Sailing: Fierce ambition of the Molls of Kintyre: Scottish Islands Peaks Race: Women's team face one of the great tests for runners and sailors. Rob Howard reports

Stephanie Merry has successfully completed round-Britain and transatlantic yacht races and Helene Diamantides is in the Guinness Book of Records for her mountain-running achievements, but this Friday they will team up for their greatest challenge yet in the Scottish Islands Peaks Race.

Both have tackled the annual Hebridean odyssey many times before, pitting their talents and strengths against the forbidding mountain heights and treacherous tidal waters of the islands. The race covers 160 miles of coastal sailing, visiting Mull, Jura and Arran, where two of the crew of five must run 60 miles across five summits totalling 11,000 feet of climbing. It is a test of endurance few could survive but in the male-dominated worlds of offshore yachting and mountain racing Merry and Diamantides intend to achieve the previously unthinkable. With an all-female crew on the trimaran Severalles Challenge they aim to win outright.

When they leave Oban harbour on Friday they will be aboard a pounds 100,000 yacht which has won the race twice and was purpose-built to do so. The millionaire businessman, Dick Skipworth, who is currently indulging another of his passions by racing his vintage Jaguar on the Continent, has sailed the 36ft trimaran to many victories and offered it to an ecstatic Merry, giving the women's team a realistic chance of victory.

A 43-year-old lecturer in mechanical engineering at Southampton University, Merry is an experienced offshore racer and has competed in the race four times with an all-female crew though she denies being anti- male. 'I've raced in many mixed crews but am often the only lady as it is very difficult for women to get the necessary experience. Most skippers prefer men for their strength so I like to give women the chance to race. They get on better, aren't afraid to ask each other for help and are more supportive. Egos don't get in the way of teamwork.'

For crew she selected Gaye Sarma and Heidi Bell, and the choice of runners was easy. Diamantides has won international mountain races as far afield as Cameroon and Borneo and last year won the 220-mile Dragon's Back race, beating the world's best male endurance runners after five days' racing across the Welsh mountains. Her partner will be Christine Menhennet and between them they have won all this year's long Scottish hill races. Menhennet recently won the Ben Lomond race and is in the Scottish national team.

Together they hold the women's records for all the runs to the summits of Ben More on Mull, the Paps of Jura and Goat Fell on Arran, and as veterans know what to expect. Storms and seasickness, rowing when becalmed, landings on slippery, seaweed-covered rocks and trackless terrain are all familiar hazards but the faster yacht makes the task harder. 'To win we may have to do three 20-mile runs in 36 hours,' says Diamantides, 'and the noise and motion of the boat allow little rest. It's like sitting in a bidet and having buckets of water thrown over you and is the only yacht I've been on that gives you a kick up the backside when they hoist the sails. It just takes off.'

Merry views the yacht differently. 'It has everything you could want, 1,000 square feet of sail, satellite navigation, four batteries with solar charges, even sliding rowing seats. It's superbly designed and is so fast sailing it is very, very exciting, especially in this race. Crossing the Atlantic is just a journey from A to B but here you've got fierce tides, rocks, whirlpools, fickle weather and rounding the Mull of Kintyre to cope with.'

In previous races Merry has suffered with poorly equipped yachts while Menhennet and Diamantides have been grounded, rowed to exhaustion, seen the skipper fall overboard and rounded the Mull only to be pushed back by the tide and forced to do it again. Since then they have been known as the Molls of Kintyre and that name is on a trophy they donated for the fastest women runners. This weekend they aim to win it back and help Merry and crew to victory.

(Photograph omitted)