“PREPARE TO SNORKEL!” shouts Sartoki. He’s a big, strong Japanese dive-guide from Euro-Divers in Vilamendhoo, and you could imagine him shouting orders on the deck of the Nagato, Admiral Yamamoto’s flagship.

There’s a scramble for masks, fins and snorkel and 10 people, all anxious to be first, scramble into the water. I wait more patiently, camera in hand.

“It’s under the boat,” one of the Maldivian crew quietly advises me. “Quick, go now!” he whispers.

I dive headfirst into the water on the opposite side of the boat to the others, just as the spotty monster appears below me. Another 10 people left on the boat are behind me.

I swim at a heart-busting pace, take a breath and head down so that I can get the important front three-quarters shot. Thank goodness for continuous shooting and the big digital buffers of modern cameras.

As a former advertising photographer, I know the best angle from which to shoot a car, and this juvenile whale shark is rather bigger than a car. I estimate it to be about 4.5m long, but it’s a baby.

Lungs bursting, I head for the surface and fin like crazy in a bid to repeat the trick. My short interval below has, however, allowed the other snorkellers to catch up, and I’m in a mêlée of thrashing arms and kicking legs.

One of my co-snorkellers even attempts to pull himself forward by grabbing hold of my body and climbing over me, such is his determination to get ahead.

There’s a distinct contrast between the relaxed tail-swishing cruise of the creature down below and those less at home in the water who are thrashing at the surface.

One more breath-hold dive and some over-the-shoulder (or should I say pectoral fin) shots, and I’m done. There has to be a better way to get images of whale sharks in the Maldives.

TWO DAYS LATER there’s another whale shark trip. It’s fully booked as usual. Euro-Divers calls it “Searching for Whale Sharks”, because it doesn’t like to make promises it can’t keep.

I suggest my plan to Mike, the dive-centre boss. As usual, he bends over backwards to be helpful.

The normal format is to do a couple of dives and look for whale sharks during the surface intervals. I opt to take scuba gear, but eschew the regular dives. I’ll be wearing my scuba kit if and when we spot a spotty monster later.

Young Hussein is detailed to come with me, to see that I don’t get into trouble. He doesn’t know it, but he’s in for a cardio dive!

Few people can sustain the speed of a whale shark while wearing scuba kit, but I can. I’ve got my Pegasus Thruster cambanded onto my tank.

A long slim cylinder culminating with a propeller in a shroud, the Thruster has one speed. It’s the cruising speed of a whale shark!

Whale sharks spend only short periods at any one time near the surface, passing most of their time in deeper water. Nobody really knows much about them, where they go or what they do there.

We know that the ocean side of South Ari Atoll is a good place to encounter juveniles when the ocean currents are inward, and the area around Maamigilli Beyru has been designated a National Park with whale sharks in mind.

There are as always several boats hanging around with people ready to snorkel. The skippers communicate with each other and, as on a safari in Africa, tell each other when they encounter the quarry. That means a lot of snorkellers, and the ensuing chaos at the surface often encourages the whale sharks to retreat into deeper waters.

An animal has been seen by those on another boat and the shout goes up: “Prepare to snorkel!”

I’m ready. The snorkellers go in. The shark starts to head deeper. Hussein and I go in. Almost at once I’m down at 30m, cruising alongside the animal. It’s about 5m long.

There’s another diver with it. He has a video camera and those long fins beloved of fit young men. I cruise effortlessly. He must be feeling a little envious as, his stamina exhausted, he gives up the chase. I cruise on.

I was a little concerned that the gentle whirring noise from the DeWalt electric motor powering me through the water would disturb the animal.

Not so. I cruise alongside it, matching its speed. If I need to get ahead, I add a few fin strokes.

My camera housing in my hand, unencumbered by flashguns and equipped with a super-wide-angle lens, I’m getting loads of pictures.

I just need to keep the button of the remote control of the Thruster firmly depressed to keep pace.

The animal doesn’t seem concerned. Far from it, it keeps heading over towards me, closing the gap between us.

Too close! Too close even for my super-wide-angle lens. Some of the remoras detach themselves and reattach themselves to me instead. I’ve been accepted as another large animal sharing the ocean.

The whale shark appears to like the company. I edge a little further away.

In fact, in getting ahead for the three-quarter-front shots, I inadvertently take the lead. I turn us both towards the reef wall, and we start to head gently upwards and back the way we’ve come, following the coral to where the light is less monochromatic. “Oh, good,” I think, “a chance for better-lit pictures.”

We cruise along the reef wall at around 15m deep, and straight into a very surprised cluster of divers who weren’t expecting such a spectacle. The whale shark scatters them as they break rank, and cameras are hastily refocused.

A few get some unique and opportunistic close-ups. I don’t think they even notice me. I hide below the outstretched pectorals of my new friend, still clicking away with my Nikon, secure in its waterproof case, and quietly whirring away with the Thruster.

We soon leave the divers in our wake. Few are athletic enough to stay the pace, even for a moment. I’ve spent 20 minutes alongside this juvenile whale shark, and it’s time to let it go. After all, I’ll need to save some battery-power of my Thruster for the next one!

I let off the Go button and turn vertically in the water, stationary. The remoras, grateful for the ride, swap back to their previous host. I wave goodbye.

Oh look, there’s young Hussein – he looks out of breath! I had warned him of what he was letting himself in for.

He grips the valve of my tank, and I tow him back some of the way towards the boat. He regains his breath while the others are doing the next scuba dive, and we get ready, rigging our tanks for the next surface interval.

“Prepare to snorkel!”

The shout goes up again, and this time I’m in first. This whale shark is on top of the reef in shallow sunlit waters at around 6m, which suits me. Not only that but I’m already ahead of it, and vector my course to let it catch up.

Behind at the top is a group of snorkellers from another boat putting up one hell of a show of pace. The wakes from their fast-beating fins scar the surface of the water.

Sorry! We can’t wait. The whale shark meanders onwards at a steady pace. We cruise together effortlessly. I’m getting good at this! I’ve set my camera to fire continuously as I hold down the release. It’s easy once you know how!

THE OTHER ICONIC ANIMAL of the Maldives is the manta ray. Also plankton-eating giants, manta rays are intelligent and sociable animals that can gather in groups at places they favour where little fish feed on the parasites that frequent their skin and gill-rakers, and give them a good cleaning.

There are madivarus or “manta points” all around the Maldives, but we head for one that’s famous as the Rangali Madivaru. It has never let me down for a manta encounter.

It’s best when there’s a strong current running and the mantas approach the reef like so many aircraft lining up to land at Heathrow. Once again, I go in equipped with my hands-free propulsion device strapped to my tank. This time it’s Norwegian dive-guide Hal from Euro-Divers who’s in for the cardio-dive, in bidding to be my official buddy.

We reach the first-known cleaning station, and I’m disappointed to find around 30 divers gathered around, clinging onto the reef in the flow and watching the ballet of a single graceful manta. It’s a circus. I don’t feel that I can get good pictures here and signal to Hal that we should move on to cleaning station number two.

We are rewarded on the way with a close encounter with a couple of mantas that are happy to stay with us.

ONCE AGAIN, the thruster proves its worth. The animals seem to tolerate it and perhaps a bit more than they would tolerate me if I needed to move my legs and fin. They let me get big close-up pictures and come back for more.

In fact I start to get buzzed by more mantas, while Hal is left to watch from further down the reef. They appear to think I’m just another big animal, merely present for the services of the busy little cleanerfish, just as they are.

I don’t like to persuade them otherwise. We cruise together along the reef and I am busy clicking away, the flashes from my camera having no discernible effect on the symbiosis between us. We make our way to the third cleaning station. It’s the mantas and me.

The rays like to cruise above me, shivering and shuddering with pleasure from the Jacuzzi effect of my exhaled bubbles. I turn on my back as I motor, keeping a wary eye for any outcrops of coral with which I might be guilty of colliding. The mantas drop their feeding lobes. They look relaxed. I feel ecstatic.

Some mantas slip away as others join the ballet. The cast seems inexhaustible, which is more than I can say for young Hal, who has been trailing behind the moving show, finning his heart out into the current!

South Ari Atoll isn’t just about big animals, though there seem to be plenty of sharks, both whitetip and grey reef.

The other animal that can grab the attention is the marble ray, and some of these are really enormous.

On one dive, Mike and I come across one of the biggest. It has just caught something, and it’s not going to move until that something is safely munched. It hunches itself up and stays resolutely still, despite the attention I give it with my camera.

THE THRUSTER STILL COMES IN useful because, during springtime, the currents at some Maldives sites can be daunting. I’m able to get into position and take pictures while others can only hang on with their current-hooks and watch.

There are crowds of ubiquitous yellow blue-line snapper, and a lot of very monochromatic sweetlips in a silvery hue that I haven’t knowingly come across before. They hover in tight groups out of the current under the overhangs while the big fish with the whirring motor hovers around, giving off strange flashes of light accompanied by clicks from the thing with the big glass eye – my camera.

Vilamendhoo Thila has some interesting current effects when water is flowing in from the ocean. At the end of one dive, Sartoki puts up his deco-buoy only to find it pushed back down to him, even though it’s fully inflated.

I tow him with the Thruster out of the very localised washing-machine effect, and make a friend for life.

LUCKY HELL IS THE OUTSIDE of a circular reef that’s known as Seventh Heaven on the inside, thanks to the masses of colourful soft corals that flourish in the open flow. We see a beautiful pure white manta there, making passage out in blue water.

Everyone holds on to watch while I sprint down the reef into the otherwise impossible current and ambush it as  it passes by. I am rewarded with a stunning couple of shots, as it barrel-rolls above me against an ultramarine backdrop.

We don’t need such help diving the intentionally sunk wreck at Machafushi. The diving is easy. It’s known as the Kudimah wreck.

Hussein and I investigate its every nook and cranny, although it’s a very popular site and full of divers from other islands as well as our own.

There’s a crane on its deck, and the crane’s cabin is crowded with glassfish and the coral grouper and redmouth grouper that prey on them. Coral grouper can be quite hard to capture close up if you have a very wide-angle lens, but I drop inside the engine-room and find quite a few surprised examples.

Under a net on the forward deck, two huge stonefish lurk. It’s best to leave them undisturbed. The sight of a little red frogfish that has attached itself to the side of the wheelhouse turns on girlie dive-guides. Hussein poses for me helpfully around the coral- and sponge-encrusted forward mast.

Vilamendhoo is quite a large island with a house reef all around it, and only a few metres from the narrow white-sand beach. Barry and his wife have come all the way from Calgary in Canada, and are so knocked out by the beauty of this house reef that they do all their dives on it.

They have a beach villa with a veranda only a few metres from the water. It’s very convenient. I have one too. It has a four-poster bed and wi-fi.

THERE IS A CHOICE of water bungalows built on stilts, garden bungalows and beach villas. One end of the island has its own bar, spa and restaurants where children are not allowed, while the other end has similar facilities where they are.

There’s something for everyone. The restaurant serves a wide variety of food, and most of the visitors are from Britain, because Thompson has pre-booked a majority of the accommodation.

Euro-Divers offers boat dives and unlimited shore diving, with nitrox and equipment hire for those who need it. During my visit its staff included Austrian, Spanish, Swiss, Norwegian, Greek, Japanese and Maldivian dive guides and instructors, with English as their common language.

GETTING THERE: Thomson Airways now flies direct to Male from the UK.
DIVING & ACCOMMODATION: Euro-Divers Vilamendhoo, euro-divers.com. Vilamendhoo Island Resort & Spa, www.vilamendhooisland.com
WHEN TO GO: Any time, though the UK winter and spring are ideal.
MONEY: US dollars.
PRICES: Regaldive offers a package including return flights with Emirates, seaplane transfers and seven nights’ full board in a garden villa on Vilamendhoo (two sharing) from £1499pp. Six days’ unlimited house-reef diving booked through Regaldive costs £324. House reef dives are unguided except for divers with fewer than 40 dives, who pay US $4 extra per dive for a guide. Boat-diving is booked on-site – Euro-Divers operates 3-4 boats twice a day and a day’s boat-diving costs $36.
FURTHER INFORMATION: www.visitmaldives.com