#manualbox

  Once he found fame impersonating bespectacled rocker Buddy Holly, and led the Crickets astray on a diving tour of the UK. Now, leading technical diver John Garvin has helped to pull together what could be the most authentic diving movie to date.  

THE 3D BLOCKBUSTER AVATAR had a $200 million budget and was rumoured to have cost at least twice that much to make.  James Cameron’s follow-up 3D movie, Sanctum, had a comparatively modest $30m budget, but this is a movie that has its feet firmly on, in fact under, the ground. Sanctum, released on 4 February, is a cave-diving thriller but essentially a rites-of-passage movie, tracking the relationship of young diver Josh McGuire, played by Rhys Wakefield, and father Frank (Richard Roxburgh), in the aftermath of a dramatic cave collapse in the South Pacific.  The movie was filmed at the Warner Bros studio in Queensland, using dry-cave sets and a 40 x 40 x 7m-deep tank in which a cave system was built and then flooded. Studio footage was later intercut with real underwater cave footage from Mount Gambier. Among a mainly Australian cast, only Welshman Ioan Gruffudd, who plays financier Carl Hurley, and Allison Cratchley (Judes), had done any scuba diving. John Garvin, the British technical diver who co-wrote Sanctum, was also the film’s diving co-ordinator, his task to lead the cast through a fearsome learning curve. On completing their Open Water courses, the actors’ very next dive in the training pool was on a Sentinel closed-circuit rebreather.  “They actually took to it very easily,” says John. “But then they had to learn how to take the rebreather off, shove it through a body tube and swim after it. And when they’d got the hang of that, we turned the lights out and shoved them into an overhead environment.”  All the cast coped – in fact some, like Gruffudd, started turning up on their days off to log more hours on the Sentinels. “On a film set, where everything’s frantic and chaotic,  it was quite nice for them to disappear for a few hours in the pool.” Rebreather training complete, the actors then had to master cave-finning techniques and use of reels, stage tanks, full-face masks, helmets, lights and DPVs. Why the intensive boot camp? Because the actors would be diving the Sentinels in an overhead environment for real.  “Although safety divers were posted, it was the actors’ responsibility to monitor their own life-support systems while down there,” says John Garvin.  “If they got uncomfortable, they often couldn’t get out because they had a cave over their heads. It was as close to getting inside a real cave as any actor is likely to be.  “In most films, it’s very obvious that it’s stunt guys doing the underwater sequences, but many of the stunts in Sanctum were done by the actors.” “You actually see Richard Roxburgh swimming through a tight body tube, and Richard and Allison at 7m dealing with a full-face mask flood emergency. And that’s a drill a lot of commercial divers baulk at, so to get actors doing that level of stunt was incredible.  “This gives Sanctum a high level of authenticity and realism,” says John.  “It contains underwater sequences that have never been seen on film before.” AS A YOUNG ACTOR, John Garvin spent four years playing the lead in Buddy: The Buddy Holly Story. Following its West End run, the stage show went on a nationwide tour in the mid-1990s, playing in different locations every fortnight.  But John was leading a double life. “The tour was fantastic for me. I could go diving with the local BSAC club during the day and do the show at night.” While the rest of the cast and crew were lugging suitcases in and out of theatres, John was carrying twin-sets. His colleagues were intrigued, and asked him to teach them to dive.  John, five years into the sport, was a BSAC Advanced Diver. “I was brought up in Cornwall and would spend all my weekends snorkelling there, because I couldn’t afford the courses at Fort Bovisand.” Then he did a degree in theatre arts and “pretty much blew my entire first grant on dive equipment”. Remember student grants? Now John decided to become an instructor, and in turn train the Buddy crew so that they could join him on his beloved wreck dives.  “Before we knew it, eight of us were diving regularly,” he says. The Buddy buddies’ passion would eventually lead them into trouble on a shore dive near Edinburgh. “It was my fault,” says John. “The tide had gone out and we couldn’t get back out of the water. By the time we’d swum about half a mile and climbed back over the fields, we were late for the opening.  “The curtain was held for 40 minutes, because I had the stage manager with me, as well as two Crickets! Diving was banned after that.”  In 1997, John became one of the first divers to train on Inspiration rebreathers. Two years later, he moved to Providenciales in the Turks & Caicos Islands and, spotting demand among visitors unable to obtain mixed gases for exploring the deep walls, set up O2 Technical Diving. He would run it until 2007. DURING THIS PERIOD, John would also establish himself as one of the world’s foremost technical diving instructors.  He became both a TDI and IANTD Instructor Trainer for open-circuit and CCRs, and helped to arrange the first rebreather expeditions to Galapagos, Bikini, Truk and elsewhere.  He has done more than thirty 100-150m dives; was safety supervisor on Tanya Streeter’s 160m No Limits freediving record and on many underwater TV documentaries; and wrote the TDI Inspiration/Evolution training manual.  He even organised a submersible diving expedition to the Titanic. John Garvin knows about diving. But his first cave-dive, in 2001, nearly ended in disaster. Cottage Pond on North Caicos is a 50m-wide sinkhole. “The locals believed in bad spirits that would suck anybody down into the bottomless caves and spit them out into the ocean.”  All John and fellow-Brit Mark Parrish knew about cave-diving came from Rob Palmer’s book Deeper Into Blue Holes. “We had a reel and some flashlights.  We didn’t have doubles, but in classic BSAC fashion we had little pony bottles and stage bottles.” John describes descending into the sulphur zone where fresh water sat above the salt water of the deeper cave – this “awful primaeval soup”.  Vis plunged to zero, the divers’ skin was burning and they could taste rotten eggs. Emerging on the other side into icy water at 24m was like being “punched in the stomach. “It was like some freefall parachutist dropping into St Paul’s Cathedral,” says John. “I shone my light around and couldn’t see the walls. It was an awe-inspiring moment – and later became the inspiration for one of the underwater sequences in Sanctum.”  The wall, when they found it, was “like a waterfall frozen in time; these incredible brilliant white speleothems pouring down it. It was stunningly beautiful. We did a full circle at about 30m above this dark void.” Then, halfway back up through the mixing zone, John says: “I suddenly hit a solid wall and felt this gut-wrenching fear.” The divers had unknowingly dropped into the cave through a tiny fissure, and while reeling around the walls had wedged the line solidly into its thinnest part.  “My good old BSAC training came back – control your breathing; stay calm. I looked up and eventually saw a sliver of black that wasn’t quite as black as the rest of the black. I made sure Mark and I were connected, and we started floating up. “I’d had three of the most intense experiences of my life on that 20-minute dive, from the elation of breaking through to a virgin cave to the fear of knowing I’d screwed up, and the relief of seeing blue sky again. I thought, if we got trained to do it properly, this could be a really cool sport.” John and Mark undertook a full cave-diving course in Florida with the celebrated Tom Mount. This training led them and US diver James Hurley  to form the Caicos Cave Project, dedicated to exploring, mapping and raising awareness of the system. “A lot of the experiences during this period fed directly into the script for Sanctum, in particular to the characters’ emotional journey,” says John. JOHN GARVIN STARTED writing screenplays in his spare time and, after winning an international competition, had several scripts optioned by Hollywood producers. One, Sunless ea, was an underwater horror film set in a cave system.  The release of The Cave scuppered that idea, but the script wound up with producer Andrew Wight and executive producer James Cameron, who had been looking for a screenwriter with a cave-diving sensibility. They set up a meeting. Australian Andrew Wight is not only a film producer but a renowned cave-diver. Back in 1988, he led an expedition to the remote Nullarbor Caves, during which a freak storm collapsed the entrance, trapping 13 divers underground for 24 hours.  Wight, who had collaborated with Cameron on 3D IMAX and TV films Ghosts of the Abyss, Expedition Bismarck, Aliens of the Deep and Last Mysteries of the Titanic, had always kept the story in mind for a screenplay.  “It’s obviously a surreal moment when you get a call to travel to LA and meet James Cameron and Andrew Wight to talk about your project,” says John. “Our 20-minute meet-and-greet turned into an eight-hour session where we just talked diving.  “Everybody knows James Cameron as the movie director, but he’s first and foremost an avid diver. I’m convinced he makes all these huge movies just to fund his diving projects.  “We started throwing ideas around about all the things that could go wrong on a cave-diving expedition. Andrew and I than went on to collaborate on the script of Sanctum.  “We saw absolutely eye-to-eye about the story. We didn’t want to make a documentary, because if done properly cave-diving is a very safe sport. Sanctum is a high-octane James Cameron roller-coaster of a ride, so we had to approach it from an entertainment point of view.”  The Fusion stereographic camera systems used for Avatar would be used again, but now the underwater director of photography Simon Christidis would have to move a camera housing “the size of a small fridge” around under water. “3D is ideally suited to tight claustrophobic environments, and works very well under water,” says John. “However, the story still has to stand up on its own in 2D.” He welcomed director Alister Grierson’s decision simply to treat the shooting as if it were two-dimensional. “While we’ve tried to be as authentic as possible, some compromises had to be made,” says John.  “For example, we used non-oral-nasal full-face masks so that the audience can see the actors’ faces, and so that they can speak to one another. We also had lights inside the masks, to help distinguish the actors. But nothing is used that couldn’t be used on a real cave dive. “Divers will also appreciate that every plot twist relating to diving in Sanctum has happened on cave-diving expeditions. Ignore one problem and it builds into another – ignore that, and it compounds itself. British divers know this as the Incident Pit. Sanctum draws a lot on that idea, and I hope divers will recognise the truth of it.” “THE BEST WAY to get acting roles in Australia is to write them yourself,” says John Garvin. “In Sanctum I play Jim Sergeant, a bossy British dive instructor who walks around shouting orders at everybody, so it didn’t take an awful lot of acting on my part.”  As the time to start shooting under water approached, apprehension grew. Everybody was aware of how ambitious the concept was, and how tight the deadlines. “The underwater shoots took place at night, over three and a half weeks,” says John. “We would work from 4.30 in the afternoon until 6 in the morning – up to nine hours under water at a time. We were all starting to look like albinos by the end of it.  “As with any dive expedition, it’s the stress of always looking for the what-ifs. Things went wrong, got delayed, didn’t go quite to plan, but that’s fine as long as you have back-up plans.  “I’m delighted that we decided to approach it all less from a film-maker’s and more from a dive-planning point of view.  “We had a model of the set, with little divers on sticks representing each character so that the director could show everyone exactly what the shot would involve. In the car park we ran guide-lines between cones and got the actors to walk through the shot.”  Wardrobe kitted the actors in wetsuits before they reported to the rebreather hut, where the five Sentinels would be prepped. “That was the one time I demanded peace and quiet while we took the actors through the pre-breathe.  “At the pool area their fins and auxiliary equipment were fitted, and they did all their last-minute checks.  The camera crew and lighting people were already set up in the pool, and when the actors got down they knew exactly what they had to do.”  John pays tribute to the “fantastic team of 20 very experienced Australian divers, who had either large amounts of CCR experience or had worked in the film industry and could share a lot of knowledge”.  The Sentinel rebreathers were rigorously tested by VR Technology’s Kevin Gurr and Phil Short in the UK before being shipped to Australia, along with Phil. Jason Blackwell was the local point of contact for the rebreathers. “The Sentinels were a godsend,” says John. “They were extremely reliable, and the very bright green heads-up display and a buddy-monitoring display on the back ensured that the actors were kept safe at all times. “Sentinels look like real warhorse rebreathers. We chose them for their reliability and ruggedness, but also because they look extremely cool.”  NOW SETTLED IN SYDNEY, John Garvin is working on two non-diving film projects, and enjoying the local diving. And he hopes Sanctum will have the same inspirational effect on a new generation of divers as The Deep and Cameron’s The Abyss once had on him. “Cave-divers get criticised, but the film explores the emotional attachment we have with caves, and why cave-diving is like no other sport.  “Cave systems are our last unexplored wilderness, and there’s nothing as incredible as being able to shine your light where nobody’s been before.  “I hope Sanctum will serve as a tribute to all those people who have been pushing the boundaries of the sport.”  Meet John Garvin in person when he guests at LIDS 2011 in March.

from.Steve Weinman.divernet.com

An action sequence from the new movie Sanctum.

John Garvin

Kitted up with their Sentinel rebreathers, the actors run through both the next scene and the next dive

Rhys Wakefield as Josh in a tight spot.

Director Alister Grierson, executive producer James Cameron and writer/producer Andrew Wight on set

Rhys Wakefield and Richard Roxburgh in a scene from Sanctum.

John Garvin on a location recce for the movie (with red ochre on face for protection from cave spirits!).

Another tense moment for Frank McGuire

You notice a shadow out in the blue. It gets bigger and closer. It's a shark. If it's your first time you'll never forget it, but your thousandth experience could be equally memorable. Gavin Parsons asks divers to describe their favourite encounters Sharks give us the willies. Oh, sure, many divers love to dive with them, but that's because the element of danger always threatens to line the inside of our wetsuits. For the purposes of this article, we can leave out nurse sharks, dogfish and whitetip reef sharks - they are poodle puppies. Grey reef sharks, hammerheads and the like are the rottweilers - not necessarily mean or aggressive, but get too close and they'll put the fear of God in you. The south-west plateau at Sha'ab Rumi in Sudan is swimming with grey reef sharks. They look the part - torpedo-shaped body, serious dental work and a burst of speed that makes a McClaren F1 look like it stalled on the starting line.  Ordinarily, they meander like youths hanging around a park - intimidating, but not football-hooligan-shouting-abuse nasty. Until, that is, you get in their way. I have dived the site numerous times and had no problems - that is, until I found a cleaning station. These are normally special places where nature waves the white flag, and predators become grannies waiting for their blue rinse. In Sudan, the sharks stop, go almost vertical and pull their heads up to reveal a surprisingly large oral cavity. Small wrasse and butterflyfish rush from a patch of reef that looks like any other, and give them the equivalent of a dental clean-up and Turkish bath rolled into one. Grey reef and other requiem sharks need to move about or to be in moving water so that oxygenated water passes across their gills. Most cleaning stations are swept by currents; if they are not, stopping off is akin to you holding your breath. At this one sharks stop often, but stay only for a short time. Figuring that great experiences come to those who dare, I entered the cleaning station and waited for a shark to stop. Soon a young male cruised by, eyeing me suspiciously, unsure of what to do. He passed several times and eventually decided he wanted some privacy, so he quickened his pace past the cleaning station before turning towards me.  There was no real aggression. The pectoral fins were not down, his body didn't arch and his head didn't swing, but he charged to show his discontent. He veered left at the last second, close enough for his wash to hit me. I figured I had pushed it long enough and left. Turning to check on the shark, I saw him upright with his mouth open, enjoying a spruce-up - exactly where I had been a moment before. It was one small moment in my life, but I won't forget it in a hurry. Sharks have that effect - try as we do to rationalise it, the underlying Jaws factor is still present. Pick up any marine life guide and the words 'potentially and dangerous' still sit together when describing many species. But that's why they make our dives so much more thrilling. Hammer between the knees Kevin Goodchild Hammerheads hold a fascination for me, so when my buddy and I happened across a shoal off Angarosh Reef in northern Sudan, I wanted to get as close as possible. Hammerheads, in my experience, are shy sharks which prefer deepwater drop-offs and keep their distance, but every so often you meet an inquisitive one. Angarosh has two plateaux, one at 24m and the other at 40m. It was a rough day, but the six of us made for the edge of the first plateau. The dive guide had indicated that this was a good place for hammerhead sightings and, sure enough, within a couple of seconds the faint outlines of about 10 sharks could be made out in the distance.  A couple of us, including the guide, swam out, my video camera recording the scene.  We were well out into the blue, but the deeper plateau was clearly below us and so was the guide. He called me down and, as I joined him, I caught sight of a solitary hammerhead moving over the coral. It came closer and closer. My eye was jammed up against the video viewfinder, which isn't the best in the world. All of a sudden there was a clonk and the housing vibrated - that was the moment I realised I was deep. The hammerhead was slowly circling me.  Closer and closer she came, but I couldn't bring myself to leave. The shark carried on around, moved up slightly, showed me its teeth and carried on circling. It moved down and that's when I managed to get the footage of it swimming between my legs. It was a very bizarre feeling, but we were both calm.  After that, it headed back out into the blue and I had to make my way slowly back to the shallows to perform some decompression. I would not have missed the experience for anything in the world. Teething troubles Tony Williams  This one is slightly embarrassing, but I was inexperienced, which is my excuse. It was, after all, my first open-water dive.  It was a hot, spring day and I was off Cornwall on a wreck near the Manacles. I went in with my club instructor, who led me around and, as it turned out, got me hooked on British diving. The wreck was full of life. Although most people on the boat had dived it before, I was amazed - I'd never seen anything like it. After about 30 minutes, we started up the shotline and stopped at 6m. I took the opportunity to gaze around and caught sight of a large shadow in the water. I studied it intently, but couldn't make it out as the visibility was bad. After a minute, it vanished. As we started the final leg, however, it returned - and it looked huge. At first I thought it was another boat, but as my head broke the surface, I saw the unmistakable shape of a large dorsal fin coming straight for me. I was petrified for a moment, but then assumed it was someone in the club playing 'let's scare the rookie'. I put my head under, expecting to see a diver with a cut-out fin, and came face to face with the massive jaws of a shark. I grabbed the handrail on the back of the boat and hauled myself in as fast as possible. I leapt aboard - fins, weightbelt and all - and dumped myself on the deck muttering 'shark', like the extras do in a Jaws movie just before they're snapped in half. To my horror and amazement, everyone on the boat laughed, grabbed their masks and fins and jumped in. I thought they were mad. 'It's a shark,' I called after them weakly. 'Yeah,' said the skipper, 'It's a basking shark.' 'So?' I almost shouted, exasperated that I was the only sane person about. I was also the only diver left aboard. 'They don't have teeth,' said the skipper patiently, just as a parent might reassure a small child that a teddy bear is quite safe. I relive that day on virtually every club night. Surface tension Neville Widdrington  Try dives aren't the most exciting element of instruction, and the sites students visit are generally not the best. A person's first time under water is generally thrilling enough for them, without whale sharks, sea-lions and manta rays to complicate matters. So instructors often don't relish the try dive, but we do in the Canaries, where just about anything can come in from the Atlantic. I had been at our usual site, about 10 minutes away from the port, with a couple who were rightly feeling pleased with themselves. On the way back, I spotted a fin breaking the surface. At that distance, I couldn't tell what sort of shark it was.  I drew the boat alongside and couldn't quite believe what I saw - I was staring at a hammerhead. It was about 1.5m long and wasn't interested in anything other than a small yellow plastic bottle floating on the surface.  You very occasionally see hammerheads off some sites, but never on the surface. I think the bottle probably contained sardine oil, used by the local fishermen to attract tuna. The shark turned in tight circles, bumping the bottle, and didn't even notice the boat stop. There was no way I wanted to pass up this opportunity, so I excused myself, grabbed my mask and snorkel and slipped in.  As I came up, the guy asked if he could join me. 'Come on in quickly,' I mumbled through my snorkel, 'this is amazing'. As he joined me, the shark didn't falter from its yellow-bottle mission. We got within a metre, and it didn't even acknowledge our presence. Its well-muscled body shimmered in the sunshafts. I was enthralled, gobsmacked even, but unfortunately I didn't have my camera. Thankfully there was someone else to act as a witness, otherwise no one would have believed it. Night fighter Alan James I love night dives. The creatures you find are so different and daytime fish are more docile and easily approached.  A couple of years ago I was in Yemen on a liveaboard and enjoyed several nocturnal diving experiences, but it was the last which remains the most memorable. Yemen is off the beaten track and our shark encounters had been varied. I had seen plenty of whitetip reef sharks, grey reef sharks, even a tiger, which thought I was lunch, but it wasn't until this final dive that I really felt intimidated. My buddy and I entered the water from the dive boat's rear platform. He had a few equipment problems and said he would join me on the bottom, knowing I was keen to get started and that it was only shallow.  I drifted down towards a collection of large boulders, interspersed with gravel. As I neared the bottom, I shone my narrow-beamed torch down to see where I was headed. Instead of the gravel beneath me, I saw a large grey fin, and I clipped it as the shark whipped past under my own fins, even though I had pulled my legs up. It then shot away, obviously as surprised as I was.  I regained some composure and raised my camera and strobe to see where it had gone. Shining my torch slowly around into the darkness, the light painted my new friend's grey, sleek form, circling me menacingly. I remember wondering whether it would be a safe time to fire the flash and capture an image, but before I had reached any decision or plucked up the courage, the shark turned away, its image growing smaller as it retreated. It's gone, I remember thinking with some relief - but it hadn't. Like the bad guy in a horror movie, the 2m-long creature returned and charged my torch beam. I turned my only defensive weapon - Nikonos V with 15mm lens and old-type viewfinder - into a hammer. As the shark made contact with me, I thumped its nose and, in the process sheered the 6mm bolt holding the viewfinder in place. My next recollection was looking up at the surface in darkness, without my regulator. I was rolling around helplessly and could see the torch on my buoyant strobe bobbing around just above the bottom.  Don't ask me my state of mind as I hugged the nearest rock and replaced my DV in total darkness. Let's just say that I was very glad I had a spare pair of swimming trunks on board. I watched my torch bobbing on the strobe for some time, surmising that the shark's anger was directed at that rather than at me. After a few minutes, I assumed that the shark had dealt its blow and gone, so I retrieved my equipment and shone the beam around, searching for my attacker. It was nowhere in sight. At that precise moment, my buddy arrived and gave me the OK signal. I returned with the internationally recognised shark sign and he gave me an even more enthusiastic OK sign and proceeded to set off into the inky blackness. I spent most of the dive looking behind me, waiting for the next blow. Luckily, it never materialised. SHARK attack behaviour PHASE ONE: The upset shark pushes its pectoral fins downward and moves erratically. (You have the chance to swim away and avoid). PHASE TWO: The back is arched and the movement becomes exaggerated, with the head moving from side to side. (You still have a chance to escape unharmed, but it doesn't take long to reach phase three.) PHASE THREE: Seeing no other way out, the shark charges, often with a bite. (Ouch, you pushed it too far). No pictures!  Matt Harris I used to work in the Marshall Islands, which is pretty much jammed with sharks. On this particular day, I was accompanying a Thai underwater photographer and film-maker who wanted some images for a brochure. He requested a lot of shark action, so we headed for the north point of Arno Atoll, renowned for its grey reefs. We were alone and there was a strong current - good shark-watching conditions. After a few minutes, we came across a juvenile grey reef shark about a metre long that seemed to tolerate us being close enough for photography. I left my companion, who was loaded down with a double-decker Nikonos V rig and strobes, and went off to find another subject. At one point, I turned and saw him in about 7m, right up against the reef wall with the shark in between. I couldn't believe anyone would voluntarily trap a shark like that. The wall virtually touched the surface and he wasn't letting the shark go. The strobes were still firing and the shark was getting more and more agitated.  Then it snapped. It had had enough and wanted to show it with the classic first-stage warning - the pectoral fins went down. I started after the photographer, screaming through my regulator for him to back off, but he just carried on oblivious to me and the shark's discomfort.  I swam as fast as I could, but the shark was getting even more annoyed and moved above the photographer, arching its back and whipping its head around until it was more or less spinning on the spot.  I stopped, knowing it was too late to save the situation. Luckily for the photographer, who was still snapping away, it was only a small shark. It moved suddenly, grabbed his camera, shook it violently for a few seconds and darted off. The upshot was a bleeding finger where the shark's teeth had penetrated his glove and a flooded camera where it had grabbed the lens and wrenched it away from the camera body.  Had the photographer backed off, he would have had some incredible shots. The bronze whaler Mark Kininmonth A couple of years ago I was working as a dive instructor in Cairns on the Great Barrier Reef. The centre was similar to many others in the region, in that it offered both training and guided dives to qualified divers. I was taking a group of three students to a popular site called Moor Reef. I had a Swiss couple and one Italian, but they spoke good English and were confident and capable in the water. It was a good day, but a slight current was running along the wall. Nothing unmanageable, but I needed to take care to ensure that I didn't lose anyone. As it turned out, the current was the least of my worries. A group of qualified divers and their guide went in as I gave the students a briefing. We entered the water about 15 minutes later. The dive went well, starting in the channel and running out to the seaward side. Everyone completed the exercises and had a blast on the tour, but one got low on air, so I decided to ascend next to the reef wall which, as it turned out, was quite near the surf zone.  Obviously we couldn't stay there, so I coaxed the divers out and signalled the boat, which was about 200m away. I got an OK back, but they were recovering the other divers, so we had to wait. We were in blue water now. It wasn't rough, but after a couple of minutes I heard a muffled call from the Swiss girl. She was gesticulating excitedly. I dipped my head under and saw that we were being scrutinised by a large shark - a bronze whaler.  These puppies are often bad news, so I organised the group into a circle, with me in the middle. After all, if anything untoward should happen, the instructor should always stay safeÉ  At this stage the shark hadn't come too close, but I decided to signal the boat a little more frantically all the same. The girl was fascinated and started to take some photographs while the shark carried on circling, its eye flicking from person to person. To their credit, the group remained calm, possibly because they didn't know just how potentially dangerous the shark was. This helped when it moved a little closer.  Bronze whalers have attacked many times and scientists think they are attracted to splashing, which is a sign of distress or injury. A nervous person makes the right noises for a hungry shark, so I spent most of my time making sure that the students remained still.  My head moved constantly between the boat and the shark for what seemed like hours, but was probably minutes. The boat eventually turned up and the shark vanished. For a time, I had visualised the headline: 'Tourists and dive instructor taken by shark while on a training dive,' but the shark was simply curious. Just another example of sharks not being the killing machines that people believe them to be. Eye of the thresher Gavin Anderson It was long, very long, possibly twice the size of your average grey reef shark. Its enormous tail, which it would use to herd and stun small shoals of fish before finishing them off, thrust gracefully back and forth through the water as it came towards us over the reef.  Peering through my viewfinder, I could scarcely believe what I was seeing, because the pelagic thresher shark (above) is extremely rare. I was diving with a small group of seasoned divers off the Brothers Islands. Tony Backhurst, who had organised this safari to the southern Red Sea, was just a few metres ahead and I had seen his eyes almost pop out of his head when he spotted the thresher. He was perfectly positioned to shoot some of the best video footage of his life. My hear thumped as I wondered how long this beautiful creature would keep coming towards us. Its silvery body glistened in the early morning sun, like a well-polished classic Porsche. It came to within 4m, and its eye, several times larger than an average shark's eye, studied us. This was one of those unique moments in a diving career, and I wished I could communicate to the shark that we meant no harm.  That eye conveyed intelligence and an unusual awareness. I couldn't imagine this shark attacking a diver though, strangely, pelagic thresher sharks are listed among the top 20 most dangerous shark species.  Our magic moment was soon over, as the thresher changed direction. Deciding to stay with it as long as I could, I swam alongside, firing off a couple of shots as it headed for deeper water. My breathing rate was returning to normal, but no sooner had we finished giving each other exaggerated OK signals, than it all began again. A second thresher appeared, possibly disturbed by half a dozen divers yelling under water and pouring out bubbles at crazy rates. Instead of disappearing into the deep, it climbed some 20m above us, circling like a plane waiting to land. Seeing it from this perspective showed off its design to best advantage. Gracefully it flew over us and away into the distance. Good to meet you Ken Sullivan Most people equate the Galapagos with hammerheads, and we certainly had our share of close encounters on a two-week liveaboard trip there. But what stuck in my mind was what happened on the last day, at a site known as No Man's Rock, which was hyped up in the briefing as offering strong currents, massive drop-offs and large sharks. We were pretty keyed up as we jumped in. The rock is a pinnacle in sight of the island and my buddy and I decided to circumnavigate it first.  The current wasn't that strong, so we finned slowly around the rock face, looking at the marine life that profited from the high-energy environment.  Then, as I rounded the seaward corner, I saw it: a 3m-long oceanic whitetip coming the other way. We met almost face to face.  Its classic elongated pectoral fins with their dazzling white curved ends were unmistakable. Not to be confused with the whitetip reef shark, this aggressive and increasingly threatened species will eat almost anything it can catch.  To say I was shocked was an understatement, but I wasn't alone. The shark looked surprised when he caught sight of me. I gulped, and weighed up my options. A thousand wildlife documentaries came to mind. I remembered that wild animals are fine unless you startle them - which is exactly what I had already done.  I decided that the best thing to do was to drift back towards the shore and get out of its way.  Unfortunately, the shark came to the same conclusion and we stayed parallel to each other.  Luckily my buddy, who still hadn't seen the shark, came the other way round the pinnacle. The shark dealt with the situation by calmly pulling its head around and moving out to sea. I wasn't scared as such - concerned, yes. However, I have seen many sharks and have yet to feel threatened. 

SHARK BITES: In 1808, a basking shark washed up on the Isle of Stronsa was reported to be a sea snake with a mane like a horse and six separate feet. Hammerhead sharks have long been the fascination of scientists trying to fathom the development of the head. Popular consensus now recognises that it probably gives the shark lift and lessens the energy output required to swim. There are approximately 350 species of shark and only a handful are known to have attacked people. The whale shark is the largest fish in the seas and can reach more than 14m in length. Most sharks must move to pass water over their gills and to maintain depth - unlike fish, they have no swim-bladders. Bottom-dwelling sharks, however, have the ability to pump water, allowing them to stay still for extended periods. Sharks' sensory organs are very advanced and little understood. They have the usual sight, smell and touch, but also the ability to detect electrical signals, thanks to organs known as the ampullae of Lorenzini. Reproduction in all shark species is slow. Relatively few young are born, some in eggs, others live. In some sharks, the sand tiger for example, the first-born devour younger siblings while still in the womb.

Do you kick your way around under water without giving it too much thought? A lot of divers do, but various finning styles can be employed at different times - and they could save on both effort and possible environmental damage. John Liddiard explains, with the assistance of Steve Murray

THE TWO THINGS THAT DO MORE THAN ANYTHING ELSE to make a diver comfortable and at home in the water are good finning technique and proper neutral buoyancy, but which to cover first? Good buoyancy control is almost a prerequisite for effective finning, especially for some of the more advanced fin kicks. But most divers learn finning first and master buoyancy later, so here we review basic finning technique and, for those who have mastered it, a selection of more advanced techniques.  While practising, always think about neutral buoyancy.

FLUTTER KICK The standard style that everyone learns during their basic training is the simple up-down flutter kick. The legs move up and down in opposing directions, with the forward thrust being provided by the downward stroke of each fin.  Water is pushed off the upper surface of the fin and the tips bend back relative to the diver's feet. The upward stroke just slips through the water to get the fin ready for the next downward stroke.  The legs are kept more or less straight, though it is OK to bend the knees a little. The important measure is that your heels stay a roughly constant distance from your backside.  If the heels move in and out from the backside, the fins will be slicing the water in an ineffective bicycling movement rather than pushing the water backwards to provide forward thrust. The flutter kick works best with long, gentle strokes, using the muscles at the front of the thighs to do most of the work. Long strokes maximise the time each fin spends pushing the diver forwards, and minimise the time each fin spends ineffective at the end of each stroke.  In a confined space, the strokes can be shortened to the point at which the fin-tips are just twitching, although most divers would move to a short frog-kick under such circumstances. The big disadvantage of the flutter kick is that the wash from the fins flows down (and also upwards to some extent) at the end of each stroke. This means that it can easily disturb nearby seabed or marine life.  It is also very easy for the fin-tips to kick marine life below the diver. However, the flutter kick is easy to use, works with all types of fin, and provides a good forward thrust that is fairly even throughout the fin cycle. WHEN TO USE THE FLUTTER KICK

On the surface

During descent and ascent

Off a wall

When well clear of the seabed

When swimming into a current

When speed is required over a period of time

WHEN NOT TO USE IT

Close to a silty or sandy seabed

Inside a wreck

In a cave

When swimming close above coral or other delicate marine life

      FROG KICK  The frog kick is the underwater equivalent of the breast-stroke kick.  From picture (1), the fins slip through the water out and sideways through (2) and (3) until the legs are fully extended to either side.  Forward thrust is then provided by twisting the fins, so that moving them back in pushes water back with the underside of the fins. This movement is shown in pictures (4) and (5), with completion of the stroke ready to start again at (6). Unlike the flutter kick, forward thrust is provided only through the second half of the stroke, the first half merely positioning the fins for the thrusting kick.  Thrust is provided from the under-surface of the fins, the tips bending upward with respect to the diver's feet during the thrusting part of the stroke. The muscles that do most of the work are the backs and insides of the thighs. A frog kick makes very little downward wash, so avoids the main drawback of the flutter kick.  However, the uneven thrust throughout the stroke and the slower repeat of strokes makes it less suitable for use in those situations in which strong continuous thrust or speed is needed.  You need to take care not to kick anything you are swimming alongside. Many divers find it relaxing to use the frog kick as a general cruising kick, either by itself or alternating with the flutter kick every few minutes, so resting the muscles used by the other stroke.  The frog kick may not work very well with some types of fin.  WHEN TO USE THE FROG KICK

For general cruising

When close above a coral reef or delicate marine life

When close to a sandy or silty seabed

To rest the muscles used by the flutter kick

Inside large caves

WHEN NOT TO USE IT

In narrow corridors of a wreck

In a tight cave

Close alongside a wall

When a prolonged burst of speed is needed

When swimming into a strong current

On the surface

      SHORT FROG KICK The frog kick previously mentioned, and the short (or modified) version here, are two extremes of what is really a continuum of kicks. Take the full frog kick, but don't move your legs as far out, picking instead a length of kick that suits you and the circumstances.  At the extreme, the movement of your thighs and knees is very limited, and it is the calves and a flick of the ankles that do all the work. From picture (1), the fins slip through the water out and sideways through (2) and (3) until they are ready to kick at (4).  Forward thrust is then provided by twisting the fins so that moving them back in pushes water back with the underside of the fins, as shown in picture (5), completing the stroke and leaving the diver ready to start again at picture (6).  The short frog kick provides very little thrust, but it is all forwards with no wash up, down or to the sides. It also keeps the fins closely in line with the diver's body.  These two features combined make it ideal for use in confined spaces, where a diver does not want either wash or the fins themselves to stir sediment or damage any delicate marine life.  The short frog kick is also popular for those exploring inside wrecks and caves, and among photographers who need to get closer to coral reefs and other marine  life to take photographs while ensuring that their fins do not disturb anything in the process.  Once again, the short frog kick may prove not to work very well with some types of fin. WHEN TO USE SHORT FROG KICK

Inside wrecks

In caves or any confined space

When close above a sandy or silty seabed

Close to a wall

When manoeuvring near delicate marine life

For stability, often used with backwards kick

WHEN NOT TO USE IT

When finning against a current

When speed is needed

On the surface

      BACKWARDS KICK The finning backwards kick is never elegant, but can be useful in situations where you need to move away from something while continuing to look at it, or where you need to reverse course for a short distance without turning round. Fins are not designed to work backwards.  The whole technique depends more on clumsily scooping water than on any refined hydrodynamic principle. Starting from picture (1), the fins are turned out and as square to the leg as they can go (2).  In (3), the legs are then spread out and the knees bent to scoop the fins forwards with respect to your body, pulling you backwards in the water.  The tricky part comes in (4), where the fins are rotated sideways to the water so that they can be moved back to the starting point without pushing you forwards again and undoing all the work, (5) and (6). The scooping is done with the upper surface of the fins, bending them downwards relative  to your feet.  The backwards kick is almost a complete reverse of the frog kick, the fins working through the first half of the kick and then slipping back through the water in the second half. WHEN TO USE THE BACKWARDS KICK

When you need to move away from something while looking at i

When you need to move backwards and must not touch anything

When you need to move back while handling a reel or camera

To reverse out of holes

For stability when you don't really want to go anywhere, partnered with the short frog kick

WHEN NOT TO USE IT

As a general cruising kick

Against a current

When speed is needed

For long distances

When you need to see where you are going

When fin tips could kick anything at the outer reach of the kick

      SPLIT KICK This asymmetric kick combines aspects of both the flutter and frog kicks. Divers who haven't tried it before are often surprised by how much thrust can be generated by a long, lazy split kick. One leg is dedicated to the upper part of the kick, the other making the lower part. Starting from picture (1), in the example the left leg is used as the upper leg and the right leg the lower.  The upper leg is moved upwards as in a normal flutter kick, the fin slipping through the water and providing no thrust during this part  of the cycle. Meanwhile, the lower leg makes a downward kick, bending the knee slightly as in  a frog kick, but keeping the fin movement downwards so that it can thrust against the water (2) and (3). This is not the main thrust stroke of the kick, but a sort of added extra. From the extreme of the split (4), the legs are then brought together, the top of the upper fin and the under-side of the lower fin acting on the water to provide thrust. In picture (5), this can be seen by the fins bending away from each other.  The stroke ends with the fins being brought together one above the other (6), squashing the last bit of water out to provide the final bit of thrust. The lower leg provides thrust through the entire fin cycle, while the upper leg provides thrust during the second part of the cycle. Because the fins are brought together, it is not practical to swap legs at the end of each stroke. Some divers favour one leg, while others will swap legs every 10 or so strokes. The split kick works best with long and powerful strokes to provide high thrust, but suffers in that it cannot be speeded up, like the flutter kick.  This is a power kick, rather than a speed kick. WHEN TO USE THE SPLIT KICK

For powerful cruising

Swimming into a current

When more thrust is required without increasing the kick rate

To rest groups of leg muscles, switching legs every few cycles of the kick

As an initial strong kick or two to get going

WHEN NOT TO USE IT

Close to a silty or sandy seabed

Inside a wreck

Inside a cave

When swimming close to coral or other delicate marine life

When ultimate speed is required