Documentary: Diving into the Unknown

Having recently dived into the 21st century (with a Netflix subscription), I looked up this Finnish documentary as soon as it became available. It covers events that took place early in 2014, when a group of Finnish cave diving friends started a traverse of a massive, deep cave system in Norway. Two did not surface from the dive.

Diving into the Unknown
Diving into the Unknown

The Norwegian police, advised by Rick Stanton, a well-regarded British cave diver, closed the cave and announced that it was too dangerous to attempt to retrieve the men’s bodies. Their dive buddies, who had pioneered exploration of the more than 100 metre deep system and felt they knew it like the back of their hands, disagreed. They also felt a duty toward their friends, and therefore planned a mission (illegally) to retrieve their bodies.

Their dives were filmed for this documentary, which features interviews with the surviving divers and another of their friends who trained some of them as cave divers, and accompanied them on their mission. Whether events mirrored those that took place at Boesmansgat in 2005, or whether the ending was quite different, I’ll leave you to find out.

Unless… you read this excellent article from the BBC, before watching the documentary. It will reveal the outcome of the body retrieval dives, but it may also enhance your enjoyment of the film. A chance to study a map of the cave system, which featured in the film but was introduced too late for it to be truly helpful, and a chance to familiarise oneself with the difficult Finnish names, may be of benefit.

This is hardcore diving, to incredible depths, on rebreathers, in overhead environments, and under ice (to start the dive, the men cut a hole in the ice covering a lake surrounded by snowy hills and bare trees). Most of us will never do anything like it. The scenes filmed inside the cave range from serene clarity to heart-stopping moments of claustrophobic intensity as the divers work through obstructions and labour to free their friends’ bodies. Even though this is likely not aspirational for many of us, the questions raised by the men’s mission, especially whether it was wise to go back into the cave at all, make for some interesting discussion.

See the documentary on Netflix, or get the DVD here (South Africa) or here. Here’s the official trailer:

Movie: Pioneer

Pioneer
Pioneer

In the late 1960s, massive oil and gas deposits were discovered in the North Sea, transforming Norway into one of Europe’s wealthiest nations. Pioneer depicts some of the early, feverish oil-related activity during the 1970s. The Norwegians needed to build a pipeline to bring the oil to land from depths of up to 500 metres. Lacking the technical expertise – particularly with respect to the underwater work that must be done by saturation divers – they bring in American assistance.

Norwegian divers (so-called “pioneer divers“) dived to depths that are now considered unsafe, even for saturation divers, and a group of them have sued the Norwegian government for compensation for damage incurred during their careers in the early days of the oil boom. Pioneer tells the story of Petter, a Norwegian diver who is present during a diving accident and embarks on a search for the cause, believing that human error was involved and that someone must take responsibility.

I enjoyed the film enormously, but most of the reviews I have read found it a bit turgid. The milieu is evoked with incredible attention to detail, including the awful 1970s moustaches and unfortunate hairstyles. The dialogue is in both Norwegian (subtitled) and English. It is beautifully filmed, with clever camera work mimicking the limited view that the divers have while working underwater and in the saturation chamber. The underwater scenes are excellent, reminiscent of those in For Your Eyes Only (I’m joking – they genuinely are extremely convincing and quite magnificent). Tension is maintained throughout, and the action takes places over a fairly short period of time.

You can get the DVD here (South Africa), here or here.

Suunto D6 in full panic mode (part I)

On the second dive we did at Doodles during our trip to Ponta do Ouro, something happened that caused my dive profile to look like this (click on the image to embiggen):

Profile (from MacDive) of a dive at Doodles
Profile (from MacDive) of a dive at Doodles

Fortunately that something was not me falling down an 89 metre deep hole in the ocean floor whilst breathing off a 12 litre cylinder of air, 45 minutes into a dive. It was something going wrong with (we think) the pressure sensor of my Suunto D6 dive computer. I have had the computer for a few years, and apart from the compass appearing to have packed up, it has been a fantastic device.

The first inkling of trouble that I had was when the computer started beeping at me, and when I looked down to see what was up, it said we were at 89 metres. Sunlight was falling on me, so I thought this unlikely. I checked with Christo, and he didn’t think we were that deep either. Nor did his computer. Fortunately I had been diving with a group for a few days, and we were well within our decompression limits at a depth of 14-15 metres. Losing the computer three quarters of the way through a dive wasn’t the disaster it could have been.

I took this picture shortly after the beeping started. The display at the top of the screen shows that the computer is reading 76.7 metres. The maximum depth of 89.0 metres shows at the bottom left. The bottom right shows the oxygen partial pressure, at 1.9. This is greater than the 1.2 limit that I have set for myself inside the computer. The computer thinking that I had rapidly exceeded the maximum PPO2 is probably the initial cause of the beeping I heard.

Suunto D6 showing 76.7 metres' depth
Suunto D6 showing 76.7 metres’ depth

In the middle of the screen you can see a large number 8.0, which is the depth to which the computer wants me to ascend in order to do a decompression stop. Next to that number is an arrow below two horizontal lines, and the number 35. This is how long I should stop at 8 metres in order to fulfil the calculated decompression obligation.

The D6 thinks we have ascended to 47 metres now
The D6 thinks we have ascended to 47 metres now

After a few minutes (I was actually busy ending my dive with a 5 metre safety stop) the computer believed I had ascended to 47.3 metres. By that stage it wanted me to go to 11 metres for a 45 minute stop. When I surfaced after about 60 minutes of dive time, the computer stayed in dive mode, thinking that I was still at a depth of about 35 metres. It continued registering a slow, quite smooth ascent for another hour and a half, as seen in the dive profile above.

The computer was still very grumpy when it took itself out of dive mode in a mug of warm water in the bathroom of Planet Scuba, while we were eating a post-dive lunch. The ascent profile it registered did not fulfil the calculated decompression obligations, and it showed that I had violated my decompression ceiling (either by taking too long to ascend to start the stops, or by not spending enough time at the stop depth).

I have put myself briefly into deco a few times (usually during days of repetitive diving during dive trips, and once or twice in Cape Town with two relatively deep and long dives in a day), so the readouts from the D6 on this dive are not unfamiliar to me. I have never before, however, seen such large numbers or heard so much beeping! I have always corrected the situation by ascending a little way, which removed the decompression obligation and returned the display to what I am familiar with as a religiously recreational, no-decompression diver. In this case, the D6 was doing its own thing and nothing I did seemed to influence the depth reading it gave.

I found this to be an excellent opportunity to re-familiarise myself with the behaviour of the Suunto D6, and also to see what all the error messages look like on the dive profile when I downloaded the computer into the MacDive software I use for electronic dive logging. The story does not end here – if the computer did not think I was dead from DCI, it wasn’t going to let me dive any time soon – check back tomorrow (or the day after).

Article: Wired on rigid dive suits

I want one of these. Wired published an article in January about a rigid diving suit built by Nuytco Research, called the EXOSUIT. The inside of the suit is maintained at surface atmospheric pressure, obviating the need for lengthy decompressions after working at depth. The suit is incredibly flexible, which sets it apart from many previous efforts to build such suits. The visual field is excellent, and if you’re not sold on the thing already, it has thrusters… So it’s like an underwater jetpack.

The EXOSUIT from Nuytco
The EXOSUIT from Nuytco

Read the full article here, or check out the full specs of the EXOSUIT here.

Surviving underwater in an air bubble

A news story in June resonated uncomfortably with me: a Nigerian sailor survived for two days in a pocket of air trapped beneath the tugboat he was in, which capsized in heavy seas. The tug was servicing an oil platform off the Nigerian coast.

I was immediately reminded of the Miroshga, an unseaworthy whale watching vessel that capsized in appalling conditions off Hout Bay in October 2012. The boat had its bilge pump installed UPSIDE DOWN, and was rated for over 40 passengers when it’s only five metres longer than our boat – which can take seven passengers (and when Seahorse is fully loaded, she feels full). Furthermore, the Miroshga hadn’t had a SAMSA inspection since fundamental changes were made to the vessel and its engines. The money-hungry decision to head out in a 25 knot south easterly wind and high seas was incredibly irresponsible.

Most people who go on seal cruises, whale watching or cage diving don’t spend half their lives on or near the sea, and simply don’t have the tools to assess whether conditions are safe and whether the boat is seaworthy. The passengers trusted the charter operator and SAMSA, and were badly let down. One man drowned, and three women were trapped under the boat in pockets of air for several hours, their limbs dangling in the freezing water, until rescue divers brought them out. I cannot imagine how traumatic the experience was for them. The rest of the passengers were rescued by a boat full of poachers, and by some incredible NSRI volunteers. It was a shameful day for the boat charter operators, and for those responsible for legislating and enacting maritime safety provisions in South Africa.

I digress. What happened in Nigeria? Out of the twelve crew on board the tugboat, ten bodies were recovered, one was lost, and the twelfth crewmember, Harrison Okene, was discovered alive, under the boat in 30 metres of water, surviving by breathing from an air pocket. Upon being rescued by divers sent to retrieve the crew’s bodies (can you imagine their shock at being greeted by a living person when they were expecting only corpses?), Okene had to undergo sixty hours of decompression in order to avoid being bent. He’d been breathing air at four atmospheres for two and a half days!

The incident prompted a fascinating discussion on StackExchange, a discussion forum for a variety of disciplines (I lurk in the statistics and quantitative finance forums). A user posed the question:

How large does the bubble have to be so that a person in it can have indefinite supply of breathable air?

The reason it’s even possible to have an “indefinite” supply of air is that if the bubble is large enough, oxygen will diffuse out of the surrounding water back into the bubble, and carbon dioxide won’t build up to fatal concentrations. You can read through the discussion if you want to (fun to see physicists arguing, nice if you like formulas!) or there’s a news article here about the theoretical bubble size that would be required for survival. Turns out the actual air bubble was close to the size calculated by the physicists that would allow survival for at least the time that Okene was submerged. Lucky, lucky man!

Update: Here’s the helmet cam video from one of the rescue divers who brought Mr Okene to the surface. The text at the beginning is wonky – persist. Note the South African accents! The diver’s voice is squeaky – I think because he’s breathing a gas mix with helium in it. It gets good at about 5:30 but it’s extremely interesting to watch in its entirety to see what sort of conditions these divers work in, and how the surface support talks them through their tasks and keeps them calm.

Series: Underwater Universe

Underwater Universe
Underwater Universe

The four episodes of this History Channel series cover waves, tides and currents, predators, and pressure – all powerful features of the ocean that can be sensationalised (some more easily than others) and presented for shock value and as imminent threats to human life. Full advantage is taken of this fact.

This very American offering doesn’t boast the measured, mellifluous tones of Benedict Cumberbatch or Steve Toussaint as narrator, but the line-up of (mostly in-studio) guest narrators is quite impressive. Bruce Parker (The Power of the Sea), Susan Casey (The Devil’s Teeth and The Wave), David Gallo (scientist presenter of the TED Talk I mentioned here), Scott Cassell (student of the Humboldt squid), Richard Ellis (writer of a number of ocean history, art and science books), and Neil Hammerschlag (shark scientist) were familiar to me, as was big wave surfer Ken Bradshaw, from this article. The strange, uncomfortable way in which the studio narrators were filmed, with silent close ups interspersed with talking, was very annoying and must have been incredibly embarrassing to shoot. Or perhaps the cameraman took the footage when the narrators didn’t realise they were being filmed.

Unlike BBC documentaries, which tend to rely purely on incredible photography and fluent narrative to convey information, the History Channel favours a CGI-heavy approach that we encountered in Treasure Quest, Deep Sea Salvage, and also in the National Geographic Shark Men series. For the subject matter of this series – particularly the sections on waves, tides and currents – it was very appropriate and informative. The first episode, devoted to tsunamis, rogue waves and “monster waves”, made good use of CGI to illustrate the concepts as they were explained. The series was produced shortly before the Japanese tsunami of 2011 (there is a hastily tacked on “thoughts and prayers” disclaimer) and features interviews with a survivor of a tsunami in Samoa. I am fascinated by rogue waves – the whole episode could have been devoted to them but they don’t make for good television – we only have indirect evidence of their existence. Also, I could have done with more footage of giant ships battling storms, but that’s what youtube is for…

The least interesting and most irritating episode was the one devoted to the ocean’s top predators, which suggested that orcas are a serious threat to humans. As evidence, the cases of captive killer whales drowning and injuring their trainers at marine theme parks were cited. No mention was made of the psychosis that these whales suffer from as a result of confinement in a small, barren, completely unnatural environment. An incident in which orcas inexplicably rammed and sank a yacht in the Pacific Ocean is also described and re-enacted. Whether the orcas did what they did because they wanted to kill the people on board is highly debatable. There is also a half-hearted attempt to paint whales as potentially vicious killers, recounting incidents when sperm whales rammed whaling boats in the 19th century. More power to the sperm whales, I say.

The other dangerous predators were (predictably) white sharks, Humboldt squid, saltwater crocodiles and Australian box jellyfish. There was a small environmental message at the end of this episode, mentioning that squid will probably end up the top predators in our oceans if current trends – fishing out large predatory fish and global warming in particular – continue.

The third episode, on the immense pressures that objects in the deep ocean are subjected to, was very interesting to Tony and me as divers. A confusing interview with a diver whose brother got DCS on a wreck dive leaves (I suspect) much out. Were they even qualified divers? Why was he surprised that his brother felt unwell and confused as to the cause after he popped to the surface from 30 metres after a 30 minute dive?

The bulk of the third episode, however, recounts a 1981 experiment called Atlantis III in which three volunteers were taken in a saturation system to a simulated depth of 686 metres while breathing Trimix 10 (70% helium, 20% nitrogen and 10% oxygen). It took 31 days for them to decompress. The chief of the experiment, Peter Bennett, was the founder and former CEO of DAN. There’s a more information about the project here – worth a read (download the pdf slowly), and a briefer account here.

The series concludes with an episode on tides and currents, including rip currents. The massive tidal range of Morecambe Bay in the United Kingdom,  is discussed at length. At low tide, up to 300 square kilometres of mudflats is exposed, and flooded again when the tide comes in. The guides who escort people out onto the mudflats when the tide is out seem like charming individuals – it is recommended not to wander around at low tide without local guidance. In 2004, the rising tide trapped and drowned 23 Chinese immigrants who were working the cockle beds – with such a large expanse of land to cover, the rising tide comes in at great speed. There is also a harrowing re-enactment of a father and his two sons getting washed out to sea in a rip current in Kauai that should make you think twice about swimming at beaches with warning signs on them.

You can get the DVDs here if you’re in South Africa. Foreigners, go here or here.

Article: Esquire on diving the Andrea Doria

The wreck of the Andrea Doria, a luxury Italian cruise ship that sank in the north Atlantic ocean in 1956, is to some divers a sort of Mount Everest. It lies in about 70 metres of seawater, 160 kilometres from land. It has claimed ten lives to date and been the subject of several books and essays. Deep Descent deals specifically with this wreck. Shadow Divers and The Last Dive describe dives on the wreck, as well as featuring several of the regular charter captains and divers who pioneered diving on the Doria.

An Esquire article from 2000, written by Bucky McMahon (author of this article on Reunion’s shark problem), describes diving on the wreck, and attempts (as do they all) to pin down the allure of this particular piece of ocean debris. The article was written after a thirteen month period (late 1998- late 1999) during which five divers from the same charter boat (the Seeker) died on the wreck. It is written in a masculine, aggressive style that may be characteristic of McMahon’s writing, but is certainly characteristic of the sort of behaviour that seems to play (or have played) out on the Andrea Doria since people started diving her.

But how does it feel? What’s it like to know you are in a story that you will either retell a hundred times or never tell? You decide to drop down into the black hole. No, you don’t decide; you just do it. Why? You just do. A little ways, to explore the wreck and your courage, what you came down here to do. What is it like? Nothing under your fins now for eighty feet but the mass and complexity of the machine on all sides–what was once luminous and magical changed to dreary chaos. Drifting down past the cables that killed John Ornsby, rusty steel lianas where a wall has collapsed. Dropping too fast now, you pump air into your b.c., kick up and bash your tanks into a pipe, swing one arm and hit a cable, rust particles raining down. You’ve never felt your attention so assaulted: It is everything at once, from all directions, and from inside, too. You grab the cable and hang, catching your breath–bubble and hiss, bubble and hiss. Your light, a beam of dancing motes, plays down a battered passageway, where metal steps on the left-hand wall lead to a vertical landing, then disappear behind a low, sponge-encrusted wall that was once a ceiling. That’s the way inside the Doria.

Read the complete article here.

Movie: For Your Eyes Only

For Your Eyes Only
For Your Eyes Only

A Top Gear special about James Bond’s cars put us in a frame of mind to enjoy some vintage Bond. Tony thinks Roger Moore was the best Bond; I am torn between Sean Connery, Timothy Dalton, and Daniel Craig. For me, Roger Moore is at the bottom of the list (jostling for position with George Lazenby). Chronology, Tony’s fondness for Moore, and the fact that we only have about three James Bond DVDs swayed us towards a re-viewing of For Your Eyes Only.

For Your Eyes Only doesn’t only feature a convoluted plot, ridiculous foreign villains with hilarious accents, and a ridculous foreign Bond girl – also with an hilarious accent. It also contains extensive underwater footage that can teach us about the behaviour of sharks, what to wear when diving (yellow PVC overalls and gumboots), and how to manoeuvre a hard diving suit inside a shipwreck.

That said, the underwater scenes are surprisingly slick and well-shot for a movie made in 1981. They were filmed in the Bahamas. Carol Bouquet, the actress who plays Bond’s main squeeze, Melina, apparently had a sinus condition that prevented her from doing underwater stunt work, so the close-ups of Moore and Bouquet were filmed on a sound stage with fans blowing and special lighting. Bubbles were added afterwards. If I’d had this knowledge when I watched the film I’d have looked more closely at those sequences; without knowing they were filmed on dry land, I admit that they are very convincing.

In the screen capture below, I’ve grabbed a moment of the action as Bond and Melina take a submersible down to a shipwreck (the St Georges) lying over 100 metres under the sea, and exit at depth to penetrate the wreck and retrieve a very important computer. They run across the sand in their yellow gumboots. While inside the wreck they encounter a villain in a hard one-man diving suit, and a vigorous battle ensues. They blow him up, but are unaffected by the concussion despite being only a couple of metres away when his suit explodes. Upon returning, victorious, to their submersible, they are set upon by another villain in a one-man submersible with various pointy bits and cutting devices. There is an extended wrestling match between Bond’s submersible and the villain’s.

The divers race across the ocean floor from their submersible
The divers race across the ocean floor from their submersible

Curiously, although both Bond and Melina are breathing a mixture of helium and oxygen (because they’re diving so deep), their voices are unaffected by the helium, and sound completely normal. They also move through the water with remarkable ease, and – mysteriously – a large amount of light penetrates down to the shipwreck at 100 metres. No mention is made of the decompression obligation they’d have after their underwater high jinks.

If you want to combine a love of diving with a fondness (or love) for James Bond, you could do a lot worse than For Your Eyes Only. You can also check out Thunderball. You can get the DVD here if you’re in South Africa, otherwise here or here.

Bookshelf: The Darkness Below

The Darkness Below – Rod Macdonald

The Darkness Below
The Darkness Below

The Darkness Below is a follow up to Rod Macdonald’s diving memoir Into the Abyss. It takes up more or less where the first volume left off, providing a brief synopsis of Macdonald’s diving credentials for the reader who is unfamiliar with his work. Macdonald is a Scottish diving legend, and has devoted much of his diving career to finding and identifying hitherto undived wrecks off the Scottish coast. He dives in the often dark, cold waters of the North Sea, with a group of diving friends, off his own rubber duck, and the impression I got from both his books is that he and his buddies are meticulous, cautious, and not motivated by ego. This is an essential quality to become an old diver, I think.

Macdonald and his friends search for wrecks using several methods. He maintains good relationships with local fishermen (he lives in a small village called Stonehaven in Scotland), and has on occasion got tips from them of locations where their nets have snagged. These are often undiscovered shipwrecks. He also scans hydrographic charts, looking for wrecks. These marked wrecks are often indicated on the charts to be some distance away from their actual location, so surveying of the sea floor is required in order to locate their exact position. I learned several useful tips for reading hydrographic charts from Macdonald’s descriptions of how he works.

Running through the book as a separate theme is the evolution of Macdonald’s diving practices, as he progresses from open circuit scuba on air to trimix to a closed circuit rebreather. A case of the bends after a series of repetitive deep dives which his friends on rebreathers completed without incident forces him to reconsider his earlier resistance to becoming a rebreather diver. The flexibility of the device for decompression dives owing to fine-tuned gas mixes and precise, on the fly calculations, leads to shorter, but more effective decompression time.

Once a wreck has been located, Macdonald and his buddies plan and execute a dive (or several dives) on it. Most of the wrecks close to shore in (relatively) shallow water have been dived and identified, leaving virgin wrecks further offshore in water up to 80 metres deep. Macdonald’s knowledge of ships of the modern era seems to be encyclopaedic, and he and his buddies are able to pick out features, patterns of damage and construction materials on the wrecks they dive that provide essential clues to identifying the wrecks. Observation and measurements combined with a lot of archival and book research leads to positive identifications, but this process is sometimes fraught with uncertainty.

As I was when I watched the BBC documentary Wreck Detectives, I was touched by the reactions of survivors and relatives of those who perished on some of the wrecks that Macdonald discovers and charts. Even though many of the wrecks he dives are of World War II vintage, the emotions and recollections of survivors and descendants are still surprisingly intense. This human element adds great meaning and significance to the work of identifying the wrecks. Many of the wrecks are war graves, or at graves of the fishermen who went down with the ship, and the divers treat them with respect and care. Not once do they contemplate looting the wreck for artifacts (compare, if you will, the divers who visit the Andrea Doria), and the motivation for doing these dives is unrelated to treasure hunting.

This is one of the best diving books I’ve ever read. If divers like Rod Macdonald are shaping the future of the sport, and establishing the ethos and ethics of wreck exploration and discovery, I’m very happy to be involved.

You can buy a copy of the book here if you’re in South Africa, and here or here if you’re not.

Bookshelf: The Last Dive

The Last Dive – Bernie Chowdhury

The Last Dive
The Last Dive

The Last Dive is a number of things: a history of how cave diving techniques came to be applied to advanced wreck diving (use of lines for wreck penetration, for example), the story of the early days of mixed gas diving in the United States, the chronicle of the close-knit bands of divers who risked their lives to explore the cold, deep waters off the north Atlantic seaboard of the USA and retrieve trinkets from the many vessels wrecked there, and a biography of Chris and son Chrissy Rouse, who were involved in all of the aforementioned threads of the tale. The central subject of the book is the Rouses’ death while (or just after) diving on the German U-boat discovered by a local dive boat skipper.

I first encountered the Rouses in Robert Kurson’s book Shadow Divers, a gripping read about the efforts to identify the same mysterious German U-boat that the Rouses perished on, off the coast of the US, and Deep Descent, which describes diving on the wreck of the Andrea Doria and features many of the same divers and dive charter operators. Their relationship is (perhaps too) sympathetically portrayed by author Bernie Chowdhury, a friend of the family.

The Rouses were extremely technically proficient divers, but their downfall seems to have been their fraught and fractious relationship that was characterised by vicious bickering and name-calling that stopped only when they put regulators in their mouths to descend into a cave or onto a wreck. Chowdhury shows how their difficult (but ultimately loving) relationship led them to doing a dive (their final one) onto the U-boat when the conditions were decidely sub par. Their choice to dive to over 80 metres on air, when they were proficient in mixed gas use, as well as what seemed to be the firm conviction of Chrissy (the younger) Rouse that he was immortal, also appears to have contributed greatly to their deaths.

Both Chris and Chrissy Rouse died of DCS – Chris died in the water within minutes of surfacing, and his son Chrissy hours later in a recompression chamber. They had both ascended rapidly without any decompression stops, from a longer than planned dive to over 80 metres, having lost their stage cylinders in their disorientation after emerging from a disastrous penetration of the submarine during which Chrissy became trapped under a fallen book shelf and a self-inflating life raft.

Earlier in the book, Chowdhury describes his own experience of very serious decompression sickness, which gives great insight into how debilitating (if not fatal) the experience of being bent can be. His enumeration at the end of The Last Dive of the serious physical conditions now prevalent among divers of his generation who have persistently pushed the envelope and, in many instances, been bent and recovered, serves as a cautionary tale to those who believe that no-decompression limits are for wussies.

As I expressed in my review of Deep Descent, I strongly disapprove of the macho cowboy attitude that seems to be (have been?) disturbingly prevalent among the divers and charters of this generation (and not limited to the United States). But Chowdhury’s book is more than an ode to the glory days of artifact retrieval and experimentation with trimix. As a history of cave diving, mixed gas diving and advanced wreck diving it’s invaluable. As a diver himself, conversant with all these disciplines, Chowdhury is able to explain in simple terms concepts that would slow down someone who hasn’t done a dive course. The book is very readable despite the technical subjects covered.

Chowdhury does not conclude that the risks taken to achieve what this particular group of divers did were unreasonable, and does not overtly criticise the Rouses for the attitudes and behaviour that – I think most sensible people would agree – contributed to their deaths instead of just a scare that might have forced an adjustment to the dive plan. While he admits to having experienced times of ambivalence about diving, particularly when he describes the strain it placed on his relationship with his wife and son and the long road to rehabilitation that followed his episode of the bends, his equilibrium surprisingly undisturbed by the loss of several friends and acquaintances to the sport he loves, and his own health difficulties.

For some more perspectives on this book and the perceived accuracy of the descriptions of the events it covers, you can read this review and this discussion.

You can purchase the book here if you’re in South Africa, and here if you’re not. The Kindle edition is available here and here.

Oh, and go sign up for some DAN insurance, please?