It is hard to describe accurately the feeling you have while travelling at 75mph in a 40ft offshore boat. But here goes: sky, sea, bang, sky, sea, pain, blurred sky, blurred sea, smash. Hot diesel fumes and deafening wind noise fill my lungs and ears as the boat launches 20ft upwards with each swell before landing on its hull.

My body is braced for a premature navy burial and I’m actually praying out loud for protection as the 4,500kg hull smacks down on the glass-hard surface of the water. It feels not unlike climbing inside a laundrette washing machine, feeding it with 20p pieces and setting it on spin.

Not for the first time, I wonder what I am doing here. The answer is that I am taking part in an experiment. As you may know, I am a petrolhead. I make my living driving fast cars very fast, and I have always maintained that nothing provides such a thrill as a machine with four wheels (or at least two) going at full throttle.

In fact as petrol prices spiralled a few weeks ago, I was firmly of the opinion that all nonroad vehicles should be banned from filling up, thereby increasing the amount of oil available for the rest of us. In an effort to disabuse me of this idea, Sunseeker invited me aboard one of its P1 powerboats, promising me the ride of my life.

In the event, I got in just in time. A few days after my drive in Sunseeker’s No 11 boat, Challenger, the company pulled out of the P1 championships, and it looks unlikely to return, for reasons we will come to later. This means I am very likely to have been the last person to experience the sheer power and seat-of-the-pants thrills of driving a Sunseeker P1 powerboat in anger.

For the uninitiated, P1 is to water craft what F1 is to cars: the fastest and riskiest form of racing, requiring the most skill. As I quickly discovered, though, there are big differences to the track. In F1 the circuit doesn’t alter its state every single second. It doesn’t create surprise potholes by magic around every corner. The track in P1 does all these things. It’s trying to kill you by throwing random waves, wakes, winds and currents at you. In car terms it would be like circuit-racing an Aston Martin with stone wheels at more than 150mph, and every so often encountering a humpback bridge mid-corner.

The Aston would also be a convertible with no roll cage, zero suspension and no brakes. And you wouldn’t be wearing a seatbelt. But you would at least have a co-driver. One of you would be steering the car and one of you would be operating the throttle and gears. P1 rules dictate there has to be a minimum crew of two – one to steer and one to control the hand throttles (which, in this case, is me). Some teams even have an extra crewman to navigate.

“We have the glamour and glitz of Formula One, with the ever-changing terrain of the World Rally Championship,” crackles the voice of Andy Wilby, the Team Sunseeker driver (they don’t call them skippers), over the helmet intercom.

The championship is divided into two classes: Evolution class, where the boats are more powerful but mostly prototypes, meaning you are unlikely to see them up for sale at your local boatyard; and SuperSport class, for open-topped modified production models, such as the boat my organs are now being pummelled in. It is restricted to “just” 85mph, which feels like double that figure in an equivalent four-wheeler.

Like the majority of P1 competitors, Wilby, 29, isn’t a full-time professional. He has a day job and spends every minute of his spare time training. After six years of racing a self-funded boat, Wilby landed the chance to compete in top-level powerboat racing at the wheel of this Sunseeker.

The P1 season runs from May to November and includes races in the waters off Britain, France and Tunisia, culminating in the final race of the season in the Middle East.

In just the second race, in France, the Sunseeker boat was involved in a spectacular crash that Wilby and his throttle man, Peter Little, were lucky to walk away from. As the team attempted to round one of the buoys that mark the course, they hit turbulent water, possibly caused by the wake of another boat. The bow of the boat “dug in”, to use the technical term, causing it to go into a barrel roll. “It skipped once, and then when it skipped again I knew we were in serious trouble,” said Wilby after the event. “As it went over, I just hung on and almost closed my eyes, but I didn’t – I saw it all happening in front of me, which was a bit scary.” Little was flung from the boat as it rolled, but Wilby, instinctively clinging onto the steering wheel, was in the cockpit as it turned over – before eventually being sucked out into the sea. The boat travelled a further 50 yards before it came to rest, upside down, and sank. After being recovered from the seabed, Challenger was rebuilt, a time-consuming and expensive task.

None of this fills me with confidence as we taxi out of Sunseeker’s majestic headquarters in Poole harbour in the very boat that only a couple of months ago was on the bottom of the ocean. All eyes are fixed on our embroidered race suits, orange helmets and Union Jack-liveried boat. Trawlermen give us the nod; tourists on ferries wave or fumble for the camcorder. I feel like the aqua-naut equivalent of Neil Armstrong (one small splash for man . . .) on a mission to disturb the maritime peace.

The idea of a powerboating innocent like me sharing control of such a machine seems utterly wrong, but the thrill of easing forward the throttle is immediate. The pair of Fiat straight-six diesels obey the order and within seconds we are away from the harbour and into the open sea.

Both tacho needles read 3000rpm and pleasure craft flash by as we charge past the Dorset coast in a drug runner’s dream ride. Suddenly the idea of having two people driving the boat makes sense. Only a fool would try to drive this thing with one hand on the wheel.

“Big wind . . . choppy . . . tabs down,” come the barely audible words from Wilby’s intercom as we approach the wake of a Channel ferry. Two buttons next to my left knee operate the trim tabs, which are hinged flaps below each rear corner. Tilting these flaps causes drag, which lifts or drops the bow, reducing the risk of us becoming a pirouetting slow-mo high-light on the Eurosport channel. Another two buttons on the throttle levers hydraulically adjust the angle of each propeller. In normal circumstances such buttons are easy to press, but not when you happen to be riding on a nautical bucking bronco.

It’s shocking what a couple of lorry engines can do to a 4.5tonne tub. The XS Challenger has the torque to drag sandbanks out to sea, the strength to brush off colossal 20ft jumps and the power to make me close my eyes and think of a happy place.

At first glance Wilby has an almost Clark Kent look about him – academic, quiet and composed. It is hard to believe he used to be a power lifter, let alone that he spends hours wrestling the ocean in his P1 Sunseeker. In an attempt to carbon-offset his nautical naughtiness, his daily drive is a humble Smart car that costs as much as one of his stainless steel competition propellers. Make no mistake, though: this guy’s got serious guts.

For the throttle man (me), too much acceleration when leaping out of the water could overrev the £14,000-a-pop engines. This means that every time we jump out of the water the stiff levers must be pulled down, then pushed forward as we land. It is not just the engines that I am trying to save: careless jabbing could send us cart-wheeling south to the lobster pots.

I remember the team manager’s words from our fish supper the previous night: “Anyone can make a boat go,” he said. “But only the very special people can make them dance across water, and they are the ones that will win races.”

He was right, I’m sure, but being gifted is not enough. Shortly afterwards, Sunseeker pulled out of the championship amid rumours that the sheer cost and effort of repairing the boat after the Marseilles crash had drained the team’s racing budget. Did I manage to make it dance? I think probably not. Did I rethink my belief that only road-eating machines provide the thrills that qualify them for a place at the petrol pumps? I think I did.