AT 46 and a self-confessed "overweight, middle-aged mum", Karen Martindale is an unlikely powerboat champion.

Yet Karen, from Bolton, has just snatched a top title at the powerboat National Grand Prix in Barrow, Cumbria.

Karen, who now lives in Ormskirk with her family, had her 72-year-old father Ken, from Chorley New Road, Heaton, as her co-driver. The pair beat a field of 19 boats, ranging from Formula One catamarans to water skiing boats, to win the superclubman race.

"We were a bit pleased," she said, with modest understatement. "The superclubman race is basically for all the boats which do not fit into any other category. You get all sorts taking part, and it works on a handicap basis where you have to get as close as you can to an established time."

Ken, a former managing director of motor company Lookers Ltd, became involved in powerboat racing when he retired. He had Karen as his co-driver when they competed as members of the Windermere Motor Racing Club.

Since the controversial 10mph speed limit put paid to racing on England's biggest lake, the national championships have moved to Ramsden Dock in Barrow.

These days Karen has her own 16-foot Phantom racing boat, Briganttia, and two years ago she won the national championships for the first time.

With a top speed of around 70mph, Karen's boat was the first to go out and took about 15 minutes to negotiate the dock's L-shaped course.

Although she was overtaken by faster boats, her mixture of skilled seamanship and common sense put Karen's penalty-free time first.

The only other woman in the race, ex-Bolton School pupil Pip Brown, came second. "Women are starting to make their mark once more in powerboating," Karen said. "But many people were still surprised that an overweight, middle-aged mum, with her 72-year-old diabetic father as co-driver, won it!"

Karen, a former Smithills School pupil, has two daughters: 16-year-old Harriet and Rowan, aged 13.

When she is not working for her husband Gordon as an accounts clerk, she is spending time as a planning officer for the Campaign for the Protection of Rural England. Her views as an environmentalist are, she conceded, at odds with a petrol-guzzling boat addiction.

Nor is she a speed-freak on land. She has just picked up her first speeding ticket in a clean 30-year driving history.

"I drive very sedately in my little old Corsa, and I was only slightly over the 30mph speed limit," she said.

"But when I get behind the wheel of a powerbeat, I just put my foot down - I get a real buzz!"