"This bear was recently hit by a truck crossing the highway out the front of the property," someone says. "But it's unlikely he was on his way to sign up for rafting," another quips.

We step around the fine-looking beast, sign a waiver form and pay for our rafting experience. The bear is about as likely a rafting participant as I am. I'm not entirely keen on the idea of launching myself down a raging river with little knowledge of reading rapids. It is an uneasy adrenaline rush, yet I seem to keep on doing it.

On my last expedition, my paddle whacked me in the face on the very first rapid of the Mohaka River, in New Zealand's north island. The minor lacerations to my mouth stung, but the dent to my pride was far worse. You can never let your guard down on a river.

My wife Rebecca is mad keen on rafting, so I rise to the challenge. Here I am again, listening to a safety briefing with a large gathering of thrillseekers. I've already clumsily bumped my leg on a wooden railing and watch as blood oozes from the abrasion. This is not a good start.

A short bus ride later and we disembark from what might have been a school bus in a previous life. We adjust safety vests and helmets, and the rafts are hauled off the roof of the bus. The launch site is filling with rafting crews doing their final safety checks and paddling drills. The five of us greet our quietly spoken instructor, Chris Pece, whose wiry frame and expert knowledge of the Ocoee​ we will depend on to guide us down the rapids.

We're instructed to pick up the raft and move next to the river. It looks like we're first in. "It's important that we work as a team," Chris says. "Try and paddle together, so watch the person opposite you out of the corner of your eye."

Rebecca and I will sit opposite up front; Kim and Will in the middle; Andrew and then Chris at the back. Paddling together at the right time enables our instructor to pick the right line, at the best speed, going into a rapid, to keep us from spilling overboard or flipping the craft. Chris reminds us of two important facts from the safety briefing: "If you go overboard, don't try and stand up. Float with your legs facing down the river. If you go into a whirlpool-like rapid and find yourself not coming out of it, don't panic – just curl up in a ball and you will sink and be spat out at the bottom of it like a stone."

It is rare to get caught in one of these, but just in case, it's good to know how to handle it, he says.

"What have you got us into?" I ask my wife, but she can hardly hear me above the din of raging water. And with that, we drag the blue inflatable raft and climb aboard. Chris is the last man in and we immediately pick up speed in the fast-flowing torrent.

"Two strokes forward," Chris says firmly as he uses his paddle as a rudder to steer us on the best line into Mikey's Ledge, the first rapid. I brace myself as our raft drops a metre and we are smashed by three waves before falling another metre as water gushes over us. Our initiation is over quickly and adrenaline is pumping through me.

The Upper Ocoee River was used as the 1996 Atlanta Olympic Whitewater Competition course for the kayakers. It was criticised for being too rough, Chris tells us, especially the last combination of rapids known as Humongous and Slam Dunk. We'll be going about eight kilometres and taking on the same challenges as the Olympians, and more, over the next two hours. There are class III and IV rapids – which basically means, big drops and huge waves.

The river quietens between rapids, giving us time to joke and enjoy the valley's scenes. The Ocoee is flooded – it is a strange feeling as we are sail between the tops of trees of the Cherokee National Forest. A series of dams controls the flow of water for the primary purpose of generating electricity, Chris says. The rafting companies pay for the water to be released to operate their expeditions. It is an incredible volume of water surging over the rocks when the dam gates are open – between 65,100 to 73,600 litres a second.

The next white water challenge is approaching. Chris instructs us to paddle forwards into Blue Holes and we are buffeted around furiously, but still aboard at the end of the rapid.  You must trust that the guide's instructions and expert rudder work with a single paddle will keep you safe. The guide picks the approach or "door" into a rapid.

Yesterday Chris graduated from university as a radiologist but, thankfully, instead of partying all night in celebration he is clearly fresh and ready for guiding us. I am grateful for this as we launch into the Olympic course, greeted by the "Entrance Wave" before passing a large rock known as Smiley's in the middle of the river. Apparently it is shaped like a smile, but I missed that in the fury of the flow. We are instructed to paddle hard out of a hydraulic, a swirling turbulent of water that pushes the raft back toward the rapid.

Slam Dunk sees us buffeted by a series of waves and we are carried over another ledge (it's more like a small waterfall). I brace my paddle with a death grip. The last jolt flips one of our crew members over the side – Kim is in the fast-moving water in an instant. The drama is over almost as quickly as she swims quickly to the side of the raft before Chris reaches over and drags her on board by her life vest. He wasn't mucking around with that manoeuvre and we soon find out why.

We paddle into a Callahan's rapid where waves rock us again before we are carried over another ledge. I've hardly caught my breath before the next famous combination of rapids. I notice dozens of people sitting on the side of the river, no doubt watching to see if rafting crews wipe out. We are rocketed into a hole known as Godzilla and as we plummet down a ledge and hit the water violently, I'm almost thrown overboard. The water is roaring.

"Keep paddling!" Chris yells at us before we are thrust down an even bigger rapid – Humongous. It feels like our raft has gone vertical for an instant before hitting a pool. For a moment we are entirely under the icy water, but somehow the blue inflatable shoots out the right way up. Everyone is accounted for and we let out a defiant cheer.

Chris guides our raft to the side and we disembark briefly so we can watch other crews face the challenge (and wipe out) as we catch our breath. There are more rapids ahead of us, but I feel like we have conquered the worst of it.  There is an element of risk to this adrenaline rush. In 2013, two women - in separate incidents on the same weekend - drowned after hitting a rapid known as Grumpy's on the middle Ocoee. Fatalities are rare, but happen.

The Ocoee is quiet now. The river is wider and deeper here as it snakes its way through a lush valley in the Smokey Mountains of south-east Tennessee before the next dam. "You can swim now if you want to," Chris says. "It's safe to."

Other crews are already in, but none of us are tempted. This thrilling adventure has come to an end.

TRIP NOTES

GETTING THERE

The major airline alliances fly to Los Angeles, which will make it cheaper to connect with a domestic carrier in the US through to Chattanooga, Tennessee. Flying with Oneworld, for example, Qantas frequent flyers can connect with American Airlines. Take a hire car from Chattanooga airport and drive east for about an hour to the Ocoee River.

STAYING THERE

Local bed and breakfast, The Company House (125 Main Street, Ducktown), is a quaint building with comfortable beds, a highly rated breakfast and porch overlooking a pond.  It's a five-minute drive from RaftOne, but also close to great hikes, trout fishing spots and mountain biking routes; see companyhousebandb.com.

RAFTING THERE

A number of rafting companies compete for your business. RaftOne (raft1.com, 4599 Highway 64 west, Ducktown, Tennessee) offers fun guided tours of the nearby Upper Ocoee River, which takes in the wild rapids of the 1996 Atlanta Olympic Whitewater Competition course. The Upper Ocoee is only open for rafting for about 50-60 days a year from June to September. Cost starts at $55 a person in groups of  up to 11.

The writer travelled at his own expense.