A cylinder, scuba tank, or dive cylinder as they are often called is a pressure vessel containing air under extreme pressure and in most recreational diving cylinders that’s all there is in it.
The air we breathe is made up of 79% nitrogen and 21% oxygen. An enriched air (nitrox) cylinder will contain just that: air, enriched with more oxygen, normally somewhere between 32% and 40% depending on the dive plan. This extra oxygen decreases the nitrogen content of the gas in the cylinder.
A recreation dive cylinder is not an “oxygen tank”. Pure oxygen, if breathed below 10 metres, can result in oxygen toxicity: this can kill you.
The most commonly used dive cylinder is a 12 litre and it has a working pressure of 232 bar (you have around two bar in your car tyres). Pumped to 200 bar, a 12 litre cylinder will have 2400 litres of air inside it (12 litres multipled by 200). In this part of the world (South Africa) a scuba cylinder is required by law to be painted yellow with a grey neck. An enriched air or Nitrox cylinder is required to be marked with an additional green band around the top, preferably so labeled.
Nitrox cylinders showing the green banded marking
Reference to an “oxygen tank” in recreational diving is just that, a cylinder filled with pure oxygen, painted black and white These are primarily for medicinal use in oxygen first aid, in treating decompression sickness or other emergencies. Their other use is or for very shallow decompression stops (6 metres or less) usually done by technical or deep divers. Oxygen tanks are also used (as in the picture below) for blending of enriched air mixes for Nitrox diving.
Correctly marked oxygen tanks at False Bay Underwater Club
If you want to talk about the cylinder of air that a scuba diver wears on his back while diving, the correct terminology (or the term that would be understood by most divers) is dive tank, cylinder or tin of sky (OK, that last one is not entirely serious).
As a rule recreational diving is no decompression diving. The dive tables are designed to ensure a huge safety margin and you could ascend directly to the surface (no faster than 18 metres per minute) and in theory you should not get bent. Safety stops are just that: a stop, usually at 5 metres for a minimum of three minutes to allow your body to eliminate some of the nitrogen it has absorbed while you were at depth.
So what if you go into deco?
Should you exceed your maximum bottom time there are a few basics and that is where decompression comes in. A regular safety stop is a deco stop and three minutes is considered adequate on most dive planning, but for example a Deep Specialty calls for a simulated deco stop of 8 minutes with some of this time spent breathing from an alternate air source.
By the time a diver gets to this level of training they invariably have their own dive computer and your dive computer will show you that you have exceeded your bottom time and now have a decompression commitment – usually an eight minute safety stop.
When we do these dives we dive on enriched air/Nitrox and leave at least one of our dive computers on air. The result is that the computer set on air will give you a warning that you are now in deco and it will indicate the length of your required safety stop and the recommended depth. Providing you have planned your air consumption and air supply correctly you will be able to fullfill the deco commitment and surface with your computer ready for another dive.
Failure to complete the required safety stop for the entire recommended duration your computer will normally not go into full dive mode until 24 hours have passed. By doing the dive on Nitrox yet leaving your computer on air you give yourself a safety margin, allowing you to experience the actual computer output screen and interpret what it is wanting you to do, without the risk to your health of actually going into deco and being unable to fulfil that commitment for some reason.
In a first for this blog, I’m going to review two books in a single post. They concern (more or less) the same series of events, were written by two men who were close friends for at least part of their lives, and come to wildly different conclusions about what actually transpired and why.
The event in question was the death of French-born freediver Audrey Mestre on 12 October 2002, at the age of 28 (here is a New York Times article on the incident). She was attempting to break freediving a record set by her husband and coach, Francisco “Pipín” Ferreras, in the controversial No Limits discipline of the sport, which entails the diver riding a weighted sled down a line to the required depth, and then inflating a lift bag which rockets them back to the surface.
The freediving disciplines recognised by AIDA, the most well-respected body regulating the sport, mainly involve breath-holding while swimming – down a line with or without fins, or in a swimming pool – or remaining stationary underwater. The challenges are the obvious breath holding, but also (in the depth disciplines) equalising the air spaces in the body.
No Limits is more dangerous than the other disciplines because the use of the sled enables the diver to reach incredible depths at great speed. To return to the surface (even faster than the descent in many cases) he or she must rely on an error-prone sequence of actions. The diver may not be able to successfully release herself from the sled and inflate the lift bag, or a mechanical failure could lead to prolonged time at depth or a slower ascent than planned, and ultimately drowning. Furthermore, it becomes more and more difficult to obtain support divers (on scuba, trimix or other mixed gases) qualified and capable of operating at the depths these dives can reach.
The lack of physical effort on the part of the freediver involved in getting to and from the desired depth has led some critics to comment that the only way these divers will discover the physical limit beyond which a human being cannot descend will be by dying (when their bodies can no longer withstand the crushing pressure exerted by the ocean). Many of the participants in this sport have suffered strokes, partial paralysis, decompression sickness, blackouts, convulsions and even suspected brain damage as a result both of the rapid pressure changes they experience, and of depriving their bodies of oxygen for so long.
The Last Attempt – Carlos Serra
The Last Attempt
Carlos Serra was part of the team of safety divers, organisers and support providers who worked with Ferreras on several of his and his wife’s world record attempts. He and Ferreras also ran the short-lived freediving body IAFD (International Association of Freedivers), a competitor to AIDA, which was dealt its death-blow by the drowning of Mestre.
Serra paints a disturbing picture of Ferreras, as an egomaniacal sociopath who completely controlled his wife and pushed her far beyond what she was comfortable doing. He suggests that Ferreras had put in place a bizarre and elaborate plan for his wife’s record attempt to fail, and for himself to rescue her (to wide acclaim, of course). The damage caused to his ego by her then breaking his record a few days later would be softened by the fact that he would first be hailed by the world’s press as her brave rescuer. He would also have punished her for requesting a divorce a few days earlier, and for her perceived insubordination in planning to leave him.
The allegations are compelling – there are a number of pieces of evidence that indicate that, if Ferreras was not criminally negligent (for example, he did not fill the pony bottle of compressed air that was to inflate Mestre’s lift bag and bring her back to the surface), he deliberately sabotaged her attempt to break his record. The rescue did not go as planned, and by the time he brought her to the surface she had been submerged for nearly nine minutes and her lungs were full of water.
Serra wrote this book himself, and it shows. He’s a native Spanish speaker, and his English is at best broken, and at worst appalling. His spelling is novel and inconsistent. I was charmed, however, by some obvious transliterations of Spanish idioms. The resulting effort rings with honesty, and his deep friendship with and care for Audrey Mestre lends credibility to this account.
Ferreras published his version of events in 2004, two years before Serra’s book came out. It was heavily ghost-written – for example, I find it hard to believe that a Spanish-speaking Cuban who didn’t finish school knows who John James Adubon was – and at times reads like a cheesy romance. It’s very beautifully produced, and perhaps half the book comprises both colour and black and white photographs of Ferreras and Mestre underwater, posing uncomfortably on the beach in various small and tight outfits (this seems to be a very important part of being a professional freediver) and lollygagging on the surface before and after dives.
Ferreras constantly protests his love for Mestre, and while repeatedly acknowledging his vicious temper and out of control ego, denies that he ever pushed her in her freediving efforts. He claims that the impetus to go deeper came from her, and unsurprisingly does not give any hint that he controlled her, regulated her movements, or (as Serra alleges) cheated on her and occasionally beat her up. A goodly portion of the book is devoted to his life story, growing up in Cuba and the defecting to the USA. We are also frequently reminded (even on the cover and spine of the book) of his own freediving achievements and other admirable qualities.
It’s not hard to figure out what actually happened. The entire dive – before, during and after – was captured on video from several angles, and it’s clear that the cylinder of air intended to lift Mestre from depth was not filled. The cable on which the sled descended and the lift bag ascended a short distance (after one of the support divers had partially filled it from his breathing mix) was twisted, which slowed her down at a critical point on the delayed ascent. There were not enough support divers to provide midwater assistance – not nearly enough – and the nearest thing to a doctor on hand was a local dentist watching from a nearby boat. Her husband opened her airway while he was bringing her to the surface, further flooding her lungs (as an aside, Serra prevented Ferreras from acting as the deep support diver – his scuba skills are sub par to say the least, and he has been bent more times than most of us have had breakfast). There was also no back-up or bail-out plan should Mestre get into trouble on the way down or up.
What is hard to figure out is exactly who was to blame. However, whether the narcissist Ferreras himself is solely culpable here, and went so far as to deliberately endanger his wife beyond what she was already risking, or whether the entire team caused Mestre’s death is almost a moot point. If Ferreras was as out of control, slapdash and filled with machismo as Serra alleges, the members of his support team – some of whom had been with him for 15 years and had witnessed the deaths of at least two of his safety divers on other record attempts – were morally obligated to refuse to participate instead of being swayed by Ferreras’ awesome temper and magnetic personality. He was not risking his own life in this attempt – it was the life of his wife that was on the line. Without a team of safety divers and organisers – hard to assemble at the best of times given the extreme nature of the sport – Ferreras would have been unable to operate and Audrey Mestre may still have been alive today.
This article from Outside Magazine suggests that Serra’s description of Ferreras’ character aren’t entirely baseless (and it was written about five years before the death of Mestre). It also suggests that Ferreras has an on-off relationship with the truth and enjoys embellishing his own life history and prowess, something that should be borne in mind when reading his book. Do not read only one of these books – I would strongly recommend that you read both, one after the other. I’m not sure if it’ll help you figure out the truth, but at least you’ll have heard both sides of this tragic story.
If you want to see how beautiful freediving can be – and it can be very beautiful and transcendent – watch this video of current world record holder William Trubridge diving to 101 metres without fins, and then swimming back up. The discipline he’s participating in here is called Constant Weight Without Fins.
This book is gripping – I loved it. It describes the discovery and diving on a German U-boat in the northern Atlantic Ocean. It took over six years before the vessel was conclusively identified, and Kurson describes the process followed – including multiple dead ends – by John Chatterton and Richie Kohler, the two divers who persisted with the mystery long after others had lost interest.
It’s a mixture of terrifying deep wreck diving and penetration, WWII history, and personal drama that I found quite irresistible. Three divers died on the submarine before it was identified, and every imaginable diving accident – from entanglement to DCS to panic to nitrogen narcosis (a big feature, since the sub lies at about 70 metres and initially the diving on her was on air), and the constant risk of being lost at sea if you didn’t surface on the line – occurs. I still don’t think this kind of diving is for me – the dangers are too great.
I admired the determination of Chatterton and Kohler to put a name to the submarine, thus providing closure to the families of the German officers who perished on board. Their rectitude and determination not to desecrate a war grave and the resting place of nearly sixty men was admirable. It’s possible that, had they agreed to rummage among the human remains all over the submarine, they’d have located an item of someone’s personal effects that would have speeded the identification process, but they refused to disturb the bones.
The culture of American deep wreck diving sounds as though it is quite macho and cowboy-like (one group of divers wore matching denim jackets with a skull and crossbones on it), and for Chatterton and Kohler to buck that trend was a big thing.
I learned one useful thing that has stayed in my mind since I finished the book – maybe I knew it all along, but it was articulated here in a clear manner: when you run into difficulties in the water, solve the first problem completely before you try to solve a second or third one. You need to answer each problem fully when it occurs, because accidents happen when a small thing is ignored, which then combines with another problem to cause a life-threatening situation.
In the acknowledgements, Kurson mentions Deep Descent by Kevin McMurray, which describes diving on the wreck of the Andrea Doria in the same dangerous, cold, rough piece of ocean. Many of the protagonists in MacMurray’s book appear in Shadow Divers, as do the same pair of dive boats – the Seeker and the Wahoo. He also cites Neutral Buoyancy by Tim Ecott, another of our favourite diving books, as an inspiration and source for some of the decompression theory.
Unfortunately the aggressive, fiercely competitive ethos that has been allowed to fester among this particular group of divers has led to the publication of a rival account by Gary Gentile (who appeared extensively in Deep Descent). It’s called Shadow Divers Exposed and apparently refutes much of what is described by Kurson. Gentile is clearly a bitter and angry man, with several axes to grind. It does however seem possible that in focusing the book so squarely on Kohler and Chatterton, Kurson allowed it to seem as though the two of them are due more credit for identifying the U-boat than they really are, so this book should be read with a small measure of caution. I would still strongly recommend it, however – the overarching truths and events described did take place, even if a few small-minded participants and observers would quarrel over specific details.
I’ve been wanting to arrange a chamber dive for a while. Hyperbaric chambers are like large geysers that can be pressurised to higher than atmospheric pressure. They are used in medical applications – breathing oxygen-rich gas at high pressure assists with all manner of complaints – and of course, in diving medicine for the treatment of decompression sickness. They are also used in commercial diver training.
Checking out the chamber
A chamber dive doesn’t involve water, scuba gear or buddy checks. It simulates the experience of breathing compressed air from a cylinder at the bottom of the ocean by putting you in a sealed metal chamber, pumping air into it to the required pressure, and decompressing you slowly after leaving you there for a while. It’s perfectly safe. There’s an intercom so the chamber operator can hear you at all times, and we were supplied with a rubber mallet for knocking on the chamber wall in emergencies while the pressure was being adjusted (which is a noisy process, like sitting inside a jet engine).
Goot settles in inside the chamber
The chamber we visited is on campus at the University of Cape Town and is used for commercial diver training. Eight of us did a chamber dive to 50 metres (in two groups of four). This is 10 metres deeper than Tony and I are qualified to dive in the ocean (with a Deep specialty qualification), and 20 metres deeper than an Advanced diver is qualified to go. An Open Water diver can go to 18 metres. The only requirement for this dive was an entry-level dive qualification, so Open Water was fine.
Paul the chamber operator at the controls
Paul, the chamber operator, checked that none of us had any plates, pins or bolts in our bodies. It turns out that both Goot and Tami are semi-bionic, and they were told to move the affected limb (or jaw, as the case may be) to ensure blood flow throughout the process. Nitrogen bubbles would be more prone to form around a screw or other metal fixture interrupting the natural shape of the bone. We were told to sit with our legs as straight as possible, arms uncrossed, to ensure that blood circulates well throughout the dive. He warned us that if we have a panic attack at 50 metres there’s nothing to do except sit on the affected diver, because once the chamber is pressurised it cannot be depressurised quickly without serious – life-threatening – risk to the occupants. For this reason we had a stop on the way down, at 9 metres, to check that everyone was still happy.
It's crowded in there - Bernita, Sophie, Tracy and Goot do their dive
The chamber is pressurised to six atmospheres by pumping air into it. The pressurisation was done quickly – it took two minutes (with a brief stop at 9 metres to check that we were all right) to take us down to 50 metres. We had to equalise like MAD, literally every couple of seconds, and the chamber got very very hot inside as the air was pumped in. Boyle’s law at work… Constant volume, increasing pressure!
Starting the ascent
We spent about eight minutes at 50 metres. It was an intensely strange sensation. I felt the same light-headed hot scalp feeling that I experienced last time I was seriously narcosed, in Smitswinkel Bay, but magnified to the point that I felt drowsy and woozy and quite chilled. Our voices sounded as though we’d been inhaling helium, and EVERYTHING was very funny. I had a very nice feeling of well-being but wasn’t really interested in complicated conversations.
We had our dive computers with us in a bucket of water, and checked them periodically to see what they were telling us. Tony had his Mares Nemo Wide set on nitrox 32%, and it was flashing at him that we were perilously close to the maximum depth at which it’s safe to breathe that mixture. As expected, it gave us more bottom time than the computers that were set on air before it went into deco.
I distinctly remember trying to interpret the array of numbers on the screen of one of the dive computers, and handing it back to Tony and saying vaguely, “I don’t understand what all these numbers mean” – VERY odd for me because my entire job revolves around the complex manipulation of numbers, and I have a great fondness for statistics of all kinds!
Still feeling rather jolly, and hot - emerging from the chamber
As the chamber was depressurised, we experienced Boyle’s law in the opposite (very welcome) direction: the air cooled rapidly and mist formed to such an extent that at times I couldn’t see Tami, who was a metre away from me. There was a little bit of coughing from irritated lungs at this point!
The first group degassed by spending 5 minutes at 9 metres, 5 minutes at 6 metres, and 10 minutes at 3 metres. This is an extremely conservative decompression schedule and fulfilled all deco obligations plus more after the bottom time that was experienced. All our dive computers would have allowed us to ascend long before Paul let us out of the chamber! The second group, in which Tony and I were, had an even more conservative decompression schedule because of the particular age and physical profile of our group, and we spent 5 minutes at 9 metres, 10 minutes at 6 metres and a full 15 minutes at 3 metres.
Tracy, Goot, Sophie, Tami, Bernita, me and Cecil - Tony took the picture
Dive date: 8 March 2011
Air temperature: 26-31 degrees (inside the chamber)
Fatally Flawed: The Quest to be Deepest – Verna van Schaik
Fatally Flawed
Verna van Schaik holds the record for the deepest dive on scuba by a woman, to 221 metres in a water-filled cave called Boesmansgat in the Northern Cape. If the name Boesmansgat rings bells, it’s probably because you heard about it as the cave that claimed the lives of Deon Dreyer in 1994, and, more recently, the Australian diver Dave Shaw, who went to recover Deon’s body. The story of that mission is recounted in Raising the Dead (also called Diving into Darkness).
Verna van Schaik was present on the day when Dave Shaw died – she had a critical support role as the person managing all the divers from the surface. She describes her emotions and how difficult it was to know what to do in the situation that arose. Her account of the build-up to Shaw’s dive, the actual unravelling of events, and the aftermath, is fascinating when read in conjunction with Raising the Dead, because she was actually on the team, whereas the other book is written with the apparent objectivity of a third party. Van Schaik criticises Dave Shaw and Don Shirley for going ahead with the dive – she says that they hadn’t slept enough, and that there had been several critical equipment failures the night prior to the dive which made it a desperately risky undertaking.
The book traces her career as a female deep diver. It includes her struggles to be accepted in this very male-dominated sport, her struggle to find and keep a trusted dive buddy, and numerous descriptions of the difficulty of managing a team of divers engaged in high-risk record-seeking endeavours.
She describes the fear she has felt on some of her record-setting dives, and the experience of becoming entangled in her line while at the bottom of a cave, all alone. Very deep dives are of necessity solo dives – there simply aren’t enough people who can and want to dive that deep for buddying up to be an option, and when every single small decision is a choice between life and death, having a buddy can be more of a liability than a help.
Van Schaik does, however, stress that very deep dives require a team of support divers who meet the deep diver on his or her way up from the deepest point. She prefers continuous support (never leaving the deep diver alone during the long decompression) but Shaw and Shirley, for example, planned for divers to be with them only for ten minutes of every hour.
It’s a quick read, could have done with a spell-check, but, especially if you’re familiar with the Dave Shaw story, I recommend it.
We have done very little diving this past week, lousy weather and lots of wind.
Dive planning
This weekend I am hoping to do boat dives one day (probably Saturday, weather dependent), and shore dives with students on the other day. Let me know if you’d like to tag along on either and I’ll keep you in the loop.
Boat dives
Please note that prices for boat dives are going up as of 1 March (today) from R180 per person per dive to R210. If you want to buy a ten boat dive package you can do so directly from Grant at BlueFlash for R1600. A one-off boat dive directly from Grant is R250.
Obviously if you’re doing a boat dive as part of your course, you don’t need to pay.
Chamber dives
We have one or two spots left for the chamber dive, which is taking place on Tuesday 8 March at 5.30pm in Rondebosch. This is going to be a very entertaining (and hopefully educational) experience and I’d recommend you join us if you can. Email or call me if you’re interested.
You don’t need a medical certificate if you plan to do this dive – just an Open Water (minimum) qualification.
Wreck diving talk
On Wednesday evening (2 March) there’s a talk on shipwrecks (diveable ones) of the West Coast, given by Alistair Downing of Underwater Explorers (the diver who described his experience of being bent to Clare for a blog post on DAN membership that I mentioned two newsletters ago).
It’s happening at False Bay Underwater Club which meets just down the road from where I live in Kenilworth. This is a nice opportunity to meet some of the FBUC members (many of whom you will recognise from diving on the boat), to see what it’s like to be part of a dive club, and to learn something new and interesting.
If you’d like to attend, let me know and you can meet at our house at 7.20pm and follow us down the road from there. The talk should be over by 9pm unless things get really out of hand.
There’s no charge except the price of one drink at the bar to support the club!
Dive Site magazine
Those of you who haven’t signed up for the Dive Site magazine at www.thedivesite.co.za should do so – it’s a FREE quarterly magazine of outstanding quality (far better than the ones that actually cost you money) along with a super weekly newsletter (and I am not just saying that because I was featured in the last one!). In the next issue of the magazine will be an article about the discovery of the SS Cape Matapan, the wreck opposite Cape Town Stadium that some of you dived with me last month (with mixed success!)
Those of you who haven’t signed up for the Dive Site magazine at www.thedivesite.co.za should do so – it’s a FREE quarterly magazine of outstanding quality (far better than the ones that actually cost you money) along with a super weekly newsletter (and I am not just saying that because I was featured in the last one!). In the next issue of the magazine will be an article by our trusty boat skipper Grant about the discovery of the SS Cape Matapan, the wreck opposite Cape Town Stadium that some of you dived with me last month (with mixed success!)
Sodwana is booked and deposits paid (I have paid for those of you that have yet to pay your deposits so don’t let me down), the current water temperature there is 29 degrees celcius… I am so looking forward to warm water diving.
The pictures are some that Clare took on Sunday at Long Beach when Marinus and Dean were doing their first two sea dives for their Open Water course.
Fat plough shell at Long Beach
Clare has put together the chamber dive and we have 8 confirmed so far. The chamber holds 5-6 people so there is still space, mail me if you are interested. For those that don’t know, the chamber dive is to 50 metres, but you don’t need to be anything other than a qualified diver as it is a “dry” dive and requires you to sit on a bench and equalise your ears whilst the chamber is pressurised. Your behaviour, voice and senses will all experience the effects of a dive to depths of 50 metres but there is no water!
We will have dive computers in a bowl of water so you can learn about how a computer behaves at those depths… Computers are not as smart as us so they need to be in water. (Some dive computers have “wet contacts” and will only go into dive mode if submerged.)
Ribbed turrid at Long Beach
The southeaster continues to pound the coast and we have only had three days of diving this week.
Tuesday was a surprise and delivered good conditions, warm water, 19 degrees and 4 metres visibility. This weekend and the best part of next week will again be hampered by the wind so we will only be diving on Sunday, doing a few deeper dives to complete a few Advanced and Nitrox courses.
Dean on his first Open Water sea dive
I am not sure of how many of you read the blog but this is a very interesting post by Clare on “the bends” and why DAN insurance is such value for money. Alistair was kind enough to relate his story and how it impacted on his life. I am sure it costs under R1000 a year, read this and decide if you can afford not to join.
A large part of diving training involves making sure that you are a safe, competent underwater adventurer. You learn the consequences of various actions on the air spaces in your body, and the physiology related to breathing compressed air at depth, including how long it’s safe to stay down, how fast to ascend, and all about safety stops. The training you will do teaches you to manage your buoyancy so as not to make uncontrolled ascents or descents. All this minimises the chance that you will need emergency medical care after a dive.
Diving accidents are uncommon, but when they do happen, the cost of treatment is likely to be high. In the event that you’re bent – or possibly bent – you’ll have to go to a hyperbaric chamber for recompression treatment. For some perspective on what this involves, and what this feels like, I spoke to Alistair Downing of Underwater Explorers, technical diver extraordinaire. He’s been bent twice – here’s how he describes the first time (in 2003), after a deep dive on trimix out of Hout Bay, involving numerous long decompression stops:
The dive and deco went great. No problems at all.
On my final ascent from 6 metres (doing 1 metre/minute ascent rate), I felt a slight twinge in my thigh muscle, but put it down to being really cold and immobile for such a long dive – roughly two hours!
Finally surfaced and felt a little dizzy, but assumed with the rolling seas, it was a little seasickness (not that it is usually a problem…).
By the time the boat picked me up, I was exhausted. I couldn’t unkit and needed the safety diver to get my gear off me.
I just made it into the boat and needed to lie down. Just felt really, really tired. Again put it down to exhaustion, having just done a massive dive.
About two minutes later I called for the O2 – thought it can’t hurt.
A few minutes onto the O2 the pins and needles all over my body started – time to go!
We were all DAN members and as per DAN’s protocol, we contacted DAN first. They then contacted Kingsbury Chamber and we were advised to proceed there. At this stage, I was aware of my surroundings and besides the pins and needles, was doing OK. We were 16 kilometres out to sea from Hout Bay and en route my condition deteriorated. Some of these I can recall, but others were relayed to me after the fact. By the time we got to Hout Bay harbour I was paralysed from my waist down, had lost sight in both eyes, apparently had stopped breathing on several occasions and was basically out of it!
They had initially arranged for an ambulance to collect me at Hout Bay, but there was a delay so my crew decided to transport me in the back of a bakkie – I have only one fleeting memory of the trip from Hout Bay to Claremont.
DAN had put Kingsbury on full alert and soon after I arrived, Dr Rosenthal arrived. I basically went straight into the chamber and was there for about 8 hours. I forget the exact details of the treatment, but Rosenthal has all these details. What I can recall is that it was not a pleasant experience. Lots of pain, confusion, too hot, too cold, thirst, nausea, and feeling very uncomfortable. That evening I was admitted to High Care and spent the night there on oxygen. At this stage I was generally pain free, except for one mother of a headache… and a general ‘pap’ feeling.
Over the next several days I went for about five follow up treatments of about two hours each. I was also on massive doses of medication, specifically to reduce the swelling of my brain. I was not allowed to dive for a year, which in itself almost killed me! It also took about 6 months before my headache went away…
I was diagnosed with neurological bend, most likely caused by a helium bubble. After the year, I passed my medical and it was all systems go again.
Alistair dived with the same buddy both times he got bent, and his buddy experienced no problems either time. Alistair was later diagnosed with a PFO (patent foramen ovale, or hole in the heart that did not close completely at birth – about one third of people have them) which may have predisposed him to getting bent despite meticulously following safe decompression schedules and experiencing nothing untoward on either dive. He had this surgically repaired and since 2009 has been back in the water with no problems!
DAN emergency noticeboard at Long Beach
DAN stands for Divers’ Alert Network. They’re an international organisation that provides top-up medical aid cover for divers, as well as diving medical information and research, evacuation services, and training in diving safety.
Alistair’s treatment for the bends he’s experienced cost between R30,000 and R40,000 each time – and if a helicopter evacuation had been required, that cost would have increased sharply. Here’s what he said about the extent of the cover by DAN:
DAN covered me in full for both bends – picked up all the bills, including medicine. I basically did not pay a cent and as a DAN Business member, was really happy about this. They however did not cover anything linked to the PFO operation, as it is post injury elective surgery, not bends incident related. All in all, a good showing by DAN and reason enough to get cover from them.
While we trust medical aids to provide the peace of mind that your costs will be covered when you require hospitalisation or emergency treatment, the truth is that in many cases they will do everything they can to avoid paying out your claims. You should be certain that the medical aid cover you have will pick up the tab if you incur an injury while diving – many medical aids classify scuba diving (even recreational scuba on air to less than 40 metres’ depth) as an extreme sport, and treat associated claims accordingly – in other words, with great reluctance.
(As an aside, if you have life cover, you should make sure that the life insurance company is also aware of your diving activities for their records.)
Learn to Dive Today is a DANBusiness Member, which means that we are able to supply you with application forms and membership information, and have access to DAN training on emergency procedures and management. It also means that we are kept up to date with developments in diving medicine, and have access to the extremely efficient DAN team in South Africa for any assistance we require.
If you dive frequently, if you like to dive in remote places, if you have a penchant – or desire – to push the limits of recreational scuba, and especially if you fit into one of the risk categories for diving (old age, overweight, heart problems), you should have this kind of insurance. If you want more information or to discuss the various options DAN offers, email Tony or contact the DAN Southern Africa office. They’re very friendly and super efficient!
There is an often repeated joke that there are two types of diver: those who pee in their wetsuits and those who lie about it. Its true to say that having just paid handsomely for a new wetsuit the idea is not to pee in it. However, sooner or later it’s going to happen to you! This is why….
The physiology
Basically, you can’t help yourself. The physiological phenomenon in question is known as immersion diuresis, a term which refers to your body’s response to being under pressure. Blood is shifted to your body’s core because of the cold and pressure on your body, which increases your blood pressure. The hypothalamus gland thinks this means your total fluid volume is too high and tells your kidneys to make urine.
What can you do to avoid immersion diuresis? Avoid diuretics like coffee and other caffeine-rich drinks before you dive! Intentionally not drinking any liquids might seem like a sensible idea, but dehydration predisposes you to decompression sickness and saps your energy.
Try to stay warm. A by-product of your body’s reaction to cold is urine. Wearing a warm chicken vest under your wetsuit may save you from having to empty your bladder while underwater. Make sure you have good gloves, thick booties and a decent hoodie. On the boat, stay out of the wind if you can, wear an anorak and a beanie or cap.
Be sober, healthy, and well rested. Some over-the-counter and prescription medications can interfere with your body’s heat conservation activities, typically by hindering the constriction of blood vessels near the skin. Antihistamines, taken for hayfever and other allergies, are particular culprits as is alcohol. Make sure you are physically fit.
How to avoid it
What can you do to prevent urination on a dive? Drink less water? The counter-intuitive answer is that you should drink more.
Deliberately dehydrating yourself, in the hope you can hold it until you surface and get out of your suit, just makes the problem worse. Because of immersion diuresis and your body’s involuntary reaction to the chilly water, chances are you’ll have to pee anyway. And dehydration makes the result stronger in odor and colour.
If you do have to pee in your wetsuit…
If you’re well-hydrated, your urine will be almost clear and nearly odourless. So it can be your little secret.
There’s no health risk to urinating in your wetsuit. If you’ve watched Survivor or read anything about treating stings from jelly fish and bluebottles, you may recall that urine is sterile, unless you already have a urinary tract infection. The worst you have to fear is a case of nappy rash if the urine stays against your skin for a long time, and this is much less of a problem when your urine is diluted.
Long Beach parking area, the divemobile, and the shower in the background
The solution is to open your wetsuit under water and rinse it between dives, if you can stand the rush of cold water. If you’re at Long Beach for a training dive, there’s a conveniently located shower in the parking area!
