Extreme race for corporate sponsors
"Have you ever sailed in a 40 before?" came the question.
I shake my head and lose my footing on a trampoline stretched just feet above roaring salty green water.
The question cast a faint echo of "Have you ever been to a Harvester before?" But I was not about to get a lecture on steaks and salad.
I am the only non-sailor on an Extreme 40 racing catamaran, about to compete in a professional race in the choppy seas off Cowes on the Isle of Wight.
This white-knuckle experience is designed to allow a guest, known as a fifth man, to sample the fear and exhilaration of real racing with some of the world's top professional sailors.
As a business journalist, I am fascinated by the idea that a sporting series could be designed from scratch as a commercial venture, as corporate entertainment.
As a rookie on board, I feel rather like a large fly, crawling up and down the sloping cliff of the trampoline as we tack and gibe around the racing buoys. Shouts fly at me through the spray: "Grab her, wait back, here you go tacking, go to the other side, go-go-go!"
At one point, my heart lurches as we power towards the stony, unforgiving shore of Cowes, only to turn away as we see the ice cream in the audience's cones.
The skipper of my boat, the Ocean Racing Club, is Olympic medallist Mitch Booth, who co-designed the Extreme 40 as a high-powered, light-weight boat built for racing and able to be packed into a 40-foot shipping container for relatively easy transport.
With a background in the construction business, he emphasises the most important thing was that the boat should be commercially viable.
"The sponsor has to get value out of it," he says.
Having identical boats means there is no money wasted on a race to add technological bells and whistles, he explains. And it is compulsory for all teams to have a fifth man - a passenger on board.
All this sounds a bit cold-blooded to me. I wonder whether it is a triumph of marketing over sport?
The Extreme 40 series was designed several years ago for iShares, formerly part of Barclays Global Investors, which wanted to sponsor an event that focused on entertaining clients.
The fifth man slot is an "extra special experience money can't buy, like sitting in a seat with a Formula One driver", according to Mark Turner, the chief executive of OC Group, which organises the events.
Since the series began in 2007, races have taken place in 12 countries on five continents. The public can watch for free, because the racing always takes place unnervingly close to land.
Mitch Booth admits that professional sailors had been sceptical at first, that "we were making too much of a show, of a circus beside the shore".
"But 99.9% of the time, the best teams do win," he says.
Last year, there was an unexpected and unwelcome development.
The series suddenly lost its biggest sponsor when iShares was taken over by US investment company Blackrock, which did not want involvement in sports sponsorship.
Mr Turner admits it has been a tough year with no title sponsor. But he says "that's the essence of sponsorship. Things change."
So what does the sponsorship game look like from the sponsor's point of view - does it really make financial sense?
One sponsor that has stuck by the Extreme 40 series is the clothing company Henri Lloyd, which has supported well-known sailors and sailing events for decades. Last year, it sponsored the Brawn motor racing team that won the 2009 Formula One Championship.
Henri Lloyd's joint chief executive Paul Strzelecki says the Brawn win massively increased his company's profile and sales of its Brawn-branded clothing.
The company supplies the clothing for the Extreme 40 competitors and teams, and, according to Mr Strzelecki: "It allows the company to sell to new people and get our name out there."
He reveals that Henri Lloyd gave members of the victorious Brawn motor racing team a chance to be fifth men on the Extreme 40s.
"Fifty per cent of sponsorship is wasted, but you don't know which 50%," says Mr Strzelecki.
So what makes him back a particular event - is it the figures in media coverage or a gut feeling?
Some of it, he admits, is just blind faith: "You can make a big investment, but ultimately get a big return."
When I got back on land after the race, I was bruised but exhilarated, knees shaking as I walked from pontoon to shore.
It was a short, sharp and ferocious introduction to competitive sailing, but the adrenalin high was spectacular.
But it seems this highly commercialised sport is not just tough on the water.
As the boss of OC Events, Mr Turner told me: "We're in a pretty hard, brutal area of sport. We have to give a return on investment."
You can hear more about Lesley's day at the Extreme 40 event in Cowes at 0830 BST on Thursday on the BBC World Service's Business Daily programme.