For the second night in a row, I can’t sleep. Perhaps it’s the sound of the boat’s generator, the pitch black cabin, or that cute French girl sleeping in the bunk above. Or perhaps it’s that I’m about to experience the single most terrifying thing in the world?

I had a similar feeling of apprehension two days ago when I first headed to Port Lincoln, in South Australia. Since then, tension has been mounting. It’s the first trip of the season and in return for a discount I’m helping get the boat ready; scrubbing, organising dive gear, stocking cupboards and filling the freezer with bait.

There’s a slowly de-frosting 60kg tunafish hanging off the back of the boat and it’s starting to smell. I keep finding incredible photos that set my heart racing, reminding me that tomorrow I will be face to face with a great white shark. For years I have been fascinated with the world’s greatest predator and I’m absolutely terrified of them!

I wake early and I’m finishing the chores as lots of interesting people arrive. There’s a photographer overloaded with equipment, a couple of famous divers, a marine biologist, a slightly crazy Canadian, her boyfriend, and a couple of Frenchies. I can’t help thinking it’s going to be an interesting trip.

We set sail. Everyone’s getting to know each other and our excitement mounts as the seas roughen. I go up to the wheel room and watch the horizon. I don’t say much, fighting off sea sickness, as the captain shares his life story. We’re soon talking about sharks.

He casually remarks, “I know at least five people around here that have been eaten by sharks”. I queasily listen as he tells the stories. This just adds to the tension as it’s no secret that the owner of the expedition company is himself a famous shark attack victim – Rodney Fox.

I make it to the Neptune Islands without being sick. After dinner we get the ground rules: no touching, keep your hands and head in the cage and don’t feed the sharks. This is it, tomorrow…

I wake up later than planned and there is excitement on deck, a large chunk of tuna has been eaten sometime around 7am. Suddenly I hear shouts of “shark, shark”.

Rushing outside I see a huge dark shadow prowling at the back of the boat. Marie, the French girl, puts on her wetsuit and jumps into the cage. I decide to wait and see how this is done. Marie comes out beaming, shouting “beee-ute-iful” in her lovely French accent. Inspired, I suit up and slide into the cage.

Firstly I focus on keeping upright as the cage sways with the swell, but soon I figure out to lock my feet under the foot bar to gain stability. The water’s murky and my heart’s beating fast. Then I see him.

Immediately I’m struck by his size as he gracefully glides past. I’ve stopped breathing, waiting for the fear, but incredibly I’m not intimidated at all. If anything, it’s the shark that’s timid, carefully checking the bait out to see if it’s safe to eat. This isn’t the evil, aggressive and threatening creature I was expecting, but a docile, graceful and stunning animal, my eyes wide as I take it all in.

Then we see another and I start to notice the unique markings on their bodies that enable the Rodney Fox team to identify these sharks. I’m looking at Big Bro and Kalell who have been coming to the Neptunes for the last seven years.

They are circling, checking things out, getting closer and closer to the bait on the surface, but suddenly both disappear. Everyone in the cage starts looking around, peripheral vision blocked by our masks. Then, out of nowhere, this huge mass swells up from the depths and engulfs the tuna in its giant mouth.

I’m blown away by the speed of surprise and the shark’s ability to expand its jaws so wide. It could easily swallow a human whole. First hand I’m seeing why my fear of these predators is justified, but I’m beginning to respect them. One of the crew later tells me that, “they can hook their top jaw up so they can lock down hard on prey and not let it get away”.

Lunchtime, I’m hungry and exhilarated, the table is full of chatter as people proudly show off their photos. The captain moves the boat to shallower water as the marine biologist Charlie goes ashore to check his tracking data.

“Who wants a go in the submersible cage”? I put my hand up… I’m a qualified diver, but I’ve never been deeper than 18m before, and certainly never lowered by crane in a cage that I can’t escape from! However, with backup air and a pro diver going with me for support, it was an opportunity I couldn’t miss.

My scuba gear starts to feel heavier and my confidence drains as I’m ushered into the cage which starts to lower. I’m knee deep and there’s no going back. By the time my head’s under the water, relieved, I start equalising, only to immediately spot a huge 4m shark.

We continue down to the bottom at 25m and spend the next 45 minutes admiring this amazing creature casually swimming around and above the cage. This is the way to see sharks. I’m relaxed and in awe. Big Bro is docile, incredibly muscular and effortlessly cruising the depths – stunning.

Warming up in a hot shower I catch my smiling face in the mirror and I know I’ve just experienced something that very few are privileged to see. Scuba pioneer Carl gives us a slideshow of a lifetime of underwater photography from all over the world and I go to bed truly satisfied.

The action gets better over the next two days. The highlight is when Big Bro gets into a feeding frenzy, circling the cage for 45 minutes, getting closer and closer until we are making eye contact as he sizes me up.

Amazingly, I see personality in those bright blue pupils. He continues to work up the aggression until he goes for Mark’s camera and bites the cage literally 10cm from my face! The excitement mounts as a seal suddenly appears and Big Bro makes a lunge for it, but the seal’s too clever this time. I find a book called Shark Attack and read about victims all over the world.

Most deaths occurred after the victims were spat out and then bled to death. Sharks don’t like to eat humans. Fact. But if you’re in their territory and they are hungry they may mistake you for edible prey. If you are injured or bleeding then you really are at risk – they are designed to keep the seas clean and they’re very good at it. There are 120,000 deaths a year in Australia and on average you can count on one hand those caused by sharks, crocs, spiders and snakes. The danger is real but the risk is very low.

Arriving back in Port Lincoln we meet Rodney Fox himself, who shows off his massive scar. I’m glad to be back on dry land but disappointed to be leaving the boat. I have an underlying feeling of satisfaction as a lifelong dream has been realised.

I don’t think many friends or family believed I would do it, but I’m proud that not only have I fulfilled a dream, I’ve had the best adventure of my life and replaced my fear of the world’s best predator with respect. I’m a much more relaxed Bondi surfer these days!

The damage & the details: Cage dive expeditions with Rodney Fox (Ph: 08 8363 1788, cost from $1,995 for a three-night trip.