Peter is one of a number of Austrian rafting dudes who work out of Haiming, in the west of the country. Like surfer dudes (apart from being land-locked), they laze around in a shack that contains battered equipment and bottles of beer chilling in a horse trough. Like surfer dudes, they wander around flaunting their washboard abs. Fortunately, I've left behind my daughter, but even so my 14-year-old son, John, and Peter lock horns almost immediately.
"OK, team, we put our paddles in the dinghy now," says Peter. "Why?" growls John, capriciously delaying the launch of our eight-man raft. Time for me to take my teenager to one side and tell him that when all you have between you and death by drowning in glacial waters are the split-second reflexes, and goodwill, of an Austrian with pierced nipples, you don't cop an attitude - or ask dumb questions.
We do something like this once a year, my boy and me; a father-and-son trip that supposedly helps us to maintain the familial bond through physical adversity. We've done it hanging from rocks, plunging down canyons and suspended from parachutes. Now, we were going to be ploughing the ice-cold waters of the Austrian Tyrol together for 90 minutes.
"OK, team, in the water now!" cries Peter as we scramble on board and hook our feet into the loops on the bottom of the dinghy. I find myself at the front with a 16-year-old from Northampton called Tim. Tim is cool. As I get to know him I find he can even keep his sunglasses on when falling overboard. Our job is to set the pace when Peter calls on all eight of us to paddle. John sits behind me. His job is to do exactly what I do and not ask any more stupid questions.
Initially our route is calm and smooth. "We call this stretch of water 'the swimming pool'," says Peter, and he encourages each of us to practise falling in so that everyone else can practise hauling them out. John likes this bit and throws himself in three times. I do it once, to show willing. The water is cold despite my wet suit, and opaque with grey-green alluvium. I can see nothing till someone grabs my life-jacket and lifts me bodily out of the water.
Our first rapid is nothing (compared with what comes later) but it's a salutary shock. We don't crest the waves, we plough into them, and I am blinded by some very white water. "Keep paddling!" I shout to John. A minute later, all is calm again.
Peter amuses himself by encouraging us to rough-house with other boats, splashing water over them. As they always seem to come up on starboard, my bow, John and I find ourselves being splattered on a fairly frequent basis. Tim keeps paddling on the port bow, I notice, his cool undented.
Then come the first of our 12 rapids. Down we plunge and up we rise in an explosion of noise and water, and I find myself paddling in mid-air at one point. Amazingly, we lose no one from our boat but I think this is because we've all kept our feet well anchored in those straps.
Apart from Tim, and his mum and dad, our crew consists of a builder from Sevenoaks, who looks like Legolas, and his wife, a fierce splasher of rival craft. When things fall calm between rapids, Peter encourages us all to perform minor acrobatics, standing up on the rim of the dinghy, holding on to each other's life jackets for support or using our paddles as crutches to maintain position. It feels like the ideal way to make sure everyone falls in but surprisingly we don't. Not even John. "Not enough water," says Peter, sadly. "Not enough sun melting the glaciers."
The scenery is impressive. Most of our route is along the Tschirgant, a mountainous moraine dumped here 10,000 years ago by a departing glacier when the last ice age gave up the ghost.
We grow more confident, which is good because the plunges get bigger and the games that Peter plays with us in between times get rougher. Both John and Legolas take up his challenge to stand on the prow while Peter instructs us to paddle back, forward and round and round in order to dislodge them. I'm glad to say that when my son falls he does so sensibly, into the raft and on top of the rest of us, like a crowd-surfer at some aquatic rock concert.
Rivalry with our competitors gets wilder, too. It reaches such a pitch that John belts rather than splashes our main rivals with his paddle, and in return they try to pull him aboard their boat. I pull John back so they settle for abducting Legolas. He disappears with a surprised look on his face and is set, like a galley slave, to row with everyone else.
Our other bit of fun is when Peter gets us all to the back of boat and then steers straight at a rock that looks for all the world like a ski jump. We lurch right up it but don't fall back in (as I think was Peter's plan).
Eventually, we reach the Rafting Alm Gasthaus, where we were kitted out for this trip, and several of the men go off to jump in from the road bridge before handing back their suits. John prefers the idea of attacking the crew whose boat dogged our blades all the way down, but when Peter tells him he can't he settles for an ice cream. Me, I buy a beer from the rafting dudes.
"Not bad," I say. "A bit tame," John replies. I can tell that next year we'll be bungee-jumping off the Victoria Falls.
Crystal Active (0870 888 0266; www.crystalholidays.co.uk) offers seven-night active holidays to Kitzbühel from £409, including flights to Salzburg and full-board accommodation. White water rafting costs £38 per day.