The task assigned the top whitewater canoeist in the world was to shape a flat piece of foam into a contoured cushion for an artificial leg, and do it well enough that the wearer would feel neither bump nor seam.

Close work, but for Davey Hearn in his new job, no problem.

"As long as nobody rushes me," said Hearn as he began to measure, cut, bevel, glue, heat and mold the foam, "I know I can do a good job."

Hearn works the same way he plays: meticulously. Paddling cohorts who have watched him over the last decade say he brings to practice every day a fastidious attention to detail. Finally, it's paid off.

Three months ago he did as good a job as ever has been done at paddling a canoe in international competition. At Augsburg, West Germany, the 26-year-old native of Garrett Park won the slalom gold medal at the biennial world championships with a clean run of 223 seconds, 13 seconds faster than his closest competitor.

The performance broke the record for comparison times against kayaks, the standard measure of how well a canoeist is doing, since kayaks go faster than canoes.

It was a great run that was a long time coming, said Hearn's sister, Cathy, who was gold medalist in women's kayak at the 1979 worlds. "It was a very popular win."

It was popular because Hearn had tried three times before to win the gold, and each time came up second to his training partner and longtime nemesis, Jon Lugbill, who comes from Fairfax and is enough of an international hero to be picked to grace Wheaties boxes.

And it was popular because it was a triumph of hard work. "Davey went from someone who's not a great athlete to becoming one," said his sister. "That's something all the rest of us had over him."

Lugbill took the gold in 1979 by four seconds; in 1981 by three-tenths of a second and in 1983 by nine-tenths of a second.

But after the 13-second victory at Augsburg, Hearn figures, "I'm ahead of Jon now by as much as he was ahead of me."

Hearn went from Germany to North Carolina, where in July he won the national canoeing championship for the seventh straight year, and then came home to Brookmont, Md..

He put away his gold medals and went looking for work, finding it at the Orthotics and Prosthetics Center in Fairfax, where skills he acquired building lightweight boats help him make limbs and braces for handicapped people.

He also gets to employ there the other trait he honed over the years -- methodical perfectionism.

"It's the way he's always been," said Cathy Hearn, 10 1/2 months her brother's senior. "We give him a hard time about it because he's such a perfectionist. He gets this look on his face when he sets his mind to do something, whether it's win the worlds or just beat up his sibling."

"He's very different from Jon (Lugbill)," said U.S. team coach Bill Endicott, who trains both. "He's a scientific, methodical kind of guy. He keeps a training log, for example. Right now he's putting together a complete record for me of all the time he spent training for the worlds. He has all the data.

"Jon doesn't keep a log. He's more an intuitive type. With Davey, everything is in control, put away in its niche. He's Mr. Consistency. Jon peaks for the big races, but in between he might not be up to snuff."

Hearn and Lugbill have been so far ahead of anyone else for the last four world championships that no one was considered a threat in their division, one-man decked canoe. One reason is that they had each other to train against, and despite the rivalry and the differences in approach, they are each other's biggest fan.

But when they started out 10 years ago, "they were foes," said Endicott. "They were so different they couldn't tolerate each other."

The differences continue. "Lugbill sometimes seems to win by intimidating," said Endicott. "With Hearn, you never sense rage when things go wrong."

Lugbill and Hearn work together on training and boat design and construction. They built and took to Augsburg the lightest boats in the competition. Hearn's, made of foam core covered by a Kevlar skin, weighs 11 1/2 pounds, probably two pounds lighter than any European boat.

Both began training a year ago, practicing in the slalom gates on the Potomac twice a day, seven days a week, then adding three "marathon" workouts, paddling hard for 80 to 100 minutes at a time, often going nonstop from Great Falls to Little Falls.

"I did that more than anyone," said Hearn.

Endicott agreed. "I thought, 'Boy, he's really striving,' " said the coach. "He had a great season and hit the marathon conditioning right on the spot."

Most of the hot paddlers around Washington who watched the Hearn-Lugbill rivalry figured it was a matter of time before Hearn took a gold at the worlds.

Now that he has, there's one hitch.

Nine days before the Augsburg race, Lugbill took a day off to hike in the mountains, where he fell and bruised a shoulder. He did not practice for several days, but told Hearn he was completely healed by race day.

Still, doubts linger. "If Lugbill was healthy, I don't know who would have won," said Endicott.

For Hearn, the issue is moot. "The obvious question is, is that why I won? I don't care whether he was hurt or not. I had a fantastic race and I think I would have won anyway."

Happily, there's time for rematches. Hearn resumes training this month, "to build a base," as he puts it, for the racing season that starts next March. And two years down the road lurks the next world championship.

The battle continues.