The christening of the ducky unleashes all the wilds of the Grand Canyon upon Rob McFarland.
Scotty's words are still echoing in my head: "Whatever happens, don't go in the hole."
It is too late. We are in the hole. A towering wall of water engulfs the kayak and flips it around. Suddenly, we are pointing upstream and being sucked backwards. I glance around to discover my brother is no longer behind me. He has been washed out but has managed to grab the rope at the back. Somehow he hauls himself back in and we paddle like madmen, crashing through a series of huge waves to make it to calmer water.
Scotty is waiting there, smiling and shaking his head. "I told you not to go in the hole."
The rapid at mile marker 209 might only be a grade five on the Grand Canyon's white-water rating system of one to 10, but I feel as though we have just paddled through Niagara Falls. I am not normally a high-five kinda guy but I can't stop myself from shrieking and pumping my fists in an explosion of adrenalin and relief. It is quite simply one of the most thrilling things I have ever done.
Rafting through the Grand Canyon on the Colorado River has become one of those life-changing, must-do-before-you-die travel experiences. Only 16 operators have a licence to operate in the canyon and the National Park Service strictly controls the number of people on commercial and non-commercial trips each year.
It is so popular they have had to introduce a one-trip-per-year policy to stop serial rafters from monopolising the spaces. Even so, you will still need to book up to a year ahead to secure a spot.
The rafts are launched at Lee's Ferry - mile marker 0 - and make their way over 16 days through 362kilometres of some of the most spectacular scenery on the planet. While some companies offer an option to tackle the whole thing, most split the trip into three segments, each of which has its own unique appeal.
The initial 141-kilometre section from Lee's Ferry to Phantom Ranch takes six days and is generally regarded as having the most impressive scenery. The downside is that you have an arduous eight-hour, 15-kilometre hike up Bright Angel trail to get out of the canyon when you finish.
Those looking for the wildest white water opt for the 160-kilometre Phantom Ranch to Whitmore Wash section. You have to hike in at Phantom but a helicopter flies you out of Whitmore.
The final section is the one we are on - the 61kilometres from Whitmore Wash to Diamond Creek. It is tamer than the other two sections and only involves two nights' camping on the riverbank - which makes it popular with those who want a gentler introduction to a multi-day rafting trip.
Our adventure started two days ago with a 45-minute flight on a twin-propeller plane from Las Vegas to a remote and desolate part of north-west Arizona known as the Arizona Strip. Once the hideout of outlaws and desperadoes such as Butch Cassidy and the Sundance Kid, the area is now home to the rustic Bar 10 Ranch, which is where we spend our first night.
We pass an enjoyable afternoon horse riding and clay pigeon shooting before sitting down to a hearty dinner and some good ol' fashioned country music from an amusing band of slow-talking, Stetson-sporting locals.
The next morning a helicopter threads its way between the canyon's dramatic burnt-orange walls to deliver us to the rafts where Scotty and the other guides for the trip await our arrival. Guides can make or break this sort of trip and by all accounts Scotty is famous in these parts. He has done more than 200 trips through the canyon and with his long hair, beard and slightly maniacal pirate-style laugh, he looks and sounds every inch the rafting legend.
We pack our gear into waterproof bags and set off down the river in one of six, six-metre Neoprene rafts. Only now, as we drift serenely downstream, do I finally comprehend the scale and majesty of this natural phenomenon. Created by a combination of tectonic plate activity and erosion by the Colorado River, the canyon's walls provide one of the single most comprehensive pages of the planet's geological history anywhere in the world. To lie back and be surrounded by 2 billion years of scenery is indeed breathtaking and humbling.
As the morning progresses, the temperature steadily climbs until it is well into the 30s. It is mid-June, and staying protected from the sun is of the highest concern. The water, on the other hand, barely fluctuates from a bracing 10degrees all year round and the first time I get splashed I fail to stifle an embarrassingly high-pitched shriek.
We find a shady spot for lunch and within minutes a sumptuous buffet of cold meats, salad, fruit and biscuits has magically appeared from containers and cool boxes stored in the bowels of the rafts. I initially feel guilty, sitting around while the guides set up everything each time we stop, but I soon get over it.
After lunch, my brother and I are offered the chance to paddle in an inflatable two-man kayak known as a ducky. We agree, providing we are allowed to rename it to the more manly-sounding MacGyver. We end up spending the remainder of the trip in the MacGyver and it provides some of the most exhilarating white-water experiences I have ever had.
When it comes to summing up the difference between tackling a grade five rapid in a six-metre, 1/2-tonne raft and a two-metre, hand-inflated ducky, Scotty provides the best comparison: "In the raft it'll be interesting. In the ducky it'll be King Kong."
We set up camp for the night on a wide sandy beach and while the guides prepare a three-course feast of hors d'oeuvres, barbecue chicken and pecan pie, we all settle down in camping chairs, crack open some wine and get better acquainted.
Our group of 16 is a mixed bunch. I am here with my brother, there is a father and son from New York ("Marty, get me another cawfee will ya"), a family of four from Kansas, a middle-aged couple from Michigan and a highly entertaining extended family of six women from Texas who started drinking the minute we got on the plane.
There are enough tents for everyone, but most of us choose to sleep on cushioned mats underneath the stars. The guides go to bed at 9.30pm and after a lot of banter and several cases of wine, we are not far behind. There is no need for a torch to find your way around - the moon bathes the beach in a ghostly half light and the sky is crammed with a riot of stars.
There are sore heads when we are roused the following morning at 6 o'clock. To ease the pain there is hot coffee and a breakfast of eggs, bacon, pancakes and fresh fruit, all miraculously prepared in a makeshift kitchen in the middle of the wilderness.
We are packed up and back on the water by 9am and, looking back at the beach, you would never know we had been there. Everything taken into the canyon has to be taken back out (including you know what) and it is reassuring to see this pristine environment being treated with the respect it deserves.
We tackle three large rapids today (205, 209 and 217) and Scotty talks us through each one first. He can remember the nuances of every major rapid along the river, including the swirling vortex hole in rapid 209 that we are explicitly told to avoid.
Between rapids we let the current carry us downstream while we marvel at the majestic scenery and wildlife. Falcons, eagles and osprey soar high above us while big horn sheep negotiate impossibly steep slopes.
For the first time we see boats from other operators: large, motorised 10-metre monsters that can carry 15 people. The passengers all sit perched high on top and they look strangely detached and uninvolved as they power relentlessly downstream.
We enjoy one final evening of feasting, storytelling and stargazing on the river before we paddle towards Diamond Creek, where the rafts will be unloaded and we will be shuttled back out to civilisation.
During those final few kilometres, the river narrows and we find ourselves hemmed in by a natural amphitheatre of towering rock. While we drift silently downstream, one of the guides stands up and sings a slow, haunting rendition of Amazing Grace, her voice echoing off the canyon walls. It is a poignant end to a magical trip.