stephen Frink except where noted

MY INCIDENT I’ve been diving for more than 10 years and consider myself experienced. My incident occurred on the island of Kadavu in Fiji, where my partner (and dive buddy) Sandra and I were on our final day of diving. We had taken the previous day off, having dived the previous two days, so were rested and hydrated. The first

dive of the day was over a sheltered coral cliff and garden. After 40 minutes, with a maximum depth of 24.5 metres, we began our controlled ascent to five metres for our safety stop.

As I was ascending I began to feel dizzy and increasingly disorientated. I signalled to Sandra that I was experiencing difficulty, and descended to seven metres to see if that would help. My symptoms worsened: my vision turned into a whirlpool, and I began to lose any sense of up or down. I was able to return to a shallow depth (three metres) under control, but I was increasingly worried that I was going to pass out underwater.

The next few seconds are a bit of a blur, but in hindsight I am sure I began to lose control of my buoyancy and, from about two metres, fully lost control and popped to the surface.

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Luckily the boat was less than 10 metres away. My dizziness progressed to increased confusion and weakness. I was able to hang onto the side of the boat, but I needed help with my gear. Before I could climb the ladder, my legs, and then my right arm, became useless and the skipper had to pull me aboard.

THE IMMEDIATE RESPONSE During the 20-minute boat ride back to shore, Sandra and the divemaster attempted to keep me conscious and responsive. After being carried ashore I was laid onto a sun lounger (the improvised stretcher) and emergency oxygen (O₂) was administered. After a few minutes I regained my vision and I could understand what I was hearing but couldn’t verbally respond.

Sensation was returning to my limbs but I still wasn’t able to move them.

Some 20 minutes later my condition was relatively stable so I was carried back to the boat and we began the 45-minute journey to Vunisea, which had a small local hospital and an airstrip. Fortunately, I was kept on O₂ all the way. There are no roads here, so it was the only and quickest way to get there. This was a surreal experience and though calm, I basically feared whether I would survive or not. Fortunately, the crew from the resort were level headed, professional and caring.

When we arrived at the hospital I was placed on their (only) ICU bed and began breathing from a big tank of O₂. But the medical facility was small and the oxygen supply limited, so the team wanted to moderate the supply in case it was needed for other emergencies or procedures.

By now, DAN AP had been contacted and spoke to the hospital staff to negotiate an acceptable flow rate. DAN AP’s preference was to arrange an air ambulance for me from Kadavu direct to Australia. However, given the time taken to get the rescue flight to me (Fiji red tape for air ambulances coming in and local nighttime flight restrictions) meant there was a concern my O₂ supply would run out before the flight was available.

The decision was made to evacuate me to Suva hospital (a short 35-minute flight) as it was equipped with a hyperbaric chamber.

I was evaluated by the head anaesthetist, who was also one of the few hyperbaric medicine qualified specialists. After a chest X-ray to check for damage (all clear) I was wheeled to the chamber. The programme of treatment was a single session per day: descend to 18m, 30 minutes on O₂, five off, thirty on, five off, and then slowly ascend over 30 minutes. DAN AP’s preference was for a more aggressive treatment, which led to them wanting to evacuate me to Australia. I had arrived in Suva on Friday and by Sunday evening, after three similar treatments and some improvement, I was evacuated to Brisbane by air ambulance.

THE TREATMENT On arrival late Sunday night at the Royal Brisbane and Women’s Hospital, I had a thorough assessment by the head of the hyperbaric chamber, who was called in late at night on the last day of his own sick leave (I was so grateful to him for being there). The next morning I commenced my first treatment. In Fiji, the chamber was a metal cylinder housing two bench seats. Here, it was the size of a shipping container, split into three independently pressurised chambers, with room for a bed and a fully qualified nurse to accompany me.

My first treatment was over five hours, and I then had 15 more treatments over the next eight

My vision turned into a whirlpool, and I began to lose any sense of up or down. I was able to return to a shallow depth, but I was increasingly worried that I was going to pass out underwater

Fiji boasts some of the most beautiful, colourful coral reefs in the world. It is also a remote location with very basic infrastructure

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Nigel was kept on oxygen therapy for the duration of the journey to the hospital – a critical factor in the outcome of the incident

days. At each stage, I was assessed to see how my symptoms were improving. On arrival I had been able, just, to get out of bed and walk about three metres. My skin from my mid-torso down was either hypersensitive or, from my thighs down, desensitised.

With successive treatments I saw incremental improvements in my ability to walk, and in my energy level. Changes were small, but the team were determined to continue treating me so long as I showed even the smallest improvements, as once stopped, improvements would be either much slower or non-existent.

Finally I reached a point where improvements were so small as to be hard to describe. In addition, I was beginning to show signs of oxygen toxicity, not uncommon after so much oxygen in successive sessions. So after well over 30 hours of hyperbaric treatment I was discharged from the care of the hyperbaric unit.

Without exception, they had been a fantastic team: kind, caring, fun and with a professional concern to reach the best possible result for my long-term prospects. I was again immensely grateful to DAN AP, without whose advice and support I am sure I would have remained in Suva

for adequate treatment but with much reduced recovery prospects.

THE RECOVERY One of the little talked about effects of nerve damage affecting your torso is the problems it can have on your ability to urinate. I was unable to pass water naturally and this impact evolved into the most tiring, frustrating, uncomfortable and depressing part of my recovery. Suddenly being left with the prospect of having to pass water through what is clinically known as clean self-catheterisation, led to a lot of physical and mental anguish. Fortunately the situation has improved a great deal, and whilst not back to normal six months later, things are much more natural.

Jumping forward to six months after my accident, in many ways, especially considering the severity of my initial condition, I am unbelievably lucky. As a normally active and fitter-than-average middle-aged man, I’m happy to say that I am still, on the whole, fitter than the average Australian male of my age.

What did knock me was the nearly two months fighting off a urinary tract infection (a 59

Wherever I am diving ....

I Take

With Me CMYK Version

CMYK Version

CMYK Version danap.org/take_dan.php

Comment from Nigel’s Partner and Dive Buddy, Sandra When incidents like this occur, it is the partner or dive buddy who also experience significant stress in trying to get their loved one the best care in what is often a foreign and remote location. Nigel’s partner and dive buddy, Sandra, shares her experience: Nigel’s incident was a traumatic experience for both of us. DAN AP was an incredible support to me as well as Nigel. The local doctors had limited experience dealing with diving-related incidents and DAN AP’s expert knowledge was there at all stages, which made a significant difference.

It was comforting for me to know DAN AP was on the case.

That first night they contacted me at the Vunisea hospital a number of times to check on Nigel and me. I wasn’t sleeping so kind words from someone who knows what you are going through at 3am in a hospital where the generator went off at 11pm (and we were using torches), helped me not completely lose it. They were there for me in the hours overnight when I needed it most. DAN AP far exceeded my expectations in care, expertise and support, and helped more than I can say at a very challenging time.

Read an analysis of Nigel’s Incident, including his CAGE diagnosis at www.danap.org/nigel.php

Safety Tip HELP DAN: Contribute to DAN’s dive safety research. If you experience a diving incident, submit it to our Online Incident Reporting system. Your experiences will help us continue to gather data making diving even safer for all of us! www.danap.org/accident/nfdir.php

ALWAYS have DAN AP cover. My two evacuations alone cost more than US$110,000

Nigel in the chamber during one of his treatments. He is still recovering from the incident Image courtesy of Nigel Smith

common occurrence when catheterising). On top of everything else this draining, uncomfortable condition really wore me down.

My “new normal” at the moment is not too far removed from the old normal, to the outsider looking in; but my stamina remains greatly reduced. I have some ongoing sensation and function issues around my lower torso. My legs still do not feel like how I expect them to feel, though they are improving. They tire, they ache, the skin feels strange, and in the evenings I get small twitches. My social life is more limited, partly because I get tired quickly, sometimes because I’m physically not in the mood. And occasionally I just don’t want to be social.

I am still improving, however. I don’t really think about returning to “normal” as that is history. I don’t think about being lucky and that I could have been much worse – I know that is the case but what I am dealing with is how I am, not how I could have been. What I do think of is doing the things I love. I can still run, swim, cycle and many other things that are all a part of my active life.

FINAL THOUGHTS Emotional resilience, the support of a good partner, and an understanding employer have all been vital to my initial emergency and subsequent recovery phase. Improvements

have not been day by day, but week by week I continue to see changes, improvements.

Physically and mentally I am still on a journey to recovery. I suffer bouts of anxiety and have a lack of confidence in my own body. The changes in my mental state are sometimes the most challenging. But I also have a deep appreciation of life that you hear can come to those who have suffered a near death experience.

MY ADVICE Apart from keeping to all the normal dive precautions, always have DAN AP Membership and Dive Injury Treatment Insurance. I only had DAN AP Membership, which meant dealing with another insurer for the non-evacuation costs.

Compared to DAN, they were nowhere near as professional and caring. Do your homework and assess the emergency options when choosing your next diving destination (and dive operator) – and if you don’t like what’s available, choose another destination. Make sure you have a good buddy, one who can stick with you should things go wrong. My experience would have been immeasurably harder without my partner and buddy, Sandra.

And finally, did I mention always have DAN AP cover? My two evacuations alone cost more than US$110,000.

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DIVER’S BACKGROUND “James” (not his real name) is a 62 year-old Australian male. He is an experienced diver, logging more than 1,500 dives over 33 years, mainly in the cooler waters of southern Australia.

However, he has also done at least one overseas diving trip each year, mainly to tropical locations.

He is taking medication to lower his cholesterol, as well as vitamin D to offset a related deficiency. He had what appears to have been a relatively mild middle ear barotrauma two years earlier, involving his right ear. This cleared up with saline rinses and decongestant spray.

CASE REPORT THE DIVING James was on a diving holiday in Papua New Guinea and had done three dives per day for the past three days. He was breathing EANx32 and using a Mares Icon dive computer with the relevant nitrox setting. He had not dialled up any extra conservatism into the computer.

His profiles for the last day were: Dive 1: 25m/65 min; SI = 1:13 Dive 2: 15m/61 min; SI = 1:34 Dive 3: 16m/61 min.

James indicated that he had gone to the maximum depth early in each dive and then worked his way shallower, spending a lot of the time in shallow water on the top of the reef.

Safety stops were done on all dives and there were no reported problems in or under the water. However, he noticed ringing in his left ear (tinnitus) after the second dive. Believing this to be from water trapped in his ear, James unsuccessfully used ear drops to try to clear the water and decided to do the next dive.

When the tinnitus persisted for the next two days, along with some hearing loss, James became concerned and went to a local clinic. The doctor found that James had ruptured his right ear drum and she could see swelling in the left ear and prescribed antibiotics.

INCIDENT INSIGHT

QUIET RUPTURE A “mild” barotrauma leaves a diver with potentially permanent hearing loss A ruptured ear drum isn’t always obvious and even a seemingly mild barotrauma should be treated seriously

Text by John Lippmann, DAN AP Founder, Chairman, Director of Research Images by Stephen Frink

THE CALL TO DAN ASIA-PACIFIC James then called the DAN Diving Emergency Service (DES) Hotline and spoke to the on-call doctor, Dr David Wilkinson, who was concerned about James having a possible inner ear barotrauma (IEBT) in the left ear. Being the DAN AP staff on call that day, I received a call from Dr Wilkinson to give me a “heads-up”, and we decided that it would be advisable to bring James back to Australia and arrange a consultation with an ear, nose and throat (ENT) specialist. Such appointments are often difficult to arrange at short notice and, as this was a weekend, we were aware that it could be hard to have James seen quickly.

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In the event of a suspected inner ear injury, it is important to stop diving and any straining activity immediately, rest, and get appropriate specialist medical advice

After a barotrauma, specialist medical treatment should be sought as soon as possible

James wasn’t due to fly home for another 10 days but his travel agent (Diversion Dive Travel) worked hard to rearrange flights so he could fly back the next day. I asked James to call me after landing on each leg of the journey so I could intervene and change plans if his symptoms worsened. This was done religiously and, happily, James reported no deterioration with flying.

MEDICAL TREATMENT AND OUTCOME The following morning James presented at the emergency department (ED) at the major local hospital, as advised. He was examined by an ED doctor and sent home after being told that an ENT specialist would be in contact within seven days. James then called me to provide an update, as requested. In frustration, I called several of the hyperbaric doctors based at that hospital and asked them to intervene, which they did successfully. James was examined by an ENT that same day and tests were scheduled. The hearing test (audiometry) revealed substantial hearing loss in James’ left ear and he was prescribed medication (steroids) to facilitate healing.

It is now nearly five months later and James is still suffering from substantial hearing loss in his left ear. Despite some slight improvement, it is likely to be permanent. Fortunately, his tinnitus has abated.

THE FUTURE? As a very keen diver, James is now trying to weigh up whether or not he is prepared to continue with

diving. The main concern is the ramifications of an injury to his good ear. If he suffered a severe barotrauma in that ear, he could be potentially left with hearing loss in both ears, which would be disabling.

COMMENTS In the event of a suspected inner ear injury, it is important to stop diving and any straining activity immediately, rest, and get appropriate specialist medical advice as soon as possible.

Unfortunately, James failed to realise the potential severity of his injury and dived again, probably exacerbating the problem. By the time DAN AP was called several days later, most of the damage was likely already done.

DAN AP deals with many cases of inner ear injury and, unfortunately, continued diving and delay to reporting is not uncommon. This can lead to permanent hearing loss, tinnitus or problems with balance.

One important aspect of this incident is that James has been unable to really identify how the initial problem was caused. He did not notice any problem when equalising and there was no uncontrolled ascent or descent to explain the barotrauma. In addition, the ENT specialists who have examined him have not noted any particular anatomical deformity that might have put James at an increased risk. This makes the decision about future diving more difficult.

SAFETY TIP Enter DAN as a contact in your phone. Make sure you have your lifeline when you need it. Visit “Emergency” at www.danap.org. Whilst all divers can call DAN for advice, DAN can only arrange an emergency evacuation and pay for associated treatment costs for current Members (within the limits of their coverage option). Not yet a DAN AP Member?

Join at www.danap.org.

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Skills In Action

REMOTE BUT READY An experienced research team avoids a potentially fatal emergency in the remote Pacific Ocean Text by Danielle Claar Images by Stephen Frink

Proper planning helps ensure safer dives

In the crystal-clear waters of the tropical Pacific, our research team from the Baum Lab at the University of Victoria studies coral health and diversity to understand the future of reef ecosystems. We document the reef and conduct coral surveys on a remote and relatively undeveloped Pacific island. On a recent expedition, a seemingly small issue turned into an emergency that, if not for the support of DAN and a great team, might have ended very differently.

We were surveying corals in around 10 metres (33 feet) of seawater. This particular dive, which turned out to be our last that day, was different from others. I felt slow and unable to concentrate. I tried to count corals – four, five, six… what comes after six again? My brain felt foggy, and I slowly realised that something might be wrong.

After surfacing from a dive earlier that day my buddy had a slight headache. It went away

quickly, so we attributed it to swimming against a strong current. But after we surfaced from our final dive I was certain something was wrong: I felt ill, and my buddy’s headache was back in full force. Our emergency response plan kicked into action. We headed back to shore, where one of our team members contacted DAN. My buddy and I began breathing emergency oxygen, and team members monitored our condition.

Everyone prepared to enact the evacuation plan to fly us off the remote island if necessary.

Our primary symptoms subsided, and we were able to wait a week for the next scheduled flight off the island. We discovered that the most probable cause of our incident was carbon monoxide poisoning. Insidious low levels of carbon monoxide in our breathing gas, which came from an old, gasoline-powered compressor on the island, combined with repetitive dives over multiple days may have allowed carbon monoxide to build up in our

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Research, Education & Medicine

bodies. While the risk of carbon monoxide contamination is very low when using modern compressors, it should never be ignored, especially in remote locations.

PREPARED Our team uses a variety of strategies to prevent and manage emergencies in the field: Emergency Response Plan: As scientific divers we are required to write an extensive dive plan in advance of our trip. Our plan covers emergency oxygen, nearby medical facilities, evacuation procedures and contact information for the Coast Guard and DAN. No matter what type of diving you do, it’s a good idea to put together a detailed emergency response plan before you dive in a new location.

DAN Support: Immediate access to a DAN oxygen unit and the DAN DES Emergency Hotline (+61-8-8212 9242) are essential elements of our emergency response plan. In addition to having a DAN emergency oxygen unit on site, DAN’s assistance over the phone helped our team make decisions about treatment and follow-up throughout this incident.

Diver Support: One of the most important skills when diving anywhere is knowing when to call off a dive.

During this incident, as soon as one of the divers said, “I’m not OK,” diving operations came to an abrupt halt. When a diver has an objective, such as science or photography, it’s hard to admit that something’s wrong and stop work underwater.

Calling off a dive is difficult, but it is absolutely vital to foster a team mentality that supports a diver’s decision to stay out of the water. Being honest with yourself and others about your symptoms can be the difference between, “I am glad we stopped diving” and “If only we had stopped diving…”

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FAR AFIELD People who have dived primarily in developed locations might not realise the additional risks present in less-developed areas. Here are a few recommendations for diving in remote locations: Investigate air quality: Ask the dive shop when their air was last evaluated by a certified testing laboratory.

Consider learning to use and bringing air test kits with you; these range from simple colourchanging sensors to electronic analysers. If a compressor looks so shabby or dirty that it makes you uncomfortable, don’t use it.

Being honest with yourself and others about your symptoms can be the difference between, ‘I am glad we stopped diving’ and ‘If only we had stopped diving…’

Ensure emergency oxygen is available: Ask whether oxygen is available through the local dive operation, confirm there is a reliable way to administer it, and ensure there is enough to last for two or more divers to get to the closest medical facility. In some locations, this may be for an extended period, even overnight in some cases.

Be aware of cultural differences: When communicating with dive shops in countries other than your own, make sure you’re talking about the same things. Ask detailed, specific questions about dive safety so you know what resources will be available to you in the event of an emergency. If possible, learn about relevant cultural differences beforehand.

Safety measures are location specific. Just because a dive shop has a compressor doesn’t mean its tanks are safe for diving. When you’re off the beaten path, be vigilant in verifying tank inspections (visual and hydrostatic), testing air quality and watching for symptoms.

As for me and my dive partner, we made full recoveries, thanks to the quick assistance of our dive team and the professionals at DAN.

Final Word from DAN AP Many diving destinations simply don’t have the same safety standards and monitoring that we have come to expect in our home countries.

Any time you are diving in a remote or lessdeveloped country you should also ensure that you manage your diving plan to include conservative profiles and long surface intervals.

Research, Education & Medicine

position, much like a flag in a 15-kilometre-perhour breeze. At currents approaching 1 knot, turning your head to the side can result in a dislodged, flooded mask; letting go of an ascent line in a 2-knot current for even a brief instant can mean being swept away.

UNDERSTANDING CURRENTS Before you consider diving in a current, it’s important to have a basic understanding of how they work, especially as currents can vary in intensity as you descend through the water column. As a general rule, currents closer to the surface and in midwater will be stronger than the currents on the bottom. Just as you can stand behind a building to block a cold wind, the contour of objects on the bottom slows the flow of water. If a structure is big enough, like a shipwreck, moving behind it can completely stop the effects of the current; however, even small reef structures can significantly slow the water’s speed.

Divers should be aware that currents do not necessarily travel in the same direction from top to bottom. Some currents, such as tidal currents, can reverse direction during the dive.

It is not unusual to have surface currents change speed or direction midwater.

A detailed dive briefing should always precede a dive involving currents; it will orient you to the possibilities you’ll encounter and provide the protocols for dealing with them.

Before you go too far into your dive, stop and use a visual or physical reference, like an anchor line, during the descent to help you judge the strength of the current and how it will affect your dive.

Diving in a current requires one of two strategies: You can either choose to work with (or fight) the stream or go with the flow.

Advanced Diving

DIVING IN CURRENTS Going with the flow Text by Mike Ange Images by Stephen Frink

Diving in currents is either about going with the flow or fighting the stream

Of all the obstacles a diver can encounter, currents can be one of the most underestimated and physically demanding. Even experienced divers sometimes seem unable to assess accurately the speed and impact of a current.

Currents can accelerate your air use and exhaust you; they can even make it impossible for you to return to your dive boat.

Water is 800 times denser than air, so it creates resistance magnitudes stronger than the resistance caused by even a storm-level wind. At one-half knot, divers hanging on an ascent line will feel their bodies moving into a horizontal

GO WITH THE FLOW Going with the flow, or drift diving, is an extremely relaxing way to dive. You should plan to stay in a group, and the group will have a dive flag floating on the surface and tethered to a diver below; this allows the boat captain to follow the group’s underwater progress.

In lieu of a dive flag, you can also use safety sausages or similar signal devices; deploying them to the surface while keeping the line with you underwater makes it much easier for the “bubblewatchers” to track you. Regardless, you should have at least a visual and audible signalling device with you on every drift dive to aid in surface recovery. In addition, the boat crew should provide you with a detailed protocol that includes your dive profile and pick-up instructions for exiting the water.

Once your plan is established, your surface crew is in place and your signalling devices are set, simply fall into the water, get neutral and relax; from there you literally go where the 67

water carries you. Swimming should be limited to depth and minor course changes. At the end of the dive, ascend slowly, do your safety stop, surface and wait for the boat to approach you, and execute the pick-up plan.

If you’re doing a drift dive from the shore, the protocols are similar. You’ll still prepare a plan, and you’ll still carry signalling equipment.

However, instead of a boat captain, you’ll need to arrange some shore support, such as a car to pick you up at a prearranged rendezvous point.

You’ll also have to plan to exit the water on your own, or with only the help of your buddy.

WORKING WITH THE FLOW If your dive boat anchors in a current, or if you plan to dive a site where you know you’ll encounter a current, the dive can be a bit more stressful. Wrecks are good examples of this: You need to stay on the wreck for the duration of the dive, but the current can make it difficult. For these dives you must be able to move your body and equipment against the current; this requires some advanced preparation.

Swimming against even a mild current is physically taxing; it depletes your air supply more quickly and can even accelerate gas loading, which is a concern as it relates to the risk of decompression illness (DCI). When descending in a current, hold onto a line and descend hand over hand; it’s much less demanding than using the muscles in your legs.

Carrying accessories, like a camera, can make the hand-over-hand approach a challenge, so

you may wish to clip accessories to a lanyard to keep your hands free.

In strong currents, dive boats frequently use current lines. Holding a “tag line” behind the boat provides an effortless wait for a buddy or for waiting your turn to reboard after your dive. A current, or “granny,” line is one that attaches the tag line to the anchor line; granny lines help to decrease the effort of reaching the descent line.

Once you are on the bottom, get neutral and begin your dive by swimming into the current. Effective current swimming requires three steps:

Before you consider diving in a current, it’s important to have a basic understanding of how they work

• Gear preparation. Your dive gear should be streamlined with no dangling items. Even an extended regulator hose or a dangling console can create a lot of physically taxing drag. Cave divers have a good rule of thumb: Prep your gear so you can take a piece of twine, extend it across your mask, and drag it all the way to your fin tips without catching it on anything while in a face-down position. Of course the task is impossible, but a properly streamlined setup will get you close.

• Proper weighting. Divers have a tendency to overweight, especially in strong currents.

Although it accomplishes the goal of helping you descend more quickly, once you reach the bottom and attempt to get neutrally buoyant, the added weight will make it difficult, if not impossible, for you to achieve a streamlined swimming attitude in the water. Divers who are properly weighted and trimmed can easily swim in a position that aligns

Depending on the dive plan, a descent line is sometimes an essential piece of equipment

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Before you jump into the current, get some training in the skills you’ll need, practise them in a controlled environment, and expand your experiences slowly

Sometimes it is possible to identify strong currents from the surface. An in-water current check is also important when diving in currents

their fins directly behind their head. This attitude allows for movement through the water, opening the smallest hole possible in the force of resistance the water creates against your body.

position in relation to the boat, and if there are other divers on the platform when you arrive, grab onto the tag line and hang well back from the ladders until it is your turn to exit the water.

• Position. Both the position of your body and your position in the water column are important.

Stay as close to the bottom as possible without making contact with objects, especially delicate ecosystems. Position your body in a streamlined manner; for example, dangling arms create drag, so tuck them in close to your sides or behind your back.

MISSING THE BOAT If you make the mistake of getting down-current of the boat, and the current is too strong to swim against, don’t fight it. Get positively buoyant, dumping weight if necessary, and inflate your safety sausage as soon as possible. If you have to make a safety stop during your ascent, inflate your safety sausage from below the surface; in a heavy current, even a five-minute safety stop can take you far from the boat. By alerting the crew to your location from underwater, they can track you while you offgas, relieving you of the decision of whether it’s better to be lost or risk DCI. The closer you are to the boat when the safety sausage is inflated, the more likely the crew will see it. Complement the visual signal with an audible one; continue to signal the crew until you are sure they have seen you.

Remember that the crew may have other divers to pick up before they can come to you, so stay calm, keep your mask and snorkel in place, and try to maintain eye contact with the boat. If you are with your buddy, stay together.

Knowing how to dive in a current exponentially expands the number of sites you can dive; confidence in your skills makes each dive a safer, more enjoyable adventure.

Before you jump into the current, get some training in the skills you’ll need, practise them in a controlled environment, and expand your experiences slowly as your comfort level grows.

At the beginning of your dive you should swim into the current, as the energy you’ll expend will deplete your gas and physical reserves more quickly. When you reach the turn point, usually after one-third of your gas supply is gone, simply drift back toward the ascent line. Be cautious not to pass it. You should use much less air and energy on the return trip, giving you time to explore the route and the area immediately around the anchor line (provided you still have enough gas and time). Just remember to keep the ascent point in view and stay close.

When it’s time to ascend, maintain physical contact with the ascent line. On crowded boats, using a “jon line” to hang well away from the anchor line can make your safety stop a lot less crowded without forcing you to swim against the current. After the safety stop, slowly ascend to the surface, using the granny line if there’s one available, and allow the current to push your body to the stern. Always maintain contact with the line. If necessary, use your fins to adjust your

69

DAN Was There For Me DAN AP member Nigel underwent two air evacuations after experiencing a severe case of Decompression Illness while on a diving holiday in Kadavu, Fiji.

First a helicopter to neighbouring Suva, then an air ambulance to Brisbane, Australia.

The Cost: $110,000 Out of Pocket Expense: $0 Fully Covered by DAN AP

Nigel’s Advice: “Always have DAN AP Cover!”

CMYK Version www.danap.org

EMERGENCY OXYGEN UNITS Proper care and maintenance is vital to ensure yours is ready for action.

Text by Robert N. Rossier

An effective emergency oxygen unit should contain all necessary parts in perfect working order

Nobody likes bad news, but sometimes a diving tragedy serves as an important reminder. A fatal dive accident on a liveaboard in the Maldives was just such a case. The accident involved carbon monoxide contamination of breathing gas, which caused the death of one diver and injured nine others. Among the disheartening details from the news reports: The shipboard emergency oxygen system was broken, and thus oxygen could not be provided to the victims.

In a diving emergency, oxygen first aid can save lives, but only if the emergency kit is filled with oxygen and in good operating condition.

Proper maintenance is vital, especially in tropical environments.

MAINTENANCE CONCERNS Emergency oxygen systems do not require an inordinate amount of maintenance, but they do require periodic attention. The problem becomes one of “out of sight, out of mind”.

Most emergency oxygen systems aren’t used regularly, and over time components made of plastic, rubber and other synthetic materials can deteriorate and become brittle. Oxygen systems should be professionally serviced at least every two years, more often if they are used heavily.

Beyond periodic professional maintenance, the best practice to ensure the readiness of an emergency oxygen system is to remove the unit from the boat after each trip and 71

completely inspect it. For commercial operators, DAN recommends a bimonthly check of shipboard emergency oxygen systems.

First, inventory all parts, and make sure all components are available.

COMMON PROBLEMS When all parts are accounted for, make sure the components are in good condition and ready for use. Look for these common problems:

of metallic rings encompassing an elastometric element made of a flexible polymer. These are generally more expensive than the crushable seal, but they can be safely reused many times without the need for additional torque to ensure a proper seal. All DAN oxygen units come equipped with this type of “oxygen washer”.

Deteriorated delivery masks: Heat and exposure to the elements can result in deterioration and cracking of rubber and synthetic components. DAN often sees old Empty cylinders: Before heading out on a dive or dive trip, ensure that the oxygen cylinder is full. To masks left to harden and turn brown in cases.

Non-rebreather masks are designed for singlebe filled, oxygen cylinders must also be hydropatient use and should be kept in their protective tested every five years, so check the hydrostatic bag until they are needed. We often see an old test date as part of the bimonthly inspection. mask wadded up inside the case that was used for training at some point, and that Corroded regulators and components: Perhaps the single biggest environmental concern is the only mask available for use in regarding oxygen systems is corrosion of the metal an emergency. parts. The locker of a dive boat represents a harsh environment with plenty of heat, humidity and corrosive salts. Even the slightest amount of salt air that gets trapped inside a case and then sealed up begins to corrode the equipment. At DAN we’ve opened up units stored on dive boats that are so rusted and corroded you would be afraid to turn them on for fear they would explode.

To protect an oxygen system from corrosion, store it in a watertight case with a silica gel packet to absorb any moisture trapped inside.

Damaged regulator and control valve assembly: The regulator/control valve is really the heart of the emergency oxygen system, and it must also be kept clean, dry and free from physical damage.

One potential problem with the cylinder/regulator assembly is physical damage to the pressure gauge. Mishandling, dropping or improperly stowing the emergency oxygen system can sometimes result in a damaged gauge that may not provide a reliable pressure reading. If physical damage to the pressure gauge or the regulator assembly itself is noted, have the unit repaired.

Staff training in the use of the emergency oxygen unit should be standard for every member

Oxygen System Basics Emergency oxygen systems come in various sizes and styles, but most incorporate the same basic elements: a high-pressure oxygen storage cylinder, a regulator/control valve assembly and a delivery mask.

The two primary types of emergency oxygen systems for divers are constant-flow systems and demand systems.

1. Constant-flow systems provide a regulated, and in some cases adjustable, flow of oxygen to the delivery mask.

2. Demand systems provide oxygen in response to the user’s inhalation, thus delivering a higher percentage of oxygen and wasting less gas.

Because treatment needs can vary from case to case, DAN recommends a multifunction system that can provide oxygen using both the demand and constantflow options.

Damaged or deformed cylinder-regulator seals: Faulty or improper seals have resulted in regulator fires. At issue were the two different types of seals commonly used in emergency oxygen systems; they have decidedly different characteristics.

One type of seal is a crushable plastic or nylon device designed for a single use. When the regulator is tightened to the cylinder, the material deforms to create a good seal, but the deformation is permanent. If these seals are reused, they require additional torque to ensure a good seal.

If they start to leak, the friction caused by the flow of oxygen across the face of the seal can cause ignition.

Many manufacturers recommend a different type of seal, referred to as a “sealing washer,” that is designed for multiple uses. These consist 72

HERE’S WHAT YOU’RE MISSING IN THIS ISSUE OF SCUBA DIVER AUSTRALASIA Scuba Diver AUSTRALASIA is the official media partner of DAN Asia-Pacific.

Scuba Diver AUSTRALASIA is one of the most well respected dive magazines, full of mind-blowing images from the world’s best photojournalists, the low-down on the newest dive equipment, the most exciting destinations, stories from the world of science and conservation, and much, much more!

FROM THE EDITOR Island. The word conjures up images of palm-bedecked beaches, gleaming sand, pellucid turquoise water, birds twittering in the trees and fish swirling on dazzling reefs – in short, paradise.

But islands are so much more than dream holiday destinations: These are fragile ecosystems and, unfortunately, many are under threat – subjected to pressure from runaway tourism and pollution, but also by rising sea levels.

Island nations like the Maldives and Kiribati are already making plans to relocate their people in the coming decades.

Importantly, islands are vital oases in (generally) nutrient-poor expanses of ocean. They may appear to be isolated pockets of life, but the coral reefs surrounding them are the living, pulsing heart of the interconnected seas, and are often havens to which the waters’ wildlife comes to feed, breed and be cleaned.

As the poet said, “No man is an island”; all are interconnected. Well, judging by the way life works in the waters off these tiny specks of land, perhaps we can say that no island is really an “island”, either…?

36 THE LURE OF On the cover

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