Fat Tony is standing on the cold concrete stairs of the surf club, still dressed, gazing down at the waves at the south end as if they might bite.

- Come on, I say.

- No bloody way. I'll leave it to you two, he says laughing nervously but with certainty. - Don't tempt fate. You're bloody mad.

Rosie doesn't look mad, she looks like a racehorse ready to start track work as she hops quietly from foot to foot beside me in the ribbed Lycra of her one-piece.

- You have to go back in some time, she says.

- Well, not to-f---ing-day it won't be, says Tony.

It's been four days since the shark attack and I've not yet swum again but this will be my last time in Bondi's waters for the foreseeable future. I've had dips and body surfs, but not swum the bay, out deep beyond the break.

The shark - they say it was a bronze whaler - hit the guy just on dusk as he was surfing the rights at south end, taking his left hand above the wrist but leaving it dangling by a piece of skin and muscle. He lived, but they couldn't reattach the hand, so he won't be playing snooker again. I hope he was right handed for his doodle's sake. It's also the first shark attack at Bondi for almost 100 years and it's set a charge into anyone who uses the water regularly.

- I wonder what they did with his hand? I say and Rosie creases the wrinkle-tree above her nose but stays silent. She's endearingly shy among the old boys as they shuffle out of the fuggy warmth of the surf club. They squint into the morning sun, suitably unmoved and unsurprised by Rosalie Killon joining them to swim.

- They'd wrap it in foil so you can take it home, says Foxy.

- I'm serious. What do they do with it?

- Shhh, says Rosie.

By now there are almost 10 of us in the sun on the promenade. The morning wind is cool, but the warmth is just enough to keep us snug as the early walkers pass us, no doubt wondering why we'd subject ourselves to the danger. Shark sightings are the new black in Bondi, with every f---wit you talk to recounting a great white taking a fisherman's bait or a whaler cruising under a ski paddler around at Bronte.

I'm surprised the shark doesn't have his own agent there are so many squirrels and models and advertising types claiming to have seen it.

I've thought it through and realised that, if you're any more than 100 metres from shore and you're bitten, you're pretty much screwed. The act of swimming would see you pump so much blood, you'd be dead by the time you got to the beach.

- I've thought it through, I say to Rosie. - If either of us get bitten, I'll pull the drawstring out of my cossies and we'll use that as a tourniquet.

- If you're trying to scare me, Ned, it's not going to work, she says.

- I'm not trying to scare you. I'm being pragmatic.

- It doesn't bother me. I'm not scared of sharks, she says, probably because she's surrounded by them every time she steps into a bar for a drink and chews them up with a wrinkle of that nose.

What eats sharks? I wonder. Killer whales? Killon the killer whale?

Trudging down the hard sand, it's difficult to countenance that Rosie's actually here, walking beside me and at one point I glance back at her footprints, peanut shapes in the sand, for confirmation.

I'm not quite ready to admit my secret life as a smoker to Rosie, so for the last two nights that she's slept at my place I've not indulged and my lungs feel liberated, like a cold is clearing up. She's talking to one of the old girls about her art gallery and I'm talking to little Allen, attempting the impossible of listening to one conversation while holding another.

I hear the odd "Ned" and "Manly" and "You should come in" but no "he's fantastic" or "I love him" or "man of my dreams". It is early.

At the water's edge at south we pause to goggle up and Rosie stretches my white latex cap over her head. She looks like a character pulled from one of those iconic Tooth's beer posters that used to adorn the outsides of pubs – all primary colours, against cotton wool clouds, "as refreshing as a sea breeze".

- It's pretty rough, she says, looking at the waves pouring in. It's only about two to three foot, but the sandbar is jacking the surf up and flattering its size.

- You think so?

- I don't really like it when it's rough.

- The waves are the least of our concerns. I'll stay with you, don't worry.

We wade out into the white water and easily clear the first few sets. When one breaks on us and turns us over like we're in a cement mixer, I surface to see Rosie a little wide eyed and breathing quickly.

- It's OK, I say and pull her in deeper. Once in the blue water she seems to calm down, which is perverse because now we're closer to the shark(s).

As we begin to swim, she strokes deeper, far wider than any of the old boys, so I dutifully follow her, aware this is well past the point of no return. If a shark got either of us out here, it's all over. We'd bleed out like an overturned wine bottle and be empty as a drug dealer's promise by the time they fished us out.

I step down on the thoughts and stay with her. Rosie's fast, though I've got a little left in the tank. She moves at a steady pace, with elegant strokes, a high action, her beautiful long brown legs twisting in the blue beside me.

I could never have done this with Karen or with Gemma or Bella or Alessandra. They didn't want to get their hair wet or were frightened of seaweed or couldn't swim that well. Rosie? My god, I can't let her beat me, I think, and plough after her, surprised by her speed.

Twenty minutes later we roar out of the icy water, arms thick with exertion, heads crystalline, pumped fresh with oxygen and we smile at each other that we've shared this, that we can share this.

We stand at north, watching the waves bulge into the rocks and sand, the exhalations of the tide, the reds and green of the seaweed tressing, the shining water draining down the sand after the waves have expired.

The sun is starting to bite as it checks in for the morning, the dead cold of my fingertips tingling as the spa-like eddies of warmth roll off the surf. The morning is ours, a crisp, crystal shell hung over the ocean and, as I turn to head for the surf club and the showers, Rosie grabs my hand.

- Stay here for a second, she says and we stand on the sand just feeling the morning around us, touching the air, each other.

Sam de Brito's latest novel Hello Darkness is in bookstores now. You can follow him on Twitter here. His email address is here.