In the middle of Poland's largest lake covered by ice, a hundred or so speed demons fly across the frozen surface in special sailboats on blades.

Sleek and built to race, the narrow boat hulls are fixed on a base of three gleaming blades and sports sails like those used in windsurfing to harness wind power and roar across frozen water.

"It's the speed that gives you an adrenaline rush," said Tomasz Zakrzewski, ranked number fourth in the world in the DN class iceboat racing.

Sailing on ice is his passion.

"Among the disciplines that use wind and sails, it is the fastest,” he said on a recent day when despite low winds, iceboats were cruising at 100 kilometres (62 miles) per hour. “We sail at three times the speed of the wind. The manoeuvres have to be made very quickly, much faster than on a conventional sailboat and its much more exciting.”

 DN class type Iceboat skipper Tomasz Zakrzewski is seen warming up before a local competition on the frozen lake Sniardwy - Polands largest lake, in northern Poland on 31 January 2009.

Flying may be the best word to describe the high-speed sport, where the unofficial record hovers around 140 kilometres per hour.

European leaders
"The Poles are Europe's leaders in the sport,” said Zakrzewski, who is ranked fourth. “During the last DN-class championships in St. Petersburg from January 16 to 23, four of the top five competitors were Polish."

Tomasz’s brother Lukasz won the silver in the competition.

Zakrzewski was one of dozens of ice boaters who competed in the Mazurian Cup, Poland's leading iceboat competition, held in late January on the 114-kilometre surface of the shallow and fast-freezing Lake Sniardwy.

He placed sixth last month at the 2009 IDNIYRA World Gold Cup Championships held in Traverse City and Torch Lake, both in the American state of Michigan. His brother Lukasz took fifth spot.

Clad in protective goggles and crash helmets, iceboat competitors also wear neon-coloured life jackets just in case the ice cracks.

"It's the rule but there's no danger -- the ice sheet is more than 20 centimetres (nearly eight inches) thick," explained Grzegorz Hammerszmidt, an iceboat coach in Poland's northeastern lake resort town Mikolajki. "A 12-centimetre sheet of ice is enough to let kids go fly on it."

Hammerszmidt coaches children as young as seven in ice boating, or ice yachting, as the sport is also known.

A long history
Though reminiscent of windsurfing or sailboarding, ice boating is not new, and is said to have originated in The Netherlands in the 18th century.

Prior to World War II, pilots in the German air force or Luftwaffe practised the discipline as part of their aerodynamics training on the Mazurian lakes in what was then East Prussia, now northeast Poland.

"The speed that can be reached on the lakes allowed the pilots to become accustomed to the wind and master its currents," said Hammerszmidt. "To get a 'black' ice surface without a snow cover, pilots would dam the Sapina River to gather water and then break it, allowing the water to flood onto the frozen Lake Swiecajty. They made a magnificent surface this way, as smooth as an ice rink.”

In 1966, Dutchman Wim Van Acker acquainted Poles with the DN class iceboat. This class of iceboat was invented in the United States in 1937 and named after the Detroit News, a newspaper in the Michigan port city of the same name, which ran a competition for a model iceboat.

The DN rapidly became the most popular model in Poland, where the sport has attracted a thousand or so enthusiasts.

With a DN boat costing around 7,500 euros (9,700 dollars), the sport does not come cheap. Yet, it is global warming that perhaps poses the greatest danger to the future of ice boating.

"Winters are more and more unstable,” said Zakrzewski. “But for the time being we still get more or less two months of ice."

Maja Czarnecka/AFP/Expatica