World champion free-diver
hspace=5 Growing up on a Caribbean island, I spent my early days poring over rockpools near the shore, and later taking off for hours to snorkel along the reef. But like any little girl I dreamed of befriending a dolphin. It never happened, but every now and then, in my sleep, I revert to being that little girl and have a dolphin dream.
My best diving experience comes close to that dream. Again in the Caribbean but this time in my late 20s, I was snorkelling alone around a shallow wreck - rusty metal in dazzling white sand, schools of brightly coloured fish and a menacing barracuda which would hang just off my fin-tips each time I descended
Then one time the barracuda failed to join me. It felt strange, different. I looked behind - and the four large bottlenose dolphins made me jump!
I was used to hearing dolphins long before seeing them, so it was a shock to see them hanging still. As we made eye contact, their squeaks and whistles began, complete with head-nodding. On the sand away from the wreck, I watched them dance around me.
The encounter lasted perhaps 30 minutes. They investigated me, as I lay grinning, and eventually let me swim closer and closer to them.
I never reached out to touch them, scared that it would end my dream.
But more than once, as we turned circles, a dolphin would press against me briefly, sandwiching me between another dolphin, and we would move together in synchrony.
Then their attention turned to feeding, and they buzzed me one last time before disappearing. How could any other experience be my best diving moment
Spearfishing, one of the oldest sports, is arguably the most environmentally friendly way to fish. My husband Paul and I set out one Sunday afternoon to get dinner on a reef where we could free-dive for hours. We carried only one gun, to keep us together.
Paul soon surfaced with a nice grouper alive on his spear. He had merely pierced its flank, a terrible shot. We decided not to kill it as normal but to put it in our mesh bag while we looked for lobster. After an hour, our meal complete, we decided to head back.
Then a nice mutton snapper led us off our route to a stunning spot on the edge of the wall, a spearos heaven with fish everywhere! Paul took a shot, unsuccessfully, at a dogtooth snapper. As he reloaded, I pointed out the 3m bull shark moving restlessly around the edge of the wall.
I lifted the bag clear of the water, hoping to remove the noise and scent of the wounded fish, and we kicked calmly but strongly for the empty beach, about 250m away.
After a few minutes I looked down to see only empty reef. Minutes later, another nervous glance revealed a sight burnt into my memory.
The shark was a metre or two from the surface and about 10m behind, swimming at us with arched back and dropped pectoral fins
We sensed that giving this big shark our one grouper and a lobster tail would simply whet its appetite. For an hour it had been tormented by the sound of a dying fish it couldnt find.
The next time I looked down we were in 5m of water. My arms were tired, so Paul took the bag and I took the gun. When the water was barely a metre deep we walked wearily backwards in our longblade fins, breathless but relieved. Paul stopped to take off his mask. Dont mess around, babe, I said. We have to get out of the water!
Then the water metres away went dark and turbulent. Three large dorsal fins rapidly approached. The sharks must have been scraping their bellies on the rocky seabed!
The bull sharks were right at our legs as Paul threw the mesh bag with all his strength into the boiling water. I struck hard with the speargun butt. The sharks turned on the small meal, jaws gaping from the water, as we clumsily ran backwards.
I fell once, but we made it to shore. We watched the battle for possession of the pink mesh bag until one shark darted away, pursued by the others. It must have had the handle of the bag in its jaws, as the bag was seemingly balanced on its head. Another attack and the bag was history.
After that day we equipped a two-man 5m ocean kayak with a holding tank for our catch, and would leave the area at first sight of a shark. Experience isnt the preferred teacher, but it is the best!

Underwater film-maker
hspace=5 I had been diving on the Rhone in the British Virgin Islands around 1980, and as I approached the surface, a large object suddenly obscured the sun. It was a huge humpback whale, and at its side her calf, itself some 4m long. They were curiously still, and I realised that the calfs dorsal fin had been injured by a boat.
I moved very close to the mother and floated motionless while gazing into the deep well of her eye, which was watching me intently.
It generated a feeling beyond anything I had experienced before, being so close to this legendary creature both persecuted and venerated by humankind.
The spell was broken only by the sound of a boat engine, which stirred her into motion. I almost forgot to use my camera, and Im glad I have a photographic record to remind me of this extraordinary encounter.
My worst diving nightmare is in the process of happening. I recently read that 90% of the worlds coral reefs are dying because of rising sea temperatures, not to mention all the ecosystems destroyed daily.
It would be tragic if the only way future generations could witness the wonders of nature would be to view films made in our era, but they might become the only visible fossil record of what was but is forever gone.
Perhaps the time has come for us to stop the world and take a long hard look at what were doing and where were heading, before its too late. I believe there is still time.

Maritime archaeologist
hspace=5 In 1971 the BBC flew me to Donegal following the discovery of the Armada wreck La Trinidad Valencera by City of Derry SAC. Some bronze guns were to be lifted, and I had conned myself into being the underwater cameraman.
On-site I was kitted in borrowed gear and hurled, clutching the unfamiliar camera, from the boat. I hit the bottom as the gun broke free, sand pouring from it to reveal the king of Spains coat-of-arms, crisp and fresh as the day it was cast. The film recorded the moment for posterity and launched me into a project that is only now coming to fruition, with the establishment of a museum for the wreck in its finders home town.
In 45 years diving Ive also had my share of anxious moments, but the worst was in 1968, when I was catapulted by a freak wave from an inflatable in Blasket Sound, off south-west Ireland.
I was over-weighted, my mask came off and I couldnt find my regulator. The world suddenly turned wet, green, blurred and very frightening. How I sorted myself out and surfaced has always been a mystery to me, but Ive been a careful diver ever since!

Maritime archaeologist
hspace=5 There have been so many fantastic moments in 40 years of diving but a fine one occurred in the Indian Ocean, half a Kalashnikovs range from Somalia, excavating the shattered remains of the 19th century steamer Meï-Kong of the Messageries Maritimes.
With members of my Groupe de Recherche Archéologique Sous-Marine Postmédiévale, I am seeking a consignment of 13th century Cham statues lost en route from Cochin China to Marseilles. We have found the 20 high reliefs, tympanums, friezes and statues but what I am now looking at is priceless, uniquely moving.
I have just taken from the remains a high relief in grey stone, a holy man who sits before me cross-legged, hands joined in an offering attitude. The internal peace that radiates from his face hypnotises me.
I have found many kinds of treasures, but this holy man is opening my eyes to the inner beauty, to the wisdom that emanates from his haughtily serene face, from the, half-closed eyelids. The faint smile on his lips invites me to share his internal peace.
I can only envy the creator of such a work of art out of a mere block of stone. He could not have created it had he not known the same inner peace.
As for worst diving moments, the day I tried to reinvent cave-diving in the resurgence of the Eau Noire at PŽtigny in Belgium sticks out almost alone in my memory.
No visibility, vertical or horizontal, no left or right, no rocky walls, only the very deep insides of a mineral sponge; the impression is of progressing from the inside of one snail shell to another and another. When I arrive in yet another sponge hole some 30m in, with thin streams of water seeping through the rock, I realise that its time to turn back.
I start to follow my guideline back through the spiralling conduits, then suddenly realise that its loose. Its a good line, almost new, and if I leave it, it will get stuck. So, armful by armful, I start to recover the 10m that I have left behind.
When I feel the end of it, I realise my mistake. There is tangled rope everywhere, around my fins, my Mistral, stuck in my weightbelt. It cannot lead me anywhere, and if I try to cut it blindly I may well cut the good end.
All I can do is stop, bound hand and foot, save my air and hope that my diving companion Jacques ThŽodor still has some air and will come for me. How long the minutes are, especially after the first 10! I breathe less and less frequently.
Then I hear the banging of a diving tank on rock and, soon after that, the strident whistle of a regulator. A nervous hand touches my back, gropes for my arm, then for my hand.
I answer with two quick handshakes and suddenly, miraculously, I have a taut line in my hand to lead me out of the trap.
Thats how I taught myself cave-diving lesson no 1: always keep your guideline taut.

Presenter of TVs Wreck Detectives
hspace=5 Ive dived with dolphins and whales, but most magical of all were manatees. Sadly, this wasnt in the wild but while filming for a wildlife TV series in Brazil I visited a rescue centre where they were kept in large tanks. No one was usually allowed to swim with them but the vet.
Weve all heard the stories about sailors being lured into the sea by these sirens, and until youve heard them sing, youd have thought those sailors mad! Under water I was surrounded by the most beautiful symphony of sound from these sluggish creatures. They wooed me with their songs before moving in for the touchy-feely bit!
Manatees like to explore with their bristly lips, which are usually used for collecting vegetation. First my arm received a bristly massage, then my leg, then all my hoses were explored and tugged. Never before have I experienced such trust from a wild animal.
I started my television career presenting World Gone Wild for Fox TV in the USA. Six of the 13 stories I was to present were underwater but it was my first time combining work with my diving hobby, wearing an Aga mask and talking under water, and my first time with any of the animals I was to film.
In the Bahamas to film reef sharks, the director was seasick just minutes from land, so we had to turn round, drop her off and shoot the sequence undirected.
I was a fairly inexperienced diver and a bit apprehensive, but our aim was to film a feeding frenzy while indicating that the sharks were interested only in eating the fish.
Within minutes we were surrounded by these huge sharks. Ones on your head, Miranda! shouted Stuart. I never saw it; instead, I felt another on my arm - biting it!
Thank God we had chain-mail on our arms. I felt a huge pressure but no pain.
After what seemed an eternity we ascended, and realised we had been too preoccupied to monitor the dive. My computer was bleeping for 10 minutes of deco. I checked my air - not enough!
Its not easy to rip off an Aga mask and swap tanks. All I could do was surface to the RIB, grab a mask and another cylinder and redescend (I dont recommend this!) Back at my stop, I checked the air. Nearly empty! They must have given me a used tank. Bastards!
So it was up again for a third, full tank, amid many expletives! I finally surfaced unharmed. I learnt a lot of lessons but the film was excellent, with magnificent shots of us surrounded by huge sharks.
I got a lot more underwater job-offers after that went on my show-reel!

Photographer and extreme diver
hspace=5 With the grace of a clumsy seal I slid off the edge of the open lead, and was immersed in a viscous pea soup of ice and snow, preparing to descend deep below the ice of the Geographical North Pole, 90N. This isnt everyones idea of an enjoyable dive, with the months of planning, logistical nightmares, research, training, polar bears and the -40C atmospheric temperatures.
Looking up to the surface, any feelings of isolation and vulnerability were replaced with a euphoric sense of discovery. My best dive experience is rather a personal thing, and gauged on so many levels. It is overcoming the odds to attain a goal, or to capture the money shot for a client.
I reluctantly recall my worst experience as having to administer some contact counselling to a moron who thought he would impress his mates if he slammed a rock on an octopus and killed it.
My dive buddy and I saw this as we were heading back to our entry point. After exiting the water I managed to embarrass the culprit suitably in front of his friends.
Its our collective responsibility as divers and co-inhabitants of our planet to enforce responsible diving practices and educate others.

President of IANTD UK and MD, Phoenix Oceaneering
hspace=5 My worst moments have involved losing friends and seeing people who wont listen or pay attention to history.
Another was nearly dying at a dive show in a display tank because my rebreather stopped injecting O2 and I didnt notice - which could have been embarrassing! But despite several near-death experiences, a memorable low, though ultimately a high, was the week of my Cave Instructor qualification.
The Instructor-Trainers tried to fool us at every turn and one had a favourite trick of tieing you into your own reel-line while you were attending to a student. He did it to one candidate so often that on the last dive the candidate swapped his reel for a loaded rat-trap. I nearly drowned as I saw the IT go for it and realise only just in time!
A week later we passed, and I immediately fell ill. I had survived that week purely on adrenaline.
Highs include using a rebreather for the first time in anger and being buzzed by dolphins; diving the Lusitania as part of a mini-expedition; and my first dive on the Britannic, a recon dive before the main expedition in 1997.
I have no words for the emotion, but it was as if the years of planning and training finally meant something.
I also shared several treasure/archaeological projects with Billy Deans, one of the fathers of technical diving. He has forgotten what most of us are still learning, and hopefully some of it rubbed off.
Taking my two girls diving for the first time was great too - even the pony cylinders they used were too big for them! But a recent best moment has to be looking out of a MIR submarine at the Titanic.
Two weeks in mid-Atlantic for one dive - but what a dive!

Photographer and big animals expedition organiser
hspace=5 I was swimming among ice floes in the Canadian High Arctic waiting for narwhals or beluga whales when I heard the warning signal. A polar bear had come between me and the boat.
I submerged, hoping to catch a glimpse of this ultimate predator from below. What was I thinking
After a few seconds I saw the bears big legs moving through the water, graceful, powerful and closing fast.
It had realised that I was something different and I had little time to react.
I saw its two black eyes and raised the camera with its 20-35mm zoom lens. But, looking through the viewfinder, it was bear paws that filled the frame.
From fear or pure survival instinct, I exhaled and dived as fast as I could, ignoring the pain in my ears. I levelled off at about 18m and saw the bear still coming after me.
How far could this animal dive I moved down another 6m and looked over my shoulder. I saw the bear slow up and start paddling just above me.
I took a deep breath and reached for the camera, sizing up this prize image of a polar bear at 24m.
But by then the bear had started its ascent. All I could see was its behind.
My best encounter was in Tonga. Three of us free-dived to 9m for an awesome view of a female humpback whale and her two-week-old calf as they swam upwards.
I moved away from the others to get a clear image, but the angle was just too wide.
Twenty seconds later, when the other two divers had surfaced and my lungs were burning, a magical sight unfolded.
The gentle giant female was stretching vertically, all 14m of her. She was supporting her young one at the surface while it took a breath of air.
I closed the distance and just had time to take the picture before surfacing, gasping for air.
It was painful, but I was very happy to have witnessed this unique behaviour.

TV presenter
hspace=5 Ive been diving since the 60s. As an optimist, I believe that the next dive will be the best ever. As a realist, I know that the worst dives are always my own fault.
So worst first. Out of a few humdingers, I would note one dive in Sardinia a couple of years ago.
I was feeling a bit bored on shore, so despite a rough sea and grey sky I joined a few locals and visiting divers to dive a Roman wreck site.
As soon as I got on the boat and noticed the incredibly thick wetsuits, gloves and hoods of my fellow-divers, I knew that I was under-equipped, but stupidly went ahead anyway.
The dive was challenging: strong currents, poor visibility, too darn deep and freezing cold.
I was shivering, sucking air like a pig and not at all amused. Another dismal example of letting enthusiasm overtake common sense and disobeying my own golden rule that Ive never been too hot on a dive but, gosh, theres nothing worse than being too cold.
Arbitrarily choosing one dive as the best, it might have been my first at the usually overcrowded Shark Point off Phuket. It is an almost iron rule that at anywhere called Shark Point there will be no sharks. Not so this time: we were blessed with leopard sharks and a National Geographic-worthy array of eels, barracuda, octopus, cuttlefish - you name it. It was warm. And my tank had 10 bar more than usual in it. Hard to beat.

Marine biologist & photographer
hspace=5 My most memorable times under water come not from a particular dive but from a recurring theme; watching large shoals of fish. Scad circling the bow of the James Eagan Layne, a sprat shoal dive-bombed by seabirds off St Abbs, sand-eels swirling above hungry pollack in Devon and jack mackerel sweeping through a Californian kelp forest have all had me in raptures. The movement, the patterns of light and the sense of drama make an exquisite combination.
I cannot think of a bad dive - selective memory perhaps. Only a few instances were mildly unpleasant when, distracted by photography, I ended up far from where I wanted to be.
But then, it was something marvellous that got me distracted in the first place!
One of my most sobering experiences was when a large grey seal tired of me taking too many photographs near him, and ushered me out of the water and onto the beach. It was a good reminder that we are guests in their world.

Cave/wreck diver, founder of Global Underwater Explorers
hspace=5 Early in my cave-diving career I was exploring a very low, silty area in a distant section of Thunder Hole, a local Florida cave. The two other divers and I were travelling in single file in very limited visibility.
On one of the longer sections of clearwater passage, I stopped to ensure that we had all turned the corner together and noticed to my consternation that a team-member with whom I had not dived before was no longer in sight. I suggested to my remaining buddy that we rejoin the missing diver.
His response was surprising; he told me not to worry. After some argument I called the dive and we returned to the entrance. I found the missing diver finishing his deco and about to head to the surface. I stopped him and noted his gas supply - he had only 20 bar left.
Later a long discussion ensued. I was told that turning the dive in such a manner was common practice, that the rule of thirds was too conservative and that it was impossible to get in a good dive without stretching oneself.
As I listened in horror, all I could think of was how many things could have gone wrong, and how fortunate I was to have returned with my team intact. This was the last serious dive I did with someone I didnt know, and initiated a lifelong quest for solid dive buddies and similarly minded teams.
It is tempting to seize on my exploration dives in Floridas mammoth Wakulla Springs for my best moment, but two stories about caves does a disservice to my love of ocean- and wreck-diving.
There was something oddly special about diving one of the worlds largest cruise liners. Perhaps it was the Britannics association with her enigmatic sister the Titanic, or maybe the mystery surrounding her wartime sinking.
Clear, warm water and a well-preserved wreck made the diving appealing, yet the joy lay in a sense of communion. Our international team was sharing in a legacy of historical discovery, in the footsteps of the worlds first technical diver Jacques Cousteau, who had dived it before technical diving became popular.
One dive stands out, on a day of calm sea and beautiful weather.
Riding alongside Barry Miller, I saw at first a dark elongated shape, then the majestic Britannic became more visible. As details emerged, it became impossible to maintain perspective.
Our mission was to explore the forward section, and locate the site of the rumoured second explosion, believed by some to be the forward coal bunker.
Picking through the mangled bow section was surreal. Torn metal and twisted wreckage dominated my perspective.
Suddenly Barry signalled with his light. We pushed through a restrictive area of torn metal and found ourselves in a fully intact bunker, still filled with coal. I felt transported back in time; we had just debunked the coal-bunker theory.

Editor-in-Chief of Diver
hspace=5 We were diving in forbidden territory, Howard Rosensteins Red Sea Diving Centres boat having strayed inexplicably into Saudi waters. An Israeli gunboat warned us of its presence but the captain, a friend of Howards, would turn a blind eye so long as we went no further and didnt stay long.
Howard, a Red Sea diving pioneer, was eager to see this unexplored reef and we jumped in. The wall was beautiful. He glided up to a tiny cavern and suddenly pointed. Inside were two sleeping sharks. I went close and lined up my viewfinder. The flash went off - and so did a shark, a big one. It flashed past me like a bullet and disappeared. The other one stayed put. Thank you!
When my film was developed, it revealed something extraordinary. A moray eel, with a head the size of a football, was also languidly sleeping in that tiny space, between the two sharks. It was something completely unheard of.
I was not an experienced diver when I had my worst moment. I was in the Bahamas as Editor of the magazine. Some of the initial dives at UNEXSO on Grand Bahama were great, but then the people there suggested a dive to the Cup Handle, a coral outgrowth from a wall inhabited by a giant grouper.
I had never been near a depth of 67m. It involved a check-stop at 30m at the edge of the wall before a stunning descent into the deeper blue.
I had been led to believe that nitrogen narcosis was euphoric, but at 55m I began to feel strange. My head was spinning, and at around 60m it was whirling. The surface was a long way away. I grabbed the arm of my buddy Dick Clarke, a truly great diver, and circled my head with my finger, and up we went. What a scare!

Film-maker and shark expert
hspace=5 We were in the open ocean off Pico in the Azores when I had what must be about the best moments I have experienced in more than 40 years of diving.
Doug Seifert, my husband Ron and I met a family of female sperm whales caring for a newborn calf. The dear little fellows body was all wrinkled, his tail curled and his tiny dorsal fin flat to his back.
What made the encounter so special was the incredible love shown to the baby by his family. They took turns holding him on their bodies, carrying him along so very tenderly.
We had permission to snorkel with them, which I did for 30 minutes. To be in their presence was a privilege that made me feel shiny all over. Compared to those whales I was a floating speck of nothing, yet I loved them totally.
I see them still, that enchanting family floating like the purest crystal through the stony muddle of my daily thoughts, and I know I am the most fortunate of women.
Another time I was photographing nudibranchs off Lontor Rock in Sape Strait, Indonesia, when I felt a strong force dragging me down. At first I thought: No problem, go with the flow and as soon as I can Ill swim out of it, but the speed of my descent increased until I was fairly rushing down.
With visibility hampered by exhaust bubbles and the rapid pressure increase, all I could think was: What a terrible way to die! I have never felt so helpless or so alone.
At about 55m, above a tumble of dark boulders, the current slowed, then seemed to stop - but only for a moment. Suddenly I found myself hurtling back towards the surface, grabbing frantically at growths on the rock wall to try to slow my ascent, but so great was the maelstrom that the corals broke away and joined me on my upward flight.
I knew my air must be low but I could not slow my breathing. In fact the thought seemed to make me breathe harder.
The water brightened. I saw swirling foam on the surface and swam up with all my strength, my heart pounding madly. I could feel the flow turning again and knew a second descent would be fatal. My legs seemed weak, my fins wobbling uncontrollably as I broke into the sunlight.
Rons hand reaching for me over the side of our dory was one of the most welcoming sights I have ever seen.
All my companions had felt the vortex starting and surfaced. Only I, in a sheltered niche, had been unaware.
I have had some very scary experiences but always felt able to help myself. In that whirlpool I was terrified, helpless and totally out of control.

Underwater photographer
hspace=5 We had spent two weeks unsuccessfully seeking sperm whales in the Azores, cruising the Atlantic in our Zodiac. Those we had seen had been too distant to photograph. I was searching the horizon as usual for a blow when I noticed a flock of seagulls just above the surface.
By the time we arrived the birds had gone, but I jumped in the water anyway. It was very clear, about 2000m deep but with nothing to see.
I was ready to wave for the boat, which had drifted away with the wind, when I heard noises behind me.
I turned to see a large group of false killer whales. They had killed a 3m-long tuna, and the big bulls were breaking up the fish and passing the pieces to the females to give to their babies. This was one of my best moments, not only to be alone with these beautiful animals but because I had a Nikonos RS with 36 exposures and a 13mm fisheye lens in my hands. Perfect!
My worst dive was one of many I did in the Tibuta Channel at Rangiroa in Polynesia. The only way to see the giant hammerhead sharks which face into the current there was to drift into the lagoon. Dives usually lasted 30 minutes, by which time the channel would be too shallow for the sharks.
Three of these 6m giants had passed but I had failed to get a picture. It was time to send up my SMB. I hooked my Nikonos and handheld strobe onto my BC and was busy unrolling the line when I realised that an enormous hammerhead had come to within 1.5m of me - perfect in the light and for my 15mm lens.
My hurried movement to retrieve the camera from the BC scared the shark off. I still feel angry whenI think of it - why couldnt he have come along five minutes earlier

Underwater film-maker
hspace=5 Heres something light for my worst moment. It was on Assumption in the Seychelles, and Id found a fascinating cleaning station 300m from the boat, with cleaner wrasse swimming into the mouths and gills of giant sweetlips.
After a lunch of two bowls of the cooks finest Israeli cabbage soup, I swam back to film the action.
Then the soup took its laxative effect. There was no way Id make it back to the boat in time.
With no diver in sight, I stripped off my gear and suit just in time. It was pure relief - until I felt a repeated nipping sensation on my exposed backside and, turning, saw that Id started a feeding frenzy, with dozens of yellowtails, snapper and wrasse homing in on the unexpected feast. It looked like a Caribbean fish feed.
It gave new meaning to the term bottom-feeding fish!
Midway between mainland Costa Rica and Cocos Island, sea-glass calm, we spotted a pod of pilot whales and dolphins. Everyone grabbed snorkels and masks and jumped in.
Fannying around trying to decide whether to take my camera or not, I was the last in, by which time the pod was moving away, followed by a group of frantic snorkellers.
There was no chance of getting near them, but the water was so beautiful I decided to duck-dive - its not often you can do that in water thousands of feet deep.
About 10m below me were a mother and baby whale, two stragglers. Shafts of sunlight filtered through the water like spotlights around them, and the water was alive with whalesong as they called to the main pod.
I stayed down as long as I could on one breath. By the time I surfaced and dived again they were gone. I hadnt taken my camera, but Ill never forget that sight.

Maritime archaeologist
hspace=5 My worst dive on the Mary Rose wasnt really a dive at all. It wasnt dangerous or difficult but I have never forgotten the feeling of utter frustration when it was over.
Maybe I was just too tired. Everyone was working flat out in that last year before the hull of the Mary Rose was recovered in 1982. Everyone had targets to achieve if the vessel was ever to come home to Portsmouth.
My target that day was to record some oysters, which had flourished under the overhanging starboard side of the hull after the ship sank in 1545. They had died when the scour-pit beneath the hull filled with silt, and I wanted to record where they were and their size.
I had already dived earlier that day, so I waited six hours before getting kitted up. Dave, the dive supervisor, asked me to check on a diver working in the hold as I went past.
At the bottom viz was good at almost 2m and I followed the steel grid to the hold. No sign of a diver! I swam all round the site but found no activity.
I had to go up and report to Dave. As I clambered onto the dive platform, Dave said: Its OK, Margaret, she came up the starboard shotline when you went down on the portside. I snorted and turned to go back down. Dave smiled and said gently: You cant go back - its your third dive.
Hell. A dive wasted, or was it Rules are rules but I can still remember the frustration, and Dave and I are still friends.
My best dive was in 1984 when a good friend, Richard Keen, asked me to look at a wreck he had found in the entrance to St Peter Port Harbour in Guernsey. As it was in the middle of a busy shipping channel, our permission to dive was limited to a brief window at first light.
We arrived on site already kitted up and Richards boatman put us over the wreck. It was slack water and I rolled off the gunwale and looked down.
I will never forget the sight of my first Roman wreck laid out beneath me. Massive timbers fastened with iron bolts, partially covered by a layer of solidified pitch. Remains of the galley roof and shards of Gallo-Roman pottery provided convincing evidence of the date. It was a dream come true.
Over the next two years a small team of ex-Mary Rose divers recorded the wreck, backed up by members of the Blue Dolphins Sub Aqua Club. We recovered it, published the ship and the finds and the timbers have now been conserved. One day soon I hope that this important seagoing Gallo-Roman ship will be on display in St Peter Port.
I have spent the years since 1994 diving in cleaner, warmer waters on scattered wreck sites that were finds-rich, but nothing will ever match my first view of my lovely Roman ship in Guernsey.

BBC Natural History Unit producer
hspace=5 Happy birthday, Diver! I cant think of two dives that more completely encompass the staggering range of emotions evoked by our brief and cumbersome visits beneath the waves than Wreck 37 and Baja 2000.
Worst was Wreck 37. Back in 1984 a friend and I, both humble 3rd Class divers, were diving with our new club, Hampstead SAC, at Littlehampton.
The club had some highly skilled wreck-divers, so our targets were fairly demanding.
For some reason we new bods were buddied together. We embarked on a 42m dive that proved to be black as pitch under a thick blanket of plankton.
Carrying only one five-year-old rubberised torch of dubious quality between us, what followed was a seemingly endless nightmare of narcosis following a tiny, dying ember of a torch, while paddling back and forth around the edge of the panic pit.
A very long 10 minutes or so later we reached the sunshine, shattered. To our amazement, two of the clubs old salts were comparing notes about the wrecks structure and size, the number of portholes and what a great dive it had been. Clearly we had much to learn.
Years later, to my glee, I heard those two old salts reminiscing about Wreck 37. Perhaps mellowed by ale or time, they revealed the truth - it had been so spooky that even they had resorted to holding hands! Looking back, I cant help thinking that my buddy and I were fortunate to get off so lightly.
My best dive came in November 2000 off the coast of Baja California, filming striped marlin attacking anchovetta schools for the BBCs Blue Planet.
This was open-ocean snorkel/pony bottle diving at its very best - incredible animal behaviour and spectacle provided by the most beautiful fish in the ocean.
In such circumstances, its impossible to feel anything other than effervescently alive.

Expedition organiser and writer
hspace=5 Best moment: A beautiful summers evening at Sennen Cove in Cornwall. After a day spent surfing crackling breakers in blazing sunshine, the tide had turned and the surfline had been replaced by lazy ankle-slappers.
This was normally a time to trudge wearily home with a surfboard tucked under one sunburnt arm to tell tall tales of kickbacks, green rooms and muscular Atlantic swells. As divers, however, we had an ace up our sleeve.
Minutes later we were swaying gently under the swell, flat on the seabed under 3m of crystal water. A glance upwards showed the evening sun lancing through flickering shoals of sand-eels, while a sideways look revealed the sleek, predatory shapes of several large pollack trembling in the valleys between sandy ridges, sizing up their prey as it swirled overhead.
As if on a silent signal, the pollack suddenly exploded, rising like squadrons of Spitfires from behind a hill.
The sand-eel shoals shattered into crystal splinters before the onrushing predators, swirling all around us like a silver whirlwind.
Through their midst came the pollack, twisting and turning, leaving vapour trails of tiny bubbles. A hundred dogfights broke out as we sat in their midst, ducking as desperate sand-eels flew past, inches ahead of those gaping jaws and needle-sharp teeth.
It was strange to trudge up the beach later, and see the couples strolling along the sea-front or clinking glasses in cosy restaurants. A few metres away, a massacre had taken place on a gentle summers evening in Cornwall.
As for my worst dive, I should have known better. My shoulder-tap came in the Galapagos. Blinded by the wonder of a great school of golden rays, stacked like stealth bombers all around me, I pinned my eye to the viewfinder of my camera, my legs pumping hard to drive me along with the school.
The rays gently inclined a collective wingtip and headed for the sanctuary of deeper water. I powered after them, my middle ear telling me that I was going deeper, my addled brain telling me I was getting the shot of my diving life.
Click! The camera jam may have saved my life. I stopped to peer at the lens, suddenly aware of the gloom of 40m and my steady downward passage. I fumbled for my gauges - 30 bar of air remaining, wild breathing, negative buoyancy, 40m - the place none of us ever wants to be.
Then a heroic figure emerged from the gloom - my buddy, finning after me, gesticulating at her gauges and computer, eyes showing only anger. Latching a hand onto my jacket, she slowed my downward passage enough for me to gather my senses, draw a few deep breaths, and begin a hurried ascent.
We broke the surface as I sucked an empty tank, my buddys look of reproach saying it all. I was a chastened figure sitting apart from the post-dive banter on the boat going home, struggling to digest a vast slab of humble pie as the sun sank. Saved by a malfunctioning camera shutter, and infinitely the wiser for it.

Cave-diver and Blue Holes specialist
hspace=5 One of my worst dives was the first one after Rob Palmer, my late husband, died. Rob was my buddy on most of my dives to collect samples for scientific analysis. Once in the cave, Rob would wander off and do what he wanted to do while I worked.
When I get stuck into some task, I forget about the guideline, my air supply and where I am - bad habits, but I was allowed that leeway with Rob as my guardian. He would remind me when it was time to go, escort me out of the cave and provide another pair of hands if needed.
This particular day started badly. Driving along a narrow, flooded road, my truck was blocked by a fallen tree. I couldnt turn round or back up and the tree was poisonwood, one of the worst tortures the Bahamian bush can dole out.
Half an hour later, soaking and covered in mud, I had managed to move the tree enough for the truck to pass. I would deal with the aftermath of the poisonwood later. I was mad, hot, bug-bitten but determined to reach the cave.
Once there I submerged, secured my guideline and went through the squeeze entrance into the peaceful atmosphere of the Mermaids Lair. Metres in, the water switched from brown to the bluest imaginable. The first chamber was as big as a small aircraft hangar. More than 5.5 miles of this system have been mapped and the cave is still going.
Three huge stalagmites, the Three Sisters, marked the transition from upper chamber to lower passage. At 18m I passed through the shimmering transitional zone between fresh and salt water.
I needed to collect Saharan dust from the cave floor. I had secured the line when I noticed a better sampling site and moved towards it. But I had moved deeper into the cave than I thought and was well out of sight of the guideline - and in big trouble, as became screamingly obvious as I prepared to leave.
I hung in the water column looking in a circle for the line. I had forgotten that my extra pair of eyes were no longer with me.
I checked my air supply - I had not reached thirds yet but time was passing. I swore that if I survived this dive, I would never be so careless again. I felt angry with myself, angry with Rob for not being there and downright miserable. I didnt care any more.
As I sat feeling sorry for myself, I happened to look up again, and spotted a small bit of line between two rocks. I swam towards and over them with raised hopes. The cave had given me another chance to live, for there in all its beauty was my guideline.
It took about 15 minutes of swimming before the most welcoming of lights appeared before me; beams of yellow sunlight.
Following a short decompression period, I was released from the underworld unharmed. I embraced the warmth of the sunlight on my face. I was ready now to move on.
One dive that sticks out as the best was my return expedition to the Black Hole of South Andros. It gave me the chance to make several new discoveries, one of which was a novel species of bacteria and the other an explanation of what makes black holes black [read the full, incredible story of this trip soon in Diver].

Deep wreck/cave-diver
hspace=5 My best underwater moment is difficult to pinpoint, so I have to include a few: diving the Carpathia in 155m was a treat, as was swimming the decks of the Flying Enterprise in 78m with Leigh Bishop in 2000.
Ive also had some great cave trips, and diving to the end of the then-current line in St Saveur in France was a fantastic experience, as was a cave dive with Martin Robson and Ed Pavia in the Durzon. Diving the Britannic just recently was good fun, especially watching Leigh trying to set up a camera tripod at 120m!
The worst moment is unfortunately easier to select: hearing the news that Andy Wilde had gone missing off the Loyal Watcher, which was on the first trip Id arranged for everyone when we first got the boat.
Andy was Steve the skippers best mate, and the grief that emerged was a poignant way of underlining the fact that none of us is immortal.