For much of the work week, Emily Bramhall inhabits a world devoted to the creature comforts of the indoor world - stuffed pillows, luxurious bedsheets and cozy handknit sweaters sold at her store on Main street Vineyard Haven.

It was all the more shocking then to see Ms. Bramhall wearing a crash helmet and scrunched into the wooden cockpit of a vessel capable of reaching 60 miles per hour across the ice of a frozen pond.

"It's just you and the wind and the cold, and you're just hauling," she said.

Ms. Bramhall and roughly a dozen other ice boaters converged on Squibnocket Pond in Chilmark this weekend for hours of open-throttle sailing and racing.

Speed, without a doubt, is the main selling point, and it's addictive. Boaters like Ms. Bramhall will tell you so in strings of adjectives that attempt to convey just what it must feel like to scream across this mile-and-a-half-long pond at such an amazing clip.

It's exhilarating, a charge and a high, they said. And as much fun as it must be to climb aboard and set sail onto an icy racetrack of almost zero friction, it's also become a huge draw as a spectator sport.

The parking lot at Squibnocket reached overflow status early Sunday afternoon with cars parked all along the steep road down to the beach. Skating and skittering on foot, they came out to watch the boaters and embrace the singular experience of standing in the middle of a frozen pond separated from the Atlantic Ocean by a barrier beach.

Over the distant rattle of steel runners on the ice, you could easily hear the ocean surf pounding the shore just past the sand dunes.

What was amazing was that with so many people and so many boats, you could feel almost entirely alone on that massive pond if you ventured just a few minutes away from the clumps of people. Squibnocket Pond isn't just more than a mile long. It's also almost as wide.

"It's still my favorite place to sail," said ice boater Scott McDowell of Chilmark, who has competed in ice-boating championships around the globe.

Obviously, however, this was a rare event and all the more precious given the lengthy wait time. The last freeze deep enough to seize up the water molecules on this south shore pond was three years ago.

Testing the ice was the first order of business, and despite the jokes, entirely serious. "The process is you get a big fat guy to walk out before you," said Charlie Blair Jr., one of the leading ice boaters and also the Edgartown harbor master.

Actually, Mr. McDowell ventured out on the pond with a portable drill and checked the thickness of the ice. "I did the entire circuit," he said. "I went everywhere, even down by the Herring Creek. I got between six to eight inches."

Mr. McDowell is convinced that even with this week's slight thaw, the ice on Squibnocket will hold for the next month, aided by the insulation from Wednesday night's snowfall.

But make no mistake, these ice boaters relish the thrill, the taste of danger. You could tell as much from the tool dangling around their necks. It looked like a simple piece of red plastic until Mr. Blair demonstrated its real purpose.

They're rescue spikes, a pair of five-inch ice picks sheathed in plastic handles and intended as a life-line enabling boaters to claw their way to safety if they went crashing through the ice.

Mr. Blair also wore special shoes, brightly colored high-tops with metal spikes on the sole. "They're javelin shoes," he said as he assembled his gear at the back of his truck.

Traction is critical for skippers who must give their boats a running start and then leap in the cockpit much like their bobsledding comrades. "You run it up to speed, and you know when to step in," said Mr. McDowell.

It doesn't take much wind to get going. Remember, these boats can go up to four times the speed of the wind.

The boats on Squibnocket were all one design, the DN, named after the Detroit News, which sponsored an ice boat design contest decades ago. Many of the boaters on the pond this weekend built their own boats, which are gorgeous in their simplicity.

Some are varnished, blond wood. Others are painted green or red. A couple are built out of metal tubing, looking a lot like contraptions from the cable-TV show, Junkyard Wars.

Mr. McDowell now builds high-tech boats for a company in Weymouth that can cost as much as $6,000. Simpler versions can run about $3,500.

Old-timers on the Vineyard, according to Mr. McDowell, used to build their own boats, crude vessels constructed of two-by-fours and hockey skates. "They would lay on their stomachs and go hell-bent for leather all over the pond," he said with a laugh.

These days, the boats look more like a sports car, 12 feet long, low-slung and aerodynamic. "You're lying flat and you're just six inches off the ice," said Ms. Bramhall.

With two side runners and one in the front, the boats made a pleasant rumble over the rippled ice. With a good breeze, a windward runner will lift off the surface, adding to the thrill.

The challenge for the ice boater is to let that runner "float back down to the surface," said Ms. Bramhall.

Vineyarders weren't the only boaters. Competitors from Estonia and Finland were also on the Squibnocket ice, friends now of the McDowell and Blair clan that races off-Island.

Ms. Bramhall got her first taste of ice boating three years ago and was hooked instantaneously, buying one of Mr. McDowell's boats and then waiting another three years before she could get on the ice again.

She is an avid sailor in the warm weather months, but Mr. McDowell, ironically, is not. As he put it - in language that could only be applied to such an obscure sport - "I'm not a soft water sailor."

Indeed, this event that should continue for the next few weekends possessed a wonderful, odd Vineyard quality. Families who skated out on the pond picnicked on an outcropping of rocks and watched ice boat races in the distance.

Even at a half mile away, you could sense their speed, racing more like windsurfers than any conventional sailboat plowing hull and keel through the chop.

The race was a simple sprint, first one across the finish line, about a mile from Herring Creek out toward the barrier beach. Smiles were on people's faces, people happy they made the trek, happy they stayed put for a frigid Island winter that could give them this.

"Squibnocket Pond," said Ms. Bramhall, "is just so spectacular, the physical beauty and the scale out there in the middle of this pond."